Toxic Poisoning Of Pigs Encountered Naturally In Smallholder Farms In Nairobi And Its Environs

Abstract

Eighty four pig carcasses received in Department of Veterinary Pathology and Microbiology between June 2004 and June 2007 were examined for toxic poisoning. Systematic necropsies were conducted and tissues collected and processed for light microscopy. Affected farms were visited to gather epidemiological data. Four of the 84 (4.8%) pigs were diagnosed as pulmonary, neuronal, renal and hepatic poisoning. They emanated from smallholder farms in Nairobi and its environs. The first one was a pig that was found dead with upto 1L of watery fluid in thoracic cavity and microscopically, edema in the interlobular septae and alveoli. A commercial feed kept in a damp store was responsible for the pulmonary poisoning. The second one was a boar that was dull, staggering and head-pressing. At post mortem, fluids were encountered in body cavities and at histopathology, cerebral edema, infiltration of mononuclear cells into meninges and acidophilia of cortical neurons were observed. This chronic salt poisoning occurred in pigs feeding on swill but without water for two weeks. The third one was a pig that was off-feed and trembling. At necropsy, pale kidneys were embedded in thick gelatinous edema. At histopathology, nephrons contained amorphous eosinophilic masses. This renal poisoning occurred in a farm where swill was supplemented with farm weeds especially Amaranthus spp. The fourth was a pig that had respiratory distress and cyanosis. Gelatinous edema on gastric serosa adjacent to an edematous gallbladder and enlarged liver, highly friable with dark-red circular areas that at histology showed periacinar necrosis and hemorrhage were observed. This hepatic poisoning affected a farm using self-formulated feeds. Toxic poisonings which are associated with feed and/or managerial practices are some of the causes of pig losses in the area. However, toxicological analyses in addition to above findings would be required to define the diagnosis further.