Traumatic myiasis in dogs caused by Wohlfahrtia magnifica and its importance in the epidemiology of wohlfahrtiosis of livestock

Transcriptomic profiling of different developmental stages reveals parasitic strategies of Wohlfahrtia magnifica, a myiasis-causing flesh fly

BACKGROUND

Wohlfahrtia magnifica is an obligatory parasite that causes myiasis in several warm-blooded vertebrates. Adult females deposit the first-stage larvae directly onto wounds or natural body orifices (e.g., genitalia) of the host, from where they quickly colonize the host tissue and feed on it for development. The infestation of W. magnifica can lead to health issues, welfare concerns, and substantial economic losses. To date, little is known about the molecular mechanisms of the W. magnifica-causing myiasis.

RESULTS

In this study, we collected parasitic-stage larvae of W. magnifica from wounds of naturally infested Bactrian camels, as well as pupae and adult flies reared in vitro from the wound-collected larvae, for investigating the gene expression profiles of the different developmental stages of W. magnifica, with a particular focus on examining gene families closely related to the parasitism of the wound-collected larvae. As key proteins related to the parasite-host interaction, 2049 excretory/secretory (ES) proteins were identified in W. magnifica through the integration of multiple bioinformatics approaches. Functional analysis indicates that these ES proteins are primarily involved in cuticle development, peptidase activity, immune response, and metabolic processes. The global investigation of gene expression at different developmental stages using pairwise comparisons and weighted correlation network analysis (WGCNA) showed that the upregulated genes during second-stage larvae were related to cuticle development, peptidase activity, and RNA transcription and translation; during third-stage larvae to peptidase inhibitor activity and nutrient reservoir activity; during pupae to cell and tissue morphogenesis and cell and tissue development; and during adult flies to signal perception, many of them involved in light perception, and adult behavior, e.g., feeding, mating, and locomotion. Specifically, the expression level analysis of the likely parasitism-related genes in parasitic wound-collected larvae revealed a significant upregulation of 88 peptidase genes (including 47 serine peptidase genes), 110 cuticle protein genes, and 21 heat shock protein (hsp) genes. Interestingly, the expression of 2 antimicrobial peptide (AMP) genes, including 1 defensin and 1 diptericin, was also upregulated in the parasitic larvae.

CONCLUSIONS

We identified ES proteins in W. magnifica and investigated their functional distribution. In addition, gene expression profiles at different developmental stages of W. magnifica were examined. Specifically, we focused on gene families closely related to parasitism of wound-collected larvae. These findings shed light on the molecular mechanisms underlying the life cycle of the myiasis-causing fly, especially during the parasitic larval stages, and provide guidance for the development of control measures against W. magnifica.

Genome and Transcriptome Analyses Facilitate Genetic Control of Wohlfahrtia magnifica, a Myiasis-Causing Flesh Fly

Myiasis caused by Wohlfahrtia magnifica is a widespread parasitic infestation in mammals. The infested host suffers from damage as the developing larvae feed on its tissues. For the control of myiasis infestation, genetic methods have been shown to be effective and promising as an alternative to insecticides. Combining genome, isoform sequencing (Iso-Seq), and RNA sequencing (RNA-seq) data, we isolated and characterized two sex-determination genes, W. magnifica transformer (Wmtra) and W. magnifica transformer2 (Wmtra2), whose orthologs in a number of insect pests have been utilized to develop genetic control approaches. Wmtra transcripts are sex-specifically spliced; only the female transcript encodes a full-length functional protein, while the male transcript encodes a truncated and non-functional polypeptide due to the presence of the male-specific exon containing multiple in-frame stop codons. The existence of five predicted TRA/TRA2 binding sites in the male-specific exon and the surrounding intron of Wmtra, as well as the presence of an RNA-recognition motif in WmTRA2 may suggest the auto-regulation of Wmtra by its own protein interacting with WmTRA2. This results in the skipping of the male-specific exon and translation of the full-length functional protein only in females. Our comparative study in dipteran species showed that both the WmTRA and WmTRA2 proteins exhibit a high degree of similarity to their orthologs in the myiasis-causing blow flies. Additionally, transcriptome profiling performed between adult females and adult males reported 657 upregulated and 365 downregulated genes. Functional analysis showed that among upregulated genes those related to meiosis and mitosis Gene Ontology (GO) terms were enriched, while, among downregulated genes, those related to muscle cell development and aerobic metabolic processes were enriched. Among the female-biased gene set, we detected five candidate genes, vasa (vas), nanos (nanos), bicoid (bcd), Bicaudal C (BicC), and innexin5 (inx5). The promoters of these genes may be able to upregulate Cas9 expression in the germline in Cas9-based homing gene drive systems as established in some flies and mosquitoes. The isolation and characterization of these genes is an important step toward the development of genetic control programs against W. magnifica infestation.

