Estimation of Post-Mortem Interval in Drug Misuse Deaths Using Successional Patterns of Insects Colonizing Pig Carcasses in Niger State College of Education, Minna, Nigeria.

Abstract

Drug abuse constitutes a significant public health concern and is increasingly associated with 
unnatural mortality among young adults, particularly within tertiary institutions. In forensic 
investigations, accurate determination of the cause of death and estimation of the post
mortem interval (PMI) in suspected drug-related fatalities is often complicated by delayed 
discovery of bodies and advanced stages of decomposition. This study evaluated the influence 
of selected commonly abused substances on carrion insect succession and decomposition 
dynamics under tropical environmental conditions in Minna, Nigeria. A structured 
questionnaire administered to 300 students identified ethanol, tramadol, cough syrup (PiS), 
and a combination of ethanol and cough syrup as the most frequently abused substances within 
the study population. Five domestic pig carcasses (Sus scrofa domesticus), widely accepted 
as human analogues in forensic entomological research, were utilized for the experimental 
investigation. Four carcasses were administered the identified substances prior to death, 
while one carcass served as a control and was euthanized through oxygen deprivation. Each 
carcass was exposed under natural environmental conditions and monitored throughout the 
five classical stages of decomposition: fresh, bloated, active decay, advanced decay, and dry 
remains. Systematic insect sampling was conducted during both early and late decomposition 
phases. A total of eleven insect species belonging to three orders and eight families were 
documented. Dipteran species—including members of Calliphoridae, Muscidae, Sarcophagidae, 
Phoridae, and Stratiomyidae—dominated early colonization events. Although initial insect 
arrival occurred during the fresh stage across all experimental treatments, notable variations 
in decomposition duration were observed. Ethanol-treated carcasses exhibited the longest 
decomposition period, followed by tramadol-treated carcasses, whereas the control carcass 
decomposed most rapidly. These findings demonstrate that the presence of abused 
substances can significantly alter decomposition trajectories and insect colonization 
patterns. Consequently, drug exposure represents an important variable in forensic 
entomotoxicology and must be considered when estimating PMI in drug-related deaths within 
tropical environments.