Exposure of pigs to Trichinella spp. in three districts in Central and Eastern Uganda

Since the 1980s, pork has become very popular in eastern Africa, with Uganda currentlyleading per capita consumption. Most of the pork is produced locally by smallholder pigfarmers who ventured into piggery as a profitable income–generating activity. Yet, knowledgeof good husbandry practices is limited and the majority of the pigs are kept in systems thatallow free–ranging and scavenging. Nematodes of the Trichinella genus are known to enterthe human food chain through the consumption of undercooked pork. In the East AfricanCommunity, data on the presence of Trichinella spp. in domestic pigs is scarce and limited toerratic surveys using diagnostic methods with a low sensitivity such as trichinoscopy. Thisstudy aimed to determine if the domestic cycle of the parasite plays a role in Ugandan pigsand if consumers are at risk of contracting trichinellosis from eating undercooked pork.In a cross–sectional survey conducted from April to July 2013 we sampled more than 1,000smallholder pig farms in three districts in Central and Eastern Uganda. As part of a multi–pathogen assessment we collected pig sera, bio–data of the individual animals, herdcomposition and husbandry practices at production. The sera were examined using acommercially available enzyme–linked immunosorbant assay detecting anti–Trichinella–IgG.Positive samples underwent Western Blot for confirmation.Seven percent (80/1124) of the sera tested positive and 97.5 % of these sero–positivesoriginated from rural production systems. Only one third of these were confirmed IgG positivein the Western blot. Subsequently, 500 pork meat samples from four geographical clusterswith a high seroprevalence were collected from November to December 2014 and examinedusing the artificial digestion method. All samples were negative for Trichinella larvae.The presentation will discuss the implications of a sensitivity analysis, potential reasons forthe high number of false–positives using the commercial ELISA as well as the suitability ofindirect serological diagnostic tools developed in industrialized countries for utilization inextensive production systems in tropical countries.