Assessment of transplacental transmission of Neospora caninum and Toxoplasma gondii in Neotropical deer: An estimative based on serology

Transplacental transmission of Neospora caninum and Toxoplasma gondii is well known in some domestic species and despite both parasites having been proved to infect deer fetuses during gestation, the congenital transmission rate in South-American deer species is still unknown. This study aimed to estimate the congenital transmission rate of neosporosis and toxoplasmosis in captive deer populations from Brazil, through serological techniques (IFAT and ELISA). Serum samples from 82 deer were tested by both techniques 20.73 % (IFAT) to 25.60 % (ELISA) were seropositive for T. gondii; the kappa test showed an index of 0.277 of agreement between both techniques. For N. caninum, 40.24 % (IFAT) to 39.02 % (ELISA) were seropositive, with an index of 0.833 of agreement between techniques. Family trees for each species were drawn and we estimated the congenital transmission rate of the diseases. We found a rate of 81.25 % congenital transmission of N. caninum and no evidence of congenital transmission of T. gondii. Vertical transmission appears to be the main route of introduction and maintenance of N. caninum in these captive deer populations, while T. gondii seems to be favored by the horizontal route.