The aim of this study was to isolate and identify fungi on the external surfaces of adult house fly, Musca domestica and the blow fly, Chrysomya megacephala. These flies were collected from two districts in Northeastern Thailand: Muang and Warinchamrap in Ubon Ratchathani province, in September 2010. The main fungi isolated were Mucorales, followed by Yeast, Aspergillus niger and Penicillium spp. However, various species were identified including Aspergillus fumigatus, Gliocladium spp., Fusarium spp., Drechslera spp., Scedosporium apiospermum, Cladosporium spp. and Nocardia spp. This study demonstrated that both adult; M. domestica and C. megacephala have the ability to function as carriers for fungal spores and might be important in the transmission of fungi to humans in this area.

The blow fly is considered to be a medically-important insect worldwide. This review is a compilation of the currently known occurrence of blow fly species in Thailand, the fly’s medical importance and its morphological identification in all stages. So far, the 93 blow fly species identified belong to 9 subfamilies, including Subfamily Ameniinae, Calliphoridae, Luciliinae, Phumosiinae, Polleniinae, Bengaliinae, Auchmeromyiinae, Chrysomyinae and Rhiniinae. There are nine species including Chrysomya megacephala, Chrysomya chani, Chrysomya pinguis, Chrysomya bezziana, Achoetandrus rufifacies, Achoetandrus villeneuvi, Ceylonomyia nigripes, Hemipyrellia ligurriens and Lucilia cuprina, which have been documented already as medically important species in Thailand. According to all cited reports, C. megacephala is the most abundant species. Documents related to morphological identification of all stages of important blow fly species and their medical importance also are summarized, based upon reports from only Thailand.

Chrysomya megacephala (F.) (Diptera: Calliphoridae) is a medically important blow fly species in many parts of the world. In this study, we examined the ovary of C. megacephala at the ultrastructural level using light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Dissection of the ovaries revealed eight stages of ovarian development, thus providing a means of estimation of the age of females based on this organ. In the initial stage I (day 0-2), freshly-emerged flies up to three days old each display piriform germaria while the follicles are not yet well differentiated. In stage II (day 3), each follicle is nearly spherical and separating from the germarium. During stage III (day 4), each follicle is now easily distinguished from the germarium and is only connected by a thin interfollicular stalk. The nurse cells are completely surrounded by the cuboidal epithelial follicular cells. In stage IV (day 5-6), each follicle is spherical and considerably enlarged; whereas, the nurse cells within are more differentiated into individual round inclusions and grouped in the follicle chamber. Stage V (day 7) marks appearance of the visible oocyte at the posterior pole of the follicle. During stage VI (day 8), each follicle displays oocyte expansion anteriorly to occupyfrom one-third to one-half of the total length. In stage VII (day 9) the oocyte characteristically fills the posterior two-thirds of the total length of the follicle and in the final stage VIII (day 10), each follicle is completely filled by an oocyte and nurse cells have disappeared. The micropyle and narrow, elongate median area are clearly seen in this final stage. SEM images reveal that the ovary is covered by an ovarian envelope, which is tough and thickened in 3-day-old adult ovarioles; whereas, it becomes thin and fragile in 9-day-old adult ovarioles. TEM analysis of ovarioles of 3-day-old adult flies shows that cuboidal follicular cells containing large nuclei with visible fibrils of muscle simply encircle the large compartments of nurse cells; whereas, ovarioles of 7- day-old adult flies displayed a more completely developed enclosure for the developing oocyte. This was observed by the presence of the outermost follicular cell layer with underlying eggshell, vitelline envelope, trabecular layer, and layer of granular material that surrounded the innermost oocyte.

The objective of the current study was to isolate and identify the bacterial fauna associated with populations of the Oriental latrine fly, Chrysomya megacephala, collected in the Muang district of Ubon Ratchathani province, an area of high diarrhoeal disease incidence. A total of 294 flies were collected from September 2010-August 2011 using a sterilized insect sweep net at each collection site including freshfood markets, garbage piles, restaurants, school cafeterias and paddy fields of Muang Ubon Ratchathani in the Ubon Ratchathani province. Each specimen was transferred into individual sterile glass vials for bacterial isolation using standard bacterial isolation techniques from the external surfaces of the flies of the 294 flies collected, 98.64% were found to be carrying multiple species of bacteria. A total of 15 bacterial genera were isolated, including both potentially pathogenic and non-pathogenic bacteria.The most common bacterium isolated from C. megacephala was coagulase-negative staphylococci (80.27%) followed by Streptococcus group D non-enterococci (69.05%). Among these were human pathogenic enteric bacteria including Escherichia coli O157:H7 (EHEC) and Salmonella typhi with the prevalence rates in flies being 3.06% and 20.88% respectively. Furthermore, other human pathogens were found such as Staphylococcus aureus and Pseudomonas aeruginosa. The present study demonstrates the potential of C. megacephala to vector pathogenic enteric bacteria to humans.

Anopheles mosquitoes are still considered to be important vectors worldwide, with approximately 80 species of them incriminated as vectors of malaria, filarial nematode and encephalitis virus. Among these, at least 30 species exhibit species complexes, which comprise about 145 sibling species members. The exhibition of species complexes within the taxon of some Anopheles lead to complication of vector control that results from the difficulty in precisely identifying sibling (isomorphic) species members and their difference in biological characteristics. During the past 3 decades in Thailand, at least 6 malaria vectors, i.e., An. dirus, An. minimus, An. maculatus, An. sundaicus, An. barbirostris and An. leucosphyrus were proven to be species complexes. Thus, the objective of this review is to provide the current taxonomical information of Thai Anopheles species complexes, including techniques used in the identification of sibling species members, their geographic distribution, bionomic status and malaria-vector importance.