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Las parasitosis por la moscas de los cuernos (Haematobia irritans) en el trópico de México generan importantes pérdidas económicas. El objetivo de esta investigación fue evaluar bajo condiciones de infestación natural, la eficacia de tres prototipos farmacéuticos indicados para el control de la mosca de los cuernos. Se utilizaron 80 vacas asignadas aleatoriamente a cuatro grupos de 20 animales en dos regiones México. Grupo 1: 593.10, Grupo 2: 593.11, Grupo 3: 593.12 y Grupo 4: control-sin tratamiento. El tratamiento fue por derrame dorsal a una dosis de 1 mL/10 kg de peso vivo. Se determinó la eficacia contando el número moscas en los días 1, 3, 7, 14, 21 y 28 post-tratamiento, las moscas fueron contadas in situ y comparado mediante fotografías de alta resolución que fueron tomadas sobre condiciones normales de pastoreo. El porcentaje de eficacia de los prototipos de prueba fue de aproximadamente 70-80 % al día 21 y ≥ 50 % entre los días 25 y 28 post-tratamiento. Los prototipos de prueba (mezcla de activos) resultaron altamente eficaces contra la mosca de los cuernos y podrían ser una alternativa para el control del parasito, contemplando las condiciones ambientales de las diferentes zonas geográficas donde son evaluados, la época de mayor incidencia de la mosca y estableciendo el umbral de carga parasitaria que provoca estrés en los bovinos. No se registró diferencia estadística significativa en eficacia entre los tres ectoparasiticidas, el uso de fármacos alternativos podrían ser una estrategia en la rotación de productos que disminuya la resistencia a las diferentes moléculas que contienen los productos comerciales.

Use of nonpesticidal chemicals to minimize or eliminate horn fly (Haematobia irritans) populations on cattle could be helpful in combating insecticide resistance. One recent approach is the use of natural products with repellent properties against the target pest. A rapid on-animal evaluation system that accounts for both host and pest interactions and bypasses the need for costly multiyear field assessments is needed. The objective of this study was to develop a system to quantify product repellency of horn flies on cattle in a laboratory setting. Animal pair treatment groups were utilized to assess product efficacy and carrier effects across three experimental trials. A treatment solution consisting of 3% geraniol in mineral oil was the natural product repellent. Horn fly populations on animal pairs receiving the geraniol treatment were significantly reduced when compared with untreated animal pairs. However, animal pairs receiving a mineral oil-only treatment showed reduced horn fly populations similar to animals treated with mineral oil plus geraniol. Thus, there was a strong carrier effect that could be difficult to distinguish in the field but was easily observed using laboratory methods.

Made available in DSpace on 2020-12-12T02:49:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Bovine trypanosomosis has been spreading in Brazil. In the present study, we evaluated the spatial distribution, prevalence and risk factors of this disease in the state of in Goiás, Brazil, and performed both molecular and phylogenetical analyses of Trypanosoma vivax. A total of 4,049 blood samples were collected from cattle for a period of two years. The parasitological diagnosis was performed using the Woo method and a questionnaire was administered to the farmers to document risk factors associated with the disease in the herd. Positive samples were DNA sequenced and compared to GenBank codes. The prevalence of T. vivax was 8.84%, occurring on 24 ranches only in dairy cattle and mainly in the central and southern portions of the state. The acquisition of new animals infected with T. vivax and the administration of exogenous oxytocin to cows using the same syringe and needle were the main associated factors (P ≤ 0.05). After an outbreak, milk production decreased by 39.62%. The presence of biting flies (tabanids, Haematobia irritans and Stomoxys calcitrans) were not a risk factor (P > 0.05) for the occurrence of T. vivax. The epidemiological data demonstrate the importance of restricting the practice of auctions as well as eliminating the use of exogenous oxytocin in animals during milking. The samples tested by PCR were positive for T. vivax and were genetically homologous with T. vivax found in different states of Brazil and west Africa based on the 18S rRNA gene. Centro de Parasitologia Veterinária Escola de Veterinária e Zootecnia Universidade Federal de Goiás-UFG Go Departamento de Medicina Veterinária Preventiva Escola de Veterinária Universidade Federal de Minas Gerais-UFMG Mg Centro Universitário Central Paulista (UNICEP), Rua Miguel Petroni n.5111, Saõ Carlos Universidade Brasil, Campus de Descalvado, SP Departamento de Clínica Cirurgia e Reproducąõ Animal Faculdade de Medicina Veterinária Universidade Estadual Paulista-Unesp Sp Departamento de Biociências e Tecnologia Instituto de Patologia Tropical e Saúde Pública Universidade Federal de Goiás-UFG Go Departamento de Clínica Cirurgia e Reproducąõ Animal Faculdade de Medicina Veterinária Universidade Estadual Paulista-Unesp Sp

Haematobia irritans is a cosmopolitan obligate blood-feeding ectoparasite of cattle and is the major global pest of livestock production. Currently, H. irritans management is largely dependent on broad-spectrum pesticides, which has led to the development of insecticide resistance. Thus, alternative control methods are needed. Essential oils have been studied as an alternative due to their wide spectrum of biological activities against insects. Thus, the main aim of this study was to evaluate the insecticidal, repellent and antifeedant activity of the essential oils from Blepharocalyx cruckshanksii leaves and Pilgerodendron uviferum heartwood against horn flies in laboratory conditions. The composition of the essential oils was analyzed using gas chromatography coupled to mass spectrometry. Accordingly, α-pinene (36.50%) and limonene (20.50%) were the principal components of the B. cruckchanksii essential oil, and δ-cadinol (24.16%), cubenol (22.64%), 15-copaenol (15.46%) and δ-cadinene (10.81%) were the most abundant compounds in the P. uviferum essential oil. Mortality of flies and feeding behavior were evaluated by non-choice tests, and olfactory response was evaluated using a Y-tube olfactometer. Both essential oils were toxic to horn flies, with LC50 values for B. cruckchanksii essential oil of 3.58 µL L−1 air at 4 h, and for P. uviferum essential oil of 9.41 µL L−1 air and 1.02 µL L−1 air at 1 and 4 h, respectively. Moreover, the essential oils exhibited spatial repellency in the olfactometer using only 10 µg of each oil, and these significantly reduced the horn fly feeding at all doses evaluated. Although further laboratory and field studies related to the insectistatic and insecticide properties of these essential oils against H. irritans are necessary, B. cruckshanksii leaves and P. uviferum heartwood essential oils are promising candidates for horn fly management.

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an important and cosmopolitan blood feeding ectoparasite of cattle. Resistance to conventional insecticides is increasingly problematic and alternative pesticides, including natural products, are being investigated. Limonene is a cyclic monoterpene repellent to some insects that occurs in citrus fruit rinds and in other plants. We assessed laboratory grade limonene and a commercial product, Orange Guard (5.8% AI limonene), against H. irritans irritans in terms of their contact effects upon contact on egg mortality, adults, and larval and pupal development; adult repellency as well as sublethal and fumigation effects. Egg viability declined when they were exposed to Orange Guard at concentrations of 1.45%, 2.9%, and 5.8% whereas laboratory grade limonene at 5.8% and 11.6% was ovicidal. Contact exposure of adult H. irritans irritans to 5.8% laboratory grade limonene and 2.9% Orange Guard caused up to 100 and 88% knockdown (immobilization), respectively. At higher concentrations, laboratory grade limonene and Orange Guard resulted in less, and often shorter periods of knockdown. Although direct contact of 2.9 and 5.8% laboratory grade limonene caused mortality it was negligible when flies were sprayed directly with undiluted Orange Guard. Female H. irritans irritans exposed to sublethal concentrations of Orange Guard did not reduce the numbers of eggs produced, but the undiluted product reduced egg hatchability. Interestingly, limonene and Orange Guard attracted adult H. irritans irritans at concentrations

Horn flies (Haematobia irritans (L.)) have long posed animal health and welfare concerns. Economic losses to the cattle and dairy industries from their blood-feeding behavior include decreased weight gain, loss in milk productivity, and transmission of bacteria causing mastitis in cattle. Horn fly management strategies are labor intensive and can become ineffective due to the horn fly's ability to develop insecticide resistance. Research indicates that for some cattle herds, genetically similar animals consistently have fewer flies suggesting those animals are horn fly resistant (HFR) and that the trait is heritable; however, it is currently unknown if cattle producers value this trait. Tennessee and Texas cow-calf producers were surveyed to estimate their willingness to pay for HFR bulls and to identify the factors affecting their decision to adopt a HFR bull in their herds. Results indicate that Tennessee and Texas cow-calf producers were willing to pay a premium of 51% and 59% above the base price, respectively, for a HFR bull with the intent to control horn flies within their herd. Producer perceptions of horn fly intensities and the HFR trait, along with their pest management practices, were factors that affected Tennessee and Texas producer willingness to adopt a HFR bull. In Texas, demographics of the producers and their farms also had a role. Knowing producers are willing to pay a premium for the HFR bull indicates that producers value the HFR trait and warrants additional research on the development, implementation, and assessment of the trait.

