New developmental data of Chrysomya megacephala (Diptera: Calliphoridae) in tropical temperatures and its implications in forensic entomology

@#The estimation of the postmortem interval (PMI) is an essential information in death investigations. It is necessary to know the developmental data of the most important necrophagous insect species in every geographical area. Chrysomya megacephala (Fabricius, 1794) (Diptera: Calliphoridae) is one of the most common species associated with human body decomposition, especially in the tropics, so a precise knowledge of its life cycle is crucial. However, despite its ubiquity, developmental data in a range of tropical temperatures is scarce. For this reason, the aim of this study is to provide the developmental data of the blowfly, C. megacephala, in a range of tropical temperatures and to apply these data in forensic entomology. Four temperatures were examined (i.e., 27.0°C 29.5°C, 32.0°C and 34.5°C) and the time of developments from egg to adult were recorded. To build the growth curves, five larvae per day were measured with a digital caliper. Accumulated degree-days were calculated and the isomorphen diagram for this species was plotted. As we predicted, the results showed that the life cycle of this species was affected by the increasing temperature. The implications of these new data for determining the minimum PMI in forensic entomology were discussed.

Potential application of Gustatory Receptor 1 (CmegGr1) gene as a molecular marker for identification of Chrysomya megacephala (Diptera: Calliphoridae)

@#Chrysomya megacephala larvae can easily be identified using cheap traditional microscopy techniques. Nevertheless, identification using taxonomy keys may be hampered, if the morphological characteristics of the larvae are incomplete, or immature for microscopic identification. To overcome the difficulty of species determination, molecular identification has gained relevance and is applied in forensic investigations. This study aimed to identify a novel target gene, known as the gustatory receptor 1 gene (CmegGr1), which has never been used for identification. The third instar larvae of Ch. megacephala (n = 30) and eight other forensically important fly species were obtained from two sources; rabbit carcasses and the Forensic Entomology Unit collection. Their DNAs were extracted and the CmegGr1 gene was amplified using polymerase chain reaction (PCR). The resulting sequences were subjected to phylogenetic analysis. A 209 bp fragment of the CmegGr1 gene was successfully amplified in 80% (24/30) of Ch. megacephala samples, while all of the non-Ch. megacephala species were not amplified. The phylogenetic analysis revealed that the evolutionary tree of CmegGr1 shares many traits with the 21a gustatory receptors of Calliphora stygia and Lucilia cuprina (Gr21a), which are also classified as necrophagous fly species. The high specificity of species identification was demonstrated in the present study using DNA barcoding, which led to the conclusion that the CmegGr1 gene could serve as an alternative marker for identifying Ch. megacephala.

Epidemiological determinants of Chrysomya (Diptera: calliphoridae) infestation in layer farms of Minas Gerais, Brazil / Determinantes epidemiológicos da infestação por Chrysomya (Diptera: Calliphoridae) em granjas avícolas de postura de Minas Gerais, Brasil

Aspects related to the epidemiology of Diptera belonging to genus Chrysomya were studied in order to determine predisposing factors for their occurrence in commercial laying hens farms from the state of Minas Gerais, Brazil. An observational, analytical and sectional survey was conducted to verify the main epidemiological determinants of infestations by Chrysomya spp. Forty-three farms were visited in 2012 and these 13 (30,23%) were infested by Chrysomya putoria, 4 (9,30%) by Chrysomya megacephala and 2 (4,65%) by Chrysomya albiceps and in 2 farms (4,65%) was not possible to identify the species of Chrysomya. The epidemiological determinants for the occurrence of infestations by Chrysomya spp. were investigated using multiple logistic regression models. Housing clustering type and its conditions were important factors involved in epidemiology of these species (OR=5.05, 95% CI = 2.66 to 9.58, p = 0.000). It was also observed that the increase of the humidity of manure leads to increase chances of infestations (OR = 1.81, 95% CI = 1.36 to 2.40, p = 0.000). The presence of the beetle "lesser mealworm" (Alphitobiusdiaperinus) (OR = 0.15, 95% CI = 0.067 to 0.36, p = 0.000) was characterized as a protective factor against infestations, probably due to predation behavior of the beetle. Some regions of the state were characterized as lower risk areas for Chrysomya spp. infestation as compared to other regions. Management measures, such as constant monitoring of water leaks on manure, adequate composting of dead poultry and periodic removal of manure could assist in decreasing the presence of Chrysomya spp. inside the laying houses.

