Forensic entomotoxicological evaluation of a normal lethal dose of Acetonitrile (PDF)

Scientific Study from the year 2023 in the subject Medicine - Other, grade: A, University of Ibadan, language: English, abstract: A study was carried out on the forensic entomotoxicological evaluation of carrion insects of rabbits euthanized with Acetonitrile between February and March, 2023, at the stadium of the University of Ibadan. The rabbits were obtained from The Teaching and Research farm, University of Ibadan, Oyo state.

The rabbits were then euthanized with 10ml of Acetonitrile while the control group were scarified by cervical dislocation. Adult carrion insects were collected from the carrions using a sweep net and stored in 70% alcohol. The larvae were collected into a bowl by using a scoop, immobilized with hot water and later placed in sample bottles containing 70% alcohol. Pupae were also collected using forceps immobilized with hot water and later placed in sample bottles containing 70% alcohol. Ambient and carcass temperature was measured using infrared thermometer while relative humidity was recorded with a digital hygrometer.

Calliphoridae and Muscidae were the initial pioneers of the decomposing carcass and were seen during the fresh stage, while Sarcophagidae arrived shortly after the fresh stage of decomposition. It was found that Calliphoridae was the most dominant carrion insect while Sarcophagidae was the least dominant among the pioneer. The control group had more abundance and species composition of carrion insects than the paraquat-poisoned rabbits. The length and weight of the larvae as indices of growth were also observed to be comparatively higher in the control than the 10ml acetonitrile rabbit. The highest mean temperature value for the decomposing 10ml Acetonitrile-treated rabbits was 31.90°C while its lowest mean value was 22.60°C. The highest mean relative humidity value was 99% while the least recorded was 42% due to the rainy season.

Acetonitrile was found to retard the growth of carrion larva as shown in Musca domestica when compared with the control. Overall, rapid decomposition rate was recorded due to high ambient and carcass temperatures in the tropics. It can be deduced from this study that carrion insects are essential in providing the essential ecosystem service of decomposition and can be used in solving suicide puzzles through the extrication of post mortem intervals in conjunction with environmental variables. More studies are therefore needed to test the specific effects of other commonly used suicide poisons on carrion insects in Nigeria.