The immunology of myiasis: parasite survival and host defense strategies

Exploring the molecular and toxicological mechanism associated with interactions between heavy metals and the reproductive system of Mytilus galloprovincialis

A large number of heavy metals resulted toxic to the reproductive system, but invertebrate infertility has been poorly explored, and above all, there are limited molecular, cellular and toxicological studies. In the present work, we exposed Mytilus galloprovincialis to three individual metal chlorides (CuCl2 15 μM, CdCl2 1.5 μM, NiCl2 15 μM) and their mixture for 24 h, to evaluate the effects on the protamine-like proteins (PLs), sperm DNA and on their interaction in the formation of sperm chromatin. Under all exposure conditions, but particularly after exposure to the metals mix, relevant changes in the electrophoretic pattern, by AU-PAGE and SDS-PAGE, and in fluorescence spectroscopy measurements of PLs were shown. In addition, alterations in DNA binding of these proteins were observed by Electrophoretic Mobility Shift Assay (EMSA) and through their release from sperm nuclei. Moreover, there was evidence of increased accessibility of micrococcal nuclease to sperm chromatin, which was also confirmed by toluidine blue staining. Furthermore, morphological analyses indicated severe gonadal impairments which was also corroborated by increased PARP expression, by Western blotting, and sperm DNA fragmentation, by comet assay. Finally, we investigated the expression of stress genes, gst, hsp70 and mt10, in gonadal tissue. The latter investigations also showed that exposure to this metals mix was more harmful than exposure to the individual metals tested. The present results suggest that these metals and in particular their mixture could have a negative impact on the reproductive fitness of M. galloprovincialis. Based on these evidences, we propose a molecular mechanism.

Comparative Analysis of Different ELISA Methods for the Serodiagnosis of Przhevalskiana silenus Infestation in Goats

Przhevalskiana silenus (warble fly) grubs cause myiasis in goats, in mountainous and semi-mountainous areas and different regions in Pakistan, and cause substantial losses to livestock. The palpation method for detecting warble flies generally neglects the infestation intensity; therefore, the development of a reliable and efficient diagnostic technique is extremely necessary. This study compared three indirect enzyme-linked immunosorbent assay (ELISA) methods for detecting anti-P. silenus antibodies using the hypodermin C (HyC) purified from Hypoderma spp. Larvae collected in cattle (local isolate, Microbiology Laboratory, PMAS-Arid Agriculture University, Rawalpindi), the crude antigen from the first instar stage of P. silenus, and a commercial Bovine Hypodermosis Antibody ELISA kit (IDEXX Laboratory), for accurately estimating the seroprevalence of goat warble fly infestation (GWFI) in the Pothwar plateau, Punjab, Pakistan. The ELISA with the crude antigen of P. silenus proved very sensitive and specific, 91% and 93%, respectively. The optical density exhibited a monthly variation, and the antibody titer began increasing from June, continually increased from July to December, and gradually decreased thereafter until March. The study confirmed the endemic status of GWFI in the Pothwar region and identified that ELISA based on the crude antigen of P. silenus was a more sensitive and specific immunodiagnostic method for determining seroprevalence, and could be employed for initiating nationwide eradication campaigns.

Seroprevalence of nasal myiasis in camels determined by indirect enzyme-linked immunosorbent assay utilizing the most diagnostic Cephalopina titillator larval antigens

Background and Aim

Nasal myiasis is a serious parasitic disease among camels caused by Cephalopina titillator larvae that negatively affect animal health and production globally. The diagnosis of the infestation relies on postmortem examination of the head region, which considers a cause impeding treatment of live animals and may be misdiagnosed as central nervous system disorders. This study aimed to identify the most diagnostic larval antigen with the capacity for monitoring C. titillator infestation, and to estimate the seroprevalence of nasal myiasis in camels in Egypt, using indirect enzyme-linked immunosorbent assay (ELISA).

Materials and Methods

Three hundred and six male camels of Egyptian and Sudanese breeds, aged 2-5 years, were clinically evaluated for respiratory and/or nervous disorders in Cairo Governorate, Egypt. At the time of slaughter, blood samples were collected from all examined animals. The postmortem examination of 38 animals was conducted. Salivary glands, hemolymph, and somatic antigens were extracted from the second and third larval instars.

Results

The results revealed that the salivary gland antigen was the most potent antigen in detecting C. titillator specific total IgG antibodies compared to haemolymph and crude somatic antigens. Using receiver-operating characteristic curves and area under the curve, the salivary gland antigen had a sensitivity of 91.67% and a specificity of 92.31%, respectively. It has the highest positive predictive value, 95.7%, and negative predictive value, 85.7%. However, using somatic and hemolymph antigens revealed a sensitivity of 79.17% and 70.83% and a specificity of 76.9% and 84.6%, respectively. There was complete concordance between ELISA results and autopsy findings (true positive). One hundred and forty out of 306 (45.8%) camel serum samples were found to contain C. titillator.

Conclusion

This study demonstrated that salivary gland antigen is more effective than somatic and hemolymph antigens in accurately detecting nasal myiasis in camels. In addition, determining the seroprevalence of nasal myiasis with the salivary gland antigen through indirect ELISA revealed that it is a prevalent disease among camels in Egypt. Periodic surveillance of the C. titillator prevalence is necessary for effective management and control measures.

Prevalence and pathology of Cephalopina titillator infestation in Camelus bactrianus from Xinjiang, China

BACKGROUND

In camels, nasopharyngeal myiasis is caused by the larvae of Cephalopina titillator, which parasitize the tissues of nasal and paranasal sinuses, pharynx, and larynx. C. titillator infestation adversely affects the health of camels and decreases milk and meat production and even death. However, the C. titillator infestation in Bactrian camels has not been widely studied.

METHODS

The present study was conducted to determine the prevalence and risk factors of C. titillator in Bactrian camels of northwestern Xinjiang. Suspected larvae recovered from infested camels were evaluated for C. titillator by microscopy and polymerase chain reaction. Nucleotide sequences of the partial mitochondrial cytochrome c oxidase subunit I (COX1) and cytochrome b (CYTB) genes from the C. titillator of camels were aligned from the NCBI database. Furthermore, the gross and histopathological alterations associated with C. titillator infestation were evaluated via pathological examination.

