Slaughterhouse survey of Trichinella infections in pigs of Tanzania

Abstract

Trichinellosis is ahuman zoonotic disease caused by larval and adult stages of parasitic nematodes belonging to the genus Trichinella. The parasite has a wide range of host species, mostly mammals. Humans acquire the infection by eating raw or inadequately cooked meat infected by larvae present in the muscle cells. Worldwide, the most common sources of human infections are pig, wild boar and other game meat. In Tanzania, a human outbreak with several deaths occurred for the consumption of warthog meat in 1977. Trichinella nelsoni has been documented in carnivores and warthogs of Serengeti. A slaughterhouse survey was conducted in five regions of Tanzania to determine the prevalence of the nematode in domestic pigs slaughtered for human consumption in the framework of an OIE Twinning project. At least five grams of diaphragm muscle was taken from each sampled carcass. A total of 1,078 adult pigs were randomly sampled in Arusha (163), Dar es Salaam (291), Dodoma (236), Iringa (297), and Kilimanjaro (91). Magnetic stirrer method was used to digest the muscles for 30 minutes at 44 - 460C, and the digested liquid was left to sediment for another 30 minutes. The sediment was examined under a dissecting microscope at magnification of x15. No Trichinella larva was detected. This result suggests that the prevalence of Trichinella infection in domestic pigs of Tanzania if any is lower than1%. From these findings it can be concluded that the pork entering the food chain at the time of this study was safe from Trichinella infections.

Keywords: Magnetic Stirrer Technique, meatborneinfection, Trichinella larvae, Zoonosis