The horn fly, Haematobia irritans irritans (L.) (Diptera: Muscidae), is an important bloodsucking ectoparasite of cattle throughout much of the world. The fly is mostly controlled using conventional synthetic insecticides but as concerns about resistance increase, alternative tactics have come under heightened scrutiny. Four desiccant dust products: Surround WP, a kaolin clay-based wettable powder; CimeXa, comprised of silica aerogel; Drione, silica aerogel + pyrethrins; and EcoVia, silica aerogel + thyme oil, were assessed for their lethal effects against horn fly eggs, larvae, pupae, and adults, under laboratory conditions. Although Surround WP and CimeXa did not prevent egg hatching and (when mixed with manure substrate) pupal development, the two products were associated with moderate reductions of emerged adults, and with complete adult contact mortality within 6 hr and 24 hr, respectively. Drione and EcoVia eliminated egg hatching, pupal development, and adults within 15 min to 1 hr, respectively, whether the flies were exposed to treated filter paper substrate or exposed by immersion in the dusts. Implications for horn fly control and advantages of inert desiccant dust formulations are discussed.

Background The horn fly, Haematobia irritans irritans, causes significant production losses to the cattle industry. Horn fly control relies on insecticides; however, alternative control methods such as vaccines are needed due to the fly's capacity to quickly develop resistance to insecticides, and the pressure for eco-friendly options. Methods We used a reverse vaccinology approach comprising three vaccine prediction and 11 annotation tools to evaluate and rank 79,542 translated open reading frames (ORFs) from the horn fly's transcriptome, and selected 10 transcript ORFs as vaccine candidates for expression in Pichia pastoris. The expression of the 10 selected transcripts and the proteins that they encoded were investigated in adult flies by reverse transcription polymerase chain reaction (RT-PCR) and mass spectrometry, respectively. Then, we evaluated the immunogenicity of a vaccine candidate in an immunization trial and the antigen’s effects on horn fly mortality and fecundity in an in vitro feeding assay. Results Six of the ten vaccine candidate antigens were successfully expressed in P. pastoris. RT-PCR confirmed the expression of all six ORFs in adult fly RNA. One of the vaccine candidate antigens, BI-HS009, was expressed in sufficient quantity for immunogenicity and efficacy trials. The IgG titers of animals vaccinated with BI-HS009 plus adjuvant were significantly higher than those of animals vaccinated with buffer plus adjuvant only from days 42 to 112, with a peak on day 56. Progeny of horn flies feeding upon blood from animals vaccinated with BI-HS009 plus adjuvant collected on day 56 had 63% lower pupariation rate and 57% lower adult emergence than the control group (ANOVA: F(1, 6) = 8.221, P = 0.028 and F(1, 6) = 8.299, P = 0.028, respectively). Conclusions The reverse vaccinology approach streamlined the discovery process by prioritizing possible vaccine antigen candidates. Through a thoughtful process of selection and in vivo and in vitro evaluations, we were able to identify a promising antigen for an anti-horn fly vaccine. Graphical abstract

Horn flies (Haematobia irritans [L.]) contribute to major economic losses of pastured cattle operations, particularly in organic herds because of limitations on control methods that can be used. The objectives of this research were to determine if resistance to horn flies is a heritable trait in organic Holstein cattle, determine associations with yield traits, and to detect genomic regions associated with fly infestation. Observations of fly load were recorded from 1,667 pastured Holstein cows, of which 640 were genotyped, on 13 organic dairies across the United States. Fly load score was determined using a 0 to 4 scale based on fly coverage from chine to loin on one side of the body, with 0 indicating few to no flies and 4 indicating high infestation. The scoring system was validated by counting flies from photographs taken at the time of scoring from 252 cows. To mitigate the effect of our data structure on potential selection bias effects on genetic parameter estimates, survival to subsequent lactations of scored animals and herd-mates that had been culled before the trial was accounted for as the trait stayability. Genetic parameters were estimated using single-step genomic analysis with 3-trait mixed models that included fly score, stayability, and a third phenotype. Model effects differed by variable, but fixed effects generally included a contemporary group, scorer, parity, and stage of lactation; random effects included animal, permanent environment, and residual error. A genome-wide association study was performed by decomposing estimated breeding values into marker effects to detect significant genomic regions associated with fly score. The rank correlation between the subjective fly score and the objective count was 0.79. The average heritability of fly score (± standard error) estimated across multiple models was 0.25 ± 0.04 when a known Holstein maternal grandsire was required and 0.19 ± 0.03 when only a known Holstein sire was required. Genetic correlation estimates with yield traits were moderately positive, but a greater fly load was associated with reduced yield after accounting for genetic merit. Lower fly loads were associated with white coat coloration; a significant genomic region on Bos taurus autosome 6 was identified that contains the gene KIT, which was the most plausible candidate gene for fly resistance because of its role in coat pattern and coloration. The magnitude of heritable variation in fly infestation is similar to other traits included in selection programs, suggesting that producers can select for resistance to horn flies.

Fipronil was registered in Uruguay in 1997, and, since then, it has been used for the control of Haematobia irritans irritans and Rhipicephalus microplus. The susceptibility of H. irritants to this drug has not been evaluated. Therefore, the goal of the present study was to evaluate the resistance of H. irritans to fipronil. Additionally, a survey was carried out with the farmers to evaluate the use of fipronil for H. irritans control in the ranches where the flies came from. For the bioassays, 31 field populations of H. irritans were exposed to 10 concentrations of fipronil (3.2-16.0μg.cm2), and their LC50 values were calculated using probit analysis. A bioassay was performed with horn flies from the susceptible colony maintained at the USDA-ARS Knipling-Bushland U.S. Livestock Insects Research Laboratory for comparison and calculation of resistance ratios (RRs). All 31 field populations surveyed in the study were susceptible to fipronil, with resistance ratios ranging from 1 did not differ significantly from the susceptible strain. A single population showed an RR >2.2. Overall, the survey shows that fipronil was mostly used for R. microplus control, and in only three ranches, which were free of R. microplus, was fipronil used for horn fly control. Seventeen farmers did not use fipronil at all in the last three years. It is concluded that, in Uruguay, field populations of horn flies remain susceptible to fipronil.

Haematobia irritans is a hematophagous insect that affects the welfare of cattle reducing weight gain and it is present in most countries. The objective of this work was to determine the prevalence of flies, mainly H. irritans in 36 Red Angus calves under four farming ecosystems in Brazil, and to assess an individual threshold limit to treat for horn fly and to attain better animal welfare and farm sustainability. The animals (n = 9) were allocated in livestock (L), crop-livestock (CL), livestock-forestry (LF) and the full integration of crop-livestock-forestry (CLF) conditions. Adult flies were determined between systems on each animal at weekly intervals and in each environment by counting larvae and pupal stages that emerged from selected dung pads. Individual animals were treated for H. irritans infestation after reaching the transient threshold abundance (TTA) of > 100 flies. The data from 1008 evaluations showed that animals in the CLF had significantly (P < 0.05) more horn flies, than animals from the other systems. The level of infestation by horn flies was strongly influenced by the particular ecosystem (P < 0.002), and by the month of the year (P < 0.001). However, the difference in fly numbers did not influence the weight gain of the animals. We found four other genera of the Diptera order (Brontaea spp., Cyrtoneuropsis spp., Fannia spp. and Morellia spp.) that emerged from dung pads. The data suggests that it may be possible to perform evaluations in one animal at a time to control H. irritans with no impact to the performance of the animals when using a low TTA index of infestation. CLF was considered to be the richest environment, favoring fly populations. In our conditions, cattle and different fly species/genera may coexist using sustainable TTA management protocols at farm level in opposite to the concept of fly eradication or mass acaricidal treatment.

In cattle, parasitic flies such as the horn fly, Haematobia irritans, or the stable fly, Stomoxys calcitrans, are a serious nuisance for the animals and, in high populations, can cause substantial reduction in milk production, as well as significantly defer weight gain in calves. In 2012 annual losses associated with such pests were estimated to be up to 2200 million USD in the United States alone, and new effective treatments were therefore deemed highly valuable. The dinitriles were identified as a very promising class for combatting these pests, with additional potential for flea and tick control in companion animals. The molecules act as highly potent GABA-gated chloride channel blockers with IC50 values down to the single-digit nanomolar range. In addition, they possess fast knockdown activities close to state-of-the-art pyrethroids. In this chapter, the research efforts from early hit discovery to initial field testing will be described in further detail.

The horn fly, Haematobia irritans (L.), is an obligate hematophagous ectoparasite of cattle, and one of the most important pests of cattle causing unrealized gains or losses in meat and milk production. The present study describes the difficulties that arise when research programs have attempted to maintain this pest, both on-host and off-host, in a laboratory environment. Suggestions aimed at assisting future researchers in successfully colonizing horn flies in the laboratory are provided.