RESULTS

Of 1263 camels examined 685 (54.2%) camels were infested with suspected C. titillator larvae. Different larval stages were topically detected in the nasal passages and pharynx of the camel heads. Microscopy analysis of the pharyngeal mucosa tissue revealed necrotic tissue debris and some inflammatory cells. Molecular detection of the larval COX1 and CYTB genes indicated that pathogen collected in Bactrian camels was C. titillator. The epidemiological study demonstrated that the prevalence rate of C.titillator infestation was significantly higher in camels of Bestierek Town Pasture (67.2%) and Karamagai Town Pasture (63.6%) compared to Kitagel Town Pasture (38.7%) and Qibal Town Pasture (35.8%) (P < 0.05). No significant difference was observed between the prevalence rates in male (52.6%) and female (54.6%) camels (P > 0.05). The prevalence was higher in warm (64.2%) than that in cold (48.4%) seasons (P < 0.001). The prevalence in camels with non-nomadic method (67.2%) was significantly higher than in animals with nomadic method (47.5%) (P < 0.001). The prevalence of C.titillator infestation was significantly higher in animals of aged 5-10 (60.1%) and aged > 10 (61.1%) years old compared to those of aged < 5 (31.7%) years old camels (P < 0.001).

CONCLUSION

Our results confirm that there is a high prevalence of C. titillator in Bactrian camels from Xinjiang, closely related to age, season, pasture environment, and husbandry methods. Developing prevention, diagnosis, and control programs to prevent transmission is necessary.

Association of Environmental Factors with Seasonal Intensity of Erysipelothrix rhusiopathiae Seropositivity among Arctic Caribou

Several caribou (Rangifer tarandus) populations have been declining concurrently with increases in infectious diseases in the Arctic. Erysipelothrix rhusiopathiae, a zoonotic bacterium, was first described in 2015 as a notable cause of illness and death among several Arctic wildlife species. We investigated epidemiologic and environmental factors associated with the seroprevalence of E. rhusiopathiae in the Arctic and found that seropositivity was highest during warmer months, peaking in September, and was highest among adult males. Summer seroprevalence increases tracked with the oestrid index from the previous year, icing and snowing events, and precipitation from the same year but decreased with growing degree days in the same year. Seroprevalence of E. rhusiopathiae varied more during the later years of the study. Our findings provide key insights into the influence of environmental factors on disease prevalence that can be instrumental for anticipating and mitigating diseases associated with climate change among Arctic wildlife and human populations.

Myiasis by Cordylobia anthropophaga (Calliphoridae) in rodents from Cape Verde

Purpose

The tumbu fly, Cordylobia anthropophaga (Diptera: Calliphoridae), is widely distributed in continental tropical and subtropical Africa, being the most common cause of furuncular myiasis in Sub-Saharan Africa. The aim of the present work was to analyze the role of rodents as possible reservoirs of C. anthropophaga in Cape Verde, considering the zoonotic character of this fly species.

Materials and Methods

A total of 150 peridomestic rodents were studied in Santiago island. For the obtained larvae, morphological and molecular characters were analyzed.

Results

Cordylobia anthropophaga was found in 6.4% of the peridomestic Rattus rattus analyzed. The present work unveils the presence of C. anthropophaga in rodents of the African archipelago of Cape Verde, introduced probably with West African humans and/or animals.

Conclusion

The presence in peridomestic animals, and the wide range of species that this fly can affect, entails a zoonotic risk of myiasis by tumbu fly.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11686-022-00576-8.

Oestrid myiasis at a cross-road

The oestrids are a genuinely unique group of Diptera that represent many species whose larvae parasitize mammals, feeding on live tissues of a wide range of hosts, from mice to elephants, causing obligatory myiases. Those have had greatest impact on the activities of humans and their use of animals (e.g., as food, recreation, in the conduct of wars). To a large extent their impact has been controlled through the use of therapeutic application of synthetic chemical treatments. While in some limited cases eradication has been achieved, it is unlikely to become the norm as these parasites seem well adapted to survive at low population densities and small smoldering foci are likely to present a challenge in the future. Should organic production eschew the use of parasiticides, other than for rescue of seriously ill animals, the foci of infection by these parasites will remain. In this article, we explore current scientific information on this group of parasites that may have become an anachronism in modern livestock parasitology, identify gaps in our knowledge as well as the suggestions for the management of these parasites in the era of genomics and proteomics.

First molecular characterization of hypodermin genes of Hypoderma bovis and serodiagnosis of bovine hypodermosis with recombinant hypodermin C antigen and a synthetic peptide containing its linear B-cell epitope

Hypodermins A (HA), B (HB), and C (HC) of warble flies are modulatory antigens involved in host inflammation and immune responses during migration of the warble fly larvae through host connective tissues. In the current study, molecular characteristics of the genes encoding HA, HB, and HC were revealed from cDNA constructs of third-instar larvae of Hypoderma bovis. The open reading frame (ORF) of each hypodermin gene was amplified with modified gene-specific primers, and the resulting PCR products were cloned into pGEM-T Easy Vector to produce recombinant plasmids (rHA, rHB, and rHC). The ORF sequences of rHA, rHB, and rHC genes are 705 bp, 771 bp, and 783 bp long and encode proteins of 234, 256, and 263 amino acids with predicted sizes of 25.74 kDa, 27.79 kDa, and 28.51 kDa, respectively. The rHC gene was subcloned into the pET 100/D-TOPO Expression Vector, and the recombinant HC was purified using affinity chromatography. Western blotting indicated that rHC was recognized by the sera of cattle naturally infested with H. bovis. The rHC and a synthetic peptide (sHC) containing its linear B cell-specific epitope were evaluated as serological markers in indirect ELISA (iELISA) for the diagnosis of bovine hypodermosis. Both sHC and rHC iELISAs had sensitivity values equal to or higher than 90 % and specificity values of 100 %. A total of 200 serum samples from cattle in the Central Anatolia Region of Turkey were also analyzed by rHC and sHC-iELISAs to reveal the seroprevalence of bovine hypodermosis. The results of both iELISAs were consistent with one another and revealed a hypodermosis prevalence of 62 %. Our study provides the first data on molecular characterization of hypodermin genes of H. bovis and indicates the efficacy of recombinant antigen and peptide-based iELISA for serodiagnosis of bovine hypodermosis.

