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Rainfall incidence as a risk factor for umbilical myiasis by Cochliomyia hominivorax in newborn beef cattle and the preventive and curative efficacies of injectable and topical products against its larvae were evaluated. The prevalence of navel myiasis did not differ between sex, however, it did differ between seasons of the year, independent of animal sex, with it being higher in the rainy season than in the dry season for both sexes (males 64.6%, females 62.1%). During the rainy season, rains occurred intermittently and the number of rainy days in a week had a direct influence on prevalence, with an increase (≥87%) in the number of calves with navel myiasis caused by C. hominivorax. When it rained intermittently for four, five and six days in a week during the rainy season, calves had ≈12, 24 and 11 times greater chances, respectively, of having navel myiasis compared to a week without rain during the rainy season. The injectable products did not reach preventive efficacies higher than 35%, while all treatments of topic products reached 100% preventive efficacy at 10 days post-treatment. Only the formulations with 30% dichlorfenthion and 0.32% fipronil achieved 100% curative efficacy. The results reinforce the need for intensified inspection and healing of the umbilicus during the rainy season, mainly during rainier weeks. Furthermore, topical formulations may be a better alternative as a preventive treatment than avermectin formulations. However, the curative efficacy of the topical product containing dichlorvos did not demonstrate a relationship with preventive efficacy for newborn calves.

Background Feral swine (Sus scrofa) are highly invasive and threaten animal and human health in the Americas. The screwworm (Cochliomyia hominivorax) is listed by the World Organization for Animal Health as a notifiable infestation because myiasis cases affect livestock, wildlife, and humans in endemic areas, and outbreaks can have major socioeconomic consequences in regions where the screwworm has been eradicated. However, a knowledge gap exists on screwworm infestation of feral swine in South America, where the screwworm is endemic. Here, we report screwworm infestation of feral swine harvested in Artigas Department (Uruguay), where the Republic of Uruguay shares borders with Brazil and Argentina. Methods Myiasis caused by the larvae of screwworm were identified in feral swine with the support and collaboration of members of a local feral swine hunting club over a 3-year period in the Department of Artigas. Harvested feral swine were examined for the presence of lesions where maggots causing the myiasis could be sampled and processed for taxonomic identification. The sites of myiasis on the body of infested feral swine and geospatial data for each case were recorded. The sex and relative size of each feral swine were also recorded. Temperature and precipitation profiles for the region were obtained from public sources. Results Myiases caused by screwworms were recorded in 27 of 618 the feral swine harvested. Cases detected in males weighing > 40 kg were associated with wounds that, due to their location, were likely caused by aggressive dominance behavior between adult males. The overall prevalence of screwworm infestation in the harvested feral swine was associated with ambient temperature, but not precipitation. Case numbers peaked in the warmer spring and summer months. Conclusions This is the first report on myiasis in feral swine caused by screwworm in South America. In contrast to myiasis in cattle, which can reach deep into host tissues, screwworms in feral swine tended to cause superficial infestation. The presence of feral swine in screwworm endemic areas represents a challenge to screwworm management in those areas. Screwworm populations maintained by feral swine may contribute to human cases in rural areas of Uruguay, which highlights the importance of the One Health approach to the study of this invasive host species–ectoparasite interaction. Graphical Abstract

Introduction: Myiasis is common in tropical regions, but now increasing incidence is seen in the west due to international travel. Otorhinolaryngological myiasis is uncommon and is seen in diabetics, alcoholics or patients unable in self-care.Objectives: To study presentations of otorhinolaryngological myiasis, identify associated risk factors and species of flies causing myiasis.Methods: Clinical findings and co-morbidities of 67 myiasis cases were noted. Maggots were identified, manually removed, and patients were managed with topical treatment, systemic ivermectin and antibiotics.Findings: Thirty-three nasal myiasis, 13 aural myiasis and 5 patients with oral myiasis were noted. Seven patients with head neck wounds myiasis and nine patients of tracheostome myiasis were recorded.Discussion: Warm humid climate of tropical regions is a major concern along with co-existing conditions like poor sanitation, alcoholism, psychiatric diseases and neuropathies. Hesitancy is seen in attendants and health care professionals to deal with myiasis.Conclusion: Awareness about risk factors is important in avoiding myiasis along with prompt treatment which reduces morbidity. Tracheostome myiasis is an under-documented entity rather than a rare presentation.Keywords: Myiasis, Ivermectin, screwworm, Chrysomya bezziana, Musca domestica, Lucilia sericata.Funding: None

Eradicating screwworm, Cochliomyia hominivorax (Coquerel), from continental North American via the sterile insect technique has provided huge economic benefit to livestock producers by eliminating screwworm myiasis. After confirmatory identification of fly samples from infested deer by the USDA National Veterinary Services Laboratory on September 30, 2016, an alert was issued that screwworm myiasis was discovered in the Florida Keys. Personnel from USDA Animal and Plant Health Inspection Service, Agricultural Research Service, the State of Florida, U.S. Fish and Wildlife Service and local officials responded to the outbreak focus on Big Pine Key. After witnessing infested Key deer (Odocoileus virginianus clavium Barboyr & Allen), screwworm adult sampling was initiated at 0930 h on October 5, 2016 using nets to collect flies arriving at putrid liver, with the first female collected within 1 h. Larval samples were collected from infested animals for DNA analyses and to develop a "Florida outbreak" colony to test mating compatibility with the mass-produced strain used for sterile fly releases. Ground release chambers for sterile screwworm releases were placed in favorable habitats based on satellite image analyses. Sterile pupae were first placed in the chambers on October 11, 2016. Further liver trapping showed that 13 Keys were infested. One case, presumably through animal movement, occurred near Homestead on the Florida mainland. Ultimately there were 35 sterile fly release stations, including 4 located around Homestead, but no further cases were identified. About 188 million sterile flies were released until successful eradication was declared on March 23, 2017. Containing the outbreak prevented economic losses to livestock producers and other wildlife on the mainland and kept eradication costs to a minimum.

