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Despite the efforts of practical medicine and virology, influenza viruses remain the most important pathogens affecting human and animal health. Swine are exposed to infection with all types of influenza A, B, C, and D viruses. Influenza viruses have low pathogenicity for swine, but in the case of co-infection with other pathogens, the outcome can be much more serious, even fatal. Having a high zoonotic potential, swine play an important role in the ecology and spread of influenza to humans. In this study, we review the state of the scientific literature on the zoonotic spread of swine influenza A viruses among humans, their circulation in swine populations worldwide, reverse zoonosis from humans to swine, and their role in interspecies transmission. The analysis covers a long period to trace the ecology and evolutionary history of influenza A viruses in swine. The following databases were used to search the literature: Scopus, Web of Science, Google Scholar, and PubMed. In this review, 314 papers are considered: n = 107 from Asia, n = 93 from the U.S., n = 86 from Europe, n = 20 from Africa, and n = 8 from Australia. According to the date of publication, they are conditionally divided into three groups: contemporary, released from 2011 to the present (n = 121); 2000–2010 (n = 108); and 1919–1999 (n = 85). [ABSTRACT FROM AUTHOR]

Insect pest species are generally expected to become more destructive with climate change because of factors such as weakened host tree defences during droughts and increased voltinism under rising temperatures; however, responses will vary by species due to a variety of factors, including altered interactions with their natural enemies. Entomopathogens are a substantial source of mortality in insects, but the likelihood of epizootics can depend strongly on climatic conditions. Previous research indicates that rates of infection of the spongy moth (Lymantria dispar) by its host-specific fungal pathogen, Entomophaga maimaiga, increase with environmental moisture and decrease as temperatures rise. High temperatures may have direct and indirect (due to the associated drying) effects on the fungus, but the interactive effects between temperature and moisture level on larval infection are unclear. Here, we test the hypothesis that warmer, drier conditions will decrease rates of infection of spongy moth larvae by E. maimaiga. We evaluated the effects of precipitation and temperature on larval mortality caused by E. maimaiga with a manipulative field experiment, conducted in one of the northernmost and coldest parts of the spongy moth's non-native range in North America. We caged laboratory-reared spongy moth larvae in experimentally warmed open-air forest plots, exposing the larvae to soil inoculated with E. maimaiga resting spores during two consecutive trials. Caged larvae were exposed to three temperature treatments — ambient, 1.7 °C above ambient and 3.4 °C above ambient — and either supplemental precipitation (+173 mm per trial) or ambient precipitation. Opposite to our hypothesis, there was no significant effect of supplemental precipitation, nor an interaction between precipitation and temperature. There was, however, a significant positive effect of increasing temperature on the number of larvae infected. On average, in each respective trial, larval infection increased by 44% and 50% under the elevated temperature treatments compared to ambient temperature. Experimental warming may have increased infections because ambient temperatures at the field site were suboptimal for fungal germination. The results from this experiment suggest that, in colder portions of the spongy moth's invasive range, increasing temperatures due to climate change may enhance the ability of E. maimaiga to help control populations of the spongy moth. [ABSTRACT FROM AUTHOR]

Pandora neoaphidis is a common entomopathogenic fungus on Sitobion avenae, which is an important aphid pest on cereals in Europe. Pandora neoaphidis is known to cause epizootics (i.e. an unusually high prevalence of infected hosts) and the rapid collapse of aphid populations. We developed a weather-driven mechanistic model of the winter wheat-S. avenae-P. neoaphidis system to simulate the dynamics from spring to harvest. Aphid immigration was fixed at a rate that would lead to a pest outbreak, if not controlled by the fungus. We estimated the biocontrol efficacy by running pair-wise simulations, one with and one without the fungus. Uncertainty in model parameters and variation in weather was included, resulting in a range of simulation outcomes, and a global sensitivity analysis was performed. We identified two key understudied parameters that require more extensive experimental data collection to better assess the fungus biocontrol, namely the fungus transmission efficiency and the decay of cadaver, which defines the time window for possible disease transmission. The parameters with the largest influence on the improvement in yield were the weather, the lethal time of exposed aphids, the fungus transmission efficiency, and the humidity threshold for fungus development, while the fungus inoculum in the chosen range (between 10 and 70% of immigrant aphids carrying the fungus) was less influential. The model suggests that epizootics occurring early, around Zadoks growth stage (GS) 61, would lead to successful biocontrol, while later epizootics (GS 73) were a necessary but insufficient condition for success. These model predictions were based on the prevalence of cadavers only, not of exposed (i.e. infected but yet non-symptomatic) aphids, which in practice would be costly to monitor. The model suggests that practical Integrated Pest Management could thus benefit from including the cadavers prevalence in a monitoring program. We argue for further research to experimentally estimate these cadaver thresholds. [ABSTRACT FROM AUTHOR]

Background: The study highlights the significance of data availability in molecular genetic research, focusing on cattle nodular dermatitis virus. Limited data on Russian genetic variants hinders comprehensive virus characterization. Molecular genetic methods are crucial for accurate diagnosis, considering cross-reactions with poxviruses. Increased data availability is essential to improve diagnostics and biosafety in the region. Method: The researchers conducted a molecular genetic analysis of the gene sequences of the nodular dermatitis virus to assess the variability of the virus. The authors used the GenBank database to compare sequences and used the MEGA X program for phylogenetic analysis and sequence alignment. Results: The sequences of the nodular dermatitis virus closest to the Russian genetic variants have been determined. The volumes of available epizootiological and molecular genetic data were compared, and the circulation of the vaccine strain was confirmed. Conclusion: The article emphasizes the need to increase the availability of data on the genetic sequences of Russian samples to fully characterize the genetic diversity of the nodular dermatitis virus. Despite the limited data, the authors observed a tendency to increase genetic diversity. They recommend isolating and storing the virus in the cell culture to enhance genetic information. [ABSTRACT FROM AUTHOR]

The horn fly Haematobia irritans is a cosmopolitan hematophagous ectoparasite of great importance in livestock. In Mexico, H. irritans is distributed across the country, and is found during the whole year. The fluctuation of H. irritans population is related with climate conditions. Despite its wide distribution, the effects on animal health, and its negative impact on meat and milk production, little data exists on its infestation and epidemiology is limited. This paper is a review on the current situation of H. irritans in cattle in Mexico, its economic impact, control methods, perspectives, and research opportunities. [ABSTRACT FROM AUTHOR]

Tapeworms (Cestoda) represents a species rich (about 5000 species) group of flatworms (Neodermata) parasitizing all groups of vertebrates including humans, with about 1000 species parasitizing elasmobranchs and almost 500 occurring in teleosts as adults. They are common parasites of cultured fish, both as adults and larvae (metacestodes), but only few adult tapeworms are actually pathogenic for their fish hosts. In contrast, cestode larvae can be harmful for fish, especially plerocercoids migrating throughout their tissue and internal organs. Current knowledge of host–parasite relationships, including immune response of fish infected with tapeworms, is still insufficient to enable adequate control of cestodoses, and most data available were obtained several decades ago. Treatment of fish infected with adult tapeworms is effective, especially with praziquantel, whereas the treatment of metacestodes is problematic. Control measures include interruption of the complex life cycle and prevention of transport of uninspected fish to new region. [ABSTRACT FROM AUTHOR]

The corn leafhopper Dalbulus maidis is one of the most important pests of maize in Latin America. Here we report, for the first time, the natural occurrence of two fungal species infecting the adult stage of this pest. In 2020, insects killed by a pale bluish green fungus in irrigated maize fields located in Northeast Brazil were found attached to the abaxial surface of leaves. Using morphological characters and multigenic phylogeny, it was identified as Metarhizium brasiliense. In the beginning of 2021, the same pathogen was seen on adults in a maize field in the Central-Western region, alongside an entomophthoralean fungus during an epizootic. The latter pathogen was molecularly identified as a species in the genus Batkoa. The number of Batkoa -infected leafhoppers, displaying the typical swollen abdomen and extended wings, reached an average of 1.88 per maize leaf (86.42% of the sampled adults). The incidence of M. brasiliense was higher in plots in the Northeastern region (0.22 and 0.53 adult per leaf) when compared to the Central-Western region (0.04 adult per leaf). The report of D. maidis adults infected by M. brasiliense in agricultural settings located in different geographic regions and over 550 km apart indicates probable widespread occurrence of this pathogen in Brazil. Moreover, this opens the possibility of more applied biological control studies and, perhaps, the development of new tools to manage D. maidis populations. - The natural occurrence of fungal entomopathogens on Dalbulus maidis is reported - Two fungal species were found infecting D. maidis adults in two regions of Brazil - Pathogens were identified as Batkoa sp. and Metarhizium brasiliense - Coepizootic of Batkoa sp. and M. brasiliense was detected in one of the corn fields [ABSTRACT FROM AUTHOR]

