Toxoplasma gondii tissue cyst formation and density of tissue cysts in shoulders of pigs 7 and 14 days after feeding infected mice tissues

Publication date: Available online 10 April 2019Source: Veterinary ParasitologyAuthor(s): S. Rani, Camila K. Cerqueira-Cézar, Fernando H.A. Murata, M. Sadler, O.C.H. Kwok, A.K. Pradhan, D.E. Hill, J.F. Urban, J.P. DubeyAbstractAmong the meat sources of Toxoplasma gondii, pork is considered important in the epidemiology of toxoplasmosis in the USA. How soon after infection T. gondii forms tissue cysts in pork is unknown. In the present study, eight serologically negative ˜3 months old pigs were fed mouse tissues infected with VEG (Type III) strain of T. gondii and euthanized 7 (4 pigs) and 14 days (4 pigs) post-inoculation (p.i.). Meat from the right shoulder of each pig was bioassayed in mice for T. gondii tissue cysts by peptic digestion and feeding it to T. gondii free cats. Feces of cats fed pork were tested for oocyst excretion. From each pig, the shoulder muscle was cut at random spots into 5 g, 10 g and 50 g portions. Extreme care was taken to use different scalpels and forceps to minimize cross contamination among 17 samples (6 replicates of each 5 g and 10 g portions and 5 replicates of 50 g). From the four pigs euthanized at 7 days p.i., a composite of ˜200 g of leftover meat from each shoulder was bioassayed cats. All eight pigs developed T. gondii antibodies (modified agglutination test, MAT, 1: 80 or higher) and viable T. gondii was isolated from shoulder meat of each pig. All four cats fed pork from the pigs euthanized 7 days p.i. excreted T. gon...
Source: Veterinary Parasitology - Category: Veterinary Research Source Type: research