Objective To determine the prophylactic and therapeutic efficacy of Australian-registered insecticide formulations against Old World screwworm (OWS) myiases for potential use in screwworm containment and eradication programs. Methods The longevity of protection provided by six insecticidal formulations (subcutaneous ivermectin, doramectin and abamectin, a topically applied aqueous formulation of spinosad, ivermectin controlled-release capsule and a dicyclanil spray-on formulation) was tested using implants of 1st-instar OWS larvae on Javanese thin-tail sheep. Therapeutic efficacy of four formulations (topical ivermectin, chlorfenvinphos/cypermethrin mixture, aerosol spinosad formulation and a formulation containing propetamphos and eucalyptus oil) was tested against 2- and 4-day-old OWS strikes. Results Both the ivermectin capsule and dicyclanil spray-on formulation gave 100% protection against screwworm implants for the full 12 weeks of the study. Ivermectin, doramectin and abamectin administered SC all gave 100% protection at 3 days post-treatment, but at 2 weeks the protection had become incomplete. Spinosad dipping did not give complete protection at any time. All four therapeutic treatments gave complete resolution of 2-day-old strikes and topical ivermectin, spinosad and chlorfenvinphos/cypermethrin, but not the propetamphos/eucalyptus oil formulation, gave complete resolution of all 4-day-old strikes. Conclusion Dicyclanil spray-on and ivermectin capsule formulations, both registered for use in sheep, but not for cattle or other livestock species, gave much longer protection against screwworm implants than the currently recommended SC ivermectin. Pre-emptive action to facilitate rapid deployment of these formulations in the event of a screwworm incursion is urgently needed.

Although wound or traumatic myiasis is common in tropical countries, only recently cases associated with underlying dermatoses, such as seborrheic dermatitis and psoriasis, have been reported. We describe a patient with seborrheic dermatitis and an ulcerated lesion on the scalp, in which the dermatological examination with the aid of dermoscopy allowed the identification of larvae (maggots) compatible with infestation by Cochliomyia hominivorax. Treatment was performed with oral and topical ivermectin, followed by manual extraction of the larvae.

We present the case of nosocomial myiasis, which occurred in a Peruvian hospital, whose etiological agentwas identified as Cochliomyia hominivorax, associated with an 82-year-old patient who was admitted to anintensive care unit, due to acute respiratory failure type I, and sepsis due to abscess hepatic, which underwentintubation to provide assisted mechanical ventilation. On the third day of admission to the ICU, multiple maturelarvae were observed in the oral cavity. The treatment consisted of the manual extraction of the larvae, andivermectin therapy at a rate of 0,2 milligrams per kilogram of weight with favorable response. One month afterbeing diagnosed with myiasis. The patient died of complications of hepatic sepsis and pneumonia., Presentamos un caso de miasis nosocomial ocurrido en un hospital peruano, cuyo agente etiológicoidentificado fue Cochliomyia hominivorax, en un paciente de 82 años que estuvo internado en una unidadde cuidados intensivos por insuficiencia respiratoria aguda tipo I, y sepsis por absceso hepático, el cualfue sometido a intubación para brindarle respiración mecánica asistida. Al tercer día de ingreso a UCI seobservó presencia de múltiples larvas maduras de tercer estadio en cavidad oral. El tratamiento consistió enla extracción manual de las larvas y terapia de ivermectina a razón de 0,2 miligramos por kilogramo de pesocon respuesta favorable. Al mes de ser diagnosticado de miasis el paciente fallece por complicaciones desepsis hepática y neumonía.

Presentamos un caso de miasis nosocomial ocurrido en un hospital peruano, cuyo agente etiológico identificado fue Cochliomyia hominivorax, en un paciente de 82 años que estuvo internado en una unidad de cuidados intensivos por insuficiencia respiratoria aguda tipo I, y sepsis por absceso hepático, el cual fue sometido a intubación para brindarle respiración mecánica asistida. Al tercer día de ingreso a UCI se observó presencia de múltiples larvas maduras de tercer estadio en cavidad oral. El tratamiento consistió en la extracción manual de las larvas y terapia de ivermectina a razón de 0,2 miligramos por kilogramo de peso con respuesta favorable. Al mes de ser diagnosticado de miasis el paciente fallece por complicaciones de sepsis hepática y neumonía. We present the case of nosocomial myiasis, which occurred in a Peruvian hospital, whose etiological agent was identified as Cochliomyia hominivorax, associated with an 82-year-old patient who was admitted to an intensive care unit, due to acute respiratory failure type I, and sepsis due to abscess hepatic, which underwent intubation to provide assisted mechanical ventilation. On the third day of admission to the ICU, multiple mature larvae were observed in the oral cavity. The treatment consisted of the manual extraction of the larvae, and ivermectin therapy at a rate of 0,2 milligrams per kilogram of weight with favorable response. One month after being diagnosed with myiasis. The patient died of complications of hepatic sepsis and pneumonia.