Lucilia sericata (Diptera: Calliphoridae) as Agent of Myiasis in a Goose in Italy and a Review of Myiasis by This Species in Birds

Myiasis is a type of parasitosis by larvae of Diptera that may affect vertebrates, including wild and domestic birds. Traumatic myiasis was discovered in a domestic goose, Anser anser domesticus L. (Anseriformes: Anatidae), in June 2020 in a rural area of the region Calabria (Southern Italy). The myiasis was caused by Lucilia sericata (Meigen) (Diptera: Calliphoridae). In Italy, this was the first case of myiasis by L. sericata ever described in a bird. It was also the first case of myiasis detected in a goose in Italy. The description of the case is integrated by a discussion on nonhematophagous dipteran larvae causing myiasis in birds and by an updated and detailed review of literature cases of myiasis by L. sericata in birds reported worldwide, useful for monitoring and management of dipteran species of medical and veterinary interest.

Catalogue of the Diptera (Insecta) of Morocco— an annotated checklist, with distributions and a bibliography

The faunistic knowledge of the Diptera of Morocco recorded from 1787 to 2021 is summarized and updated in this first catalogue of Moroccan Diptera species. A total of 3057 species, classified into 948 genera and 93 families (21 Nematocera and 72 Brachycera), are listed. Taxa (superfamily, family, genus and species) have been updated according to current interpretations, based on reviews in the literature, the expertise of authors and contributors, and recently conducted fieldwork. Data to compile this catalogue were primarily gathered from the literature. In total, 1225 references were consulted and some information was also obtained from online databases. Each family was reviewed and the checklist updated by the respective taxon expert(s), including the number of species that can be expected for that family in Morocco. For each valid species, synonyms known to have been used for published records from Morocco are listed under the currently accepted name. Where available, distribution within Morocco is also included. One new combination is proposed: Assuaniamelanoleuca (Séguy, 1941), comb. nov. (Chloropidae).

Traumatic myiasis by Wohlfahrtia magnifica in sheep flocks from southeastern Spain: prevalence and risk factors

Wohlfahrtia magnifica (Diptera: Sarcophagidae) is an obligate myiasis-causing fly of livestock that is widely distributed throughout the Mediterranean basin. A total of 73 683 sheep from 122 flocks in Albacete Province (southeastern [SE] Spain) were examined to detect active traumatic myiasis. The influence of several individual and flock factors on the prevalence was also assessed. The overall flock prevalence of traumatic myiasis was 95.9%, with an individual prevalence of 7.1%. Wohlfahrtia magnifica was identified in all of the positive animals except one that was infested by Lucilia sericata (Diptera: Calliphoridae). Adults of both genders showed a higher risk of infestation than juveniles, whereas males of all ages displayed an increased risk of infestation than females of all ages; the existence of a lambing building on the farm, poor husbandry facilities and the location area were also identified as risk factors. Prevalence was highest in the summer, and the fly season lasted from March to November. Genitalia were the main location of infestation in males (94.4%) and females (76.3%). Our results reveal that traumatic myiasis by W. magnifica is widespread in southeastern Spain, hence preventive measures minimizing the attractiveness of sheep to gravid flies are necessary to avoid health and welfare problems and significant production losses in sheep flocks.