Background and Aim: Tuberculosis is an infectious disease that affects humans and animals. This study aimed to review the influence of economic and organizational, veterinary, and sanitary measures on the epizootic situation of animal tuberculosis and the epidemiological situation of human tuberculosis in the Republic of Kazakhstan. Materials and Methods: The epizootic situation of cattle tuberculosis in Kazakhstan was studied based on the annual statistics of allergy testing of animals with tuberculosis by the Committee for Veterinary Control and Supervision of the Ministry of Agriculture of the Republic of Kazakhstan, according to the results of allergic, clinical, and pathological studies, including laboratory studies of biomaterials from animals that reacted to tuberculin. Tuberculinization of cattle in the country is performed twice in the spring and autumn using tuberculin purified protein derivative for mammals. In addition, mass diagnosis of human tuberculosis is conducted by radiology. Results: The authors assessed the epizootic situation of tuberculosis in cattle in Kazakhstan from 1991 to 2019. The analysis results showed that at the beginning, the epizootic situation in cattle tuberculosis was challenging. However, since 2001, there has been a noticeable decrease in tuberculosis in animals in Kazakhstan, which has had a favorable effect on the epidemic situation of human tuberculosis. Conclusion: According to the analysis results, the measures used in the Republic of Kazakhstan to prevent tuberculosis improved the well-being of livestock farms. The proper conduct by qualified veterinary specialists on allergy testing of animals and differential diagnosis of nonspecific tuberculin reactions allows establishing an accurate epizootic picture of tuberculosis. Furthermore, strict adherence to instructions on the diagnosis and prevention of tuberculosis, implementation of developed veterinary, sanitary, and organization, and economic measures can improve the epizootic picture of tuberculosis, reducing the risk of human tuberculosis. [ABSTRACT FROM AUTHOR]

The present study report on epizootiology, pathogenicity and haemato-immunological aspects of Streptococcus agalactiae (Group B Streptococcus, GBS) serotype Ib (GBS-Ib) affecting climbing perch (Anabas testudineus) in southern Thailand. Study on growth of GBS-Ib under various conditions indicated that this bacterium grew from 25 to 35°C, pH 5 to 9 and 0.5 to 4.0% NaCl. Climbing perch inoculated by intraperitoneally injected GBS-Ib at concentrations of 10¹ to 104 CFU/mL exhibited 60.00-96.67% mortality, with 60 h-LD50 and 72 h-LD50 at 4.5x10² CFU/mL and 6.3x10¹ CFU/mL inoculums, respectively. Study of the haemato-immunological changes in the fish infected with GBS-Ib revealed declines of haematocrit, haemoglobin, serum protein, red blood cells, and respiratory burst activity. On the other hand, white blood cells, lysozyme activity, phagocytic index, and average beads per cell, were significantly increased in the infected fish. Study on the effect of environmental factors on the susceptibility of fish to GBS-Ib infection indicated that high water temperature and low dissolved oxygen levels proved to increase mortality of climbing perch. These findings indicate that GBS-Ib is a pathogenic bacterium responsible for fish mortality in Thailand. [ABSTRACT FROM AUTHOR]

Background: Apprehensions about the safety and the environment regarding the insecticidal application against insect infestations have directed our attention toward advancement of biological mediators so that they are assimilated into the concept of integrated pest management stratagems to develop a more practical approach for the management of insect pests. Management of insect pests by making use of biological approaches (such as fungal entomopathogens (EPF) or others which are antagonistic to insect population) provides a substitute approach which reduces the continuous use of chemical amalgams against insect pests. Main body: The present review provides a framework of the present status of information on EPF as it identifies with their current use as biological control of pest infestations. To utilize a variety of biological control methodologies against insect hosts, it is essential to improve our comprehension of the ecology of EPF and also their role in nature. This article may assist us with understanding the virulence and the virulence factors related with EPF and present the latest developments and accomplishments in the significant field. We focus on recent instances of studies that show the overall patterns in interactions among insect pests and EPF prompting the advancement of epizootics. Also, we sum up the topical discoveries on current status of mycoinsecticides and propose future research needs. Conclusions: As the current mechanism of fungal pathogenesis on insects is moderately slow and needs improvement, there is likewise the requirement for additional comprehension of the interactions among entomopathogens and insect pests so as to grow soundly planned procedures by identifying potential targets and via the improvement of fungal strains for improving the adequacy of these organisms in field applications. [ABSTRACT FROM AUTHOR]

Coronaviruses have always been part of our biozoenosis. Different biological properties are part of their evolutionary strategies, such as the change of host systems, pathogenicity, organotropism, antigenicity and immunogenicity. In addition to humans and domesticated animals, a wide range of susceptible animal host systems exists. Coronaviruses have been divided into former group 1 and group 2 based on the different antigenic relationships. The new taxonomy now divides these viruses into the genera alpha-, beta- (man and animals) and gammacoronaviruses (poultry). The first isolation of typical coronavirus particles was found by electron microscopy in faecal samples from foals in Kentucky. They died or were killed in the acute stages of gastroenteritis, described by Bass and Sharpee (1974). Neutralizing antibodies against calf diarrhoea coronavirus were identified in equine sera. Durham et al. (1979) investigated foals in New Zealand with profuse watery diarrhoea and detected coronavirus in their faeces. They described a wide range of ages of the animals infected and serological cross-reaction with calf coronavirus More virus-positive cases of enteric foal disease were reported in the following years. Eugster and Jones (1988) reported on coronavirus in an aborted equine foetus and Ward et al. (1983) described the presence of coronavirus in foals with diarrhoea. Sato et al. (1981) demonstrated neutralizing antibodies to calf diarrhoea coronavirus also in horses in Japan. All these reports deal with cases of severe gastroenteritis and foal diarrhoea. The first coronavirus-associated diarrhoea in mature horses was documented by Huang et al. (1983). There were 113 clinical cases of an acute form of diarrhoea in Maryland, USA, in the summer of 1982. The isolated virus was not related to bovine coronavirus, swine transmissible gastroenteritis or avian infectious bronchitis based on fluorescent antibody tests. Coronavirus could be isolated not only from faeces but also from plasma samples of the sick horses. The classic virological diagnostic techniques have been now replaced by molecular tests using qPCR. Reports on disease associated with equine coronavirus (ECoV) infections mainly in mature horses in the U.S.A. have been based on qPCR positive faeces since about 1990. The description of the clinical signs, virus transmission and diagnosis of the ECoV disease could be summarized as follows. It is spread via oral investigation of qPCR positive faeces and faecal-oral transmission can also occur when horses make oral contact with surfaces or objects that have been contaminated with infected faeces. The disease is diagnosed most commonly in winter. Subclinically infected horses (11–93 %) can spread ECoV depending on their carrier status. This pertains to foals and adult horses. Incubation is two to four days and the clinical signs are fever up to 40.5 °C, anorexia, depression, sometimes colic, diarrhoea may or may not be present, and frequent lying down. Low white blood cell count (leucopenia, lymphopenia), hyperammonemia could be responsible, with signs of encephalopathic disease. The faecal virus load (ECoV genome equivalents per gram of faeces) might be of prognostic value in the horses affected. Prognosis is good in most cases. Exposure to the virus can result in up to 85 % infection rate, however, most horses do not show clinical signs. A horse with fever and no respiratory clinical signs may have ECoV in the faeces. Therefore, the qPCR of their faeces is recommended. Epidemiological studies of ECoV infections are still limited. The seroprevalence has been investigated by an indirect enzyme-linked immunosorbent assay (ELISA) utilizing ECoV spike S1 protein since 2017. Using this test, Zhao et al. (2019) demonstrated seroconversion by analysing 27 paired sera from horses involved in an ECoV outbreak. Seropositivity was carried by 25.9 % (young horses) to 82.8 % (adult horses) from 1084 sera from healthy Dutch horses. Sera of Icelandic horses reacted positive in 62 %. This ELISA demonstrated the surprisingly high percentage of seropositive European horses. Seroprevalence in 9.6 % of 5247 sera of healthy horses from different geographic regions of the U.S.A. was demonstrated by Kooijman et al. (2017). Summarizing the results available, ECoV could be demonstrated in high percentages in faecal material and nasal secretions (Pusterla et al., 2019) and plasma and blood (Huang et al. 1982, Goodrich et al. 2020) from healthy and/or diseased horses. Therefore, it seems to be questionable whether faecal-oral transmission is be the only infection chain. Further investigations are necessary. This is also part of the recommended methods of prevention. The latter are based on the following: high standards of sanitation in all equine facilities; disinfection methods; isolation of horses for three weeks, especially those with fever and no evidence of respiratory illness and horses moving to new facilities, especially in cases where they moved from a facility with ECoV; and positive faeces test are recommended. [ABSTRACT FROM AUTHOR]