Before its eradication from North America, the subtropical‐tropical new world screwworm fly Cochliomyia hominivorax (Coquerel) invaded southwestern temperate areas of the U.S.A., where it caused myiasis in wildlife and livestock. Outbreaks of the fly occurred during years when adult migrants were carried northward on North American monsoon winds from the northern areas of Mexico and south Texas. We deconstruct, retrospectively, the biology and the effect of weather on the eradication of the fly in North America. Screwworm was found to be an ideal candidate for eradication using the sterile insect technique (SIT) because females mate only once, whereas males are polygynous, and, although it has a high reproductive potential, field population growth rates are low in tropical areas. In northern areas, eradication was enhanced by cool‐cold weather, whereas eradication in tropical Mexico and Central America is explained by the SIT. Despite low average efficacy of SIT releases (approximately 1.7%), the added pressure of massive SIT releases reduced intrinsically low fly populations, leading to mate‐limited extinction. Non‐autochthonous cases of myiasis occur in North America and, if the fly reestablishes, climate warming by 2045–2055 will expand the area of favourability and increase the frequency and severity of outbreaks., Deconstruction of the invasion biology of new world screwworm explains the role of North American monsoons with respect to its dynamics and eradication using the sterile insect technique (SIT).SIT programme myiasis data explained the time lagged effects of weather on observed and potential myiasis outbreaks in Texas. A demographic model explained the fly dynamics in tropical regions.The efficacy of sterile fly releases was assessed and the effects of climate change on the potential expansion of the fly's geographical range in North America were estimated.

Background Myiasis due to Old World screw-worm fly, Chrysomya bezziana, is an important obligate zoonotic disease in the OIE-list of diseases and is found throughout much of Africa, the Indian subcontinent, southeast and east Asia. C. bezziana myiasis causes not only morbidity and death to animals and humans, but also economic losses in the livestock industries. Because of the aggressive and destructive nature of this disease in hosts, we initiated this study to provide a comprehensive understanding of human myiasis caused by C. bezziana. Methods We searched the databases in English (PubMed, Embase and African Index Medicus) and Chinese (CNKI, Wanfang, and Duxiu), and international government online reports to 6th February, 2019, to identify studies concerning C. bezziana. Another ten human cases in China and Papua New Guinea that our team had recorded were also included. Results We retrieved 1,048 reports from which 202 studies were ultimately eligible for inclusion in the present descriptive analyses. Since the first human case due to C. bezziana was reported in 1909, we have summarized 291 cases and found that these cases often occurred in patients with poor hygiene, low socio-economic conditions, old age, and underlying diseases including infections, age-related diseases, and noninfectious chronic diseases. But C. bezziana myiasis appears largely neglected as a serious medical or veterinary condition, with human and animal cases only reported in 16 and 24 countries respectively, despite this fly species being recorded in 44 countries worldwide. Conclusion Our findings indicate that cryptic myiasis cases due to the obligate parasite, C. bezziana, are under-recognized. Through this study on C. bezziana etiology, clinical features, diagnosis, treatment, epidemiology, prevention and control, we call for more vigilance and awareness of the disease from governments, health authorities, clinicians, veterinary workers, nursing homes, and also the general public., Author summary Chrysomya bezziana larvae are characterized by feeding aggressively on the living tissues and body fluids of the host. The dreadful feelings of patients suffering from myiases with severe tissue and bone destruction, even death, and the enormous economic losses in the livestock industries have been described previously. But our findings indicate that C. bezziana myiases still appear to be under-recognized as a serious medical or veterinary condition throughout the world. Both in China and the world at large, it is probable that C. bezziana distribution could well be greater than currently reported. Our study provides an opportunity for clinicians and health authorities to gain a comprehensive understanding of this disease from its etiology, clinical features, diagnosis, treatment, epidemiology, prevention and control. In addition, our findings will engage governments, health staff, veterinary workers, aged-care facilities, and also the general public, in efforts to recognize, prevent, and control such infestations.

North West Pakistan (NWP) is characterized by four eco-zones: Northern Montane Region, North Western Hills, Submontane Region and Indus Plains. Present study identified 1037 cases of traumatic myiasis in the region during 2012-2015. Screw worm larvae were classified as 12 species: Chrysomya bezziana (Villeneuve), Chryomya megacephala (Fabricius), Chrysomya rufifacies (Macquart), Lucilia cuprina (Wiedemann), Lucilia sericata (Meigen), Lucilia illustris (Meigen), Lucilia porphyrina (Walker), Hemipyrellia ligguriens (Wiedemann), Calliphora vicina (Robineau-Desvoidy), Wohlfahrtia magnifica (Schiner), Sarcophaga crassipalpalis (Macquart), Sarchophaga species. Among these C. bezziana, L. cuprina and W. magnifica with approximately 882 case reports were the principal agents of traumatic myiasis. The species W. magnifica is a first report from Pakistan. In order to investigate spatial distribution of these dominant species we used MaxEnt niche model. Our results revealed a well-established occurrence of C. bezziana and L. cuprina in the four eco-regions while W. magnifica is currently contained in the Submontane Region. Several hot spot areas of infestation were detected all characterized by high human population density showing synanthropic nature of these species. Wohlfahrtia magnifica was excluded from Northern Montane Region with severe winters and Southern Indus Plains with harsh summers revealing that invasive species are initially sensitive to extreme of temperatures. Presence of L. cuprina in the wet areas of North Humid Belt (Maximum annual precipitation: 1641mm) depicted a moisture preference of the species. In perspective of changing climate and future predictions of severe events such as droughts and flooding in NWP, W. magnifica can potentially alter the species composition. Considering these findings in an eco-geographically dynamic region of Pakistan we predict that two factors (1) Growing human population (2) Climatic conditions, equally contribute to range shift of synanthropic species.