Haemaíobia irritans é uma das mais importantes pragas de bovinos. O uso em grande escala de inseticidas convencionais no seu controle tem resultado no surgimento de populações resistentes à maioria deles. Além disso, tem-se buscado alternativas de controle desta praga que não sejam danosas à saúde humana, a outros animais e ao meio ambiente. Diflubenzuron, um inibidor de desenvolvimento de insetos, vem sendo estudado como alternativa no controle de várias pragas, inclusive contra a mosca-dos-chifres. Este trabalho teve por objetivos: verificar a susceptibilidade de H. irritans a diferentes concentrações de diflubenzuron em Uberlândia - MG; determinar as concentrações letais do produto para 50% e 95% (CL50 e CL95) da população de moscas; verificar a atuação do produto nos seus diferentes estádios imaturos. Os experimentos foram realizados a partir de ovos e larvas obtidos de moscas adultas coletadas em campo sobre bovinos e mantidos em meio de criação contendo fezes bovinas + diflubenzuron (meio tratado) e meio constituído somente de fezes (meio controle). Observou-se que as concentrações 300 ppb, 100 ppb e 50 ppb foram letais para 100% da população. A partir da concentração 100 ppb houve o aparecimento de pupas com formato larviforme que aumentaram em número com a redução na concentração do produto até 35 ppb. Nesta concentração começou-se a observar a emergência de imagos. Os valores da CL50, da CL95 e do coeficiente angular da reta regressão foram respectivamente, 25,521 ± 1,011 ppb; 34,650 ± 1,021 ppb e 12,720 ± 1,096. O alto valor do coeficiente angular da reta e a susceptilidade de H. irritans às baixas concentrações de diflubenzuron indicam haver alta susceptibilidade da população testada a este inibidor de desenvolvimento. As larvas de terceiro estádio mostraram ser as mais susceptíveis ao diflubenzuron em concentração subletal. Haematobia irritans is one of the most important cattle pest. The wide use of conventional insecticides to control this pest has resulted in arising of resistant populations to the majority of the insecticides. Apart from this, alternative means of control, which are not harmful to humans and other animal’s health or to the environment have been sought. Diflubenzuron, an insect growth regulator, has been studied as an alternative in the control of various pests, including the horn fly. This study had three objectives: to verify H. irritans susceptibility to different concentrations of diflubenzuron in Uberlândia - MG, to determine the lethal concentrations of the product to 50% and 95% (LC50 and LC95) of the fly and to verify the actions of the product in its different immature stages. Experiments were done using eggs and larvae obtained from adult flies from cattle fields and maintained in medium containing dung + diflubenzuron (treated medium) and medium containing only dung (control medium). Concentrations of 300 ppb, 100 ppb and 50 ppb were lethal to 100% of the population. Pupae larvae shaped appeared, which increased in numbers with the reduction of the concentration of the product to 35 ppb, from the concentration of 100 ppb on. The emergence of imagoes was observed at concentration 35 ppb and increased in number with the reduction of diflubenzuron concentration in the breeding medium. The values of LC50, LC95, and the linear angular coeficient were 25.521 ± 1.011 ppb; 34.650 ± 1.021 ppb and 12.720 ± 1.096, respectively. The high value of the angular coeficient of regression line and the susceptibility of H. irritans to low diflubenzuron concentrations suggest that there is a high susceptibility of the tested population to this growth regulator. The third larvae stage were shown to be the most susceptible to diflubenzuron in sublethal concentration. Dissertação (Mestrado)

The horn fly, Haematobia irritans irritans, is a hematophagous parasite of livestock distributed throughout Europe, Africa, Asia, and the Americas. Welfare losses on livestock due to horn fly infestation are estimated to cost between $1 billion and $2.5 billion (U.S. dollars) annually in North America and Brazil. The endosymbiotic bacterium Wolbachia pipientis is a maternally inherited manipulator of reproductive biology in arthropods and naturally infects laboratory colonies of horn flies from Kerrville, TX, and Alberta, Canada, but it has also been identified in wild-caught samples from Canada, the United States, Mexico, and Hungary. Reassembly of PacBio long-read and Illumina genomic DNA libraries from the Kerrville H. i. irritans genome project allowed for a complete and circularized 1.3-Mb Wolbachia genome (wIrr). Annotation of wIrr yielded 1,249 coding genes, 34 tRNAs, 3 rRNAs, and 5 prophage regions. Comparative genomics and whole-genome Bayesian evolutionary analysis of wIrr compared to published Wolbachia genomes suggested that wIrr is most closely related to and diverged from Wolbachia supergroup A strains known to infect Drosophila spp. Whole-genome synteny analyses between wIrr and closely related genomes indicated that wIrr has undergone significant genome rearrangements while maintaining high nucleotide identity. Comparative analysis of the cytoplasmic incompatibility (CI) genes of wIrr suggested two phylogenetically distinct CI loci and acquisition of another cifB homolog from phylogenetically distant supergroup A Wolbachia strains, suggesting horizontal acquisition of these loci. The wIrr genome provides a resource for future examination of the impact Wolbachia may have in both biocontrol and potential insecticide resistance of horn flies. IMPORTANCE Horn flies, Haematobia irritans irritans, are obligate hematophagous parasites of cattle having significant effects on production and animal welfare. Control of horn flies mainly relies on the use of insecticides, but issues with resistance have increased interest in development of alternative means of control. Wolbachia pipientis is an endosymbiont bacterium known to have a range of effects on host reproduction, such as induction of cytoplasmic incompatibility, feminization, male killing, and also impacts vector transmission. These characteristics of Wolbachia have been exploited in biological control approaches for a range of insect pests. Here we report the assembly and annotation of the circular genome of the Wolbachia strain of the Kerrville, TX, horn fly (wIrr). Annotation of wIrr suggests its unique features, including the horizontal acquisition of additional transcriptionally active cytoplasmic incompatibility loci. This study provides the foundation for future studies of Wolbachia-induced biological effects for control of horn flies.

In horn flies, Haematobia irritans irritans (Diptera: Muscidae) (Linnaeus, 1758), target site resistance to pyrethroids can be diagnosed by an allele-specific PCR that genotypes individual flies at both the super-kdr (skdr) and the knock down resistance (kdr) associated loci. When this technique uses genomic DNA as template, modifications, such as alternative RNA splicing and RNA editing are not specifically detected. Alternative splicing at the skdr locus has been reported in Dipterans; thus, the genomic DNA-based allele-specific PCR may not accurately reflect the frequency of the skdr mutation in horn fly field populations. To investigate if alternative splicing occurs at the skdr locus of horn flies, genomic DNA and cDNA sequences isolated from two wild populations and two laboratory-reared colonies with varying degrees of pyrethroid resistance were compared. There was no indication of alternative splicing at the super-kdr locus neither in the wild populations nor in the laboratory-reared colonies.

Acetylcholinesterase (AChE) was previously reported to be present in saliva of the southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), with proposed potential functions to 1) reduce acetylcholine toxicity during rapid engorgement, 2) modulate host immune responses, and 3) to influence pathogen transmission and establishment in the host. Potential modulation of host immune responses might include participation in salivary-assisted transmission and establishment of pathogens in the host as has been reported for a number of arthropod vector-borne diseases. If the hypothesis that tick salivary AChE may alter host immune responses is correct, we reasoned that similar cholinesterase activities might be present in saliva of additional arthropod vectors. Here, we report the presence of AChE-like activity in the saliva of southern cattle ticks, Rhipicephalus (Boophilus) microplus; the lone star tick, Amblyomma americanum (Linnaeus); Asian tiger mosquitoes, Aedes albopictus (Skuse); sand flies, Phlebotomus papatasi (Scopoli); and biting midges, Culicoides sonorensis Wirth and Jones. Salivary AChE-like activity was not detected for horn flies Haematobia irritans (L.), stable flies Stomoxys calcitrans (L.), and house flies Musca domestica L. Salivary cholinesterase (ChE) activities of arthropod vectors of disease-causing agents exhibited various Michaelis–Menten KM values that were each lower than the KM value of bovine serum AChE. A lower KM value is indicative of higher affinity for substrate and is consistent with a hypothesized role in localized depletion of host tissue acetylcholine potentially modulating host immune responses at the arthropod bite site that may favor ectoparasite blood-feeding and alter host defensive responses against pathogen transmission and establishment.

