Resumen

ROMERO P, José A; SOGBE M, Elias  y  DIAZ, Carmen. Serological and Histopathological Study of Toxoplasma gondii Infection in Pigs of Aragua State -Venezuela. Rev. Fac. Cienc. Vet. [online]. 2007, vol.48, n.2, pp.85-95. ISSN 0258-6576.

Pigs, as well as cattle and sheep are considered at epidemiological risk in the dissemination of Toxoplasma gondii to humans. The consumption of raw meat and pork by-products insufficiently cooked, or the contamination of water or food with the infective forms of the parasite are the means of infection. The aims of this investigation were two-fold: to determine the seroprevalence and to study the histopathology of Toxoplasma gondii in pigs for human consumption in the Aragua State, Venezuela. A cross-sectional study was undertaken. A total of 425 blood samples from pigs prior to slaughter were collected. Post mortem samples (n = 450) of skeletal muscle were also taken. For the serological analysis of positive cases, the indirect haemoagglutination test (IHA) was used. Hematoxilin-Eosin (H-E) and Periodic Acid of Schiff (PAS) stains were used for the histopathology study of seropositive cases. The results show an overall seroprevalence rate of 9.41%. No significant differences by gender were found. Antibody titration ranged from 1/64 to 1/1024 in samples non-treated with 2-mercaptoethanol (2-ME), indicating a potential exposure of the host to the protozoan infestation. Five (12.5%) of the serum samples treated with 2-ME, evidenced the presence of IgM, typical of an acute infection without clinical evidence of the disease. This finding suggests that the infection was acquired during the final stages of the parasite’s reproductive cycle. There was no histopathological confirmation of free parasites, intracellular forms, cystic or pseudocystic organizations. The most frequent histological changes were: myofibrilar degeneration, myofibrilar fragmentation, perivascular fibrosis, and lymphocytic inflammatory infiltration of the diaphragm, semitendinous, abdominal rectus, and intercostal muscles, with mild to moderate degrees of lesions. The antibodies titration does not necessarily reveal the presence of parasitic forms in a particular organ or tissue, which could depend on several factors such as: the degree of infestation, exposure to a parasite load, epizooty of the agent, health measures in the farm, epidemiologic conditions, and sampling methods. In conclusion, it is fundamental to establish a complete epidemiologic control program, based on biosecurity measures, pest (cats and rodents) control, and both serological screening and health measures of farms

Palabras clave : Swine; Toxoplasma gondii; histopathology; immunodiagnosis; morbidity; Aragua; Venezuela.

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