In southern South America, namely Argentina and Chile, Cochliomyia hominivorax (Coquerel) is the main myiasic agent on humans and domestic animals. The distribution pattern of the species is poorly known and the southern limit of its geographic distribution is unclear. The aims of this study are to elucidate the basic environmental factors associated with occurrence of this myiasic species, evaluation of models constructed on the basis of occurrence data based on adult specimen records to predict geographic occurrence of myiasis, evaluation of unsurveyed sites of high potential of occurrence of the species, and recognition and prioritization of areas that need medical control and specific prophylaxis practices related to this pest. The maximum entropy modeling system (Maxent) was used. Maps of potential distribution of C. hominivorax were produced using two different datasets, models obtained with all localities known for the species (combining medical data and taxonomic data) and only-taxonomic models (excluding medical data). The results obtained include an updated compilation of occurrence of the species in Argentina and Chile. Predictive models obtained in this work indicated that large areas of central-eastern territory of Argentina has the potential for C. hominivorax occurrence, probably reaching the parallel 42° S as is indicated by the complete datasets. Only-taxonomic models fail to predict those myiasic cases occurring in the nearer areas of the Andean chains. The main variables associated with the distribution of C. hominivorax were, alternatively, isothermality or minimum temperature of the coldest month. These results provide a new analytical resource of high potential for the prevention of myiasis and to supports further epidemiological studies.

BACKGROUND Myiasis, or the invasion of living tissues of humans and other mammals by dipterous larvae, is considered the world's fourth most common travel-associated skin disease after cutaneous larval migrants, pyodermas, and pruritic arthropod-reactive dermatitis. METHOD The present study recorded the cause, anatomical position, and severity of the wounds of myiasis patients admitted to 11 hospitals located in the central region of Sri Lanka from February 2016 to July 2017. RESULTS Altogether, 28 myiasis incidences were noted within the study period. Of the total identified myiasis patients, nine were female while the remainder were male. The greatest number of patients was recorded from the Mawanella Base Hospital and Peradeniya Teaching Hospital (seven patients each). The ages of recorded patients ranged between 30 and 92 years with the average being 59.4 years. The greatest number of myiasis cases was diagnosed in wounds located in lower limbs (24). In addition, scalp, urogenital, and umbilical infestations were recorded. Eighteen out of the total patients had diabetes mellitus, and two patients suffered from filarial lymphedema. Psychiatric illnesses were a predisposing factor of larval infestation of six patients including the recorded scalp and two urogenital myiasis patients. Of the 28 myiasis cases, 27 were caused by the old world screwworm, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), and one by the blowfly, Chrysomya megacephala Fabricius (Diptera: Calliphoridae). CONCLUSION The awareness of patients with ulcers about this disease helps to decrease further risk of being infected by fly larvae.

The purpose of this study was to evaluate the overall efficacy, larval expulsion and larvicidal effect of spinosad on the treatment of myiasis caused by New World screwworm Cochliomyia hominivorax in naturally infested dogs. Six Beagle dogs presenting with myiasis were treated once with spinosad 560 mg, with dosages ranging from 43 to 577 mg/kg. Dogs were observed with 15 min post treatment, and with intervals of 15 min within the first hour followed by hourly evaluations up to six hours post-treatment. After this period, the remaining larvae were mechanically removed. Spontaneous expulsion of larvae was variable among dogs. All dogs received support treatment and were followed up for healing of the myiasis-associated lesion. On average, the highest larval expulsion occurred four hours after treatment. A single spinosad treatment had an overall efficacy of 79.7% (56.7–100%). The average larval expulsion rate was 73.3% (56.7–100%), reached its maximum within 6 h post-treatment, and the average larvicidal effect was only 23.7% (0–58.3%). No animal needed a second dosage 24 h post-treatment, lesions were completely healed within 8 days post-treatment. Despite not reaching the desirable 100% efficacy, spinosad treatment is an option in managing NSW myiasis, in conjunction with mechanical removal of maggots that remain in the lesion and support treatment.

The New World screwworm (Cochliomyia hominivorax) is an obligate parasite that affects warm-blooded animals. It causes myiasis in livestock and humans, which is a problem for animal production and public health. The health and economic burden of myiasis on livestock production is largely unknown in Ecuador. We investigated the presence of the screwworm and analysed the epidemiology and spatial and temporal trends of myiasis in cattle farms of San Miguel de Los Bancos county. In total, epidemiological questionnaires were conducted in 110 farms, which were subsequently monitored for 12 months. The findings show that the initial and final prevalences in farms were 70% and 61.81%, respectively, and the average monthly prevalence was 15.08%. The initial and final prevalences in animals were 3.87% and 4.60% for bovines and 2.91% and 3.36% for all animals examined. The average percentage of new cases reported per month was 17.68% with a minimum of 10 and a maximum of 28 cases in October and May 2015, respectively. The cumulative incidence estimated that the risk for non-infested farms to become infested could reach 100% in approximately 6 months. The incidence rate is 168 per 1,000 farms at risk-monthly. The annual incidence was 459 per 10,000 for bovines at risk-annually. An analysis of hotspots based on the Getis-Ord Gi* index revealed no temporally stable hot spot, but one temporally stable cold spot, suggesting that most of the study area is generally favourable to infestation, except one cluster of farms.

Infestations caused by fly larvae (Myiasis) have been observed in patients with risk factors and in tropical zones. The aim of our study was to describe the clinical and epidemiological aspects and the risk factors associated with the occurrence of obligatory myiasis, as well as the therapeutic approach to patients. We identified the cases of myiasis diagnosed in two referral hospitals in northern Peru from January 2012 to December 2015 and included patients in whom larval development and a compatible clinical profile were observed. Epidemiological, clinical, analytical, diagnostic, therapeutic, and follow-up data were collected from clinical files. Nine clinical cases were compatible with a diagnosis of myiasis; of these, two were pediatric patients, one was a middle-aged adult, and six were elderly patients. Four of the nine patients were male. The identified species were Dermatobia hominis and Cochliomyia hominivorax. The therapeutic approach included antiparasitic therapy with ivermectin, antibacterial, and in some cases, anti-inflammatory drugs. Dermatobia hominis and C. hominivorax are the predominant species causing myiasis in northern Peru.