Advanced immunological studies on Cephalopina titillator with special references to the epidemiological uses of Dot-ELISA in camel sera

Cephalopina titillator (C. titillator) is a common worldwide nasal bot fly larval infestation of camels, which belongs to the family Oestridae. This study aimed to evaluate two new immunologic diagnostic techniques; indirect-ELISA and Dot-ELISA, for the screening of C. titillator infestation in camels. Thirty slaughtered camel heads were examined carefully for the presence of C. titillator larvae. One hundred, third-stage larvae (L3), were dissected for the collection of their salivary glands, for the preparation of the salivary gland antigen. Blood samples were obtained for hematological and serological examinations. Results revealed a true prevalence of C. titillator in the sampled camels being 80% (24/30). Infested camels showed a significant reduction in leukocytes (P < 0.0001) and neutrophils (P = 0.045), and a significant increase in eosinophils and monocytes (P < 0.0001). The serological examination estimated apparent prevalence as 80% (24/30) and 90% (27/30) by Dot-ELISA and indirect-ELISA, respectively. Dot-ELISA revealed 100% sensitivity, specificity, and accuracy. While, indirect-ELISA displayed 100% sensitivity, 50% specificity, and 90% accuracy. Dot-ELISA exhibited perfect agreement with the gold standard test, so it could be considered an ideal, simple, and accurate immunologic screening technique for the detection of C. titillator in camels.

Efficacy of some essential oils on Cephalopina titillator with special concern to nasal myiasis prevalence among camels and its consequent histopathological changes

Nasopharyngeal myiasis is an important high incidence disease among camels in the Middle East and North of Africa caused by Cephalopina titillator (C. titillator) that results in sever economic losses in many camel breeding areas around the world. The current study was conducted to evaluate the efficacy of three essential oils; camphor, ginger and cinnamon oils and their histopathological effects on the 3rd larval instar of C. titillator, with special regard to the prevalence percentage of C. titillator infestation in slaughtered camels at Egyptian abattoirs in addition to investigate histopathological alterations of the infested animal's tissue. This study fulfilled that the prevalence of C. titillator infestation was 35.2% among slaughtered camels during summer season. The three tested essential oils were caused a significant mortality of C. tittilator; however, camphor oil was exhibited greater and quicker insecticidal effect than ginger and cinnamon oils at the same concentration in terms of mortality of the 3rd instar C. tittilator larvae. There was a concentration-dependent effect on the larvae among the tested essential oils. The tested essential oils were caused remarkable histopathological alterations on the treated larval cuticle. The main salient lesions of the examined infested camel's tissue were necrotic and inflammatory alterations associated with cystic dilation of submucosal glands.

Contrasting consequences of different defence strategies in a natural multihost-parasite system

Hosts counteract infections using two distinct defence strategies, resistance (reduction in pathogen fitness) and tolerance (limitation of infection damage). These strategies have been minimally investigated in multi-host systems, where they may vary across host species, entailing consequences both for hosts (virulence) and parasites (transmission). Comprehending the interplay among resistance, tolerance, virulence and parasite success is highly relevant for our understanding of the ecology and evolution of infectious and parasitic diseases. Our work investigated the interaction between an insect parasite and its most common bird host species, focusing on two relevant questions: (i) are defence strategies different between main and alternative hosts and, (ii) what are the consequences (virulence and parasite success) of different defence strategies? We conducted a matched field experiment and longitudinal studies at the host and the parasite levels under natural conditions, using a system comprising Philornis torquans flies and three bird hosts - the main host and two of the most frequently used alternative hosts. We found that main and alternative hosts have contrasting defence strategies, which gave rise in turn to contrasting virulence and parasite success. In the main bird host, minor loss of fitness, no detectable immune response, and high parasite success suggest a strategy of high tolerance and negligible resistance. Alternative hosts, on the contrary, resisted by mounting inflammatory responses, although with very different efficiency, which resulted in highly dissimilar parasite success and virulence. These results show clearly distinct defence strategies between main and alternative hosts in a natural multi-host system. They also highlight the importance of defence strategies in determining virulence and infection dynamics, and hint that defence efficiency is a crucial intervening element in these processes.

Immunological evaluation of some antigens of Lucilia sericata larvae

The present study aimed to select an antigen of Lucilia sericata larvae showing both high antigenicity and cross-reactive binding abilities with other related antigens of L. sericata larvae for obtaining a promising candidate vaccine antigen. The ELISA results primary concluded that among the excretory secretory (ES) and midgut (MG) antigens of the different larval instars of L. sericata, MGL2 could be characterized as antigen which was able to reflect the highest level of antigenicity and cross-reactivity with the other tested L. sericata antigens. The results were extended to spot the light on the relation between different protein bands in MGL2 and rabbit hyper- immune sera (HIS) raised against the other tested antigens using SDS-PAGE and Western blot technique. Analysis by SDS-PAGE of ES and MG antigens of the different larval instars of L. sericata revealed common protein bands at molecular weights of about 10, 12, 16, 20, 28, 33 and 46 kDa. Western blotting of MGL2 antigen transferred to nitrocellulose sheet revealed reaction by MGL2 HIS to five polypeptide bands; 20, 28, 33, 46 and 63 kDa. Three bands of 28, 33 and 63 kDa were the most prominent bands detected whereas; there was a weak reaction with bands of 20 and 46 kDa. But what was apparent in Western blot was a strong reaction of all tested HIS with a polypeptide band of 63 kDa. This band might be considered to be the main cause of cross reactive binding ability of MGL2 antigen that had been recorded previously in ELISA technique.

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.

An overview on different aspects of hypodermosis: Current status and future prospects

Livestock plays a vital role in economic development of a nation and is being used in agriculture for draft power, production of farmyard manure as well as milk and meat production. Bovine hypodermosis is the top culprit among all parasitic infections across the world. Hypodermosis is an endemic disease in the mountainous areas/plain areas and is regularly observed in the northern hemisphere of the globe affecting cattle, deer, yaks and buffaloes. There is a wide variation in geographical distribution of Hypoderma spp. during the years 1945-2015. The manuscript includes a geospatial study that tries to maps the global distribution of hypodermosis in different areas of the world in order to detect hotspots or endemic areas that may be a potential source for disease spread. This information's are very useful to predict the potential high risk areas that are prone to disease outbreak. The present review aims to evaluate the global distribution, molecular discrimination, diagnostics and vaccination of hypodermosis, focusing on its current status and future perspectives towards the management of the disease and its control strategies.