Aspectos relacionados à epidemiologia das infestações por dípteros do gênero Chrysomyaforam estudados com o objetivo de determinar os fatores predisponentes para sua ocorrência em granjas comerciais de postura do estado de Minas Gerais, Brasil. Foi realizado um estudo observacional, analítico e seccional para verificar os principais determinantes epidemiológicos das infestações por Chrysomya spp. Foram visitadas 43 granjas avícolas em 2012 e dessas 13 (30,23%) apresentaram infestação por Chrysomya putoria, 4 (9,30%) por Chrysomya megacephala, 2 (4,65%) por Chrysomya albiceps e em 2 granjas (4,65%) não foi possível identificar as espécies de Chrysomya. A verificação dos determinantes epidemiológicos foi realizada utilizando modelos de regressão logística múltipla. Diferenças entre os núcleos das granjas avícolas e que não foram avaliadas neste estudo, apresentaram-se importantes na epidemiologia destas moscas (OR=5.05 95% IC = 2.66 a 9.58, p = 0.000). Observou-se também que o aumento na umidade do esterco dos aviários aumenta as chances de ocorrência de infestações (OR = 1.81, 95% IC = 1.36 a 2.40, p = 0.000). A presença de coleópteros popularmente conhecidos como "Cascudinhos", Alphitobiusdiaperinus (OR = 0.15, 95% IC = 0.067 a 0.36, p = 0.000), foi caracterizada como um fator protetor contra infestações, provavelmente devido ao comportamento predador deste coleóptero. Algumas regiões do estado apresentaram menores chances de ocorrência de infestações por Chrysomya spp. quando comparadas a outras regiões. Algumas medidas de manejo, como monitoramento constante de vazamentos de água no esterco, compostagem adequada de aves mortas e remoção periódica do esterco, poderiam auxiliar na diminuição da presença de Chrysomya spp. no interior dos galpões de postura.

Use of maggot therapy for treating a diabetic foot ulcer colonized by multidrug resistant bacteria in Brazil.

This study reports the efficacy of maggot therapy in the treatment of diabetic foot ulcer infected with multidrug resistant microorganisms. A 74 year old female patient with diabetes for over 30 years, was treated with maggot therapy using larvae of Chrysomya megacephala. The microbiological samples were collected to evaluate aetiology of the infection. The therapy done for 43 days resulted in a reduction of necrosis and the ulcer’s retraction of 0.7 cm2 in area. Analysis of the bacteriological swabs revealed the presence of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. Further studies need to be done to confirm the role of maggot therapy in wound healing using a large sample and a proper study design.

Sensitivity of last larval stadium of Chrysomya megacephala (Fabricius) to anti-allatin ageratochromene Precocene II.

Treatment of early and late third instar larvae of economically important insect C. megacephala with the ageratochromene precocene II resulted into precocious metamorphosis. The other effects included mortality, production of pupal-adult mosaics, reduction in percentage of adult emergence and formation of non-viable deformed adults that died after a few hours of emergence. The application of precocene II adversely hampered the normal growth, development and metamorphosis of the insect and the results show that precocene II has vast potential for excellent control of this insect of medico-veterinary importance and can be used in insect pest management programs.

Effects of Temperatures on Larval Development of Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) (Diptera: Calliphoridae): Application in Forensic Science / Jurnal Sains Kesihatan Malaysia

Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) are two important species of blow flies that could be utilised as indicators to estimate the Post Mortem Interval (PMI) of corpses in forensic science. Determination of PMI of corpses is based on the larva size and its development stages. Development studies of eggs, larvae and pupae of Ch. megacephala and Ch. rufifacies at 27ºC, 30ºC and 33ºC were carried out using an insect growth chamber. Data from these studies were used to construct growth curves and Accumulated Degree Hours (ADH) for both species. Ch. megacephala needs 9.15 days to complete one life cycle at 27ºC, 8.54 days at 30ºC and 6.76 days at 33ºC. Development for Ch. rufifacies is slower than Ch. megacephala and takes 9.92 day at 27ºC, 9.13 days at 30ºC and 7.44 days at 33ºC. Eggs of the two species hatch faster at 33ºC compared to the two other temperatures. Low value of ADH shows shorter life cycle of that particular species. This study’s findings are useful in estimating PMI of the corpses found under various environmental temperatures.