Modelling the occurrence and spatial distribution of screwworm species in Northern Pakistan

We use binomial kriging to model the spatial distribution of myiasis by three species namely Chrysomya bezziana, Wohlfahrtia magnifica and Lucilia cuprina in the livestock of Khyber Pakhtunkhwa, Pakistan. Traditional species distribution models are usually based on assumption of independence of observations. Species data often come in presence-only form for which background points are generated based on some covariates using statistical and machine learning techniques such as MaxEnt. We assume a symmetric binomial distribution based on the principle of maximum entropy in order to decide the number of pseudo-absences. Our results showed that the spatial models fitted very well and prediction distributions were estimated with excellent accuracy. Moreover kriging maps were more accurate as most of the non-spatial variation has been picked up by external drift with higher values of the sensitivity focusing partial AUC for all the three species. Land-use-land-cover was a common factor significantly affecting spatial distribution of all the three species suggesting that for established species anthropogenic factors such as land use become a strong determinant of their spatial distribution. Our results also revealed that for invading species like W. magnifica elevation acts as a barrier to species dispersal and therefore is more limiting to distribution. Furthermore the higher overall prediction accuracy demonstrated that our models performed well in predicting the distributions of the three species, which would lead to better understanding and management of the larval infestation.

Cutaneous myiasis in cats and dogs: Cases, predisposing conditions and risk factors

Two cases of cutaneous myiasis diagnosed in 2018 in Emilia‐Romagna region (northern Italy) were reported. The first one, described in a domestic cat Felis silvestris catus L. (Carnivora: Felidae) and caused by Calliphora vicina Robineau‐Desvoidy (Diptera: Calliphoridae), was the first one of this type ever reported in Italy in cats. The second one was described in a domestic dog Canis lupus familiaris L. (Carnivora: Canidae) and caused by Lucilia sericata (Meigen) (Diptera: Calliphoridae) and was unusual because it occurred in absence of lesions. An extensive literature search on cutaneous myiasis in these two domestic animal species was performed in order to draw attention to predisposing conditions and risk factors.

Wohlfahrtiosis in Italy: a case in a puppy and overview of geographical distribution

The report describes a case of urogenital myiasis in a puppy, Canis lupus familiaris (Carnivora: Canidae) caused by Wohlfahrtia magnifica (Diptera: Sarcophagidae) in Calabria, southern Italy. This species is an obligatory agent of myiasis in human and other warm-blooded vertebrates. The puppy was healthy and was not living near farm animals, usual hosts of this flesh fly. An overview of cases of human and animal myiasis caused by W. magnifica in Italy and of data and specimens documented in entomology museum collections is also reported.

First reports of nasal and traumatic myiasis infection in endangered Przewalski's horses (Equus ferus przewalskii)

Myiasis has great economic and medical importance. However, myiasis in wildlife that is caused by oestroid flies is relatively rarely recorded compared with that in humans and domestic animals. Recently, during our research on the conservation of Przewalski's horse (PH), we observed two new records of oestroid flies parasitizing wildlife in China. The first is the horse nasal bot fly, Rhinoestrus sp. (Diptera: Oestridae), found in a dead PH from Kalamaili Nature Reserve. One morphotype (R. purpureus-like) was identified. The second is the Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica (Schiner, 1862) (Diptera: Sarcophagidae), which was collected from an open wound of a PH in the Wild Horse Breeding Research Centre. These observations extend the records of known hosts of these two oestroid myiasis agents. To the knowledge of the authors, infestation by Rhinoestrus and Wohlfahrtia larvae causing myiasis in wildlife has not been reported in China previously.

A formulation of neem and hypericum oily extract for the treatment of the wound myiasis by Wohlfahrtia magnifica in domestic animals

