Case report on Cochliomyia hominivorax (Coquerel, 1858) and Co. macellaria (Fabricius, 1775) (Calliphoridae, Diptera) myiasis prior to death: Implications on postmortem interval estimation

Abstract

The most important contribution of forensic entomology is the estimation of the postmortem interval (PMI) or time since death. The forensic entomologist assumes that the biological clock of necrophagous insects that develop by feeding on cadaver tissues begins when the victim's biological clock is turned off. However, tissues can be invaded while the host is still alive (called myiasis), so the period of activity of necrophagous insects would not be indicative of PMI. The aim of this work was, through the presentation of a case report, to highlight the importance of expertise in the identification of necrophagous species associated with a corpse and their type of relationship in order to avoid an erroneous estimation of PMI. The corpse of a woman, missing for 14 days, was found outdoors in a small river 15 cm deep. Her corpse had numerous lesions infested with dipteran larvae that were collected during autopsy. Entomological evidence included second and third instar larvae of Cochliomyia hominivorax and Co. macellaria. The obligate parasitic nature of Co. hominivorax as a primary producer of myiasis and secondary of Co. macellaria allowed us to establish the time when the victim was still alive and from there to estimate the PMI.