Unusual presence of Ornidia robusta (Diptera: Syrphidae) causing pig myiasis in Argentina

Myiasis is caused by dipterous larvae from the Calliphoridae, Sarcophagidae, Muscidae, Cuterebridae, and Syrphidae families. In this work, Cochliomyia hominivorax, Chrysomya megacephala, and Ornidia robusta were identified causing vulva, ear, and leg myiasis in pigs in Tucuman province, northwestern Argentina. The report of the presence of C. hominivorax and C. megacephala is very important due to their role as myiasis-causing and disease vectors. The occurrence of Ornidia robusta is remarkable, since it constitutes the first record of myiasis in general and of myiasis in pigs in particular. Lastly, the presence of Sarcophaga spp. is also interesting, since some of them originate myiasis and are therefore of concern for cattle, wild animals, and human populations.

Profiling of proteins and proteases in the products of the salivary gland, digestive tract and excretions from larvae of the camel nasal botfly, Cephalopina titillator (Clark)

Proteins and proteolytic activities in the contents of the salivary gland (SGc), digestive tract (DTc) and excretory-secretory products (ESP) from larvae of the camel nasal botfly Cephalopina titillator were separated electrophoretically, and characterized. The protein profiles of the different samples were qualitatively quite similar in the larval stages L2 and L3. Zymogram analysis of proteases in the samples indicated that the digestive tract contained a greater variety of proteases than the salivary gland or the excretory-secretory products. They are mainly serine proteases. Proteases of ESP and DTc (especially of 3rd instar) contain trypsin- and chymotrypsin-like serine proteases, while the serine proteases of SGc are not of the trypsin- or chemotrypsin-type.

Human Cutaneous Myiasis by the Australian Sheep Blowfly, Lucilia cuprina (Diptera: Calliphoridae), in Oklahoma

This case report describes an incident of myiasis in Oklahoma City, Oklahoma. Paramedics treated a 53-year-old man in the field when he suffered cardiac arrest. He was intubated by the paramedics and transported to an emergency room, where he received two stents and a balloon pump. He was found to have a GCS of three and remained in the hospital for 7 days before passing away. After his death, the breathing tube was removed, revealing the presence of several maggots. On closer inspection, the dipteran larvae were found in both the oral and nasal cavities. Four of these larvae were reared to adulthood and identified as Lucilia cuprina (Weidemann) (Diptera: Calliphoridae), commonly known as the Australian sheep blowfly, by the Biology Department of the University of Oklahoma. Based on the fly's life cycle and rate of development, the infestation is suspected to be hospital acquired.

The immunobiology of myiasis infections--whatever happened to vaccination?

The current state of myiasis vaccine technologies are reviewed mainly in the primary research genera of Lucilia and Hypoderma. The importance of myiasis flies as primary causes of morbidity and mortality in agricultural species and man has not diminished despite the existence of good control strategies. However, the development of vaccines against myiasis infections has been relatively quiescent for more than 10 years despite the rapid development of genomic and proteomic analysis and of skills in data interpretation. The value of vaccine research in an era of chemical primacy is analysed. In fact, recent findings of drug resistance and the impact of animal welfare concerns should mean a renewed interest in alternative controls. The reasons that this has not been true to date are explored and new possibilities discussed.

Unusual pseudomyiasis with Musca domestica (housefly) larvae in a tracheostomy wound: a case report and literature review

We report a case of pseudomyiasis (accidental myiasis) in a 52-year-old man who had previously undergone surgery and placement of a tracheostomy tube for laryngeal cancer. The patient presented to our outpatient department with a foul-smelling, blood-stained discharge and frequent and severe episodic pain at the site of the tracheostomy. He also reported the discharge of many whitish larvae from the site. On clinical examination, 3 of these larvae were removed from the tracheostomy wound and later identified as Musca domestica (housefly) larvae. The patient underwent further mechanical removal twice daily for 3 days, during which time 23 more larvae, or maggots, were removed. His condition improved, and he returned for regular follow-up with no recurrence or complications. Myiasis is an infestation of humans and vertebrate animals by insect larvae that feed on both dead and living tissue. Myiasis is most common in hot and humid climates in tropical and subtropical regions, such as the underdeveloped areas of India, Africa, and Southeast Asia, which provide favorable breeding grounds for flies. Myiasis is classified as specific, semispecific, or accidental, depending on whether the fly larvae require a host in order to develop. We review the literature on myiasis and its entomologic aspects in general. We also discuss the need for the proper care of tracheostomy wound myiasis because the site of such an infestation is close to vital organs in the neck. To the best of our knowledge, only 3 cases of tracheostomy wound myiasis have been previously reported in the English-language literature; 2 of them involved infestation with Chrysomyia bezziana larvae and 1 with Lucilia caesar larvae. We believe our case is the first case of tracheostomy wound pseudomyiasis attributable to M domestica larvae.

Neurological and ocular fascioliasis in humans

Fascioliasis is a food-borne parasitic disease caused by the trematode species Fasciola hepatica, distributed worldwide, and Fasciola gigantica, restricted to given regions of Africa and Asia. This disease in humans shows an increasing importance, which relies on its recent widespread emergence related to climate and global changes and also on its pathogenicity in the invasive, biliary, and advanced chronic phases in the human endemic areas, mainly of developing countries. In spite of the large neurological affection capacity of Fasciola, this important pathogenic aspect of the disease has been pronouncedly overlooked in the past decades and has not even appear within the numerous reviews on the parasitic diseases of the central nervous system. The aim of this wide retrospective review is an in-depth analysis of the characteristics of neurological and ocular fascioliasis caused by these two fasciolid species. The terms of neurofascioliasis and ophthalmofascioliasis are restricted to cases in which the direct affection of the central nervous system or the eye by a migrant ectopic fasciolid fluke is demonstrated by an aetiological diagnosis of recovered flukes after surgery or spontaneous moving-out of the fluke through the orbit. Cases in which the ectopic fluke is not recovered and the symptoms cannot be explained by an indirect affection at distance may also be included in these terms. Neurofascioliasis and ophthalmofascioliasis cases are reviewed and discussed. With regard to fascioliasis infection giving an indirect rise to neurological affection, the distribution and frequency of cases are analysed according to geography, sex, and age. Minor symptoms and major manifestations are discussed. Three main types of cases are distinguished depending on the characteristics of their manifestations: genuine neurological, meningeal, and psychiatric or neuropsychic. The impressive symptoms and signs appearing in each type of these cases are included. Brain examination techniques and neuroimaging useful for the diagnosis of neurological cases are exposed. Within fascioliasis infection indirectly causing ocular manifestations, case distribution and frequency are similarly analysed. A short analysis is devoted to clarify the first reports of a human eye infection. The affection of related and close organs is discussed by differentiating between cases of the dorsal spine, pulmonary manifestations, heart and vessel affection, findings in blood vessels, skin and dermatologic reactions, cases of ectopic mature flukes, and upper body locations. The clinical complexity of the puzzling polymorphisms, the disconcerting multifocality of the manifestations, and their changes along the evolution of the disease in the same patient, as well as the differences between the clinical pictures shown by different patients, are highlighted. The many syndromes involved are enumerated. The pathogenic and physiological mechanisms underlying neurofascioliasis and ophthalmofascioliasis caused by ectopic flukes and the physiopathogenic processes indirectly affecting the central nervous system and causing genuine neurological, meningeal, psychiatric, and ocular manifestations are discussed. The diagnosis of neurological and ophthalmologic fascioliasis is analysed in depth, including clinical and paraclinical diagnosis, eosinophilia in the blood and cerebrospinal fluid, differential diagnosis from other parasitic infections such as helminthiases and myiases, an update of human fascioliasis diagnosis, and fluke and/or fluke egg recovery by surgery. Diagnostic analyses with faecal and blood samples for fascioliasis patients are updated. Therapy for patients with major neurological manifestations includes both antiparasitic treatments and anti-inflammatory therapeutics. Prognosis in fascioliasis patients with neurological manifestations is discussed, with emphasis on sequelae and fatal cases, and the care of patients with ophthalmologic manifestations is added. Conclusions indicate that neurological cases are overlooked in human fascioliasis endemic areas and also in developing countries in general. In remote zones, rural health centres and small hospitals in or near the human endemic areas do not dispose of the appropriate equipments for neurological analyses. Moreover, physicians may not be aware about the potential relationship between liver fluke infection and neurological implications, and such cases may therefore remain misdiagnosed, even in developed countries. Priority should henceforth be given to the consideration of neurological and ocular affection in human endemic areas, and efforts should be implemented to assess their characteristics and frequency. Their impact should also be considered when estimating the global burden of fascioliasis.

