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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

The New World Screwworm fly, Cochliomyia hominivorax, is a major pest of livestock in South America and Caribbean. However, few genomic resources have been available for this species. A genome of 534 Mb was assembled from long read PacBio DNA sequencing of DNA from a highly inbred strain. Analysis of molecular evolution identified 40 genes that are likely under positive selection. Developmental RNA-seq analysis identified specific genes associated with each stage. We identify and analyze the expression of genes that are likely important for host-seeking behavior (chemosensory), development of larvae in open wounds in warm-blooded animals (heat shock protein, immune response) and for building transgenic strains for genetic control programs including gene drive (sex determination, germline). This study will underpin future experiments aimed at understanding the parasitic lifestyle of the screwworm fly and greatly facilitate future development of strains for efficient systems for genetic control of screwworm., Maxwell Scott et al. report the genome of the New World screwworm, a devastating livestock pest in South America and the Caribbean. Using transcriptomic analysis of the insect’s developmental stages combined with genomic analyses, the authors identify genes that may be important for its parasitic lifestyle.

Insect population control through continual releases of large numbers of sterile insects, called sterile insect technique (SIT), is only possible if one can mass-rear large quantities of healthy insects. Adaptation of insect stocks to rearing conditions and artificial feeding systems can have a multitude of negative effects such as inbreeding depression, reduced compatibility with wild strains, unintentional selection for traits that lower fitness after release, and an altered microbiome. Changes to insect microbiomes can have many effects on insects ranging from a reduction in sex pheromones or reduced fitness. Thus understanding these systems is important for mass rearing and the performance of the sterile insect control programs. In this study we explored the microbiome of the New World screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) an economically important parasite of warm-blooded animals. Samples from myiases in cows and wild adults were compared to and mass-reared flies used by the SIT program. Significant differences were observed between these treatments, with wild captured flies having a significantly more diverse microbial composition. Bacteria known to stimulate oviposition were found in both wild and mass-reared flies. Two bacteria of veterinary importance were abundant in wild flies, suggesting screwworm is a potential vector of these diseases. Overall, this study provides the screwworm eradication program a platform to continue exploring the effects associated bacteria have on screwworm fitness.

The New World screwworm, Cochliomyia hominivorax (Coquerel 1858) (Diptera: Calliphoridae), is a serious parasite of livestock, humans, and other warm-blooded animals. It has been eradicated from the northern parts of its historical range down to the Panama—Colombian border where a permanent barrier zone is maintained. This eradication was accomplished through using the sterile insect technique (SIT). In 2016 there was an outbreak of C. hominivorax in the Florida Keys. In only six months, this pest was successfully re-eradicated using SIT, but the geographic origin of the invasion has yet to be resolved. It was previously determined that the Florida flies most likely represented a single invasion, and it was recommended that a finer-scale genetic assessment should be completed. Thus, this current proof-of-concept study aimed to develop a population genetic database using single nucleotide polymorphisms (SNPs) to reference outbreaks and potentially identify the origin of the Florida outbreak. This initial database consists of wild-caught samples from 4 geographic locations as well as laboratory colony samples that originated from 7 additional locations using a genotyping by sequencing (GBS) approach. Geographic population structuring was identified for twelve populations that clustered according to geographic location. The Florida outbreak samples appeared similar to samples from the outer Caribbean cluster which included samples from Dominican Republic and Trinidad and Tobago, however, these results will be further clarified with the replacement of laboratory colony samples with future wild-caught samples.