Untreated, traumatic, or wound myiases can cause severe consequences to animal health and welfare as well as economic losses to livestock productions. For healing myiasis-caused wounds, disinfectant such as creolin is wrongly but currently used in association with insecticides. Though effective, creolin is highly toxic to the patients, is inadequate with respect to the repellent effect, and may delay the healing of treated wounds. In this uncontrolled study, the efficacy of the patented plant-derived formulation 1 Primary Wound Dressing© (1-PWD), composed of neem oil (Azadirachta indica A. Juss.) and the oily extract of Hypericum perforatum (L.) flowers, has been investigated. Forty-four domestic animals of different species suffering from wound myiasis lasting for up to 25 days, at different parts of the body, were enrolled in the study. No systemic or local antibiotic or disinfectants' treatment was administered. Larvae recovered on open wounds and adults reared from mature larvae were identified as Wohlfahrtia magnifica. All the treated wounds healed in a range of 10 to 32 days without further infestation. None of the recruited animals presented bacterial complications. Data herein presented indicate that the tested natural plant-derived formulation is able to manage the infestation caused by W. magnifica larvae and the healing process of traumatic infested wounds in several domestic animal species, without any side effect on the living tissue and without the need to use local or systemic chemical or other products.

A brief review of forensically important flesh flies (Diptera: Sarcophagidae)

Forensic entomology could provide valuable data for the minimum postmortem interval (PMImin) estimation and other relevant information, such as causes and circumstances of death. Some representatives of flesh flies are one of the dominant necrophagous insects during early stages of decomposition, demonstrating unique biological characteristics compared with other necrophagous flies. Moreover, they lead to global health concerns as carriers of various pathogenic micro-organisms, and dominantly result in the traumatic myiasis. Thus, sarcophagid flies are considered important in decomposition processes for PMImin estimation. However, the utility of sarcophagid flies has been seriously hampered by limited ecological, biological and taxonomic knowledge of them. The aim of this paper is to provide a brief review on the species, distribution and biological habit of forensically important sarcophagid flies. In addition, the relation between traumatic myiasis and flesh flies, molecular identification methods and developmental pattern of flesh flies are summarized.

Distribution Modeling of three screwworm species in the ecologically diverse landscape of North West Pakistan

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.

Traumatic Myiasis: A Neglected Disease in a Changing World

Traumatic myiasis, the parasitic infestation by fly larvae in traumatic lesions of the tissues of living vertebrates, is a serious medical condition in humans and a welfare and economic issue in domestic animals. New molecular studies are providing insights into its evolution and epidemiology. Nevertheless, its incidence in humans is generally underreported, particularly in tropical and subtropical regions. Myiasis in domestic animals has been studied more extensively, but continuous management is difficult and expensive. A key concern is the inadvertent introduction and global spread of agents of myiasis into nonendemic areas, facilitated by climate change and global transport. The incursion of the New World screwworm fly (Cochliomyia hominivorax) into Libya is the most notable of many such range shifts and demonstrates the potential risks of these parasites and the costs of removing them once established in a geographic area. Nevertheless, the insect agents of myiasis can be of societal benefit to forensic science and in medicine as an aid to wound treatment (larval therapy).

First report of emerging zoonotic pathogen Wohlfahrtiimonas chitiniclastica in the United States

Wohlfahrtiimonas chitiniclastica is an emerging human pathogen that has been identified as the cause of septicemia in humans in Europe and South America. Here we report the first case of a unique disease manifestation of Wohlfahrtiimonas chitiniclastica-induced bacterial septicemia secondary to wound myiasis in a deer in Michigan in the United States.

The investigation of lipid peroxidation, anti-oxidant levels and some hematological parameters in sheep naturally infested with Wohlfahrtia magnifica larvae

Wohlfahrtia magnifica is the main agent of traumatic myiasis in many central and eastern European countries as well as in the Mediterranean basin and Asian countries. The present study was aimed to investigate the effect of myiasis infestation on lipid peroxidation, antioxidant levels and several hematological parameters in the sheep naturally infested with W. magnifica larvae. A total of 38 sheep, including 19 awassi sheep naturally infested with W. magnifica larvae and 19 clinically healthy awassi sheep, were studied. The infected animals were divided into three groups depending on the number of larvae (Group 1: <50 larvae; Group 2: 50-100 larvae; Group 3: >100 larvae). In blood samples, red blood cell counts, hemoglobin, hematocrit concentration and white blood cell, neutrophil, lymphocyte, eosinophil, basophil counts, plasma malondialdehyde, erythrocyte glutathione levels and erythrocyte glutathione peroxidase activity were studied. The results revealed a marked decrease in red blood cell counts and hemoglobin concentrations along with a significant increase in white blood cell and neutrophil counts. The elevation in plasma malondialdehyde levels, a function of lipid peroxidation, established a significant difference between the control group and groups 2, 3. Decreased activity of erythrocyte glutathione peroxidase was found significant in the control group and all parasitemia. We conclude that in natural infestations with W. magnifica, as in infestation with Lucilia cuprina, there is a notable increase in inflammatory activities resulting from the movements, secretions, and toxins of the larvae and form the toxins secreted by the bacteria - which leads to an impression of anemia - and that the tissue injury results in an increase in level of free radicals in the organism.