The aim of this study was to evaluate the larval expulsion, larvicidal effect, retention rate of dead larvae and overall efficacy of sarolaner on the treatment of myiasis caused by New World screwworm Cochliomyia hominivorax in naturally infested dogs. Eight Beagle dogs received a single dose of saroalner 40 mg, with dosage ranging from 2.7 mg/kg to 3.7 mg/kg. Evaluations occurred every 15 min in the first hour, every hour for up to 6 h, and after 24 h of treatment. At 24 h post-treatment, total wound cleaning was performed, including removal and counting of remaining live and dead larvae. The animals received antibiotic, analgesic and wound cleaning support until complete wound healing. The average expulsion of the larvae was 50.9 % occurring mainly after 4 h of treatment. The larvicidal effect was 70.6 % at 6 h after treatment and 100 % at 24 h. The mean retention rate of dead larvae of sarolaner was 33.9 %, The overall efficacy was 100 %, thus making sarolaner an excellent treatment option in myiasis caused by C. hominivorax larvae in dogs.

ObjectivesTo compare the sensitivity of inspections of cattle herds and adult fly trapping for detection of the Old World screw-worm fly (OWS). ProceduresThe incidence of myiases on animals and the number of OWS trapped with LuciTrap (R)/Bezzilure were measured concurrently on cattle farms on Sumba Island (Indonesia) and in peninsular Malaysia (two separate periods for the latter). The numbers of animal inspections and traps required to achieve OWS detection at the prevalent fly densities were calculated. ResultsOn Sumba Island, with low-density OWS populations, the sensitivity of herd inspections and of trapping for OWS detection was 0.30 and 0.85, respectively. For 95% confidence of detecting OWS, either 45 inspections of 74 animals or trapping with 5 sets of 4 LuciTraps for 14 days are required. In Malaysia, at higher OWS density, herd inspections of 600 animals (twice weekly, period 1) or 1600 animals (weekly, period 2) always detected myiases (sensitivity = 1), while trapping had sensitivities of 0.89 and 0.64 during periods 1 and 2, respectively. For OWS detection with 95% confidence, fewer than 600 and 1600 animals or 2 and 6 LuciTraps are required in periods 1 and 2, respectively. ConclusionsInspections of cattle herds and trapping with LuciTrap and Bezzilure can detect OWS populations. As a preliminary guide for OWS detection in Australia, the numbers of animals and traps derived from the Sumba Island trial should be used because the prevailing conditions better match those of northern Australia.

Background Cutaneous screw-worm myiasis in companion animals either due to the New World screw-worm, Cochliomyia hominivorax or the Old World screw-worm, Chrysomya bezziana, has been reported particularly in tropical and subtropical regions of the world. Although treatment of screw-worm myiasis in dogs has been described, few studies have been conducted regarding its clinical and epidemiological aspects in companion animals. Objectives To describe clinical and epidemiological aspects of canine and feline screw-worm myiasis. Animals Naturally infested dogs and cats, presented to five veterinary clinics in four Malaysian states from September 2017 to February 2018. Methods and materials Cutaneous screw-worm myiasis was diagnosed based on clinical signs and visual examination of burrowing larvae within lesion. Age, breed, gender, anatomical site of infestation and suspected underlying predisposing causes were investigated. Results A total of 55 dogs and 21 cats were included in the study. Intact male mixed breed dogs (mean age 58 months) and intact male domestic short hair cats (mean age 24 months) with suspected fight-related wounds were most commonly presented with exudative and ulcerative lesions associated with screw-worm myiasis. The most common anatomical sites of infestation in the dogs were the external ear canals, followed by the perineum and medial canthus. For the cats, the most commonly affected areas were paws and tail. Five cats with screw-worm myiasis were concurrently infected with sporotrichosis. Conclusion and clinical relevance Aggression between unneutered animals is a likely underlying cause for cutaneous screw-worm myiasis in both cats and dogs. Sporotrichosis was also a potential predisposing cause for screw-worm myiasis in cats.

Fly larvae were collected from 181 cases of traumatic myiasis in livestock in 10 regions of four countries in the Middle East Gulf region: Iran, Iraq, Saudi Arabia and Oman. The predominant fly species responsible for cases was the Old World screwworm (OWS) fly, Chrysomya bezziana Villeneuve (Diptera: Calliphoridae). In cases from Iran and Oman, which included non-OWS fly species, OWS fly was found solely responsible for 67.6% of cases and jointly with other fly species for a further 12.7% of cases. The major hosts were sheep and goats, together comprising 84.6% of the total, which reflects their predominance among the livestock of these Gulf countries. The major site of wounding on sheep and goats was the tail (40.3%), followed by female genitalia (14.0%). The 3′ terminal 715 nucleotides of the mitochondrial cytochrome b gene were sequenced for 178 larvae of OWS. Five haplotypes were identified: three had been recorded previously in the region (two were common throughout and one was unique to Oman), and two were newly identified, one from southern Iraq and the other from Saudi Arabia, both in regions sampled for the first time. The haplotypes varied from one another only at one or two nucleotide sites, equivalent to an intraspecific difference of 0.14–0.28% across the entire 715-bp fragment. There was a single statistically significant association between host species and haplotype in Saudi Arabia, a first such record for OWS fly. The small degree of genetic diversity between geographical populations of OWS fly within the Gulf region suggests that a single Gulf colony could be used to implement the sterile insect technique within an integrated control programme.