The most common fly species associated with screwworm myiasis in Southeast Asia is Chrysomya bezziana (Ch. bezziana), the Old-World screwworm. Treatment of screwworm myiasis in cats traditionally has comprised subcutaneous injection of ivermectin or oral administration of nitenpyram, combined with aggressive tissue debridement and larval removal under general anaesthesia. Two cats diagnosed with cutaneous myiasis caused by the larvae of Ch. bezziana were treated with lotilaner. In both cats, a single dose of lotilaner at 6-26 mg/kg, killed all larvae within 24 h, negating the need for general anaesthesia. Both cats were simultaneously infested with Lynxacarus radovskyi (L. radovskyi) which also was eradicated with lotilaner. No adverse reactions were observed and both cats recovered without complications.L’espèce de mouche la plus fréquemment associée à la lucile bouchère en Asie du sud-est est Chrysomya bezziana (Ch. bezziana), espèce du vieux continent. Le traitement chez le chat consiste en une injection sous-cutanée d’ivermectine ou une administration orale de nitenpyram, associé à un débridement tissulaire agressif et retrait des larves sous anesthésie générale. Deux chats avec myase cutanée causée par les larves de Ch. Bezziana ont été traités avec lotilaner. Pour les deux chats, une dose unique de lotilaner à 6-26 mg/kg, a tué toutes les larves en 24h, sans besoin d’anesthésie générale. Les deux chats ont été infestés simultanément par Lynxacarus radovskyi (L. radovskyi) qui a également été éradiqué par le lotilaner. Aucune réaction indésirable n’a été observée chez les deux chats guéris sans complication.La especie de mosca más común asociada con la miasis de larvas barrenadoras en el sudeste asiático es Chrysomya bezziana (Ch. Bezziana), la larva barrenadora del Viejo Mundo. El tratamiento de la miasis de larva barrenadora en los gatos ha consistido tradicionalmente en inyección subcutánea de ivermectina o administración oral de nitenpiram, combinado con debridamiento agresivo de tejido y eliminación de larvas bajo anestesia general. Dos gatos diagnosticados con miasis cutánea causada por las larvas de Ch. bezziana fueron tratados con lotilaner. En ambos gatos, una dosis única de lotilaner a 6-26 mg/kg, eliminó a todas las larvas en 24 h, evitando la necesidad de anestesia general. Ambos gatos estaban infestados simultáneamente con Lynxacarus radovskyi (L. radovskyi), que también fue erradicada con lotilaner. No se observaron reacciones adversas y ambos gatos se recuperaron sin complicaciones.Die häufigste Fliegenspezies, die in Südostasien mit einer Schraubenwurm Myiasis gesehen wird, ist Chrysomya bezziana (Ch. Bezziana), der Schraubenwurm der Alten Welt. Die Behandlung einer Schraubenwurm Myiasis bei Katzen besteht traditionell aus subkutanen Injektionen von Ivermectin oder einer oralen Administration von Nitenpyram in Kombination mit einem aggressiven Gewebe Debridement und einer Entfernung der Larven in Vollnarkose. Zwei Katzen, die mit einer kutanen Myiasis, die durch Larven von Ch. Bezziana verursacht worden war, wurden mit Lotilaner behandelt. Bei beiden Katzen reichte eine einzige Dosis Lotilaner bei einer Dosierung von 6-26mg/kg, um alle Larven innerhalb von 24h abzutöten, wodurch keine Vollnarkose nötig war. Beide Katzen waren gleichzeitig mit Lynxacarus radovskyi (L. radovskyi) befallen, welcher ebenfalls durch Lotilaner abgetötet wurde. Es wurden keine Nebenwirkungen beobachtet und beide Katzen erholten sich komplikationslos.在东南亚，与螺旋蝇蛆病相关的最常见的蝇种是蛆症金蝇（Ch.bezziana），一种旧大陆螺旋蝇。传统上治疗猫的螺旋蝇蛆病，包括皮下注射伊维菌素或口服希啶虫胺，并在全身麻醉下进行积极的组织清创和幼虫清除。两只猫被诊断为蛆症金蝇幼虫引起的皮肤蝇蛆病，用洛替拉纳治疗。给两只猫6-26mg/kg的单剂量洛替拉纳，在24h内杀死了所有幼虫，无需全身麻醉。两只猫同时被猫毛螨 (L. radovskyi) 侵扰，后者也被洛替拉纳根除。未见不良反应，2只猫均痊愈，无并发症。.東南アジアにおいて、螺旋虫による蝿蛆症に関連する最も一般的なハエ種は、旧世界螺旋虫であるChrysomya bezziana（Ch. bezziana）である。 猫における螺旋虫による蝿蛆症の治療は、伝統的に、イベルメクチンの皮下注射またはニテンピラムの経口投与と、全身麻酔下での積極的な壊死組織切除および幼虫の除去を組み合わせたものであった。Ch. bezzianaの幼虫による皮膚蝿蛆症と診断された猫2頭がロチラネルによって治療された。 2頭の猫の両方において、6〜26 mg / kgのロチラネルを1回投与すると、24時間以内にすべての幼虫が死に、全身麻酔の必要性がはなかった。 2頭の猫の両方は同時にLynxacarus radovskyi (L. radovskyi)に感染し、これもロチラネルで駆除された。 副作用は観察されず、2頭の猫の両方が合併症なしに回復した。.A espécie de mosca mais comumente associada à miíase no sudeste da Ásia é a Chrysomya bezziana (Ch. bezziana), a larva de rosca do Velho Mundo. O tratamento da miíase por larva de rosca em gatos tradicionalmente inclui injeção subcutânea de ivermectina ou administração oral de nitempiram, associado com debridamento agressivo do tecido e remoção larval sob anestesia geral. Dois gatos diagnosticados com miíase cutânea causada pelas larvas de Ch. bezziana foram tratados com lotilaner. Nos dois gatos, uma dose única de lotilaner de 6 a 26 mg / kg matou todas as larvas em 24 horas, negando a necessidade de anestesia geral. Ambos os gatos foram infestados simultaneamente com Lynxacarus radovskyi (L. radovskyi), que também foi erradicada com lotilaner. Nenhuma reação adversa foi observada e os dois gatos se recuperaram sem complicações.