Molecular identification of Cordylobia anthropophaga Blanchard (Diptera: Calliphoridae) larvae collected from dogs (Canis familiaris) in Jos South, Plateau State, Nigeria

Myiasis-causing larvae were extracted from dogs attending veterinary clinics in Plateau State, Nigeria and subjected to molecular analysis involving polymerase chain reaction amplification of the 28S rRNA gene of blowflies, cloning and sequencing techniques. All larvae were confirmed as Cordylobia anthropophaga Blanchard (Diptera: Calliphoridae) after the initial morphological identification. This is the first molecular identification of any myiasis-causing fly species in Nigeria and may serve as a reliable alternative to morphological identification where samples are not well preserved or difficult to identify to species level.

Genital myiasis by Wohlfahrtia magnifica (Diptera, Sarcophagidae) in Sicily (Italy)

Wohlfahrtia magnifica (Schiner, 1862; Diptera: Sarcophagidae), known also as flesh fly or screwworm, is a fly distributed especially in south Europe, Middle East, North Africa and China. Maggots of W. magnifica are responsible for traumatic myiasis in warm-blooded vertebrate animals and humans. In Italy data on wohlfahrtiosis in animals and humans are scant. This paper reports three cases of genital myiasis by W. magnifica in Sicily that occurred in a goat, a ram and a dog, respectively. Maggots were found in the vulva of a goat, in a wound localised in the scrotum of a ram and in the prepuce of a dog. Although the disease was not recorded before in the region, data collected from a questionnaire specifically designed for the study suggest that the disease is endemic in the area for more than 20 years. Larger epidemiological studies in the region are needed to get more data on disease prevalence and pattern of infestation as well as more information and education is needed for both farmers and veterinarians on wohlfahrtiosis and its strategies of control and treatment.

Myiasis in a dog shelter in Greece: epidemiological and clinical features and therapeutic considerations

The paper describes features of myiasis in a cohort of 163 dogs in an animal shelter, monitored over 3.5 years (4 fly activity seasons). Seven dogs (4 males, 3 females) were presented with myiasis; two dogs were presented twice with infestation in different areas of their body. The overall incidence rate (IR) of myiasis was 5.8 cases per 10(3) animal-months at risk, or else 0.0058 case per animal-month at risk. Six cases occurred from May to July and three from August to October, giving IRs of 7.7 per 10(3) animal-months and 3.9 per 10(3) animal-months, respectively, and an IR ratio of 1.97 (P=0.35). Five cases occurred in males and four in females, giving IRs of 7.8 per 10(3) animal months and 4.3 per 10(3) animal-months, respectively, and an incidence rate ratio of 1.78 (P=0.41). Three cases were diagnosed as cutaneous myiasis of the thigh, 2 cases as myiasis of the ear canal, 2 as myiasis of the prepuce, 1 as myiasis of the toes and 1 case as myiasis of the vagina. Median time from entrance into the shelter to infestation was 5 months; it was 1m in three dogs which were injured at entrance of animal into the shelter, but longer (5-15m) in the other four dogs. Larvae were identified as 2nd or 3rd stage instars of Wohlfahrtia magnifica. Signs characteristic of local inflammation, in the affected area of the body, were recorded. Treatment included mechanical removal of larvae, cleansing of the area, administration of injectable moxidectin and a broad-spectrum antimicrobial agent. Complete recovery was achieved within 1.5 months, bar that of preputial infestations which required 2.5 months.

