Epidemiologia e dinâmica sorológica na infecção natural por Neospora caninum em ovinos no semiárido brasileiro.

Abstract

Neosporosis is a disease caused by an obligate intracellular parasite, Neospora. caninum, capable of infecting several hosts and causing severe reproductive failure in females. This dissertation consists of two chapters: the first chapter entitled Dynamics of Neospora caninum transmission in naturally infected sheep under semiarid conditions aimed to carry out a longitudinal study of the occurrence of N. caninum to determine the serological profile of female lambs in the first year of life , indicating the main age group for the occurrence of primary infection in semi-arid conditions. In this study, 59 female offspring were monitored from the first to the twelfth month of life for the detection of anti-N IgG antibodies. caninum using the Indirect Immunofluorescence Reaction (IFAT). Of the lambs monitored, 61% (36/59) were positive for anti-N. caninum in at least one of the 12 months of evaluation. In daughters of positive mothers, less fluctuation in antibody production was observed over the period. There was a correlation between the antibody titers of mothers and daughters in the first month of life (r = 0.59; 95% CI = 0.39 – 0.73; P < 0.0001). It was also observed that 76.7% (23/30) of environmental infections occurred up to reproductive age (six months) (p <0.0001). concluded- It is clear that primary infection, in most animals, occurs until reproductive age. The second chapter entitled Detection of anti-Neospora caninum IgG in blood serum and colostrum samples in naturally infected sheep aimed to detect, through RIFI, the correlation of IgG antibodies to N. caninum in serum and colostrum samples from sheep matrices and evaluate the presence of this immunoglobulin in the serum of newborn puppies, after ingestion of colostrum. For this study, 162 blood and colostrum samples were collected from dams that were healthy and did not present any illness on general physical examination, recently given birth (maximum 5 days postpartum) and 182 blood samples from newborns. Of the matrices analyzed, 27.8% (45/162) were positive for the presence of anti-N IgG. caninum, of which 53.8% (24/45) did not have antibodies to this protozoan detected in colostrum. All sows that showed positive colostrum had positive offspring. It was concluded that the results obtained demonstrate good agreement between the detection of anti-N. caninum in colostrum compared to the mother and lamb, being an alternative in diagnosing the disease in herds.