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.

New World screwworm (NWS), Cochliomyia hominivorax (Coquerel 1858) (Diptera: Calliphoridae), is a myiasis-causing fly that can be a serious threat to the health of livestock, wildlife, and humans. Its progressive eradication from the southern United States, Mexico, and Central America from the 1950s to 2000s is an excellent example of successful pest management using sterile insect technique (SIT). In late 2016, autochthonous NWS were detected in the Florida Keys, representing this species' first invasion in the United States in >30 yr. Rapid use of quarantine and SIT was successful in eliminating the infestation by early 2017; however, the geographic source of this infestation remains unknown. Here, we use amplicon sequencing to generate mitochondrial and nuclear sequence data representing all confirmed cases of NWS from this infestation, and compare these sequences to preexisting data sets sampling the native distribution of NWS. We ask two questions regarding the FL Keys outbreak. First, is this infestation the result of a single invasion from one source, or multiple invasions from different sources? And second, what is the geographic origin of this invasion? We found virtually no sequence variation between specimens collected from the FL Keys outbreak, which is consistent with a single source of introduction. However, we also found very little geographic resolution in any of the data sets, which precludes identification of the source of this outbreak. Our lack of success in answering our second question speaks to the need for finer-scale genetic or genomic assessments of NWS population structure, which would facilitate source determination of potential future outbreaks.

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.

The Old World screwworm fly (OWSF), Chrysomya bezziana (Diptera: Calliphoridae), is an important agent of traumatic myiasis and, as such, a major human and animal health problem. In the implementation of OWSF control operations, it is important to determine the geographical origins of such disease-causing species in order to establish whether they derive from endemic or invading populations. Gross morphological and molecular studies have demonstrated the existence of two distinct lineages of this species, one African and the other Asian. Wing morphometry is known to be of substantial assistance in identifying the geographical origin of individuals because it provides diagnostic markers that complement molecular diagnostics. However, placement of the landmarks used in traditional geometric morphometric analysis can be time-consuming and subject to error caused by operator subjectivity. Here we report results of an image-based approach to geometric morphometric analysis for delivering wing-based identifications. Our results indicate that this approach can produce identifications that are practically indistinguishable from more traditional landmark-based results. In addition, we demonstrate that the direct analysis of digital wing images can be used to discriminate between three Chrysomya species of veterinary and forensic importance and between C. bezziana genders.

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.

Larval infestations of the New World screwworm (NWS) fly, Cochliomyia hominivorax , cause considerable economic losses through the direct mortality and re- duced production of livestock. Since the 1950s, NWS populations in North and Central America have been the target of virtually continuous eradication attempts by sterile in- sect technique (SIT). Nevertheless, in some areas, such as Jamaica, SIT-based control programmes have failed. Reasons for the failure of SIT-based programmes in some lo- cations are unknown, but it is hypothesized that failure may be related to the mating incompatibility between sterile and wild flies or to the existence of sexually incompat- ible cryptic species. Accordingly, the current research investigates intraspecific phylo- genetic relationships and associated biogeographic patterns between NWS populations from the Caribbean and South America, which represent those populations involved in, or earmarked for, forthcoming SIT programmes. Uniquely, this study also includes anal- yses of two North American samples, collected in Texas in 1933 and 1953 prior to ini- tiation of the SIT-based eradication programme. The study utilizes three nucleotide datasets: elongation factor-1 (nuclear); cytochrome oxidase subunit 1 (mitochondrial), and 12S rRNA (mitochondrial). Phylogenetic analysis of these data, representing popu- lations from across the Caribbean, South America and Texas, indicates sub-structuring of fly populations on several of the larger Caribbean islands, suggesting a period of isolation and/or founder effects following colonization from South America; signifi- cantly, our findings do not support a North American origin for Cuban flies. The impor- tance of these findings in the light of proposed SIT programmes in the region is discussed.