Prevalence of Staphylococcus aureus mastitis in buffaloes was fundamentally aimed in the current work using culturing procedures and PCR Assay. Field therapeutic trial with follow-up for 10 consecutive weeks post therapy was carried out with monitoring of shedding pattern of Staphylococcus aureus. Three hundred and eighty buffaloes of different lactation seasons were examined in Sohag Governorate. Prevalence of clinically and subclinically infected buffaloes was 10.52% and 26.84%, respectively. Epizootiologically, prevalence of clinically and subclinically infected animals with mastitis in the 2nd, 3rd, and 4th lactation seasons was 12.00% and 32.00%; 20.83% and 41.67%; and 22.73% and 36.36%, respectively. Thereafter the trend of mastitis was significantly declined by increasing the numbers of lactation season. Over the 9th lactation season, there were no signs of mastitis. Bacteriologically, Staphylococcus aureus was the predominant pathogen followed by Streptococcus agalactiae and Escherichia coli. Staphylococcus aureus were sensitive to amoxicillin, enrofloxacin and ciprofloxacin but 50 % of the tested strains were resistant to penicillin and oxytetracycline. A Field therapeutic trial with synulox (Amoxicillin plus Clavulanic acid) with anti-inflammatory and supportive drugs was carried out in 10 diseased buffaloes (3 clinical and 7 subclinical). Three clinical and three subclinical forms were culled due to failure of therapy. Four cases of subclinical mastitis were apparently successfully treated. Shedding pattern of Staphylococcus aureus during the therapeutic period was weekly monitored and revealed that shedding was intermittent. In conclusion, Staphylococcus aureus is an outstanding notoriousness mastitogen and its early detection considers a crucial goal in control. PCR is a valuable test for detection of mastitogens than culture techniques but it is still precious practically. [ABSTRACT FROM AUTHOR]

Beauveria bassiana (Bb) strain GHA is a major component of an areawide pest management program for coffee berry borer (CBB) in Hawai’i. Recent studies have aimed to provide comprehensive assessments of the efficacy of the Bb-spray component of these programs for economic analyses; however, evaluations have been complicated by activity of naturally-occurring strains of this pathogen infecting CBB. Investigations were therefore undertaken to characterize these strains, assess their natural epizootic potential, and account for their contribution to CBB population suppression. A number of field sites were encountered with no history of significant use of commercial Bb-based biopesticides and where strain GHA was not detectable. Sampling of these sites was conducted early in the coffee season. Greatest activity of wild-type Bb strains was observed on high-elevation farms (>500 m), where 24–42% of foundress beetles in green coffee berries were infected. In contrast, infection rates did not exceed 4% on farms at low elevations (<300 m). Rates of 23–29% infection, comparable to those on high-elevation farms, were recorded in a stand of feral coffee at 293 m elevation, but the coffee was completely shaded and ventilation restricted by a dense overstory of vegetation. Despite high activity of naturally-occurring Bb at some sites (primarily sites at high elevations with humid, moderate-temperature environments and dense pest populations), these fungi did not prevent CBB from exceeding the economic threshold for commercial spray applications. Nevertheless, the high natural epizootic potential of these fungal strains suggests strong potential for development as microbial biocontrol agents. [ABSTRACT FROM AUTHOR]

A multi-year study was conducted to examine the natural ecology of the microsporidium Amblyospora khaliulini and more fully characterize parasite development and histopathology in all stages of its primary mosquito host, Aedes communis and intermediate copepod host, Acanthocyclops vernalis with redescription of the species. A. khaliulini exhibits polymorphic development, produces three morphologically and functionally distinct spores, and is both horizontally and vertically transmitted. Development in A. vernalis is restricted to females, occurs within the ovaries and results in death of the host. Development is haplophasic with division by binary and multiple fission producing rosette-shaped sporogonial plasmodia and conical uninucleate spores that are orally infectious to Ae. communis larvae. Both sexes are equally susceptible and infections are confined to testes in males and ovaries in females. Initial stages of development include uninucleate schizonts that undergo karyokinesis forming diplokaryotic meronts that divide repeatedly by binary fission. Sporogony occurs in both host sexes, but sporogenesis does not progress normally in adult males and elliptical, thin walled binucleate spores that function in vertical transmission of the microsporidium via infection of the ovaries and eggs are formed in adult females only. Development of vertically acquired infections in larval Ae. communis hosts occurs within fat body tissue, leads to the production of meiospores in male hosts only and results in death during the 4th larval stadium. Initial development is characterized by merogonial multiplication of diplokarya by synchronous binary division producing additional diplokarya. The cessation of merogony and the onset of sporogony are characterized by the simultaneous secretion of a sporophorous vesicle and meiotic division of diplokarya resulting in the formation of octonucleate sporonts that undergo cytokinesis and sporogenesis to form eight uninucleate, broadly ovoid meiospores enclosed within a sporophorous vesicle. The natural prevalence of patent vertically acquired fat body infections in field populations of Ae. communis ranged from 1.6% to 3.6%. Yearly infection rates in A. vernalis copepods ranged from 57.1% to 15.0%. Prevalence rates of horizontally acquired infections in emerging adult Ae. communis ranged from 69.0% to 11.9% in males and 50.0% to 16.4% in females. [ABSTRACT FROM AUTHOR]

Aims We report the first occurrence of an epizootic of the ascomycete fungus, Isaria tenuipes (teleomorph Cordyceps takaomontana), on the ocola skipper Panoquina ocola (Lepidoptera: Hesperiidae), an insect pest affecting rice in Brazil. Methods and Results Field surveys in flooded rice fields in the state of Goiás in Brazil were conducted, and a fungal pathogen of a caterpillar pest ( P. ocola) was serendipitously found. This fungus inflicted high infection levels (average 86·2%) mainly to the pupal stage during warm, humid growing conditions. Typically, mycosed pupal cadavers produced milky-white to pale yellow synnemata bearing an average of 1·1 ± 0·2 × 109 conidia per cadaver. Based on phylogenetic analysis using beta-tubulin gene sequences, we confirmed that all 12 isolates obtained from field-mummified pupae were identifiable as I. tenuipes. Conclusions Our data expand our knowledge on the host and geographical ranges of this mycopathogen and underscore its epizootic potential to affect a lepidopterous insect pest on rice in Brazil. This finding may facilitate the exploitation of this fungus as a mycoinsecticide. Significance and Impact of the Study Isaria tenuipes may be used as an effective and environmentally friendly bioinsecticide against agricultural caterpillar pests due to its epizootic potential, as well as explored for medicinal purposes by pharmaceutical industry. [ABSTRACT FROM AUTHOR]