The New World screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), is one of the most important myiasis-causing flies in South America. It is responsible for severe economic losses to livestock producers, mainly because it causes mortality in newborn calves and reductions in the quality of leather and in the production of milk and meat. The economic losses caused by myiasis, along with those caused by other internal and external parasites, are the main factors limiting meat production. In Brazil, C. hominivorax has been controlled by applying insecticides, particularly organophosphate (OP)-based compounds. However, the improper and continuous use of these chemicals can lead to the selection of OP-resistant strains. This, associated with the fast development of OP resistance in other myiasis-causing flies, shows the importance of investigating resistance in C. hominivorax. Based on the findings of previous studies, the objective of the current work was to isolate and sequence the E3 gene in C. hominivorax. Mutations at the positions (Gly137 and Trp251) responsible for conferring OP resistance in Lucilia cuprina and Musca domestica L. (Muscidae) were identified in C. hominivorax. In addition, the orthologous region in C. hominivorax contained motifs that are highly conserved among carboxyl/cholinesterases and contribute to the catalytic mechanism of the active site. The characterization of this gene in natural populations of New World screwworm can be an important tool for monitoring resistance to insecticides throughout its current geographic distribution. This will provide information for the selection and implementation of more effective pest management programmes.

New World screwworm populations in North and Central America have been the targets of virtually continuous eradication attempts by sterile insect technique (SIT) since the 1950s. Nevertheless, in some areas, such as Jamaica, SIT control programmes have failed. Reasons for the failure of SIT-based control programmes in some locations are unknown, but it has been hypothesized that failure may be related to mating incompatibility between sterile and wild fly populations or to the existence of sexually incompatible cryptic species. This paper outlines the development of a suite of four new microsatellite loci which can be used to study intra-specific relationships between populations of Cochliomyia hominivorax from the Caribbean and South America, which represent those populations involved in, or earmarked for, forthcoming SIT control. Cross-amplification with the secondary screwworm, Cochliomyia macellaria, was also successful with three of the new loci. We present results which suggest that populations from Trinidad and Jamaica form distinct groupings of flies and that C. hominivorax from Trinidad appears particularly distinct.

The term myiasis is applied to the injurious action that larvae of certain diptera cause to the organism of vertebrate animals in the living or dead tissue in which they grow. Because of its great destructive potential, appropriate and preventative treatment are necessary. Among the sites of infestation, the human mouth is a common site, mainly in tropical countries. We present two cases of oral myiasis caused by Cochliomyia hominivorax spp. Ivermectin is an extremely effective semi-synthetic macrolides, in the treatment of this condition.

Larvae (maggots) of Cochliomyia hominivorax, the New World Screwworm fly, are voracious consumers of living flesh that have a negative economic impact by decreasing productivity, predisposing to other pathogens, and, in severe cases, causing death of domestic livestock. Screwworm caused extensive financial losses to the livestock industry in North America prior to its eradication. Sterile insect technique (SIT) was used to eradicate screwworm throughout North and Central America and continues to be the main tool to control it in eastern Panama. The goal of this study was to evaluate the temporal and spatial trends of screwworm myiasis cases reported in the Province of Darien and Comarca Embera (border with Colombia), Panama, from 2001 to 2011. We hypothesized that screwworm cases would vary seasonally and be spatially clustered near Colombia as a result of effective eradication strategies in Panama and the presence of an autochthonous population of flies in western Colombia. Temporal and spatial data were retrieved from COPEG-USDA records (Panama) and analysed by anova, Ripley's K function, discrete Poisson spatial statistic scan and Getis-Ord Gi*. No significant temporal trend was found, but cases were spatially distributed in four clusters. One cluster of cases occurred from 2001 to 2003 and was considered a focal temporal and spatial cluster. One cluster occurred in 2001 and 2007 indicating more rare outbreaks in an area with fewer cattle. The two remaining clusters contained cases from 2004 to 2011 and 2001 to 2011 suggesting regular breaks in the control barrier due to occasional failures of the SIT programme, difficulties implementing border quarantine strategies, livestock smuggling or the movement of infested wildlife.

Myiasis is the infestation of tissue by the larvae of flies. We report eight cases of human myiasis in Hong Kong. All patients were nursing home residents with an average age of 81.8 years. Seven patients were bedridden with advanced dementia. Four patients had pre-existing wounds. Five had poor oral hygiene and four of those were on tube feeding. All of the five patients with poor oral hygiene suffered from oral myiasis. Two patients had vaginal infestations and one had wound myiasis in his diabetic foot ulcer. Seven cases were infested by Chrysomya bezziana, an obligatory parasite that requires living mammalian tissue for its larval development. Larvae of the Calliphoridae family were responsible for the remaining case. Patients were managed with manual removal of larvae and irrigation of the site of infestation with saline. All infestations were nosocomial, being acquired in nursing homes. Carers of the old and debilitated should be made aware of the need for better oral care, especially for those on tube feeding. The use of window screens in nursing homes should be encouraged to reduce the chance of flies entering the vicinity of these patients. Electrocuters could also be mounted indoors to kill flies that do enter.

Following the first recorded introduction of the Old World screwworm fly (OWS), Chrysomya bezziana Villeneuve (Diptera: Calliphoridae), into the Mesopotamia valley in Iraq in September 1996, cases of livestock myiasis caused by OWS developed a distinctly seasonal pattern. The annual cycle of clinical OWS cases is explained here on the basis of environmental variables that affect the different life-cycle stages of C. bezziana. This analysis suggests that low temperatures restricted pupal development during the winter, whereas the dispersal of adult flies was constrained by hot/dry summer conditions. A restricted number of OWS foci persisted throughout the year. In these foci, pupal development was fastest during the autumn months. In autumn, rapid multiplication, lasting several OWS generations, allowed subsequent adult fly dispersal across the valley floor during the winter. Hence, the monthly incidence of clinical OWS cases in livestock peaked during December–January and was lowest during July–August. In addition to temperature and humidity, vegetation cover played a role in OWS distribution. Hence the majority of OWS cases were clustered in the medium density type of vegetation [normalized difference vegetation index (NDVI) values of 0.2–0.4] along the main watercourses in the marshy Mesopotamia valley. Although sheep were the host most commonly infested by C. bezziana, local sheep density was not found to be a major factor in disease spread. Satellite imagery and the application of Geographical Information System (GIS) tools were found to be valuable in understanding the distribution of OWS in relation to vegetation and watercourses. The presence of screwworm in Iraq, at the perimeter of the intercontinental OWS distribution, may give rise to major seasonal flare-ups.

