Detecção de DNA de Neospora caninum em colostro, leite e glândula mamária de cabras naturalmente infectadas

Abstract

Neospora caninum has dogs and other wild carnivores as definitive hosts, which shed oocysts with the faeces, that serve as a source of oral infection for other species. However, vertical transmission is considered the main source of infection and maintenance of N. caninum in herds. The transmission of the parasite via the lactogenic route is poorly studied, with no studies in goats and sheep. Likewise, in the various animal species, milk was not evaluated in different lactation periods for the presence of the parasite's DNA and the lactating mammary gland for the presence of lesions or the agent. Therefore, the aim of the present study was to revaluate the presence of N. caninum by histopathology, immunohistochemistry (IHC) and

PCR in the mammary gland, detect N. caninum DNA in colostrum and milk by PCR and anti- N. caninum antibodies in blood serum by RIFI at birth and throughout the lactation period.

Ten naturally infected goats with anti-N. caninum antibodies confirmed by RIFI were used and three seronegative goats as negative controls. Two positive goats died during the experimental period. Blood samples were collected from the goats on the day of birth (mother and goat kids before the ingestion colostrum) and monthly (mother and goat kids) until day 120 postpartum. Also, 10 mL of colostrum and milk were collected through manual milking on the day of parturition (D0), day 3 (D3), D6, D9, D12, D15, D30, D45, D60, D75, D90, D105 and D120, totaling 105 samples from positive and 39 from negative animals. The goats were euthanized under deep anesthesia at the end of 120 days and mammary gland samples were subjected to PCR and IHC. Histologically, there was discrete or moderate lymphoplasmacytic inflammation in four and three goats, respectively, however, the parasite was not observed in histopathology and IHC, but nine of the 10 positive goats presented Amplicons in the mammary gland and 62 of the 105 milk and colostrum samples were positive in the PCR, with colostrum being positive in eight of the nine samples tested (88.88%). The results demonstrate that the lactogenic via is a possible transmission route for N. caninum and draws attention to the need to test colostrum banks, frequently used in ruminants.