Proteolytic activity regarding Sarconesiopsis magellanica (Diptera: Calliphoridae) larval excretions and secretions

Sarconesiopsis magellanica (Diptera: Calliphoridae) is a medically important necrophagous fly which is used for establishing the post-mortem interval. Diptera maggots release proteolytic enzymes contained in larval excretion and secretion (ES) products playing a key role in digestion. Special interest in proteolytic enzymes has also been aroused regarding understanding their role in wound healing since they degrade necrotic tissue during larval therapy. This study was thus aimed at identifying and characterising S. magellanica proteolytic enzyme ES products for the first time. These products were obtained from first-, second- and third-instar larvae taken from a previously-established colony. ES proteins were separated by SDS-PAGE and their proteolytic activity was characterised by zymograms and inhibition assays involving BAPNA (Nα-benzoyl-dl-Arg-p-nitroanilide) and SAPNA substrates, using synthetic inhibitors. The protein profile ranged from ∼69kDa to ∼23kDa; several of them coincided with the Lucilia sericata ES protein profile. Serine-protease hydrolysis activity (measured by zymogram) was confirmed when a ∼25kDa band disappeared upon ES incubation with PMSF inhibitor at pH 7.8. Analysis of larval ES proteolytic activity on BAPNA and SAPNA substrates (determined by using TLCK and TPCK specific inhibitors) suggested a greater amount of trypsin-like protease. These results support the need for further experiments aimed at validating S. magellanica use in larval therapy.

Antimicrobial activity of untypical lipid compounds in the cuticular and internal lipids of four fly species

AIMS

This article describes the qualitative and quantitative analyses of untypical compounds in the cuticular and internal lipids of four dipteran species. For isolated compounds, antimicrobial activity against 18 reference strains of bacteria and fungi was determined.

METHODS AND RESULTS

In this study, gas chromatography (GC) combined with mass spectrometry (GC-MS) was used to analyse the surface and internal compounds of four fly species. Seven untypical compounds from both pre-imaginal and imaginal stages of examined insects were identified. Azelaic acid (AA) was the most abundant, while phenylacetic and phenylpropionic acids occurred in lower concentration. Minor quantities of sebacic acid, 2-methyl-2-hydroxybutanoic acid, tocopherol acetate and trace amounts of 2,4-decadienal were also detected. Tocopherol acetate was found only in cuticular lipids of Musca domestica larvae. Each compound was tested against several species of fungi and bacteria by determining minimal inhibitory concentration (MIC). Human pathogenic fungi were also investigated. Phenylpropionic acid showed the greatest antifungal activity. Bacterial strains were insensitive to the presence of identified compounds, apart from 2,4-decadienal which strongly inhibited bacterial growth.

CONCLUSIONS

This is the first time that the chemical composition and the antimicrobial activity of untypical compounds in the cuticular and internal lipids of four fly species has been analysed.

SIGNIFICANCE AND IMPACT OF THE STUDY

Determination of untypical compounds and their antimicrobial activity can effectively contribute to the knowledge concerning insect defence mechanisms.

Ocorrência das doenças parasitárias em ovinos e caprinos no Distrito Federal, Brasil, durante 2003 a 2009

O parasitismo é um dos principais fatores limitantes na produção animal em geral. A ovinocultura e caprinocultura são afetadas por diversos parasitas que representam significativas perdas em carne, leite e lã da cultura. A introdução recente de ovinos e caprinos no Centro-Oeste brasileiro trouxe consigo novas enfermidades antes não relatadas na região. O objetivo deste estudo é descrever a ocorrência dos principais parasitas que afetam os caprinos e ovinos no Distrito Federal e região do entorno e os fatores predisponentes destas enfermidades ao rebanho local, revisando os casos obtidos pela necropsia dos animais no período de 2003 a 2009. Nos meses de outubro de 2009 a julho de 2010 foram revistos os laudos de necropsia da região, em retrospectiva dos anos de 2003 a 2009, à procura das casuísticas por doenças parasitárias. Verificou-se a ocorrência de endoparasitoses e ectoparasitoses em pequenos ruminantes. Os principais parasitas encontrados foram o Haemonchus contortus e Oestrus ovis nas duas culturas, porém Oesophagostomun sp. ocorreu apenas em ovinos. Encontrou-se maior ocorrência de Haemonchose na estação chuvosa do Cerrado. Este é o primeiro trabalho epidemiológico descritivo sobre parasitismo em cabras e ovelhas na região.