Pradel model mark-release-recapture estimates of survivorship, phi, recruitment, f, and the rate of density-independent population growth, lambda, are presented for eight mark-recapture studies of the screwworm Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) from Costa Rica, totalling 19 573 released and 4476 recaptured flies. Corroborative estimates of survivorship and the rate of population growth based on an extensive review of the literature are also reported. Weighted-mean +/- standard error of the mean (SEM) mark-release-recapture estimates of survivorship, recruitment and the rate of population growth were phi = 0.798 +/- 0.008, f = 0.193 +/- 0.008 and lambda = 1.005 +/- 0.002, respectively. Population doubling time was estimated from lambda at 139 days. Estimates of phi and lambda from the literature both exceeded those calculated by mark-recapture methods and estimates of population doubling times were consequently shorter.

Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), the New World screwworm fly, is an important agent of traumatic myiasis, which is endemic in the Neotropical region and which has great economic impact on the development of the livestock industry. International efforts have been aimed at designing programmes to control and eradicate this species from endemic areas. Thorough knowledge of the population genetics of an insect pest is a fundamental component to ensuring the success of a pest management strategy because it enables the determination of an appropriate geographic scale for carrying out effective treatments. This study undertook an analysis of mtDNA polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) in 34 populations of C. hominivorax from 10 countries, encompassing almost all the current distribution of the species. Results showed high levels of mitochondrial DNA variability (π= 2.9%) and a complex pattern of population genetic structure for this species. Significant population structure (>st= 0.5234) and low variability were found in Caribbean populations, suggesting that, in general, islands constitute independent evolutionary entities connected by restricted gene flow. By contrast, high variability and low, but significant, differentiation was found among mainland populations (>st= 0.0483), which could not be attributed to geographic distance. Several processes may be acting to maintain the observed patterns, with different implications for establishing control programmes.

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.

Bioassays of six racemic synthesized candidate sex pheromone compounds against male New World screwworm Cochliomyia hominivorax (Coquerel) flies showed that the most potent bioactivity was found with 6-acetoxy-19-methylnonacosane and 7-acetoxy-15-methylnonacosane compared with four other isomeric acetoxy nona- cosanes and a larger aliphatic ketone. As all these methyl-branched compounds have two asymmetric carbons and four possible enantiomers, characterization of the natural enantiomers was essential. All four enantiomers for the two most bioactive isomers of the natural sex pheromone were synthesized for bioassay. Hydrolysis and derivatiza- tion of these enantiomers with different fluorescent reagents was followed by column- switched high-performance liquid chromatography. The use of two linked, reversed-phase columns of different polarity held at sub-ambient temperatures allowed good separation of each enantiomer. This analysis applied to natural material was successful, as (6 R ,19 R )- 6-acetoxy-19-methylnonanocosane, and (7 R ,15 R )- and (7 R ,15 S )-7-acetoxy-15-methyl- nonanocosane were detected in extracts of recently colonized female flies.

Diseases affecting livestock can have a significant impact on animal productivity and on trade of live animals, meat and other animal products, which, consequently, affects the overall process of economic development. The New World screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), is an important parasitic insect pest in Neotropical regions. This species has been successfully eradi- cated from North and most of Central America by the sterile insect technique, but continues to affect the development of the livestock sector in most Caribbean economies. Here, we provide some insight into the patterns of genetic variation and structure and gene flow of C. hominivorax populations from the Caribbean. Analysis of populations from 10 geographical sites in four islands revealed a moderate genetic variability within the populations. Surprisingly, a high population differentiation was found even in intra- island comparisons between populations. This observation can reflect either highly structured populations resulting from a lack of gene flow or a source - sink dynamic. Our study also suggests that New World screwworm populations can recover very rapidly from population contractions. This is valuable information that should be required prior to any investment in large-scale efforts aiming at controlling this pest.

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.

The screwworm fly, Cochliomyia hominivorax (Coquerel), is a parasite that attacks all warm-blooded animals including humans. This parasite has caused significant losses to the livestock industries of the Americas. Since the screwworm eradication program was initiated in the Southeastern United States in 1957, the eradication program has successfully progressed to its current location in Panama. A variety of technologies and tools have been used in the eradication programs. The cooperative agreement has been a significant tool in the success of the program. In the United States, the State-Federal Cooperative programs provided the mechanism for carrying out screwworm eradication. Once screwworms were eradicated from the United States, the need to expand the program internationally, in order to protect the United States, became evident. A cooperative agreement created the Mexico-United States Commission for the Eradication of Screwworms (Commission). Commission-Guatemala and Commission-Belize Cooperative Agreements were used to eradicate screwworms from these countries. Followup programs in El Salvador, Honduras, Nicaragua, Costa Rica, and Panama were implemented by cooperative agreements between the United States Department of Agriculture and the individual countries. The positive and negative aspects, as well as the necessary elements of successful cooperative agreements, are discussed.

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.