This study involved two field trials with the aim of evaluating the efficacy of diflubenzuron, via mineral supplementation, against Haematobia irritans parasitizing cattle. Concomitantly with the main trial, a stall test was conducted to ascertain the effects of a different formulation with the same active ingredient against Rhipicephalus microplus, along with the action of diflubenzuron on the reproductive parameters of R. microplusfemales that had naturally detached from cattle. Against H. irritans, it was observed that the efficacy indexes fordiflubenzuron were low (≤ 31.3% or 44.6%) or null (0.0%) throughout the study. The anti- R. microplus efficacy of diflubenzuron, at weekly intervals, ranged from 0.0 to 13.7% over the entire experimental period. Null efficacy (0.0%) was registered for diflubenzuron in relation to the reproductive parameters of R. microplusfemales that had naturally detached from cattle. The different diflubenzuron formulations, administered via mineral salt supplementation, did not show satisfactory efficacy indexes against H. irritans and R. microplus parasitizing cattle, within the experimental design of the present study. In addition, this agent did not present any deleterious effects on the reproductive parameters of R. microplus females. Resumo O objetivo deste estudo foi avaliar a eficácia do diflubenzuron, administrado via suplementação mineral, contra Haematobia irritans parasitando bovinos, em dois testes à campo. Concomitantemente, foi realizado testes em estábulo para determinar os efeitos de uma formulação diferente, com o mesmo princípio ativo, contra Rhipicephalus microplus , bem como a ação do diflubenzuron nos parâmetros reprodutivos de fêmeas de R. microplus recolhidas após desprendimento natural do hospedeiro bovino. Contra H. irritans, foi observado que foram baixos (≤ 31,3% ou 44,6%) ou nulos (0,0%) os índices de eficácia do diflubenzuron. A eficácia anti-R. microplus do diflubenzuron, observada em intervalos semanais, variaram de 0,0% a 13,7% durante todo o período experimental. Com relação aos parâmetros reprodutivos das fêmeas de R. microplus recolhidas, foi observada eficácia nula (0,0%) para o diflubenzuron. Conclui-se que as diferentes formulações administradas via sal mineral no atual estudo, contra H. irritans e R. microplus parasitando bovinos, não apresentaram eficácia satisfatória. Este agente também não mostrou efeito deletério sobre os parâmetros reprodutivos de fêmeas de R. microplus.

Although mean body lengths of females were significantly greater than males in individuals drawn from two Haematobia irritans (L.) sample populations (n = 20 females and n = 20 males from West Virginia; n = 20 females and n = 20 males from Georgia), there were no significant differences in food canal lengths for females versus males at either site. Variable numbers (21-37) of setiform sensillae occurred throughout the length of the food canal, but such sensillae were significantly aggregated in the distal-most canal region of both sexes at both sites. There was no significant difference in mean numbers of food canal setiform sensillae between females and males. Four basiconic (campaniform) sensillae were consistently observed in the food canal of every fly; always aggregated in the distal-most canal region. Setiform sensillae in the cibarium also varied in number (6-13), but were significantly aggregated in the median and proximal cibarial regions. Four (occasionally three) peg-like basiconic sensillae were also observed in the cibarium of sample individuals; always in the distal and distal median regions of both sexes. Sensory sensillae (both setiform and basiconic) in both the food canal and cibarium were similarly aggregated for both sexes at both sites. Aggregation of setiform and basiconic sensillae in the food canal suggests that the distal canal region is most critical for sensory input regarding monitoring blood flow, and stress forces brought to bear on the cuticle as the labrum tip penetrates the host's skin.

Pesticides are used worldwide to control arthropod parasites in cattle herds. The indiscriminate and/or inappropriate use of pesticides without veterinary guidance is a reality in several countries of South America. Improper pesticide use increases the chances of contamination of food and the environment with chemical pesticides and their metabolites. Reduction of these contamination events is an increasing challenge for those involved in livestock production. The horn fly, Haematobia irritans (Linnaeus) (Diptera: Muscidae), is one of the most economically important parasites affecting cattle herds around the world. As such, horn fly control efforts are often required to promote the best productive performance of herds. Pesticide susceptibility bioassays revealed that pyrethroid resistance was widespread and reached high levels in horn fly populations in the Brazilian state of Rondônia. The knockdown resistance (kdr) sodium channel gene mutation was detected in all horn fly populations studied (n = 48), and the super kdr sodium channel gene mutation was found in all homozygous resistant kdr individuals (n = 204). Organophosphate resistance was not identified in any of the fly populations evaluated.

The horn fly, Haematobia irritans irritans (Linnaeus, 1758; Diptera: Muscidae), a hematophagous external parasite of cattle, causes considerable economic losses to the livestock industry worldwide. This pest is mainly controlled with insecticides; however, horn fly populations from several countries have developed resistance to many of the products available for their control. In an attempt to better understand the adult horn fly and the development of resistance in natural populations, we used an Illumina paired-end read HiSeq and GAII approach to determine the transcriptomes of untreated control adult females, untreated control adult males, permethrin-treated surviving adult males and permethrin + piperonyl butoxide-treated killed adult males from a Louisiana population of horn flies with a moderate level of pyrethroid resistance. A total of 128,769,829, 127,276,458, 67,653,920, and 64,270,124 quality-filtered Illumina reads were obtained for untreated control adult females, untreated control adult males, permethrin-treated surviving adult males and permethrin + piperonyl butoxide-treated killed adult males, respectively. The de novo assemblies using CLC Genomics Workbench 8.0.1 yielded 15,699, 11,961, 2672, 7278 contigs (≥ 200 nt) for untreated control adult females, untreated control adult males, permethrin-treated surviving adult males and permethrin + piperonyl butoxide-treated killed adult males, respectively. More than 56% of the assembled contigs of each data set had significant hits in the BlastX (UniProtKB/Swiss-Prot database) (E

Haematobia irritans is a cosmopolitan obligate blood-feeding ectoparasite of cattle and is the major global pest of livestock production. Currently, H. irritans management is largely dependent on broad-spectrum pesticides, which has led to the development of insecticide resistance. Thus, alternative control methods are needed. Essential oils have been studied as an alternative due to their wide spectrum of biological activities against insects. Thus, the main aim of this study was to evaluate the insecticidal, repellent and antifeedant activity of the essential oils from Blepharocalyx cruckshanksii leaves and Pilgerodendron uviferum heartwood against horn flies in laboratory conditions. The composition of the essential oils was analyzed using gas chromatography coupled to mass spectrometry. Accordingly, α-pinene (36.50%) and limonene (20.50%) were the principal components of the B. cruckchanksii essential oil, and δ-cadinol (24.16%), cubenol (22.64%), 15-copaenol (15.46%) and δ-cadinene (10.81%) were the most abundant compounds in the P. uviferum essential oil. Mortality of flies and feeding behavior were evaluated by non-choice tests, and olfactory response was evaluated using a Y-tube olfactometer. Both essential oils were toxic to horn flies, with LC50 values for B. cruckchanksii essential oil of 3.58 µL L−1 air at 4 h, and for P. uviferum essential oil of 9.41 µL L−1 air and 1.02 µL L−1 air at 1 and 4 h, respectively. Moreover, the essential oils exhibited spatial repellency in the olfactometer using only 10 µg of each oil, and these significantly reduced the horn fly feeding at all doses evaluated. Although further laboratory and field studies related to the insectistatic and insecticide properties of these essential oils against H. irritans are necessary, B. cruckshanksii leaves and P. uviferum heartwood essential oils are promising candidates for horn fly management.

The horn fly, Haematobia irritans, is a bovine ectoparasite that causes large losses to cattle breeders, through lower meat and milk production and hide damage. Currently, the control of this parasite is mainly through chemicals. However, the indiscriminate use of these substances generates resistance. Pyriproxyfen belongs to an insect growth disruptors class with mechanisms of action for the control of immature forms of the insect. The aim of this study was to investigate the potential of pyriproxyfen administered orally to cattle for the control of the horn fly. In vitro bioassays were carried out by evaluating the number of adults emerged from 30 eggs per replicate, in triplicate, added in a substrate (fresh cattle feces) spiked with pyriproxyfen solutions in the concentration range of 2–130 ppb (ng.g−1). Probit analysis estimated LC50 value of 7.89 ppb and LC90 value of 70.08 ppb. The doses used in the in vivo evaluation were established based on the LC90 values and the anatomical and physiological aspects of the bovine digestive tract. Capsules containing pyriproxyfen at doses of 2.5 mg (G2.5) and 40 mg (G40) were produced and administered orally by bolus applicator for 12 days. The efficacy of pyriproxyfen against the immature forms of H. irritans was determined by incubating eggs in vitro in the feces collected on days 0, +3, +6, +10 and +13. Quantification of pyriproxyfen in feces was performed by UPLC-MS/MS, finding concentrations ranging from 13.4 to 22.6 ppb for G2.5 and between 268.5 to 509.0 ppb for G40. Pyriproxyfen administered orally is eliminated in the active form in the fecal mass and at a dose of 40 mg.day−1 (0.1 mg/kg/day) generates fecal concentrations able to produce 100 % prevention of adults emergence of H. irritans.