A field trial was carried out during a summer-fall period on a commercial beef cattle farm in Minas Gerais State, located in the Southeast of Brazil. In order to evaluate the prophylactic effect and the curative efficacy of fipronil in a 1% solution, 200 Zebu crossbred bulls, with ages varying from 20 to 30 months and weights from 233 to 362 kg, were selected. The bulls were assigned by ranked pair to an untreated control group (A) or to a treated group (B), resulting in 100 animals per group. All experimental animals were surgically castrated on day 0, following routine procedures. After castration all animals in the group B were treated with 10 mg/kg bw of a 1% fipronil solution, topically on the dorsal mid-line. The wounds were individually inspected on days: 2, 4, 7, 10, 14, 17, 21, 28 and 35. After castration the animals were naturally exposed to Cochliomyia hominivorax and remained in the same pasture throughout the trial. Among the animals in the control group, 83 were observed to harbor C. hominivorax eggs, with a total of 97 ovipositions, and among those 73 animals had active myiasis. In group B (fipronil 1%), 66 animals showed C. hominivorax eggs, with 92 ovipositions and five animals with active myiasis. Most ovipositions and active myiasis were detected until seven days post-castration for both groups. Wound parasite infestation evidenced bleeding, serous purulent exudation and presence of active C. hominivorax larvae. Treatment with fipronil 1% had a prophylactic effect on scrotal wounds against the development of C. hominivorax larvae in more than 95% of the treated animals for up to 17 days after castration. The treatment showed partial protection of 66% and 50% on days 21 and 28 post-treatment (pt), respectively. Three animals from the control group and one from the treated group showed active screwworms on day 21 pt, and one animal from the treated group and two from the control group also presented C. hominivorax larvae on scrotal wounds on day 28 pt. By the end of the observation period (day 35 pt), the castration wound had healed in all animals. All experimental animals presenting scrotal wounds infested with C. hominivorax larvae were treated with a 1% pour-on formulation of fipronil, on the same day that infestation was observed. Active C. hominivorax larvae were not seen during the monitoring period immediately after treatment. The curative efficacy of fipronil 1% against C. hominivorax larvae infestation in castration wounds was 100%.

This retrospective study examined the case records of Old World screw-worm fly myiasis in dogs in Hong Kong's New Territories. Myiasis due to OWSWF was identified and treated in 59 dogs at our clinic over a period of 1 year. Signalment, causes of initial wound, and treatments implemented, are reported. All cases recovered from myiasis with a combination of larvae removal and wound debridement, antibiotics, and topical and systemic insecticides. Whilst this parasite is currently exotic to Australia, much of the country is environmentally suitable (tropical and subtropical) for establishment of OWSWF.

The Old World Screwworm fly (Chrysomya bezziana) has recently been causing aggressive myiasis in pet dogs in Hong Kong, and the Agriculture, Fisheries and Conservation Department of Hong Kong has confirmed the presence of Chrysomya bezziana in the territory. This report describes screwworm infestation in pet dogs presented for treatment at our clinic in the past year. Screwworm fly larvae were found in typically punched out round wounds or embedded in exposed or neglected wounds. Infested wounds had a characteristic strong offensive smell and oozed a sero-sanguineous exudate or frank blood. Removal of the larvae, wound treatment, continuous monitoring for re-infestation, application of insect repellants and protective housing were essential for successful treatment. Because Hong Kong is a source of pet migration or a transit point to Australia, the fly could threaten Australia. Aust Vet J 2003;81:202-205 SWF Screwworm fly OW Old World sid Once daily bid Twice daily

Myiasis is the infestation of tissues and organs of animals and humans caused by the larvae of certain dipteran flies. It is more common in undeveloped and tropical countries and usually affects elderly patients, persons who are sick, and patients with mental illness. Oral myiasis is a rare pathologic condition and a risk to the patient's life because of its great destructive potential. Therefore, appropriate treatment is necessary. This article aimed to report a case of myiasis caused by Cochliomyia hominivorax in the palate of a patient with primary progressive aphasia, which was successfully treated through mechanical removal of larvae plus administration of ivermectin.

Myiasis caused by screwworms, Cochliomyia hominivorax (Coquerel), is devastating to warm-blooded animals and economically important to livestock producers. It is difficult to distinguish these pests, immature screwworms, from immatures of other non-pest fly species that often occur in animal wounds; it would be helpful to have tools available that do not rely on morphological characteristics. We developed two monoclonal antibodies (MAbs), highly specific for the screwworm, and used them in an enzyme-linked immunosorbent assay (MAb-ELISA), that differentiated screwworm eggs, larvae, pupae, and adults from those of the closely related secondary screwworm, C. macellaria (Fabricius) as well as Phormia regina (Meigen), Phaenicia sericata (Meigen), Calliphora vicina Robineau-Desvoidy, and Chrysomya rufifacies (Macquart). In a blind study, the microplate MAb-ELISA, which took about 4h to complete, displayed high specificity (99%), sensitivity (92%) and overall accuracy (97%) in distinguishing all life stages of the screwworm. Electrophoresis results suggested that the two monoclonal antibodies recognized identical conformational epitopes present in all screwworm life stages. The screwworm eradication program, successful in eradicating this pest from the US, Mexico, most of Central America and Libya (after an accidental introduction), could benefit in future eradication, surveillance, and exclusion efforts by developing a reliable field identification kit based on MAb-ELISA that accurately and quickly distinguished cases of screwworm myiasis.