Gill disease (GD) in farmed Atlantic salmon may be due to the impact of several agents that may interact. We followed the infections of four gill disease-associated agents during the first year of production in six farms; examining the correlation between their densities in the gills. These farms were located in an area with high risk of developing gill disease, and three of the farms were diagnosed with GD in the autumn. In the present study we show temporal changes in pathogens in salmon from all 6 farms, revealing recurring infection patterns by Desmozoon lepeophtherii and Candidatus Branchiomonas cysticola (C. B. cysticola), and large variation without an apparent pattern in densities of Ichthyobodo salmonis . Infections with the microsporidian D. lepeophtherii show a clear seasonal pattern, and high densities are associated with GD. Ca. B. cysticola appears not to be directly connected to the disease, albeit densities of this bacterium may coincide with high D. lepeophtherii densities. Amoebae ( Paramoeba spp.) were only sporadically detected with low densities. Salmon with low condition had elevated densities of D. lepeophtherii and Ichthyobodo spp., while no such pattern was seen for the other pathogens. Challenge studies are needed to substantiate the role of D. lepeophtherii in GD, but realistic challenge model (i.e. bath) has so far not been developed. Based on the present molecular screening, we suggest that D. lepeophtherii infections both may be responsible for GD, and cause runting in farmed salmon populations. Statement of relevance This is an epizootiological study of Atlantic salmon and gill diseases. There is much known about pathogen in connection with GD outbreak, less is known about the occurrence of potential pathogen in healthy farmed salmon or how such infections develop over time. High densities of the microsporidian parasite Paranucleospora theridion in the gills coincide with gill disease, making P. theridion a possible primary source to this condition. Densities of Paranucleospora theridion , Candidatus Branchiomonas cysticola and Ichthyobodo salmonis may be correlated in farmed salmon populations with gill disease. P.theridion and I. salmonis densities are elevated in Atlantic salmon with low condition (‘runts’). [ABSTRACT FROM AUTHOR]

[Display omitted] • Parathelohania iranica is an enzootic and seasonal infection in its mosquito host. • Patent infections appear with one month delay in the population of host larvae. • Concealed infections are more common in late mosquito season. • It seems that vertical transmission spreads infections in early mosquito season. • By contrast, more efficient horizontal route predominates in late mosquito season. Parathelohania is a genus of microsporidia that preferentially attacks Anopheline mosquitoes. This study explored some selective aspects of the epizootiology of Parathelohania iranica (Microsporidia: Amblyosporidae) in its malaria mosquito host Anopheles superpictus s.l. (Diptera: Culicidae). For this study, Sar-rok Village, a place adjacent to the type locality of the parasite, located at the central western part of Iran was visited twice a month to collect host larvae from mid-summer to mid-autumn of 2017–2021. Patent infections were detected by the whitish discoloration of the involved segments. Superficially uninfected larvae were reared up to 26 days in the insectary to elucidate hidden infections. Molecular investigation and laboratory trials were conducted to evaluate the possibility of secondary infections in subsequent days. Morphological characters were used to determine the sex of larvae and adults. Data were entered in SPSS 23.0 and analyzed with relevant statistical tests as needed. In total, 584 P. iranica infected larvae of An. superpictus s.l. were collected in the study years at day zero (D0). Extended observations in the insectary revealed that 849 larvae (84.2 %), 22 dead pupae (2.2 %), and 137 emerged adults (13.6 %) were also infected. In the first two years of the study, the mean infection rate for D0 and D0 + D1-D26 infections was 6.25 % and 15.6 %, respectively. Exposure experiments indicated that subsequent infections in larvae (D1-D26) were not affected by a possible source in the accompanying field water. Patent (D0) infections were seasonal and had about a month delay compared to the general population of larvae. Concealed infections of larvae (D1-D26) were significantly more frequent in late mosquito season (P < 0.01). It is proposed that the gradual decrease of ambient temperature and the shortening of day length postpones the growth and development of P. iranica in the affected larvae. Both sexes of larvae were involved and none of them survived beyond a couple of days. The frequency of infections in adult males (5.8 %) were significantly more than females (4 %) (P = 0.02). The infections of larvae were more common in the late mosquito season, and the infections of adults were more frequent in the early mosquito season. This suggests the relative importance of vertical and horizontal routes of transmission in early and late mosquito seasons, respectively. However, age-specific data revealed that only 26 % of hidden infections of larvae (D1-D26) were stemmed from I to II age group. This implies that the vertical route may be less efficient than the horizontal route in the transmission of P. iranica to the mosquito host. These inferences should be verified with further field and laboratory investigations. [ABSTRACT FROM AUTHOR]

Natural enemies and environmental factors likely both influence the population cycles of many forest-defoliating insect species. Previous work suggests precipitation influences the spatiotemporal patterns of gypsy moth outbreaks in North America, and it has been hypothesized that precipitation could act indirectly through effects on pathogens. We investigated the potential role of climatic and environmental factors in driving pathogen epizootics and parasitism at 57 sites over an area of ≈72,300 km in four US mid-Atlantic states during the final year (2009) of a gypsy moth outbreak. Prior work has largely reported that the Lymantria dispar nucleopolyhedrovirus ( LdNPV) was the principal mortality agent responsible for regional collapses of gypsy moth outbreaks. However, in the gypsy moth outbreak-prone US mid-Atlantic region, the fungal pathogen Entomophaga maimaiga has replaced the virus as the dominant source of mortality in dense host populations. The severity of the gypsy moth population crash, measured as the decline in egg mass densities from 2009 to 2010, tended to increase with the prevalence of E. maimaiga and larval parasitoids, but not LdNPV. A significantly negative spatial association was detected between rates of fungal mortality and parasitism, potentially indicating displacement of parasitoids by E. maimaiga. Fungal, viral, and parasitoid mortality agents differed in their associations with local abiotic and biotic conditions, but precipitation significantly influenced both fungal and viral prevalence. This study provides the first spatially robust evidence of the dominance of E. maimaiga during the collapse of a gypsy moth outbreak and highlights the important role played by microclimatic conditions. [ABSTRACT FROM AUTHOR]

Abstract: Rabbit hemorrhagic disease outbreaks in young rabbits have been recently observed in Spain. In this study we have tracked the spread of variant RHDV in samples collected from rabbit farms over a period of more than one year using RT-PCR and antigen-capture ELISA. The isolates were sequenced and compared to classic and variant RHDV strains and phylogenetic analyses were conducted. Mortalities have been observed in kits as young as 11 days. More than 50% of the dead rabbits had been previously vaccinated against RHDV using commercially available inactivated vaccines indicating a putative lack of protection against the variant RHDV. The large majority of the studied outbreaks (94.5%) in Spanish farms during 2012 were due to variant RHDV and only 3 out of the 55 farms were affected by classic RHDV. The data demonstrates that the variant RHDV has spread through a large number of Spanish provinces in a relatively short period of time, largely replacing the previously predominant G1 RHDV genotypes. Considering the lack of efficient vaccines against the variant RHDV strains strict disease control and greater vigilance measures should be put in place. [Copyright &y& Elsevier]

The direct and interactive effects of climate change on host species and infectious disease dynamics are likely to initially manifest\ at latitudinal extremes. As such, Alaska represents a region in the United States for introspection on climate change and disease. Rabies is enzootic among arctic foxes ( Vulpes lagopus) throughout the northern polar region. In Alaska, arctic and red foxes (Vulpes vulpes) are reservoirs for rabies, with most domestic animal and wildlife cases reported from northern and western coastal Alaska. Based on passive surveillance, a pronounced seasonal trend in rabid foxes occurs in Alaska, with a peak in winter and spring. This study describes climatic factors that may be associated with reported cyclic rabies occurrence. Based upon probabilistic modelling, a stronger seasonal effect in reported fox rabies cases appears at higher latitudes in Alaska, and rabies in arctic foxes appear disproportionately affected by climatic factors in comparison with red foxes. As temperatures continue a warming trend, a decrease in reported rabid arctic foxes may be expected. The overall epidemiology of rabies in Alaska is likely to shift to increased viral transmission among red foxes as the primary reservoir in the region. Information on fox and lemming demographics, in addition to enhanced rabies surveillance among foxes at finer geographic scales, will be critical to develop more comprehensive models for rabies virus transmission in the region. [ABSTRACT FROM AUTHOR]

This study confirmed that some glues used for trapping insects may inhibit mycosis; therefore, care should be taken to select "mycosis-friendly" glues when selecting sticky traps for monitoring entomopathogen infection levels in target pest populations. The results also showed that, rather than attempting to extract small, delicate insects from the glue for further incubation, the entire sticky trap simply can be incubated for the purpose of evaluating mycosis levels. [ABSTRACT FROM AUTHOR]