The purpose of this study was to determine the type and percentage of ectoparasites attacking the cattle cow in the Kendit Sub-District, Situbondo District. The research was conducted from July to September 2020 with 100 samples of cow taken. The identification of ectoparasites was carried out at The Laboratory of the Animal Health Center of Situbondo Regency. This study was survey with a cross-sectional design. This study found several ectoparasites of the type of flies that infested the cattle cow: Musca domestica 29.20%, Haematobia irritans 58.96%, Stomoxys calcitrans 2.82%, Tabanus rubidus 0.42%, Tabanus megalops 0.56%, Hippobosca maculata 0.14%. In addition, this study also found ectoparasites of fleas that attacked the cattle cow, among others Bovicola bovis 2.12%, and Haematopinus eurysternus 5.78%. In this study, the dominant type of fly ectoparasite was Haematobia irritans 58.96% and the dominant ectoparasite from flea was Haematopinus eurysternus 5.78%. The suggestions for this research were this research should be continued with a longer time, the fishing method must be more varied because the more fishing methods used, the higher diversity results and it is advisable to maintain cage sanitation, improve maintenance management, and the cleanliness of cattle sheds surroundings to maintain cattle condition.

Background: Stephanofilaria spp. nematodes are associated with cutaneous lesions in cattle and other livestock and mammalian wildlife species. In Australia, Haematobia irritans exigua, commonly known as buffalo fly (BF) transmits a well-described but presently unnamed species of Stephanofilaria, which has been speculatively implicated in the aetiology of BF lesions. The sensitivity of current techniques for detecting Stephanofilaria spp. in skin lesions and vector species is low, and there is no genomic sequence for any member of the genus Stephanofilaria currently available in sequence databases. Methods: To develop molecular assays for the detection of the Australian Stephanofilaria sp., skin biopsies were collected from freshly slaughtered cattle with typical lesions near the medial canthus. Adult nematodes and microfilariae were isolated from the biopsies using a saline recovery technique. The nematodes were morphologically identified as Stephanofilaria sp. by scanning electron microscopy. DNA was extracted and the internal transcribed spacer 2 (ITS2) region of rDNA, and the cytochrome c oxidase subunit 1 (cox1) region of mtDNA was amplified and sequenced. Stephanofilaria sp. specific polymerase chain reaction (PCR) and qPCR assays (SYBR Green® and TaqMan™) were developed and optimised from the novel ITS2 sequence obtained. The specificity of each assay was confirmed by testing against nematode species Onchocerca gibsoni and Dirofilaria immitis, as well as host (bovine) and BF DNA. Results: Scanning electron microscopy of the anterior and posterior ends of isolated nematodes confirmed Stephanofilaria sp. A phylogenetic analysis of the cox1 sequence demonstrated that this species is most closely related to Thelazia callipaeda, a parasitic nematode that is a common cause of thelaziasis (or eyeworm infestation) in humans, dogs, and cats. Both conventional and qPCR assays specifically amplified DNA from Stephanofilaria sp. Conventional PCR, TaqMan™, and SYBR Green® assays were shown to detect 1 ng, 1 pg, and 100 fg of Stephanofilaria DNA, respectively. Both qPCR assays detected DNA from single Stephanofilaria microfilaria. Conclusion: Molecular diagnostic assays developed in this study showed high specificity and sensitivity for Stephanofilaria sp. DNA. The availability of an accurate and sensitive PCR assay for Stephanofilaria will assist in determining its role in the pathogenesis of cattle skin lesions, as well as in understanding its epidemiological dynamics. This assay may also have application for use in epidemiological studies with other species of Stephanofilaria, most particularly closely related S. stilesi, but this will require confirmation.

Haematobia irritans (horn fly) is a bloodsucking insect that affects grazing cattle. Since this fly's introduction into Uruguay in 1992, pest management practices used to control the insect have been exclusively based on the use of insecticides, which has caused synthetic pyrethroid resistance. The use of insecticides is a major constraint to livestock production due to food safety and environmental concerns. This study evaluated the effectiveness of a walk-through fly trap for horn fly control. The field trail was conducted in 18 trail evaluations dates from 2015 to 2016 in Holstein-Frisian lactating cows on two dairy farms in southern Uruguay. The traps were placed at the exit of the milking parlor. Two digital cameras were used to record video at the entrances and exits of the traps. On each of the 18 trail evaluation, between 30 and 158 cows were randomly selected for fly counting according to video records. On Farm 1, a total of 718 cows were assessed. The median number of flies per cow at the entrance of the traps was 22 (ranging from 1 to 199), while the median number at the exit was three flies per cow (ranging from 0 to 22). The median efficiency of the trap was 88%. Farm 2 had 345 observations, and the median fly count at the entrance of the traps was of 22 flies per cow (ranging from 1 to 129) and four flies at the exit (ranging from 0 to 35) with a median efficiency of 82%. It was observed that the effectiveness of the fly traps varied depending on the number of flies at entry, the season of the year and the farm site. In conclusion, fly traps could be used for the control of H. irritans in milking cows without the use of insecticides.

Made available in DSpace on 2018-11-26T17:42:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-11-15 The use of silvopastoral systems (SPS) can be a good alternative to reduce the environmental impacts of livestock breeding in Brazil. One of the reasons for its scarce adoption is the lack of information on health and productivity of cattle raised under these conditions. The experiment reported here was designed to compare the infestation by external parasites - the cattle tick (Rhipicephalus microplus), horn fly (Haematobia irritans), and larvae of the botfly (Dermatobia hominis) - in beef cattle raised in a SPS and a conventional pasture system (CPS), evaluated for 24 months. Data on air and soil temperature, solar radiation, wind incidence and water balance were used to characterize the SPS and CPS. R. microplus adult females and D. hominis larvae were counted on the body of each animal to determine the parasites burdens, but we did not find significant differences between the two systems. Horn flies counts on animals' body, and analysis of the horn fly and its pupal parasitoids associated with the dung pats were obtained in the two systems. Horn fly infestation was significantly lower (p = 0.01) in the SPS (13.17 +/- 3.46) in comparison with the CPS (24.02 +/- 4.43). In SPS and CPS, respectively, the mean densities of pupae of H. irritansin dung pats were 9.8 and 10.7; the mean density of adults of H. irritans, 3.7 and 3.5; and the density of its pupal parasitoids were 20.5 and 5.4. The effect of production system was significant (p < 0.05) only for the occurrence of pupal parasitoids of the horn fly, where the greatest occurrences of these natural enemies were in the SPS. These data indicate that natural enemies were able to control, at least partially, the horn fly populations in the cattle. Embrapa Pecuaria Sudeste, Rodovia Washington Luiz,Km 234,CP 339, BR-13560970 Sao Carlos, SP, Brazil Univ Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazil Univ Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazil

Adult horn fly populations were tracked on cattle for 2-week periods before, during and after multiple treatments (every 3-4days) with two repellents in a mineral oil carrier. Cattle were sprayed four times in a two-week period either with 2% geraniol (125ml/cow) or a 15% mixture of short chain fatty acids (C8-C9-C10)(250ml/cow), and there were untreated control cattle. Trials were conducted in California and North Carolina for 3 summers. Short-term fly counts (same day) on treated cattle were reduced by 61-99%, depending on material and trial, and the fatty acid mixture provided better control than geraniol. Horn fly counts were suppressed for 1-3 d and rebounded somewhat after both treatments. Consecutive treatments showed evidence of persistent impact in California where herds were more isolated. Rebounds to pre-treatment levels 3-4 d after treatment occurred more often in North Carolina, where other infested cattle were closer to treated herds. By 3-4 d post-treatment, horn flies were reduced by 29-61% in California and 0-83% in North Carolina, relative to pre-treatment. Background behavior frequencies were assessed from hundreds of counts on untreated, infested California cattle, where horn flies were the only abundant biting fly. Behavior averages were 16.5 tail flicks, 7.6 skin twitches, 1.2 head throws, or 0.2 leg stamps per 2min observation period. At horn fly densities from about 200 to more than 1000 flies per animal (moderate to high numbers), fly defensive behaviors on control cattle were poorly related (or unrelated) to fly numbers. Immediately after repellent application, however, flies were almost absent and behavior frequencies dropped distinctly. Cattle fly defensive behaviors therefore seem to be quite sensitive to low (less than 100 flies/animal) horn fly densities, and behaviors would be a poor quantitative tool to track fly stress at moderate densities and above. Both geraniol and the fatty acids show promise for horn fly control, especially in organic agriculture. Treatments at 1-2 d intervals probably would keep infestations below the economic threshold (200 flies/cow).

Haematobia irritans, also known as the horn fly, is a “plague” that spreads rapidly among cattle herds, especially in the southeast of Brazil. The aim of this study was to evaluate the interaction and activity of nematophagous fungus Duddingtonia flagrans (AC001) on H. irritans (Diptera: Muscidae). The experiment was conducted using the nematophagous fungus (AC001), which is harmless to animals, humans, and the environment. At the beginning of the experimental trial, samples of adult H. irritans were collected manually, directly from the dorsal region of naturally infested cattle of the Nelore breed. The flies where divided into two groups: groups of adult flies treated with AC001 (treated group) and groups of flies that did not receive treatment (control group). During the trial, the experiment was monitored daily for five days and the results were recorded. The results showed that the AC001 fungal isolate grew, colonized, and consequently caused the death of the flies in the treated group, while in the control group, no interaction or growth was observed, and the flies remained alive. It was concluded that the fungus D. flagrans interacted with adult flies, taking into consideration a “possible attack” by chitinase enzymes, since the fungal isolate drew on the chitin contained in the exoskeletons of the insects. In addition, attention should be focused on new studies that can demonstrate that, in the future, biological control of the horn fly could be an effective and safe method when compared with other methods. Key words: Biological control, Duddingtonia flagrans, horn fly, Nelore, Brazil.