This paper reports five cases of intact adult male crossbreed cats presenting with myiasis caused by Cochliomyia hominivorax. Three were stray animals that died despite treatment due to the severity of lesions while two were client-owned cats previously treated with cryosurgery which completely recovered. Myiasis caused by the New World screwworm fly in cats appears to be more frequent than previously thought, deserving more attention from both veterinary practitioners and owners.

A case of anterior internal ophthalmomyiasis is described. A 27-year-old female from Northern Brazil presenting with anterior uveitis and vitritis had a fly larva surgically removed from the anterior chamber of the left eye. The species was Cochliomyia hominivorax. The larva was covered by macrophages and foreign body giant cells characterizing a foreign body granulomatous reaction.Um caso de oftalmomiíase interna anterior é descrito. Uma mulher de 27 anos proveniente da região Norte do Brasil com uveíte anterior e vitreíte teve uma larva de mosca cirurgicamente removida da câmara anterior do olho esquerdo. A espécie identificada foi Cochliomyia hominivorax. A larva estava coberta por macrófagos e células gigantes de corpo estranho, caracterizando uma reação granulomatosa de corpo estranho.

Objective To assess Australia's targeted surveillance to detect an incursion of screw-worm fly (Chrysomya bezziana). Methods A multi-criteria analysis shell was used to combine data on potential pathways of entry, availability of host species and environmental factors affecting survival of screw-worm fly in order to map spatial variation in the relative likelihood of a screw-worm fly incursion into Australia. Australia's current screw-worm fly surveillance activities were reviewed to determine whether they are located in the areas of highest likelihood of an incursion. Results Under average environmental conditions, an incursion of screw-worm fly in Australia is relatively more likely to occur along the north coast, down the eastern seaboard or in the south-east. Cold winter temperatures would limit the environmental suitability for screw-worm fly survival to the north and north-east coast and adjacent inland areas. Australia's current targeted surveillance conducted by the Northern Australia Quarantine Strategy program of the Australian Department of Agriculture (adult screw-worm fly trapping and myiasis sampling) correlated well with areas considered to have a high relative likelihood of an incursion of screw-worm fly. Adult fly trapping conducted at sea ports was less well correlated. Discussion Changes to surveillance at sea ports are proposed to better target areas considered to have a higher relative likelihood of screw-worm fly incursion. These include increasing the trapping intensity along the north and north-east coasts and shifting surveillance activity from the west coast to the south-east.

The geographical distribution and seasonality of the New World screwworm (NWS), Cochliomyia hominivorax Coquerel (Diptera: Calliphoridae), were monitored through the use of sentinel animals as part of a co-ordinated programme involving veterinarians and farmers, as well as undergraduate students and teachers from veterinary colleges in Venezuela. This surveillance activity made it possible to collect NWS egg masses or larvae from all 23 states in the country and to determine that the rainy season has a strong positive influence on the number of cases of myiasis caused by C. hominivorax in dogs. In addition, efforts were made to obtain the co-operation of the public health service in order to document the extent of human myiasis in the western–central region of Venezuela. Preliminary results revealed 241 cases over a 7-year period, with cases reported in infants as well as in elderly people. Larvae causing myiasis, other than C. hominivorax, were collected from primary myiasis in rabbit (Lucilia eximia [Wiedemann]), dog (an unidentified sarcophagid species), birds (Philornis sp.) and wild mice (Cuterebra sp.). The economic impact of NWS in Venezuela has not been calculated in terms of loss of milk and meat production, damage to hides or death of animals. Control costs (e.g. cost of larvicides) have been estimated at US$ 2 m per year. Control of myiasis in animals is achieved through the use of chemical compounds, mainly organophosphorus (OP) compounds, macrocyclic lactones and, more recently, a foamy spray based on spinosad. Concerns about insecticide resistance to OP compounds have been raised.

La miasis humana es el parasitismo de órganos y tejidos producido por especies de larvas del orden Díptera. El diagnóstico se realiza con base en hallazgos clínicos y se confirma con estudios entomológicos. Se presenta el caso de una niña de siete años de edad que fue llevada por su padre al servicio de urgencias por presentar fiebre asociada a una lesión abscedada en el cuero cabelludo, con salida espontánea de larvas. Como hallazgo en el examen físico se reportó pediculosis grave. La paciente fue hospitalizada y tratada con clindamicina, gentamicina e ivermectina, y mostró mejoría de sus condiciones clínicas. Se dio alta médica al cuarto día de estancia hospitalaria. Se recolectaron larvas en estadio dos de Cochliomyia hominivorax (Diptera: Calliphoridae) directamente del área lesionada, observándose la asociación miasis-pediculosis; por lo tanto, se alerta a los trabajadores del área de la salud del riesgo potencial que representa la pediculosis para el desarrollo de la miasis. Human myiasis is the parasitism of human tissues by fly larvae. Diagnoses are based on clinical pattern of tissue damage and presence of insect stages. Herein, a case myiasis is described in a seven-year-old female child. She presented with fever associated with abscessed scalp lesions containing exposed larvae. Severe pediculosis was also observed. The patient was hospitalized and treated with clindamycin, gentamicin (for bacterial secondary infections) and ivermectin (treatment for lice) after which the patient showed clinical improvement and was discharged four days later. Since human myiasis can be caused by a number of different species, larvae were collected from the patient and identified as those of Cochliomyia hominivorax (Diptera: Calliphoridae). Because other cases of coinfestation of flies and lice are on record, health workers are to be alerted about the possible pediculosis-myasis risk..

The course of the North African outbreak of New World screw-worm myiasis (Cochliomyia hominivorax) since its discovery in 1988 is described. Chemical and biological control measures are reviewed, including the current progress of the 'sterile male' (SIT) eradication programme.