The multifactorial characterization of the backyard poultry production systems was conducted in the eight municipalities of Cienfuegos province. One hundred seventy five rearing backyards randomly selected were used, for a reliability of 95 %, proportionally distributed in each municipality. In a transversal observational design with surveys, 17 social, 32 husbandry and 27 epizootiolocal variables were identified. The people inquired are described with an average age of 45 years, male sex predominating (62.90 %) and finished high education (66.9 %). Four husbandry components and five epizootiological ones characterizing the backyard poultry production in Cienfuegos province were identified, with variance explained from 72.90 and 67.22 %, respectively. The components of higher variability for the husbandry and epizootiological were: elements of the productivity, feeding oportunities, bioprotection and ectoparasitosis that explained 50.6 and 40.5% of the total variances. The indicators created: husbandry and epizootiological capacity showed low performance, without differences between the municipalities. Considering the methodology used and the results for strategies in the development of alternative of backyard poultry activity is recommended. [ABSTRACT FROM AUTHOR]

The multifactorial characterization of the backyard poultry production systems was conducted in the eight municipalities of Cienfuegos province. One hundred seventy five rearing backyards randomly selected were used, for a reliability of 95 %, proportionally distributed in each municipality. In a transversal observational design with surveys, 17 social, 32 husbandry and 27 epizootiolocal variables were identified. The people inquired are described with an average age of 45 years, male sex predominating (62.90 %) and inished high education (66.9 %). Four husbandry components and five epizootiological ones characterizing the backyard poultry production in Cienfuegos province were identified, with variance explained from 72.90 and 67.22 %, respectively. The components of higher variability for the husbandry and epizootiological were: elements of the productivity, feeding opportunities, bioprotection and ectoparasitosis that explained 50.6 and 40.5% of the total variances. The indicators created: husbandry and epizootiological capacity showed low performance, without differences between the municipalities. Considering the methodology used and the results for strategies in the development of alternative of backyard poultry activity is recommended. [ABSTRACT FROM AUTHOR]

Summary: This paper describes a study on Brucella ovis infection of sheep flocks in southern Serbia. Using serological testing, positive reactions were confirmed in 67 (29.8%) and suspicion in 31 (13.8%) out of the total 225 tested sheep sera samples. Rams originated from 113 flocks with 4751 sheep from 28 settlements in the Pirot region of southern Serbia. Pathological changes indicative of Brucella ovis infection were confirmed by macroscopic examination in the testes of 7 (58.3%) out of 12 examined rams. In 7 (58.7%) animals, unilateral epididymitis with pronounced hypertrophy of the tail, body and head of epididymis was confirmed. Using bacteriological and molecular techniques, the presence of B. ovis was confirmed in the samples (testes, epididymis, lymph nodes) in 11 (91.7%) out of 12 rams. The clinical manifestation of ovine epididymitis arose following the procurement of rams and mating season. The disease was more pronounced in flocks in which it occurred for the first time. On the basis of the results presented here, it can be concluded that B. ovis infection causes substantial economic losses in sheep production, and is manifested in reduced conception (24.85%), miscarriages (5.38%), reduced number of lambs (0.74 lambs per ewe) and increased perinatal mortality (7.78%). [ABSTRACT FROM AUTHOR]

Abstract: From a historical perspective, several protistan taxa, including the recently re-aligned Microsporidia, have been associated with or identified as causes of mortalities in crustacean populations. Depending upon the host species, associated protistan prevalences could be as low as 5% or approach 100%. It has generally been assumed that reported prevalences translated directly into significant mortalities that could impact the distribution and abundance of affected populations. However, this assumption may be incorrect especially when the dynamics of host–pathogen–environment interactions are not entirely understood. We will discuss the presumed impact of several protistan pathogens on temperate and cold water commercial crab species. By using selected examples such as a ciliate in the Dungeness crab (Cancer magister) and Hematodinium sp. infections in North Pacific crabs, we will attempt to contrast differences between prevalence and mortality, acute and chronic infections/mortalities, age or size selectivity of affected population, and geographically restricted and widespread epizootics. We will also briefly discuss the potential impact of environmental changes such as climate change and ocean acidification on both host and protistan pathogen. [Copyright &y& Elsevier]

Epizootiology is the study of variable factors, events, forces and circumstances that contribute to the occurrence, distribution, control and prevention of ill-health, diseases and other problems in animal groups. It is a key component of veterinary medicine education at the University of Ibadan, Nigeria since 1975. It started as a Graduate Certificate in Epizootiology (GCE) in 1976. Later it was revised into M.Sc. Epizootiology in 1986. At graduate level, epizootiology curriculum has supported the M.Sc. Epizootiology programme. It compliments training in Veterinary Public Health and Preventive Medicine. This epizootiology curriculum has been operational at graduate level for more than three decades. Now in 2011, a consortium of English speaking West African Universities is committed to review the current curriculum at the University of Ibadan to strengthen health systems in an interdependent world with scope for internationalized practicum in disease investigation. Emphases are made towards skills development in molecular studies on disease causal agents and the mapping of associated geographic risk factors, including indigenous knowledge and practices. It is notable that most English-speaking West African countries including Ghana, Liberia, Sierra Leone and Gambia either lack a Veterinary School or just started some, but do not have graduate programme in Epizootiology. Thus, the curriculum at Ibadan is positioned to make impact in three key areas, namely, sub-regional ecosystem health studies, improving human-animal disease surveillance programmes, and in indigenization of bio-technology for monitoring and evaluation of trans-boundary animal disease control interventions for global health in West Africa. [ABSTRACT FROM AUTHOR]

Abstract: We investigated the population dynamics of Strelkovimermis spiculatus in Ochlerotatus albifasciatus to determine the abiotic and biotic parameters involved in this host-parasite system. Weekly samplings performed from May 2007 through May 2010 in three ponds located in open areas of La Plata, Argentina revealed that parasitism by S. spiculatus in O. albifasciatus occurred throughout all seasons with differences in effectiveness among breeding habitats: A mosquito-larva reduction of 80.7% was observed in a habitat where 100% of the generations were infected by nematodes; an intermediate situation (a 41.9% reduction) involved a lower percentage of parasitism above 50% although nematode infection was likewise registered in 92.9% of the generations. Finally, a mosquito-larva reduction of 2.68% was recorded where only 46.0% of the generations were parasitized and at levels of nematode infection below 50%. We analyzed the effects of abiotic and biotic parameters on S. spiculatus infections. The flooded-surface area was the only variable significantly associated with percent infection. Infection prevalence correlated positively with the mean number of emerged nematodes per larva and with the S. spiculatus male-to-female ratio in each parasitized-mosquito generation. In conclusion, the frequency over time and levels of infection are key parameters in the regulation of mosquito populations by this mermithid. [Copyright &y& Elsevier]

Abstract: Microsporidia are believed to play little or no role in outbreaks of the jack pine budworm, Choristoneura pinus pinus Freeman (Lepidoptrera: Tortricidae), because the short duration (2–4years) of those outbreaks may not permit significant build-up of the pathogen. We conducted the first survey of Nosema sp. (Microsporidia: Nosematidae) over the course of a recent jack pine budworm outbreak in Ontario. Between 2004 and 2010 the outbreak defoliated a cumulative total of 1.78 million ha. Microscopic examination of ∼15,000 overwintering larvae collected over 6years in sites with densities of 3 larvae per branch or more revealed widespread occurrence of Nosema at generally high infection intensities. The pathogen was present in 69.5% of the 518 plots that were monitored. Prevalence of infection was generally low (below 40% in 84% of plots with infected larvae) but reached high levels (80–95%) locally and increased rapidly in most infestations within 1–2years of onset. We hypothesize that the habit of early-instar larvae to feed on developing male flowers (pollen cones) after spring emergence is critical in allowing rapid build-up of Nosema by increasing efficiency of horizontal transmission (higher density of both infected larvae and egested spores). Nosema infection may contribute to the complexity of jack pine budworm outbreak patterns by affecting egg recruitment and early-instar survival at the stand level in concert with known effects of budworm-induced reductions in pollen cone production on those processes. [Copyright &y& Elsevier]