The horn fly, Haematobia irritans (L.), is a blood-sucking livestock ectoparasite responsible for substantial livestock losses. In the present work, the potential use of recombinant hematobin (HTB), a horn fly salivary protein, as an antigen for cattle vaccination was investigated. In this trial, horn fly loads and H. irritans's blood intake were assessed in vaccinated (n = 4) and control (n = 4) crossbred dark-coated steers, which were naturally infected. The vaccinated group received a 1 ml subcutaneous injection of 100 µg of HTB protein emulsified in 500 µl of Incomplete Freund Adjuvant (AIF) on days 0 and 30. The control group received on the same days 1 ml of distilled water emulsified in 500 µl of AIF. The vaccinated group had significantly more HTB-specific IgG antibodies after the HTB booster and had a lower fly load than the control group (206 ± 23 vs. 285 ± 23 flies per animal, respectively). Blood intake by H. irritans did not differ between groups. In summary, these results suggest that vaccinating cattle with HTB could reduce cattle H. irritans load.

Horn fly, Haematobia irritans (L.), population estimates often serve as a diagnostic tool prior to implementing managerial control options available to researchers and producers. Digital photographs taken of cattle infested with horn flies have been suggested to provide similarly accurate population estimates as compared with traditional visual assessments. The objective of this study was to compare visual and digital techniques used to estimate horn fly populations. Sixteen Angus × Hereford yearling heifers artificially infested with four levels of horn flies (Low = 0 flies; Medium = 250 flies; High = 500 flies; Extreme = 1,000 flies) were evaluated. Population estimates were taken visually by experienced (VE1) and inexperienced (VE2) technicians, as well as digitally, with photographs taken on both lateral sides of the south-facing animal. Horn flies were counted in both photographs and combined (CDC) for full body estimates. In addition, the highest photographed side population times two (DDC) was used for comparison. Estimations were made at 0700, 1200, and 1900 h the day following infestation. A time of observation × infestation level interaction (P < 0.01) was detected. On average, VE1 population estimates were greater (P < 0.01) than any other counting method observed. Morning estimates were greater (P < 0.05) than those taken at noon or in the early evening regardless of counting method. Further research regarding the standardization of these techniques to ensure more accurate population estimates is needed before these methods can be incorporated into integrated pest management programs.

Haematobia irritans é uma mosca de grande importância na pecuária bovina. É responsável por causar estresse crônico ao rebanho causando desconforto e levando a redução da produção de carne e leite e depreciação do couro. Também são responsáveis por transmitir vírus, bactéria e facilitar ao desenvolvimento de míiases. O objetivo deste trabalho foi avaliar a eficácia de um produto ectoparasiticida contendo a associação de cipermetrina, clorpirifós, butóxido de pireronila e fluazuron na formulação “pour on” no controle da mosca H. irritans em bovinos naturalmente infestados. Foram utilizados 30 bovinos, mestiços, sem distinção de sexo ou idade. Todos os animais incluídos no estudo apresentaram pelo menos 50 moscas adultas de H. irritans de ocorrência natural. Os animais do grupo tratado foram medicados com a associação de cipermetrina (5mg/kg), clorpirifós (7mg/kg), butóxido de pireronila (5mg/kg) e fluazuron (2,5mg/kg), na dose de 1ml para cada 10 quilos de peso vivo, pela via tópica (“pour on”) em dose única. A eficácia mosquicida foi avaliada um, três, sete, 14 e 21 dias após o tratamento, a partir da contagem de moscas adultas sobre os animais dos dois os grupos. A eficácia da associação testada neste estudo foi de 98,65%; 96,69%; 92,01%; 87,79% e 76,43% nos dias +1, +3, +7, +14 e +21 respectivamente. A associação de cipermetrina, clorpirifós, butóxido de piperonila e fluazuron na formulação “pour on” é eficaz no controle de H. irritans em bovinos naturalmente infestados.

Strains of Salmonella enterica can be subdivided into clades that differ in their genetic composition, influencing microbial ecology and bacterial transmission. Salmonella serovar Montevideo strains 1110 and 304, representatives of two different clades, were used to evaluate interactions with the various stages of horn fly development. Sterilized cattle dung was inoculated with Salmonella monocultures, and horn fly larvae were exposed to 103, 105, and 107 colony-forming units (CFU)/g per strain. Salmonella supported horn fly development, and concentration-dependent differences in pupal survival suggested that Salmonella Montevideo 304 impacts adult emergence when larvae are reared in a high concentration. Viable bacteria of each strain were quantified from larvae, pupae, and newly emerged adults. Both strains were cultured from larvae at a mean ~105, regardless of concentration, and both strains survived pupation. Quantities of Salmonella 1110 were stationary through the midpupal stage, after which quantities declined in pupae reared in 105 and increased twofold in pupae reared in 107 CFU/g. Quantities of Salmonella 304 remained stationary throughout pupal development when reared in 105, yet increased 29-fold when reared in 107 CFU/g. At high densities, properties of Salmonella 304 may influence its interaction with horn fly larvae, enabling the bacteria to evade degradation during larval gut histolysis and to subsequently proliferate during the late stages of pupal development. This may account for the observed effect on adult emergence. The Salmonella strains were rarely cultured from newly emerged adults, indicating that transstadial carriage to the adult stage is inefficient.

The ultrastructure of the mouthparts of Haematobia irritans (L.) was investigated by scanning electron microscopy. The morphological characteristics of the maxillary palps, labium (prementum and postmentum), labrum, hypopharynx, haustellum, and labellar lobes are described, as well as of the sensilla evidenced on all the surface of the mouthparts, and the set of different positions assumed by the mouth apparatus of this fly. Based on their morphology, 12 well-differentiated sensilla were identified, among three types of cuticular sensilla: trichoidea, coeloconica, and campaniformia. A slight sexual dimorphism in the sensilla patterns found in the mouthparts of H. irritans was evidenced. These observations are discussed with reference to the current literature on the functional morphology of sense organs of Insecta. These results could facilitate the recognition of the chemosensory sensilla by electrophysiological techniques, and foment future taxonomic and phylogenetic studies to better elucidate the evolution of Diptera, Muscomorpha.

Bloodmeal feeding by the horn fly, Haematobia irritans (L.), is associated with reduced milk production and blood loss that ultimately prevents weight gain of calves and yearlings. Thus, blood feeding by H. irritans causes significant economic losses in several continents. As with other arthropods, resistance to the majority of commercialized insecticides reduces the efficacy of current control programs. Thus, innovative technologies and novel biochemical targets for horn fly control are needed. Salivary gland and Malpighian tubule function are critical for H. irritans survivorship as they drive bloodmeal acquisition and maintain ion- and fluid homeostasis during bloodmeal processing, respectively. Experiments were conducted to test the hypothesis that pharmacological modulation of H. irritans inward rectifier potassium (Kir) channels would preclude blood feeding and induce mortality by reducing the secretory activity of the salivary gland while simultaneously inducing Malpighian tubule failure. Experimental results clearly indicate structurally diverse Kir channel modulators reduce the secretory activity of the salivary gland by up to fivefold when compared to control and the reduced saliva secretion was highly correlated to a reduction in bloodmeal acquisition in adult flies. Furthermore, adult feeding on blood treated with Kir channel modulators resulted in significant mortality. In addition to validating the Kir channels of H. irritans as putative insecticide targets, the knowledge gained from this study could be applied to develop novel therapeutic technologies targeting salivary gland or Malpighian tubule function to reduce the economic burden of horn fly ectoparasitism on cattle health and production.

BACKGROUNDHaematobia spp., horn flies (HF) and buffalo flies (BF), are economically important ectoparasites of dairy and beef cattle. Control of these flies relies mainly on the treatment of cattle with chemical insecticides. However, the development of resistance to commonly used compounds is compromising the effectiveness of these treatments and alternative methods of control are required. Wolbachia are maternally transmitted endosymbiotic bacteria of arthropods that cause various reproductive distortions and fitness effects, making them a potential candidate for use in the biological control of pests.RESULTSHere we report the successful establishment of a continuous HF cell line (HIE-18) from embryonic cells and its stable transinfection with Wolbachia strain wAlbB native to mosquitoes, and wMel and wMelPop native to Drosophila melanogaster. The established HIE-18 cells are typically round and diploid with ten chromosomes (2n = 10) or tetraploid with 20 chromosomes (4n=20) having a doubling time of 67.2 hours. Wolbachia density decreased significantly in the HIE-18 cells in the first 48 hours of infection, possibly due to overexpression of antimicrobial peptides through the Imd immune signalling pathway. However, density recovered after this time and stably Wolbachia-infected HIE-18 cell lines have now all been subcultured more than 50 times as persistently infected lines.CONCLUSIONThe amenability of HF to infection with different strains of Wolbachia suggests the potential for use of Wolbachia in novel approaches for the control of Haematobia spp. Further, the availability of the HIE-18 cell line will provide an important resource for the study of genetics, host-parasite interactions and chemical resistance in Haematobia populations.

