Forensic implications of myiasis

Abstract

Myiasis has been defined variously by numerous different authors over the years. The term itself was first coined by Hope in his 1840 paper entitled On insects and their larvae occasionally found in the human body although there were some earlier accounts by other authors. Subsequently there were additional treatments but not with equal restrictions. Possibly the most enduring and practical definition is that of Zumpt in his 1965 work entitled Myiasis in Man and Animals in the Old World. In this work myiasis is defined as: the infestation of live human and vertebrate animals with dipterous larvae, which, at least for a certain period feed on the host's dead or living tissue, liquid body-substances, or ingested food. A similar definition was followed by Guimaråes and Papavero in their 1999 work on myiasis in the Neotropics. Based on the system of classifying parasites developed by Patton (1922), Zumpt divides these myiasis-causing larvae into Obligatory Parasites and Facultative Parasites. Diptera larvae within the obligatory group develop in the living tissues of the host and this is, in fact, a necessary part of their life cycle. By contrast, the facultative group includes species that are normally free-living, feeding on decaying material, such as animal carcasses, fecal material, and even decaying vegetable materials. Under some While some species included in this category, such as Phaenicia sericata, may frequently act as parasites for all or part of their larval development, more commonly, species in this classification are associated with dead tissues present in a wound and do not actually feed on living tissues. Another situation, termed Pseudomyiasis or Accidental Myiasis, occurs when Diptera larvae are accidentally ingested with food materials and pass through the digestive tract. Keep in mind that this passage is most often passive and may result in the death of the larva. Their presence in the gut of the animal will often trigger various gastric problems, as noted by (e.g. Kenny, 1945). These infestations are not to be confused with the obligatory infestations of mammal digestive tracts by species in the subfamily Gasterophilinae (Colwell et al. 2006).