Horizontal transmission of entomopathogenic fungi plays an important role in the epizootiology, because it is directly associated with the spread of causal agents of insect diseases. In hosts with restricted mobility, the presence of secondary pests in the agroecosystem can help in the formation of secondary disease outbreaks and increase the mortality of the target pest. For this purpose, the dissemination of Beauveria bassiana inoculated using tile-type baits was evaluated in a banana plantation infested with Cosmopolites sordidus (Piracicaba) and one with C. sordidus and Metamasius hemipterus (Botucatu). In Piracicaba, insects contaminated with the pathogen were not found in the control group, and infection rates in the plots that received B. bassiana ranged between 8 and 15%. In Botucatu, the infection rate of insects in the control reached 17%, whereas in the fungal treatment plots, it varied from 28 to 54%. The present results demonstrate the influence of M. hemipterus in the dissemination of B. bassiana in populations of C. sordidus, a target pest of this crop. [ABSTRACT FROM AUTHOR]

Coral diseases have increased in frequency over the past few decades and have important influences on the structure and composition of coral reef communities. However, there is limited information on the etiologies of many coral diseases, and pathways through which coral diseases are acquired and transmitted are still in question. Furthermore, it is difficult to assess the impacts of disease on coral populations because outbreaks often co-occur with temperature-induced bleaching and anthropogenic stressors. We developed spatially explicit population models of coral disease and bleaching dynamics to quantify the impact of six common diseases on Florida Keys corals, including aspergillosis, dark spots, white band, white plague, white patch, and Caribbean yellow band. Models were fit to an 8-year data set of coral abundance, disease prevalence, and bleaching prevalence. Model selection was used to assess alternative pathways for disease transmission, and the influence of environmental stressors, including sea temperature and human population density, on disease prevalence and coral mortality. Classic disease transmission from contagious to susceptible colonies provided the best-fit model only for aspergillosis. For other diseases, external disease forcing, such as through a vector or directly from pathogens in the environment, provided the best fit to observed data. Estimates of disease reproductive ratio values (R 0) were less than one for each disease, indicating coral colonies were below densities required for diseases to become established through contagious spread alone. Incidences of white band and white patch disease were associated with greater susceptibility or slower recovery of bleached colonies, and no disease outbreaks were associated with periods of elevated sea temperatures alone. Projections of best-fit models indicated that, at least during the period of this study, disease and bleaching did not have substantial impacts on populations and impaired rates of population growth appeared to be attributable to other stressors. By applying epidemiological models to field data, our study gives qualitative insights into the dynamics of coral diseases, relative stressor impacts, and directions for future research. [Copyright &y& Elsevier]

The objective of this study was to determine the prevalence of gastrointestinal parasitic nematodes in sheep at necropsy at a slaughterhouse in Tabasco, Mexico. Adult parasites from gastrointestinal tract were recovered and preserved in formaldehyde for their later counting and identification. Adult nematodes were separated by species and the final count was transformed to Log + 1 to decrease the variance. GLM procedure using SAS statistic program was performed for data analysis. Provenance, sex, physiological status, and sampling month were considered as the variation sources. From a total sample of 242 slaughtered animals necropsied for monitoring gastrointestinal parasites, 57.4% including Nematoda, Trematoda or Cestoda classes. The main identified species corresponded to Haemonchus contortus in the abomasum. Cooperia curticei, Trichostongylus colubriformis, Strongyloides papillosus and Bunostomum trigonocephalum were found in the small intestine and Oesophagostomum columbianum, and Trichuris ovis in the large intestine. Fasciola hepatica and Moniezia expansa were the Trematoda and Cestoda parasites found in liver and small intestine, respectively with prevalence lower than 7%. The average of the total count of adult nematodes in the gastrointestinal tract of the infested animals was 2175 ± 445. Among the factors studied, the slaughter month and the provenance of the animals affected the prevalence of parasite infestation in sheep at slaughter. The main adult parasites found were H. contortus, C. curticei and T. colubriformis with average counts higher than 1009, 813 and 335, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Protists are a diverse group of eukaryotes that possess a unicellular level of organization. As unicellular organisms, the differentiation of cells into tissues does not occur, although when cell differentiation does occur, it is limited to sexual reproduction, alternate vegetative morphologies or quiescent life history stages. Protistan parasites may possess simple or complex life histories that are important factors to consider when investigating protistan diseases of decapods. Unfortunately, the life histories of many protistan parasites of decapods are insufficiently described, resulting in the fact that modes of infection and transmission are often unidentified. This is surprising considering the economic importance of many marine decapods and the ability of protistan parasites to produce significant, but generally transient and area limited mortalities. However, the marine disease landscape is changing and will continue to change as climate change and ocean acidification will play important roles in disease occurrence and distribution. As a result, the following discussion attempts to summarize current knowledge on several crab diseases, their protistan etiological agents, the impact of disease on economically important crab populations and draw attention to areas of needed research. The discussion is not complete as only selected diseases are addressed, or perfect as the Microsporidia are included in the discussion (a traditional error continued in this summary) despite the recent, but controversial placement of the taxon with the fungi. [ABSTRACT FROM AUTHOR]

Abstract: This study reports a molecular survey of Hepatozoon species and of the order Piroplasmida in the Province of Burgos, northern Spain. The diagnostic techniques employed included PCR and the sequencing of the 18S rRNA gene. Eighty-nine blood samples from domestic animals plus 138 blood/coagulated blood samples from wild mammals were examined. Theilerid protozoa were found at relatively high frequencies in bovines (14.6%) and horses (36%). Theileria buffeli, T. sergenti and T. annulata were diagnosed in cows. T. equi was common in horses and T. annae was found in a donkey for the first time. A new piroplasmid was found in the European badger (20%). This appears to be distantly related to both T. annae and a piroplasmid isolated from Lontra canadensis. A moderate prevalence (14%) for T. annae was recorded in red foxes. A species of hepatozoon was found in one bank vole (17%), while 28% of the red foxes examined were found to be infected with H. canis. Twenty-five wild house mice were studied and found not to be carriers of piroplasmids or Hepatozoon species. Wild boars, roe deer, hares, Apodemus sp. and moles were also negative for haematozoan infection. The present study indicates that piroplasmid protozoa are present at a low to moderate frequency in some domestic herbivores in the Burgos area. They also infect certain wild mammalian species, which may act as zoonotic carriers. [Copyright &y& Elsevier]

Abstract: Mycoplasma conjunctivae is considered the major cause of infectious keratoconjunctivitis (IKC) in Alpine ibex (Capra i. ibex) and chamois (Rupicapra r. rupicapra). While it is known that domestic sheep can act as healthy carriers for M. conjunctivae, this question has not been addressed in wild ungulates so far. In this study, bacteriological investigations and field observations were performed to assess whether free-ranging Alpine ibex can be healthy carriers of M. conjunctivae. Among 136 ibex without clinical signs of IKC, M. conjunctivae was identified 26 times (19.1%) by TaqMan PCR. To assess the potential pathogenicity of M. conjunctivae strains isolated from asymptomatic eyes, strains from three healthy ibex and from 15 IKC-ibex and IKC-chamois were analysed genetically by DNA sequence analysis of the variable part of the lppS gene. No significant differences were observed between strains from asymptomatic and clinically affected animals, reflecting the assumption that healthy ibex may act as carriers for M. conjunctivae strains that may be pathogenic for other individuals. Our results further indicate that development of IKC is associated with M. conjunctivae load in the eyes. In addition, a questionnaire survey revealed that IKC is generally less common in ibex than chamois and that infection in wild ungulates is not necessarily linked to the presence of sheep. These data support the hypothesis that apparently healthy ibex may be important in the epizootiology of IKC and indicate that host predilection may play a role in IKC development. [Copyright &y& Elsevier]

Abstract: Very limited information is available on epizootiology of haematozoan infections in French domestic animals. In an attempt to address this issue, prevalence of piroplasmida was studied in carnivores and ruminants, whereas prevalence of Hepatozoon spp. was only investigated in carnivores. In total, 383 animals were included in the survey (namely 116 cats, 108 dogs, 91 sheep and 68 cows). Parasite diagnosis was carried out using molecular methods such as PCR and sequencing of the 18S rRNA gene. In addition, ruminant samples were analyzed with the reverse line blotting technique (RLB). Results of RLB and PCR plus sequencing were in total agreement. In carnivores, haematozoan prevalence was close to 1%. Two cats were infected by H. canis (1.7% prevalence) and one of them was co-infected by Cytauxzoon sp. (0.8%). This represents the first finding of both pathogens in French cats. One dog was infected by H. canis (0.9%) and another by Babesia canis vogeli (0.9%). In ruminants, haematozoan prevalence (piroplasmida) was significantly higher than in carnivores (4.8% in sheep and 8.8% in cow). Theileria ovis was found in 1 sheep, Theileria sp. in 2 sheep, Theileria buffeli in 5 cows and B. major in 1 cow. Evidence presented in this contribution indicates that haematic protozoa are not widely distributed in domestic mammal populations of France. [Copyright &y& Elsevier]

