IDENTIFICATION OF DIPTERA LARVAE CAUSING OPPORTUNISTIC MYASIS IN PATIENTS FROM BOLOGNA, NORTH EASTERN ITALY

INTRODUCTION: Myiasis is a condition in which fly maggots feed on and develop within living organisms’ tissues. There are two forms of myiasis: obligate, where maggots require living tissues to feed on, and facultative, where flies opportunistically use wounds, necrotic tissues, or body cavities for larval development. Among predisposing factors for myiasis are diabetes, immobility, poor hygiene, and compromised immune status (verettas et al., 2008. Trans R Soc Trop Med Hyg, 102:950-52). These opportunistic parasites pose a significant challenge, particularly in disadvantaged settings, poverty-stricken areas, and healthcare settings. Accurate identification of the myiasis-causing larvae is crucial not only for therapeutic intervention, but also to determine the source of infestation and implement prompt control and disinfection measures. Here, we present the identification of Diptera larvae that were collected from seven different cases of opportunistic myiasis. Infested patients were visited or admitted to clinical centers of bologna, north eastern Italy. MATERIALS AND METHODS: Larvae were collected from 6 patients ranging in age from 1 to 96 years. The parasites were fixed in 70% ethanol and processed for identification. Morphological identification of the third-stage larvae was conducted using identification keys (zumpt, 1965, Myasis in Man and Animals in the Old world, butter worths, London; Szpila, 2009, in Amendt et al., Current Concepts in Forensic Entomology. Springer, dordrecht, 43-56). Additionally, one specimen from each patient was processed for molecular identification: internal organs were dissected to extract DNA, and identification was performed by sequencing a 710 bp segment of the mitochondrial COI gene, commonly used as a molecular target for insect barcoding. RESULTS AND CONCLUSIONS: Larvae causing myiasis were found in different body sites: three cases involved wounds, all located in the lower limbs (mostly affecting the feet); in one case larvae were collected in the skin of the pubic area; in one case derived from nasal myiasis; and in the last case larvae were found in the drainage of an intra-abdominal collection. Sarcophaga sp., molecularly identified as S. argyrostoma, was found in the cases of heel ulcers and drainage colonization. Lucilia sericata, confirmed by COI sequencing, was identified in two cases of lower limb wounds and one case of pubic skin colonization. Additionally, Megaselia scalaris was identified through sequencing in a case of nasal myiasis in a 1-year-old child, as only first-stage larvae were present. Overall, the results indicate that opportunistic myiasis are parasitic condition that warrants consideration, particularly for individuals who are not self-sufficient, including those in healthcare settings as well as in case of poor hygienic conditions.