An abattoir survey on the occurrence and prevalence of swine parasitic helminths of public health and economic importance in kenya
Although there have been systematic and well coordinated efforts in documenting the prevalences of parasitic diseases of the pig in several countries of the world, very little has been done in Kenya. Parasitic helminths, specifically, have negative impacts on the health of the pigs, health of the consumers of pork and other products and the economics of the swine industry. The present study focused mainly on those parasites encountered during routine post-mortem meat inspection in Kenya with emphasis on those of public health and economic importance. Using records kept by the Ministry of Agriculture and Rural Development, "a retrospective abattoir survey was carried out to determine the occurence and prevalences of the various pig parasitic helminths of public health and economic importance encountered during the routine abattoir meat inspection over a ten year period (1988-1997) in Kenya. In addition, a cross-sectional survey was carried out in Nairobi's Farmers' Choice and Ndumboini abattoirs where routine physical meat inspection was done. Faecal and diaphragm muscle samples were collected for laboratory faecal egg analyses and trichinoscopy respectively. Faecal samples were quantitatively analysed for faecal helminth egg counts (eggs per gramme of sample) using the McMaster Technique, while the diaphragm muscle samples were analysed by trichniscopy for Trichinella spiralis larvae. A total of 642,295 pigs were slaughtered during the 1988-1997 period. Out of these, 31,365 (4.9%) had Ascaris suum (indicated by the presence of milk spots in the liver), 4,733 (0.7%) had hydatid 'cysts in the liver, lungs and spleen, 215 (0.03%) had lung worms, 165 (0.03%) had liver flukes and 38 (0.01%) had nodular worms belonging to Oesophagostomum dentatum and 23 (0.004%) had Cyticercus cellulosae. The cross-sectional post -mortem meat inspection performed revealed that Ascaris suum had a prevalence of 27.1%, hydatid cysts had 5.7% while Oesophagostomum dentatum, had a prevalence of 5.7%. On quantitative fecal egg counts of strongyles, Ascaris suum, Trichuris suis and coccidia showed prevalences of 50.9%, 10.7%," 3.6% and 15.2% respectively. Trichinella spirallis was never detected. These results therefore show that Ascaris suum had the highest prevalence. Generally, the prevalences of the other pig parasitic helminths were low. The presence of these parasites which are also of public health (zoonotic) importance in this country therefore calls for interventionary efforts in order to avert potential health hazards to consumers of pork and its products.