Haematobia spp., horn flies (HF) and buffalo flies (BF), are economically important ectoparasites of dairy and beef cattle. Control of these flies relies mainly on the treatment of cattle with chemical insecticides. However, the development of resistance to commonly used compounds is compromising the effectiveness of these treatments and alternative methods of control are required. Wolbachia are maternally transmitted endosymbiotic bacteria of arthropods that cause various reproductive distortions and fitness effects, making them a potential candidate for use in the biological control of pests. The first step towards this is the establishment and adaptation of xenobiotic infections of Wolbachia in target host cell lines. Here we report the successful establishment of a continuous HF cell line (HIE-18) from embryonic cells and its stable transinfection with Wolbachia strains wAlbB native to mosquitoes, and wMel and wMelPop native to Drosophila melanogaster. The HIE-18 cells were typically round and diploid with ten chromosomes (2n = 10) or tetraploid with 20 chromosomes (4n = 20) with a doubling time of 67.2 h. Wolbachia density decreased significantly in the HIE-18 cells in the first 48 h of infection, possibly due to overexpression of antimicrobial peptides through the Imd immune signalling pathway. However, density recovered after this time and HIE-18 cell lines stably infected with the three strains of Wolbachia have now each been subcultured more than 50 times as persistently infected lines. The amenability of HF cells to infection with different strains of Wolbachia and the establishment of stable sustaining infections suggests the potential for use of Wolbachia in novel approaches for the control of Haematobia spp. Further, the availability of the HIE-18 cell line will provide an important resource for the study of genetics, host-parasite interactions and chemical resistance in Haematobia populations. This article is protected by copyright. All rights reserved.

To reduce the use of insecticide treatments against Haematobia irritans we evaluated the impact of treating 15% of the bovines, with the greatest number of flies including bulls, with 40% diazinon ear tags, on the infestation of untreated cows. Horn fly susceptibility to diazinon was measured before and after treatment, and peaks of infestation were recorded. Three groups of Bradford bovines were evaluated: Group 1 (control untreated), Group 2 (15% treated) and Group 3 (control 100% treated). Weekly counts of horn flies were performed on the same animals for 78 days. Two peaks of infestation were recorded, and a higher number of horn flies occurred in the untreated control group than in the untreated cows of the selectively treated group throughout the entire period of the study, except for a single week. The horn fly field population was significantly more susceptible to diazinon than the reference susceptible strain both before and after insecticide treatment. In conclusion, treatment of 15% of the most infested animals from a herd, with 40% diazinon ear tags, quickly reduced horn fly infestations of the entire herd and may be a practical approach for horn fly control, reducing costs and chemical use.

Ectoparasitic stable flies (Stomoxys calcitrans [L.]), horn flies (Haematobia irritans [L.]), and face flies (Musca autumnalis De Geer) negatively affect dry matter intake, milk production, and health of pastured dairy cows. These flies cause fly avoidance behaviors and are a major welfare concern for dairy producers. The objective of this study was to evaluate the effects of mesh Shoofly Leggins (Stone Manufacturing & Supply, Kansas City, MO) on fly avoidance behaviors and numbers of flies attacking pastured dairy cows. In a crossover design, lactating dairy cows (n = 80) were randomly assigned to groups with and without leggings (Shoofly Leggins worn on all legs). All cows were managed in one group. Cows were observed for 2-wk periods, and then treatments were reversed in the next 2-wk interval. Counts of stable flies, horn flies, and face flies on all cows were recorded twice daily (once in morning per cow: 0930 to 1230 h; and once in the afternoon per cow: 1330 to 1630 h), 3 times per wk on Tuesday, Wednesday, and Thursday of each week during the study period. The total number of flies per cow was greater on cows with leggings than cows without leggings. The number of horn flies per cow was greater on cows in with leggings (26.4 flies/side) compared with cows without leggings (24.1 flies/side). Stable fly numbers were similar for cows with and without leggings (12.8 flies/leg). A random subset of 20 focal cows per group was observed during 5-min intervals to record frequencies of 4 behaviors: leg stomps, head tosses, skin twitches, and tail swishes. Counts of head tosses (2.6 vs. 3.1), skin twitches (20.9 vs. 19.6), and tail swishes (21.3 vs. 19.3) were similar for cows without leggings versus cows with leggings, respectively. However, foot stomps were 39% lower for cows with leggings compared with cows without leggings, and leg stomps were 26% higher in the afternoon than in the morning (2.9 vs. 2.4, respectively). A positive correlation was observed between stable and horn flies and all insect avoidance behaviors. Numbers of stable flies were 1.5 times greater in the afternoon than in the morning. The results of this study indicated that flies were associated with cow fly avoidance behaviors regardless of the use of leggings, but leggings effectively reduced foot stomps by 39%, so their use may provide some relief from stable fly injury to pastured dairy cows.

The horn fly Haematobia irritans (Diptera: Muscidae) is a blood obligate ectoparasite of bovids that causes annual losses to the U.S. beef cattle industry of over US$1.75 billion. Climate warming, the anthropogenic dispersion of bovids and the cross-breeding of beef cattle with other bovid species may facilitate novel horn fly-host interactions. In particular, hybridizing yaks [Bos grunniens (Artiodactyla: Bovidae)] with beef cows (Bos taurus) for heterosis and carcass improvements may increase the exposure of yak × beef hybrids to horn flies. The present paper reports on the collection of digital images of commingled beef heifers (n = 12) and F1 yak × beef hybrid bovids (heifers, n = 7; steers, n = 5) near Laramie, Wyoming (∼ 2200 m a.s.l.) in 2018. The total numbers of horn flies on beef heifers and F1 yak × beef heifers [mean ± standard error (SE): 88 ± 13 and 70 ± 17, respectively] did not differ significantly; however, F1 yak × beef steers had greater total horn fly abundance (mean ± SE: 159 ± 39) than female bovids. The present report of this experiment is the first such report in the literature and suggests that F1 yak × beef bovids are as susceptible as cattle to horn fly parasitism. Therefore, similar monitoring and treatment practices should be adopted by veterinarians, entomologists and producers.

Parabronemosis is a disease that severely threatens camel health, causing huge economic losses to industries involved in camel husbandry. Previous studies have reported that horn flies (Haematobia irritans) act as intermediate hosts of Parabronema skrjabini; however, the infection and developmental processes of P. skrjabini in horn flies remain unclear. In the present study, the infection rates of P. skrjabini were determined in morphologically and molecularly identified horn flies collected from Bactrian camels (Camelus bactrianus) producing regions in Inner Mongolia, China that have high P. skrjabini infection rates. The horn flies were dissected to obtain the nematode larvae at various instar stages. The P. skrjabini found in the different instar stages of horn fly instars were counted and identified to assess the infection and developmental status. Nematode larvae at different developmental stages were obtained from the horn fly instars for further molecular analysis. Sequencing results confirmed that the nematode larvae were P. skrjabini. Furthermore, we found that the mean growth rate of the nematode larva increased as the horn fly instars develops. The results suggested that P. skrjabini infected the horn flies at the larval instar stage, and that the nematode larvae developed simultaneously with the horn fly instars stages. Our findings provide useful information into the elucidation of P. skrjabini infection and life history by studying horn fly development.

The horn fly, Haematobia irritans (L.) (Diptera: Muscidae), is one of the most important pests of the beef cattle industry. Horn fly adults are blood feeders that remain in constant contact with cattle, providing management opportunities via insecticide-impregnated ear tags. Controlling horn flies in the United States is time consuming and costly, but failure to implement management can lead to weight loss and decreased weight gain of calves and yearlings. In the past decade, new chemical combinations have been impregnated into ear tags for pest management. The objectives of this project were to 1) evaluate the efficacy of ear tags against horn fly populations and 2) determine if reduced fly density results in economic return. During 2013, data were compiled by insecticide class; treated cows averaged fly reductions of 198 (s = 38.91; n = 3) for macrocyclic lactone treatments, 175 (s = 62.74; n = 4) for pyrethroid treatments, and 174 (s = 35.28; n = 8) for organophosphate treatments compared with untreated animals (214; s = 50.38; n = 9). During 2014, mean fly reductions were 187 (s = 14.15; n = 4) for macrocyclic lactone, 147 (s = 61.41; n = 13) for pyrethroid, and 143 (s = 77.16; n = 8) for organophosphate treatments relative to the untreated (200; s = 99.83; n = 14). A novel technology, the VetGun application system, tested in 2014, resulted in fly reductions (121 ±, n = 4), but means were not statistically significant from the control (200; s = 99.83; n = 14). Treatment of cattle with ear tags significantly reduced horn fly numbers compared with untreated cattle.