In vitro control of the camel nasal botfly, Cephalopina titillator, with doramectin, lavender, camphor, and onion oils

Camels are very important livestock particularly in arid and semiarid lands. The oestrid fly, Cephalopina titillator (Clark), causes nasopharyngeal myiasis in camels, and it is widely distributed in many camel breeding areas triggering health hazards and severe economic losses in camels. The prevalence of infestation of camels (slaughtered at Tokh's slaughterhouse, Qalyubia Governorate, Egypt, during the period from September 2011 to March 2012) was 41.67 % (100 out of 240). Most infested camels developed clinical signs of nasal discharge, restlessness, loss of appetite, difficulty in breathing, frequent sneezing, and snoring. Postmortem examination of infested camels explained that breathing of the animal is greatly impaired because of blockage of the nasopharynx by larvae and/or mucofibrinous secretions. The larval count per camel ranged from 1 to 250 (mean 28.45 ± 6.48). In vitro larval immersion tests were carried out to determine the efficacy of doramectin (0.003 %) as well as some essential oils (50 % each) such as lavender, camphor, and onion oils against the second and third larval stages (L2 and L3) of C. titillator. Another trial had been done for imitating what could happen if the area around camels were treated with an insecticide or an insect repellent. All treated L2 died 18 h posttreatment (PT) with both doramectin and lavender, and 100 % mortality was reached for L3 after 24 and 30 h PT with lavender and doramectin, respectively. Doramectin and lavender induced the highest response against C. titillator as their lethal time (LT50) values after treatment of L2 were 3.40 and 3.60 h, respectively, and those of L3 were 4.99 and 5.53 h, respectively. Against both L2 and L3 of C. titillator and based on LT50 values of onion oil and those of other applied materials, doramectin and lavender oil were four times more effective than onion oil, and camphor oil was two times more effective than onion oil. Based on LT50 values of essential oils and those of doramectin, as a reference substance, the relative speed of efficacy indicated that camphor and onion oils were, respectively, two and four times less effective than doramectin and lavender. With regard to fumigant technique, neither the insecticide, New Pyrosol, nor the insect repellent, Keto, was effective in controlling C. titillator larvae. Our results indicated that doramectin and lavender could be selected as drugs of choice for controlling C. titillator, but it is not permitted to use doramectin on dairy animals during lactation. Lavender (50 %) has a great potential to be developed as a novel larvicide and could be used as nasal drench against nasal botfly which will reflect on camel production and the national economy.

The characterization of Lucilia cuprina acetylcholinesterase as a drug target, and the identification of novel inhibitors by high throughput screening

Acetylcholinesterase (AChE, EC3.1.1.7.) is the molecular target for the carbamate and organophosphate pesticides that are used to combat parasitic arthropods. In this paper we report the functional heterologous expression of AChE from Lucilia cuprina (the sheep blowfly) in HEK293 cells. We show that the expressed enzyme is cell-surface-exposed and possesses a glycosyl-phosphatidylinositol membrane anchor. The substrates acetyl-, propionyl- and butyrylthiocholine (AcTC, PropTC, ButTC), and also 11 further thiocholine and homo-thiocholine derivatives were chemically synthesized to evaluate and compare their substrate properties in L. cuprina AChE and recombinant human AChE. The Michaelis-Menten constants K(M) for AcTC, PropTC and ButTC were found to be 3-7-fold lower for the L. cuprina AChE than for the human AChE. Additionally, 2-methoxyacetyl-thiocholine and isobutyryl-thiocholine were better substrates for the insect enzyme than for the human AChE. The AcTC, PropTC and ButTC specificities and the Michaelis-Menten constants for recombinant L. cuprina AChE were similar to those determined for AChE extracted from L. cuprina heads, which are a particularly rich source of this enzyme. The median inhibition concentrations (IC(50) values) were determined for 21 organophosphates, 23 carbamates and also 9 known non-covalent AChE inhibitors. Interestingly, 11 compounds were 100- to >4000-fold more active on the insect enzyme than on the human enzyme. The substrate and inhibitor selectivity data collectively indicate that there are structural differences between L. cuprina and human AChE in or near the active sites, suggesting that it may be possible to identify novel, specific L. cuprina AChE inhibitors. To this end, a high throughput screen with 107,893 compounds was performed on the L. cuprina head AChE. This led to the identification of 195 non-carbamate, non-organophosphate inhibitors with IC(50) values below 10μM. Analysis of the most potent hit compounds identified 19 previously unknown inhibitors with IC(50) values below 200nM, which were up to 335-fold more potent on the L. cuprina enzyme than on the human AChE. Some of these compounds may serve as leads for lead optimization programs to generate fly-specific pesticides.

A serological and molecular survey of cattle hypodermosis in east-Turkey

The aim of this study was to determine the seroprevalence of hypodermosis in cattle in East-Turkey and to identify Hypoderma species using morphological and molecular methods. For this purpose, a total of 778 serum samples of cattle were collected from Erzurum provinces of east-Turkey from December 2008 to February 2009. The sera were analyzed using a Hypodermin C antigen by means of indirect ELISA. In addition, 10 Hypoderma spp. larvae were collected from slaughtered animals in the abattoir for morphological identification and molecular characterization on the basis of mitochondrial CO1 gene sequence analysis and PCR-RFLP. Two hundred and twenty three (28.6%) out of 778 cattle were seropositive for hypoderma antibodies. All positive cattle were female of a local breed. Seven out of 10 Hypoderma larvae were morphologically classified as third instar larvae (L3) of H. bovis and 3 were classified as L3 of H. lineatum. The TaqI restriction enzyme was used to differentiate the Hypoderma species on the basis of the 438 and 250 bp bands for H. bovis and the 488 and 200 bp bands for H. lineatum resulting from PCR-RFLP. According to the alignment of the mitochondrial CO1 sequences of the Hypoderma species and the PCR-RFLP results, all examined larva samples were classified as H. bovis.

Spleen cell proliferation during and after skin myiasis by human bot fly Dermatobia hominis

Spleen cells from mice were examined at 5, 10, 15, 20 and 25 days post-infection (dpi) with Dermatobia hominis larva and at 5, 10, 15, 30 and 60 days post-larval emergence (dple). Cell proliferation in vitro assays were carried out with RPMI-1640 medium and larval secretory product (LSP) of D. hominis at 5, 10, 15, 20 and 25 days. When each group of mice was tested against each medium, significance was only seen for 25 dpi, with increasing order: LSP-10 d, -25 d, -5 d, -20 d, -15 d and RPMI. Significant results were also observed when each medium was tested against mice at each dpi or dple. Each dple group vs. each medium produced significant results only for 10 dple, with increasing order: LSP-5 d, -20 d, -25 d, -10 d, -15 d and RPMI. Comparative tests were also carried out between groups to refine certain observations. The LSPs were also analyzed using SDS-PAGE. The results prove that myiasis caused depletion of spleen cells, particularly under the effect of the LSP-10 and -15, but the cells tended to increase up to 60 dple. This in vitro assay may represent the real systemic immune response in the relationship LSP-D. hominis-host.