Abstract: A balanced approach to coral disease investigation is critical for understanding the global decline of corals. Such an approach should involve the proper use of biomedical concepts, tools, and terminology to address confusion and promote clarity in the coral disease literature. Investigating disease in corals should follow a logical series of steps including identification of disease, systematic morphologic descriptions of lesions at the gross and cellular levels, measurement of health indices, and experiments to understand disease pathogenesis and the complex interactions between host, pathogen, and the environment. This model for disease investigation is widely accepted in the medical, veterinary and invertebrate pathology disciplines. We present standard biomedical rationale behind the detection, description, and naming of diseases and offer examples of the application of Koch''s postulates to elucidate the etiology of some infectious diseases. Basic epidemiologic concepts are introduced to help investigators think systematically about the cause(s) of complex diseases. A major goal of disease investigation in corals and other organisms is to gather data that will enable the establishment of standardized case definitions to distinguish among diseases. Concepts and facts amassed from empirical studies over the centuries by medical and veterinary pathologists have standardized disease investigation and are invaluable to coral researchers because of the robust comparisons they enable; examples of these are given throughout this paper. Arguments over whether coral diseases are caused by primary versus opportunistic pathogens reflect the lack of data available to prove or refute such hypotheses and emphasize the need for coral disease investigations that focus on: characterizing the normal microbiota and physiology of the healthy host; defining ecological interactions within the microbial community associated with the host; and investigating host immunity, host-agent interactions, pathology, pathogenesis, and factors that promote the pathogenicity of the causative agent(s) of disease. [Copyright &y& Elsevier]

Internal parasitism in sheep constitutes one of the most important limitations in the successful development of sheep production. The first step for achieving parasite control is related to the study of the epizootiology of the etiological agents, and among them the knowledge on the species that circulate in the herds. For performing this type of study, three sheep production units of Matanzas province were selected, which animals and management system are representative of the rest of the province. The animals were found to be infested in a sympatric way by two species of the Haemonchus genus (H. placei and H. contortus) which exceed 90% of the fecal count during the whole year. Also Trichostrongylus columbriformis and Oesophagostomum columbianum were found in lower amount. The highest infestation rates were present in the rainy season in the three units, which shows evident seasonality. The offspring were infested according to the management system implemented and the lambed ewes were the most susceptible ones in a group of ewes incorporated to reproduction. These elements are essential for the implementation of parasite control plans. [ABSTRACT FROM AUTHOR]

Abstract: The epizootiology of Amblyospora camposi was studied in a natural population of Culex renatoi, a bromeliad-inhabiting mosquito, and its intermediate host, Paracyclops fimbriatus fimbriatus, over a 2-year period. Twenty Eryngium cabrerae plants were sampled monthly from January 2003 to January 2005 and the prevalence of A. camposi in P.f. fimbriatus and Cx. renatoi populations was determined. The monthly prevalence rates of meiospore infections in Cx. renatoi larvae never exceeded 5.5% and was detected in 50% of the monthly samples. Meiospores were available in plants over the course of the study at a mean concentration of 2×104 meiospores/ml. Within each plant the parasite was maintained by horizontal transmission. P.f. fimbriatus with vegetative stages and mature spores were found regularly in bromeliads suggesting efficient meiospore infectivity to field copepod populations. The mean concentration of spores from copepods found in plants was 8×102 spores/ml. Infections in copepods were detected in 54% of the monthly samples with a prevalence rate ranging from 0.55 to 17.4% and an overall average of 5.1%. Vegetative stages in fourth instar mosquito larvae (probably derived from the horizontal pathway via spores formed in copepods) were detected in 12.5% of the monthly samples with an overall prevalence rate of 1.1%. Infections in female and male adults were detected in 20.8% of the monthly samples with an overall average of 4.1% and 6.8%, respectively. [Copyright &y& Elsevier]

Abstract: A comprehensive model was developed to simulate virus epizootics in a stage structured insect population and analyse scenarios for the biological control of cotton bollworm (CBW), Helicoverpa armigera, in cotton, using wild-type or genetically modified baculoviruses. In simulations on dosage and timing of a wild-type strain and a genetic recombinant of H. armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV), the economic injury level was not exceeded against a prevailing population of 12larvaem−2 when virus was applied 10 times during the season. An early start of virus applications in each of three successive CBW generations, with sprays starting soon after egg deposition, and a short, 3-day spray interval were necessary for effective control. A recombinant virus with a lower mean time to kill provided better short-term protection than the wild-type virus. However, the number of pupae entering diapause at the end of the growing season was higher due to reduced horizontal transmission. These pupae are founders of H. armigera populations in the next season indicating that the use of fast acting genetically modified viruses in one year may enhance CBW populations in the following year. Hence, simulations indicate that there is a trade-off between short-term and long-term objectives in the biocontrol with insect viruses: fast acting recombinant viruses provide better control in the short-term at the expense of potentially inferior population suppression in the long-term. The model may be used as a decision tool for evaluating virus application strategies in interaction with virus genotype and climatic conditions that affect the phenology and population dynamics of CBW. [Copyright &y& Elsevier]

Entomophaga maimaiga Humber, Shimazu, et Soper (Zygomycotina: Entomophthoraceae) is a naturally occurring obligate fungal pathogen specific to gypsy moth, Lymantria dispar (L.) (Lepidoptera: Lymantriidae) larvae. This fungus is considered the most important natural enemy of this pest insect in North America and Asia. A critically important step for the development of E. maimaiga epizootics is the transmission of propagules to healthy larvae, a process known to require high humidity. Some pathogens are known to manipulate the time of day that hosts die so that propagules are produced to maximize chances of survival and thus enhance transmission. The objective of this study was to assess whether E. maimaiga manipulates L. dispar to die at a certain time of day. Laboratory bioassays were conducted at 15 and 20 °C to record the 24-h activity pattern of death and sporulation exhibited under an L14:D10 photoperiod and 100% r.h. by four isolates of E. maimaiga in its host L. dispar. Events were recorded every 4 h. Our results clearly demonstrate that E. maimaiga-infected L. dispar larvae die mainly in the afternoon and that the fungus sporulates during the night. The rhythm was independent of the fungal isolate tested and type of spores produced after larval death. By raising the temperature from 15 to 20 °C, the peak death time narrowed and sporulation was initiated earlier at night. [ABSTRACT FROM AUTHOR]

Abstract: Sheep are the moving banks of shepherds and their economic contribution in terms of meat, wool and skin/hide is immense. Various infectious diseases jeopardize the optimum productivity; among which sheep pox is more important as the disease restricts the export of sheep and their products besides other economic losses. Although, clinical signs are indicative of the disease but a laboratory confirmation is necessary for unequivocal diagnosis and studying epidemiology. The causative agent, sheep pox virus (SPV), is antigenically and genetically closely related to goat pox virus (GPV) and lumpy skin disease virus (LSDV), the other members of the genus capripox virus. In some countries, SPV and GPV are cross infective to small ruminants posing problem in diagnosis and epidemiology. However, recent studies have showed that the viruses are phylogenetically distinct and can be differentiated by molecular tools. Prophylaxis using attenuated vaccines is the choice of control measure as the immunity is long lasting. Detailed information on isolation, identification, pathology, epidemiology, diagnosis and prophylaxis would not only help in updating the knowledge of scientific fraternity but will be useful to the policy makers in order to formulate appropriate measures for control and eradication of the disease. This synthesis is to present an up-to-date review of the disease and its control to provide the reader with an overview of the problem. [Copyright &y& Elsevier]

