Sero-occurrence of anti-Toxoplasma gondii antibodies and vertical transmission in slaughtered beef cows (Bos indicus)

Resumo

Toxoplasma gondii is a protozoan parasite recognized as an important public health problem. The objective of the present study was to evaluate the occurrence of anti-T. gondii antibodies in pregnant and non pregnant zebus' breed beef cows (Bos indicus), their fetuses, killed at an abattoir in northern of Paraná state. In the present study 169 cows were evaluated, 92 pregnant (in different stages of gestation) and 77 non pregnant. Sero-occurrence of anti-T. gondii antibodies was performed by Indirect fluorescent antibody test (IFAT) considering positive animals with titers ? 50 for cows and ? 25 for fetuses. Blood (with EDTA) from pregnant cows and blood and tissue samples (brain, lung, heart, and liver) from their fetuses were collected and used for mouse bioassay. Antibodies against T. gondii were observed in 26.0% of cows and 2.5% of fetuses. There was no statistical difference when prevalence of toxoplasmosis was compared between pregnant (23.9%), and non-pregnant (28.6%) animals, and age of gestation (p > 0.59). However, the occurrence of anti-T.gondii antibodies increased with age of animals (p=0.004). Mouse bioassay showed three fetuses positives (3.2%), however, none T. gondii strain was isolated. The present study showed that transplacental transmission of T. gondii naturally occurs in zebu beef cows from Brazil, however, in low rate (5.4%). The anti-T. gondii antibodies occurrence increase with the age of animals, which could be related to the fact that main transmission in cattle T. gondii is horizontal.