Protein expression profile of Gasterophilus intestinalis larvae causing horse gastric myiasis and characterization of horse immune reaction

Background

Little information is available on the immunological aspect of parasitic Gasterophilus intestinalis (Diptera, Oestridae) larvae causing horse gastric myiasis. The objectives of this research were to analyze the protein content of larval crude extracts of the migrating second and third larvae (L2 and L3) of G. intestinalis in order to characterize the immune response of horses.

Results

The proteomic profile of L2 and L3, investigated by using one and two dimensional approaches, revealed a migration pattern specific to each larval stage. Furthermore, Western blots were performed with horse sera and with sera of Balb/c mice immunised with the larval crude extracts of L2 or L3, revealing a different immune reaction in naturally infected horses vs. artificially induced immune reaction in mice. The comparisons of the immunoblot profiles demonstrate that the stage L2 is more immunogenic than the stage L3 most likely as an effect of the highest enzymatic production of L2 while migrating through the host tissues. Fifteen proteins were identified by mass spectrometry.

Conclusion

This work provides further information into the understanding of the interaction between G. intestinalis and their host and by contributing a novel scheme of the proteomic profile of the main larval stages.

Subungual myiasis in a woman with psychiatric disturbance

Myiasis is caused by the invasion of tissues or organs of men and animals by dipterous larvae. The disease is infrequent in Turkey. A case of a 65-year-old woman having been initially diagnosed with chronic psychosis, and found to have a left big toe nail invaded by the larvae of Calliphora spp., is presented. A total of 17 maggots were removed from the left big toe of the patient, which were then determined as Calliphora spp. The patient has undergone surgical withdrawal of both nails of her big toes, followed by the administration of oral prophylactic antimicrobial treatment. This is the second recorded case of subungual myiasis by Calliphora spp. in Turkey. Myiasis should be considered in patients with lower personal hygiene, especially with chronic psychiatric disturbances.

Seroprevalence of hypodermosis in cattle in some provinces of Turkey

The aim of this study was to determine the seroprevalence of hypodermosis in cattle in the east and southeast of Turkey. For this purpose, a total of 634 sera samples of cattle were collected from Malatya, Elazig and Diyarbakir provinces of east and southeast of Turkey from November 2005 to February 2006. The sera were analyzed using a Hypodermin C antigen by means of indirect ELISA. One hundred and forty eight (23.3%) out of 634 cattle were seropositive for hypoderma antibodies. The highest percentage of seropositivity were detected at Elazig province (26.3%) followed by Malatya (22.3%) and Diyarbakir provinces (22.1%). The seropositivity rate was higher in female (31%) than male (14.1%). When the mean is considered by animal breed, the highest seropositivity was detected at local breed (27.7%) following crossbreed (26.8%) and purebreed (19.7%). There was a positive relation between age and seropositivity. Seropositivity rate was 15.9% in 2 and under ages while these rates were 38.1% and 30.4% in 3-4 ages and 5 and up ages, respectively.

Aural myiasis in a patient with Alzheimer's disease

Myiasis is a disease caused by fly larvae feeding on the host's tissue. We report on a 49-year-old patient suffering from Alzheimer's disease with aural myiasis. Clinical examination revealed sanguineous and smeary otorrhoea on the left side with 16 alive maggots occupying the ear. They were removed from the external auditory canal and classified as larvae of the family Sarcophagida. Aural manifestation of myiasis may become dangerous if the petrous bone is affected. Entomological aspects, clinical characteristics, and treatment of this rare disease are reviewed.

Expression of circulating leucocytes before, during and after myiasis by Dermatobia hominis in experimentally infected rats

Expression of circulating white blood cells was investigated in rats (Rattus norvegicus) experimentally infected with larvae of Dermatobia hominis, the human bot fly. Leucocytes were counted prior to infection (control group) as well as at 6, 10, 15, 20 and 28 days post-infection (dpi) and at 7, 15, 30 and 60 days post-larval emergence (dple). Total leucocyte numbers did not differ markedly among the groups. Significant differences were registered when values from control and animals harboring each larval stage of D. hominis were compared; with crescent rank: L1-, L2-, control and L3-infected groups. Leucocyte numbers were significantly higher in the control, 15, 20 or 28 dpi groups than in the 6 dpi animals. Higher counts were observed in control, L2- or L3-infected rats than L1-infected animals. Neutrophils, eosinophils and both large and small lymphocytes were also counted and analyzed. Basophils and monocytes were insufficient in number to permit statistical studies. These results stimulate the continuity of the studies about the host-parasite relationship in the dermatobiosis.

Cerebral myiasis associated with angiosarcoma of the scalp: case report

OBJECTIVE

Primary human cerebral myiasis is an exceedingly rare condition and is almost never encountered by physicians in developed countries. The case report summarizes a case of extensive cerebral myiasis in a periurban community in the United States.

CLINICAL PRESENTATION

After a minor motor vehicle accident, police brought a 75-year-old man to the emergency room because he was observed to have a large cranial lesion. Examination revealed a 15 x 17 cm frontal bone defect with eroded frontal dura, exposed cortex, and massive cortical maggot infestation.

INTERVENTION

The patient was empirically treated with intravenous antibiotics for meningitis. Maggots (Phaenicia sericata, or the green bottle fly) were removed by suction, attrition, and gentle contact exposure to a mild bleach solution. Biopsy of the scalp and cranium revealed angiosarcoma, for which operative treatment was refused. The patient was transferred to a skilled nursing facility for palliative care where he died 3 months later.

CONCLUSION

This is the first published case of cerebral myiasis in the United States. Although human cerebral myiasis is rare, conditions do exist in this country that permit myiasis.