Traumatic myiasis by Wohlfahrtia magnifica in Italy

Seven farms, two in Central Italy and five in Southern Italy, were visited for the presence of larvae-infested wounds. Ninety-six (3%) out of 3129 sheep examined had a traumatic myiasis with a very high percentage of infested animals found only in a farm (10.5%). Wounds were mainly localized on the vulva and prepuce. Infested animals were restless, anxious, and reluctant to graze. None of the 10 goats in one infested flock had wounds, whereas a shepherd dog from another flock presented a wound on the ear. All the larvae and adults reared from them in the laboratory were identified as Wohlfahrtia magnifica (Schiner, 1862) (Diptera, Sarcophagidae). The cases presented here are the first clinical cases of wohlfahrtiosis in sheep and dogs reported in Italy, and indicate that this myiasis is endemic in this country. A wider epidemiological investigation on the prevalence, incidence and seasonality of W. magnifica infestation of Italian W. magnifica population/s would be useful to understand its geographical provenience and the likely risk for its spreading throughout Italy and other non-endemic areas.

Fleshflies in the flesh: epidemiology, population genetics and control of outbreaks of traumatic myiasis in the Mediterranean Basin

Although the damaging effects on healthy tissues of its developing larvae were first described in 1770, the fleshfly Wohlfahrtia magnifica remains a serious pest for the livestock industry. Wohlfahrtiosis, the severe myiasis caused by this fly, is a grave problem in terms of both the animal welfare and economic loss. This review highlights important aspects of the biology, pest status, epidemiology, population genetic structure, economics and control of W. magnifica and wohlfahrtiosis, with an emphasis on recent outbreaks in Greece and Morocco and fly population dynamics in the Mediterranean Basin. Potential areas for future studies on genetics, host tolerance, in vitro rearing, field behaviour and range expansion of the species are also discussed.

Enabling technologies to improve area-wide integrated pest management programmes for the control of screwworms

The economic devastation caused in the past by the New World screwworm fly Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) to the livestock industry in the U.S.A., Mexico and the rest of Central America was staggering. The eradication of this major livestock pest from North and Central America using the sterile insect technique (SIT) as part of an area-wide integrated pest management (AW-IPM) programme was a phenomenal technical and managerial accomplishment with enormous economic implications. The area is maintained screwworm-free by the weekly release of 40 million sterile flies in the Darien Gap in Panama, which prevents migration from screwworm-infested areas in Columbia. However, the species is still a major pest in many areas of the Caribbean and South America and there is considerable interest in extending the eradication programme to these countries. Understanding New World screwworm fly populations in the Caribbean and South America, which represent a continuous threat to the screwworm-free areas of Central America and the U.S.A., is a prerequisite to any future eradication campaigns. The Old World screwworm fly Chrysomya bezziana Villeneuve (Diptera: Calliphoridae) has a very wide distribution ranging from Southern Africa to Papua New Guinea and, although its economic importance is assumed to be less than that of its New World counterpart, it is a serious pest in extensive livestock production and a constant threat to pest-free areas such as Australia. In the 1980s repeated introductions and an expansion of Old World screwworm populations were reported in the Middle East; in the 1990s it invaded Iraq and since late 2007 it has been reported in Yemen, where a severe outbreak of myiasis occurred in 2008. Small-scale field trials have shown the potential of integrating the SIT in the control of this pest and various international organizations are considering using the release of sterile insects as part of an AW-IPM approach on a much wider scale. Wohlfahrtia magnifica (Schiner) (Diptera: Sarcophagidae) is a screwworm of temperate regions, which, although of limited agricultural importance, has invaded several new locations in the past few years. This special issue reports on the results of a 6-year project funded by the Joint Food and Agriculture Organization of the United Nations/International Atomic Energy Agency (FAO/IAEA) Programme of Nuclear Techniques in Food and Agriculture entitled 'Enabling Technologies for the Expansion of the SIT for Old and New World Screwworm'. A major goal of the project was to better understand population genetic variation in screwworms as an aid to the identification of isolated populations. The project also addressed issues related to genetic sexing, cuticular hydrocarbons, population dynamics, genetic transformation and chromosome analysis.