Nim (Azadirachta indica): uma alternativa no controle de moscas na pecuária / Neem (Azadirachta indica): an alternative for controlling flies associated with animal breeding

As moscas Lucilia cuprina, Chrysomya megacephala, Cochliomyia hominivorax e Musca domestica, estão entre as mais importantes pragas da pecuária causando miíases e como portadoras de microrganismos patogênicos. O propósito deste estudo foi testar a eficácia de várias concentrações do óleo de nim sobre pupas das moscas mencionadas em condições de laboratório e de campo. A redução da emergência das moscas das pupas tratadas com 0,6 por cento de óleo de nim foi de 95,6 por cento em condições de laboratório e 94,5 por cento quando aplicado ao solo onde descansam os animais durante a noite. A aplicação do óleo de nim a 0,6 por cento no solo é uma alternativa viável para controle das pupas de L. cuprina, C. megacephala, C. hominivorax e M. domestica.

Flies Lucilia cuprina, Chrysomya megacephala, Cochliomyia hominivorax and Musca domestica, are among the most important arthropod pests of livestock, which produce myiasis and carry pathogenic microorganisms. The purpose of this study was to test of efficacy of various concentrations of neem oil on pupae of the above mentioned flies under laboratory and in field conditions. Reduction of fly emergence from treated pupae with 0.6 per cent of neem oil was 95.6 per cent under laboratory conditions and 94.5 per cent when applied on the soil, where the cattle rest during the night. The application of neem oil at 0.6 per cent on the soil is a viable alternative for controlling pupae of L. cuprina, C. megacephala, C. hominivorax and M. domestica.

Flies Specimens Collected from Agricultural Park, Teluk Cempedak and Bukit Pelindung in Kuantan, Pahang / Jurnal Sains Kesihatan Malaysia

This study was carried out in Agricultural Park, Teluk Cempedak and Bukit Pelindung at Kuantan, Pahang in October 2007. These three areas were different in ecological characteristic, Agricultural Park is a lowland region in Kuantan rural area, Teluk Cempedak is Kuantan’s most famous beach, and Bukit Pelindung is a reserved rainforest which is 200 meters from the sea level. Fly specimens were collected using four different kinds of baits: dry prawn, salted fish, pork and mango. Each of these baits was placed in a plastic container and exposed for one hour to attract flies. Within 5 minutes, flies started swarming around the baits. The flies were more attracted to the pork and salted fish compared to the other two baits. Fifty one flies, one moth (Lepidoptera) and one wasp (Hymenoptera) were collected. In Agricultural Park, two Lucilia cuprina, one Chrysomya megacephala and one Sarcophaga sp. were collected. For Teluk Cempedak beach, there were two Sarcophagids, 31 Chrysomya megacephala, five Musca domestica, one Lucilia cuprina and one moth were caught. Flies collected from Bukit Pelindung included five C.megacephala, two Sarcophagids, one Musca domestica and one wasp. Most C.megacephala were attracted to the pork and salted fish.

Accelerating Chrysomya Megacephala Maggot Growth for Forensic Entomology Cases / Jurnal Sains Kesihatan Malaysia

Forensic entomology is defined as knowledge about insect and its relationship with a decomposed human body. With this knowledge, post-mortem interval (PMI) can be estimated. PMI can be determined by taking into consideration the insect species and the developmental stage of the insects. Identification of the insect species requires the insect to develop into adulthood. Since this will take a relatively long time, the objectives of this study were to optimize temperature and humidity for the growth of Chrysomya megacephala larvae to adults. C. megacephala larvae were transferred into a rearing container and put inside a special incubator with temperature adjusted to 27, 30, 33, 36 and 39°C separately. Once optimum temperature for larvae growth was determined, optimum relative humidity was determined then for the length of time taken for C. megacephala larvae to develop into adults. To achieve this, the larvae of C. megacephala were incubated in a special incubator and the relative humidity set at 54.2, 57.6, 76.0 and 67.5% (control) separately. The developmental stages of C. megacephala for both temperatures and humidity levels were recorded accordingly. Results obtained indicated that C. megacephala developmental stages grew much faster in 33oC than other temperatures. The optimum relative humidity level for the species was 76.0%. By utilizing the appropriate temperature and relative humidity the development of C. megacephala, from eggs to adults could be reduced from 8 to 9 days to 5 days.