Vaccination against ectoparasites

Ectoparasites of livestock are of great economic and social importance but their effective control remains difficult. The feasibility of vaccination as a novel control measure was established over a decade ago with the commercial release of a recombinant vaccine against the cattle tick Boophilus microplus. Since then, research has continued on ticks and other ectoparasites. While some ectoparasite species will undoubtedly be refractory to immunological control, for others there has been a steady accumulation of knowledge of partially protective antigens, now accelerating through the application of genomic technologies. Nevertheless, progress towards usable, commercially available vaccines has been limited by a number of factors. The number of highly effective antigens is still very small. Although some classes of antigen have been investigated in more detail than others, we have no systematic knowledge of what distinguishes an effective antigen. Much hope has been placed on the potential of multi-antigen mixtures to deliver the efficacy required of a successful vaccine but with little experimental evidence. The application of current knowledge across parasite and host species needs to be explored but little has been done. In most cases, the path to commercial delivery is uncertain. Although many constraints and challenges remain, the need for vaccines and our capacity to develop them can only increase.

Insect/mammal associations: effects of Cuterebrid bot fly parasites on their hosts

The effect of parasites on their hosts has implications for basic and applied ecology (e.g., species' population dynamics and distributions, biological control, and threats to at-risk species) and coevolution. Cuterebrid bot flies comprise one of the most-studied groups of insect parasites of mammals. Interest in their impact dates from at least 1857, when Cuterebra emasculator was so named because of the erroneous belief that its larvae castrate their hosts. This review addresses the effects of cuterebrid larvae on host biochemistry, physiology, behavior, and ecology. Despite high prevalence (peak values commonly range from 30% to 70%), at average intensities (one to three larvae per host) these parasites generally have little effect on the fitness or population dynamics of their typical hosts. This outcome likely reflects parasite/host coevolution favoring parasites that minimize harmful effects on hosts required for their survival and hosts that best tolerate perennial parasites they cannot avoid. In contrast, aggravated effects occur at higher intensities and with atypical hosts. Additional field studies involving experimental manipulation of infestation and spanning more than a few seasons are required to confirm these conclusions.

A new approach for the diagnosis of myiasis of animals: the example of horse nasal myiasis

The myiasis caused by larvae of Rhinoestrus purpureus and Rhinoestrus usbekistanicus (Diptera, Oestridae) are of importance in the horse medicine since it causes severe respiratory diseases. Therefore an accurate diagnosis of rhinoestrosis is central to its epidemiology and control. This paper describes concisely a molecular diagnostic tool that overcomes the current inherent diagnostic constraints and, therefore, is of importance to understand the actual incidence and epidemiology of this myiasis in live horses.

Human and livestock migrations: a history of bot fly biodiversity in the Mediterranean region

The bot fly (oestrid) is responsible for myiasis in domestic animals. The presence in some regions of southern Europe of an unusually large number of different species of bot fly suggests a high degree of oestrid biodiversity in this area. The many factors that can influence parasitic species composition (e.g. host and parasite genetics, relationships with their hosts and environment, and animal management) include the movement of domestic animals in association with migrating human populations in southern Europe over thousands of years. From its geographical position, which was strategically important in controlling commercial trade routes in early Western civilization, the Mediterranean sea has for more than 3000 years constituted the hub of many different cultures, populations, genes and agricultural practices. The movement of animals and their associated parasites in this region can help to explain the evolution of parasitic biodiversity.

The evolution of myiasis in humans and other animals in the Old and New Worlds (part II): biological and life-history studies

Myiasis, which is the dipteran parasitism of living vertebrates, occurs in several forms - ranging from benign to fatal, opportunistic to obligate - and seems to have evolved through two distinct routes: saprophagous and sanguinivorous. However, the convergent evolution of morphological and life-history traits seems to have had a major role in confusing the overall picture of how myiasis evolved and this simplistic division is further complicated by the existence of both ectoparasitic and endoparasitic species of myiasis-causing Diptera, the evolutionary affinities of which remain to be resolved. As discussed in part I of this review, if we are to elucidate how the different forms of parasitism arose, it is essential to separate the evolution of the various groups of myiasis-causing flies from the evolution of the myiasis habit per se. Accordingly, whereas we focused on recent landmark phylogenetics studies in part I, we use this framework to analyse relevant biochemical, immunological, behavioural, biogeographical and fossil evidence to elucidate the evolution of myiasis in part II.

Ectoparasitic infestations

Ectoparasitic infestations are highly prevalent in resource-poor populations throughout the world and are associated with considerable morbidity. Reliable data on the epidemiology, immunology, and therapy of ectoparasitic infestations and on the biology of the parasites remain scarce. The control of parasitic skin diseases, such as scabies, pediculosis, tungiasis, myiasis, and cutaneous larva migrans in endemic areas remains a challenge. Using appropriate study designs, it is imperative to increase further the knowledge on the various aspects of the parasites and the infestations they cause.

Aural myiasis in children and literature review

Myiasis is a disease caused by fly larvae. The term "myiasis" is derived from the Greek word "myia" meaning fly. Aural myiasis is a rare clinical state and occurs frequently in children. In this article, six children with aural myiasis, caused by the fly larvae, are reported because of unusual presentation. All of the children with aural myiasis were associated with chronic otitis media. In the treatment, a combination of suctioning and alligator forceps was used to remove maggots under the light microscopic field. Additionally, antibiotics were used in all children. Thus, aural myiasis is successfully treated by direct extraction of larvae and application of preventative methods.

Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil. V. Cytokine concentrations in experimentally infected Wistar rats

Tungiasis is caused by the penetration of the female sand flea Tunga penetrans into the skin of its host. This parasitic skin disease is almost invariably associated with an intense inflammation around embedded fleas, the underlying mechanisms being unknown. A study was undertaken to determine whether Wistar rats can be used as an animal model to assess cytokine kinetics during the natural course of the infection. Laboratory-raised Wistar rats were exposed in cages put on the soil in an area with high human attack rates. Rats were examined daily and blood samples were taken before exposure and at 2, 6, 10, 13, 16 and 20 days after flea penetration. TNF-alpha, IL-1 beta, IFN-gamma, IL-4, IL-10 and CINC (a rat cytokine- induced neutrophil chemoattractant and member of the IL-8 family) were determined by enzyme immunoassay. The results showed an increasing serum concentration of TNF-alpha and IL-1 beta 10-13 days after penetration and a rapid increase in IL-4 2 days after fleas became embedded. During the natural course of the infection, the ratio of the serum concentration of TNF-alpha to that of IL-10 decreased, indicating a relative increase in the secretion of the anti-inflammatory cytokine. The treatment of lesions with silicone oil abrogated the natural disease course and changed the pattern of cytokine secretion. We conclude that the Wistar rat is an appropriate model to study immune responses in tungiasis.