The horn fly, Haematobia irritans (L.), is a blood-sucking ectoparasite that is responsible for sizeable economic losses in livestock. The salivary gland products facilitate blood intake. Taking advantage of the identification of novel H. irritans salivary antigens (Hematobin, HTB and Irritans 5, IT5), we investigated the parasite loads, H. irritans blood intake, and antibody response of naturally infected bovines during the fly season. Fly loads and fly hemoglobin content fluctuated during the trial. Each time horn fly loads exceeded 200 flies per cattle, a reduction in horn fly blood intake was observed three weeks later. All of the cattle elicited an antibody response against HTB and IT5 that declined once the fly season was over. Cattle anti-IT5 titers were positively correlated with parasite loads and negatively correlated with fly blood intake. These results suggest that the natural changes in the H. irritans blood intake observed in this study were associated with a natural host response against horn fly salivary antigens.

Horn flies [Haematobia irritans (Diptera: Muscidae) (L.)] and face flies [Musca autumnalis (Diptera: Muscidae) De Geer] use the same larval resource, but their interactions are poorly studied. Dung pats (n = 350) were core sampled in the summers of 2012 and 2013 from irrigated pastures in Pomona, California, U.S.A. (34°03'N, 117°48'W) and held for face fly and horn fly emergence. Surface areas and estimated weights were recorded for each whole pat. Almost half (42.0%) of the pat cores yielded neither fly, 29.7% yielded horn flies only, 12.9% yielded face flies only and 15.4% yielded both flies. Of the fly-positive pats, surface area and mass were larger for face fly-occupied pats, whereas horn fly-occupied pats were smaller. Pats shared by the two species were intermediate. Horn flies per positive core were unaffected by the absence/presence of face flies, but half as many face flies emerged when pats were co-inhabited by horn flies. Face flies inhabited larger pats, which might better resist heating and drying, to which they are susceptible; horn flies inhabited a broad pat size range. Horn fly tolerance of lower dung moisture probably allows horn flies to colonize and survive in a wide range of pats in dry areas like southern California.

Horn flies, Haematobia irritans (L.), were photographed on cattle and then immediately estimated visually in the field on pastured beef cattle in southern California. Horn flies were counted in the pictures later on a computer screen. For 479 counts on individual cattle, the concordance correlation coefficient between the visual and photo-based assessments was 0.790, but was better for the higher half of the counts (0.732) than for the lower half of the counts (0.217). Major axis regression indicated that visual estimates were consistently higher than the number of flies counted in the pictures across the entire density range. Based on average raw means, the visual estimates averaged 21% higher than the photo counts. Visual estimates included flies on the belly and lower legs that could not be seen in a photo, and lower densities may have been more susceptible to such error. Where flies can be seen well, e.g. for very tame animals, the visual estimates were much faster and more cost-efficient and were sufficient to track relative horn fly abundance changes.

En el municipio de Saboyá, Boyacá, Colombia, se evaluó el número de moscas Haematobia irritans, temperatura de capa, frecuencia respiratoria, actividad motora, distancia de fuga, suciedad y presencia de mastitis subclínica, como indicadores de bienestar animal en vacas Holstein presentes en un sistema silvopastoril (asociación de Cenchrus clandestinus y Alnus acuminata) y en un sistema tradicional basado en el pastoreo de C. clandestinus en monocultivo. Se realizaron 10 muestreos mensuales entre agosto de 2015 y mayo de 2016 en 20-30 vacas en lactancia, seleccionadas al azar, por finca. Los datos se analizaron usando modelos de regresión lineal generalizado. El número de moscas por animal fue mayor (p

The horn fly (Haematobia irritans) is particularly unique among the parasites that primarily affect Brazilian cattle farming. Appropriate control strategies fundamentally depend on epidemiological knowledge, which is particularly scarce in Northeastern Brazil. This study aimed to elucidate the ecology of the immature horn fly in the semiarid region of Brazil. Bovine fecal masses were collected and covered with emergence traps to collect the horn fly for sexing and counting. Weather records of the region were concurrently acquired. A total of 11,390H. irritans were collected from 601 fecal masses, with a sex ratio of 0.9:1 (male: female). Horn fly emergence was observed in 78% (15%–100%) of the fecal masses, varying from 1 to 185 (mean = 23.3) flies/fecal mass, predominantly at the beginning of the rainy season. The minimum period for egg-to-adult development of H. irritans varied from 7 to 11 days, indicating the occurrence of 30 generations per year in the region. Rapid development of the immature horn fly in the semiarid region, throughout the year may results in a high number of generations and infestations in cattle herds.

We evaluated the effects of four different 6-year duration control strategies on the resistance levels and frequency of the pyrethroid target site resistance alleles, superkdr (skdr) and kdr, at four field populations of Haematobia irritans irritans (Linnaeus, 1758) (Diptera: Muscidae) in Louisiana, USA. Consecutive use of pyrethroid ear tags for 6 years caused a significant increase in the resistance ratio to pyrethroids as well as the frequencies of both skdr and kdr resistance alleles. After 3 years of consecutive use of pyrethroid ear tags, followed by 1 year with no treatment, and followed by 2 years with organophosphate ear tags, the resistance ratio for pyrethroid was not significantly affected, the %R-skdr significantly dropped while the %R-kdr allele remained relatively high and stable. Similar results were observed when pyrethroid ear tags were used for three consecutive years, followed by 1 year with no treatment, and followed by 2 years with endosulfan ear tags; however, this treatment resulted in a slight increase in the resistance ratio for pyrethroids. In a mosaic, the resistance ratio for pyrethroids showed a 2.5-fold increase but the skdr-kdr genetic profiles did not change, as the %R alleles (skdr and kdr) remained low and stable through the 6 years. Lack of exposure to pyrethroid insecticides for 3 years significantly affected the skdr mutation but not the kdr mutation, preventing re-establishment of susceptibility to pyrethroids. SS-SR (skdr-kdr) individuals were responsible for the maintenance of the kdr mutation in two of the populations studied, and fitness cost seems to strongly affect the SR-RR genotype. None of the four treatment regimens evaluated in the study had satisfactory results for the management of kdr resistance alleles.

Haematobia irritans (Linnaeus, 1758) Material: Aragatsotn: Riv&iecy;r A&rcy;n&acy;g&iecy;t &acy;t A&rcy;n&acy;gyugh Vill&acy;g&iecy;, N 40° 26 &IEcy;44 ° 23, 1810 m, 12.vi.2005, 1&female;. Armenian distribution: Ar&acy;g&acy;ts&ocy;tn &rcy;r&ocy;vin&scy;&iecy;. N&iecy;w f&ocy;r Arm&iecy;ni&acy;. General distribution: Thr&ocy;ugh&ocy;ut th&iecy; P&acy;l&acy;&iecy;&acy;r&scy;ti&scy; r&iecy;gi&ocy;n; intr&ocy;du&scy;&iecy;d int&ocy; th&iecy; N&iecy;w W&ocy;rld &acy;nd fr&ocy;m th&iecy;r&iecy; t&ocy; H&acy;w&acy;ii; &acy;ls&ocy; kn&ocy;wn fr&ocy;m Az&iecy;rb&acy;ij&acy;n, Turk&iecy;y &acy;nd Ir&acy;n. Kn&ocy;wn &acy;s th&iecy; H&ocy;rn Fly, this s&rcy;&iecy;&scy;i&iecy;s is &acy; s&iecy;ri&ocy;us &rcy;&iecy;st &ocy;f &scy;&acy;ttl&iecy;., Published as part of Pont, Adrian C., 2018, The Muscidae (Diptera) of Armenia, pp. 1-69 in Zootaxa 4465 (1) on page 29, DOI: 10.11646/zootaxa.4465.1.1, http://zenodo.org/record/1442006, {"references":["Linnaeus, C. (1758) Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum caracteribus, differentiis, synonymis, locis. 10 th Edition. Voume. 1. Salvii, Holmiae [= Stockholm], 824 pp."]}

Stable flies, Stomoxys calcitrans, are serious pests of livestock, humans, companion animals and wildlife worldwide. During the last 20+ years, changes in agronomic practices resulted in serious outbreaks of stable flies in several countries. These outbreaks disrupted livestock production and human recreation resulting in public demands for increasing research and management efforts for this pest. A simple and inexpensive procedure for rearing stable flies for laboratory studies is presented. The procedure uses locally available diet components, equipment and supplies. The procedure can be adapted for rearing other muscoid flies including face fly (Musca autumnalis), horn fly (Haematobia irritans), and house fly (Musca domestica). The procedure produces stable fly puparia averaging 12.5 mg and ~35% egg to adult survival. Approximately 3000 flies are produced in each pan.