Avian cholera is a significant infectious disease affecting waterfowl across North America and occurs worldwide among various avian species. Despite the importance of this disease, little is known about the factors that cause avian cholera outbreaks and what management strategies might be used to reduce disease mortality. Previous studies indicated that wetland water conditions may affect survival and transmission of Pasteurella multocida, the agent that causes avian cholera. These studies hypothesized that water conditions affect the likelihood that avian cholera outbreaks will occur in specific wetlands. To test these predictions, we collected data from avian cholera outbreak and non-outbreak (control) wetlands throughout North America (winter-spring 1995-1996 to 1998-1999) to evaluate whether water conditions were associated with outbreaks. Conditional logistic regression analysis on paired outbreak and non-outbreak wetlands indicated no significant association between water conditions and the risk of avian cholera outbreaks. For wetlands where avian cholera outbreaks occurred, linear regression showed that increased eutrophic nutrient concentrations (Potassium [K], nitrate [NO3], phosphorus [P], and phosphate [PO3]) were positively related to the abundance of P. multocida recovered from water and sediment samples. Wetland protein concentration and an El Niño event were also associated with P. multocida abundance. Our results indicate that wetland water conditions are not strongly associated with the risk of avian cholera outbreaks; however, some variables may play a role in the abundance of P. multocida bacteria and might be important in reducing the severity of avian cholera outbreaks. [ABSTRACT FROM AUTHOR]

Abstract: To determine the transmission dynamics of furunculosis, Chinook salmon, Oncorhynchus tshawytscha held at various densities were challenged with a single infectious fish. Data from the in vivo experiments were compared to predicted values from a susceptible–infected–removed (SIR) model. Seven different densities were tested including 9.13, 4.56, 0.72, 0.36, 0.19, 0.06 and 0.03fish/L and each produced different transmission coefficients (β) of 0.01, 0.019, 0.0051, 0.0076, 0.0001, 0.0005 and 0.00, respectively. Furunculosis related mortality rates decreased as density of the host decreased. Mortality rates at the highest fish densities where disease specific mortality (DSM) was observed were 0.42, 0.44, 0.18 and 0.02 infected animals per day. The natural mortality rate also followed a similar pattern with 0.005, 0.005, 0.001, 0.005, 0.0001, 0.000 and 0.000 surviving animals per day. The results indicated that the transmission coefficient and the DSM of furunculosis was dependent on host density. It is possible that fish behavioral changes at the lower densities caused the reproductive rate of disease to be persistent even at very low densities. In summary, the simple SIR model suggested that low mortality does not always mean low prevalence of furunculosis in a given population. This is the first study evaluating host density as a risk factor for fish diseases using experimental furunculosis data. [Copyright &y& Elsevier]

Abstract: Epizootiological patterns of rabies are described, using antigenic and genetic analysis of samples obtained from infected domestic and wild mammals in 20 Mexican states during 1976–2002. Two independent origins are suggested for rabies in Mexican carnivores. One group shares ancestry with canine rabies, while the other group appears to share a common origin with bat rabies in North America. More than 12 sublineages were found in rabid dog populations, suggesting at least six major spatio-temporal foci. Coyote rabies was found as independent enzootic foci that probably emerged via spillover from dog rabies, translocated from major foci in the southcentral and western regions of Mexico. One focus of gray fox rabies was widely distributed in northwestern Mexico, overlapping with a focus in the same species in the southwestern United States. A skunk rabies focus distributed in the northcentral Mexican states appears to share a common origin with bat rabies foci in North America, and is a close relative of southcentral skunk and raccoon rabies in the United States. Two other skunk foci share a common ancestor with canine rabies and were distributed in northwest Mexico and Yucatan. [Copyright &y& Elsevier]

1. Wood bison (Bison bison athabascaeL.) abundance in Wood Buffalo National Park, Canada, declined from an excess of 10 000 bison in the late 1960s to a low of 2200 bison in the late 1990s.2. Bovine tuberculosis (Mycobacterium bovis) and brucellosis (Brucella abortus), were introduced to Wood Buffalo National Park in the late 1920s. As each of these pathogens has the potential to reduce survival and reproduction in bison, they are suspected to have played a role in the decline in bison abundance.3. We live-captured bison in the winters of 1997–2000, tested for tuberculosis, brucellosis and pregnancy and released animals with radio transmitters to evaluate survival.4. We found that bison that were positive for both diseases were less likely to be pregnant or to survive the winter than bison positive for one or neither disease. Further, in one population, bison that were tuberculosis-positive had a substantially lower pregnancy probability.5. Demonstrating a negative effect of diseases on survival and reproduction is a necessary, but not sufficient, test of the role of diseases in bison population decline.Journal of Animal Ecology(2005)74, 543 –551doi: 10.1111/j.1365-2656.2005.00953.x [ABSTRACT FROM AUTHOR]

During the period of 2001–2003, a total of 591 Actinobacillus pleuropneumoniae field isolates from the Czech Republic were serotyped with a high occurrence of cross-reactions. The cross-reactions were observed in 416 isolates. Most frequently, in 401 isolates (67.9%), cross-reactions with antisera specific for serotypes 9, 11, and/or 1 were observed. Two additional molecular methods, ribotyping and restriction analysis of PCR amplified apxIVA gene (PCR-REA), were therefore used for detailed characterisation of A. pleuropneumoniae. In this subsequent analysis, reference strains representing serotypes 1–12 and 25 field isolates showing the most frequent serotype cross-reactions were examined. PCR-REA enabled all reference strains to be distinguished except for the strains of serotypes 9 and 11. Ribotyping distinguished all reference strains except two pairs of serotypes: 3 versus 6, and 9 versus 11, respectively. Field isolates with serotype cross-reactivity 9, 11, and/or 1 could not be differentiated by either of these methods. [Copyright &y& Elsevier]

The entomopathogenic fungus Entomophaga maimaiga has been reported infecting gypsy moth, Lymantria dispar, larvae in the United States since 1989. Laboratory bioassays demonstrated that larvae of numerous species of native tussock moths (Lymantriidae) are susceptible to E. maimaiga. From 1997 to 2001, larvae of gypsy moth and native lymantriids were collected in long-term plots in national forests in Virginia and West Virginia to evaluate infection levels. Throughout this time, gypsy moth populations were low although increasing the last 2 years, whereas native lymantriids remained uncommon throughout. Among gypsy moth larvae, infection by E. maimaiga first occurred during 2000 and increased in both areas during 2001 as gypsy moth populations increased. Seven species of native lymantriids were collected but only three were infected: Dasychira obliquata, Dasychira vagans, and Orgyia leucostigma. Infection of these native lymantriid species did not occur in 1997–1999 and was always <50% per species during 2000 and 2001. Ecological studies were conducted to evaluate when and where native lymantriids could be exposed to E. maimaiga inoculum. Field bioassays demonstrated that E. maimaiga resting spores were active in soil at bases of trees beginning in April, especially when soil was moist, but few gypsy moth larvae were infected by airborne conidia from resting spores early in the season. In 2000 and 2001, cadavers that produced conidia were collected throughout the season and conidia were the predominant spore form produced for at least the first month of the field season. Resting spore densities in soil were high during 1997 but titers declined through the study, with the exception of an increase following E. maimaiga infections in increasing gypsy moth populations in West Virginia during 2000. [Copyright &y& Elsevier]

This study was carried out in Ankara province, Turkey, between September 1996 and August 1998. During the study 1208 sheep, 1001 goats and 1059 cattle were examined for Haemaphysalis ticks. These examinations revealed that 380 (37.96%) goats, 346 (28.64%) sheep and 203 (19.16%) cattle had Haemaphysalis infestation. In total, 5254 Haemaphysalis ticks were collected from these animals. They were identified as H. parva, H. sulcata, H. punctata and Haemaphysalis nymphs. Of the 5254 Haemaphysalis ticks 89.70% were H. parva adults, 0.28% H. parva nymphs, 6.64% H. sulcata adults, 2.05% H. punctata adults and 0.13% H. punctata nymphs, while 0.89% were unidentified Haemaphysalis nymphs and 0.28% unidentified Haemaphysalis adults. The infestation rate of adult H. parva, H. sulcata and H. punctata reached the highest level on sheep, goats and cattle twice a year. These periods were determined as October and March for H. parva and H. punctata, and November and March for H. sulcata. Nymphs of H. parva were found on sheep and goats in April and August. Nymphs of H. punctata occurred on sheep and goats only in August. Nymphs of H. sulcata were not found on the animals. We dissected 1702 Haemaphysalis sp. and their salivary glands were stained with Methyl green/Pyronin. The salivary glands were examined under microscope, but no theilerial sporoblasts were found. [ABSTRACT FROM AUTHOR]