Evaluation of a therapeutic protocol against Neospora caninum-induced abortion in domestic buffalo (Bubalus bubalus) in Italy

Neospora caninum is a coccidian protozoa that very closely resembles Toxoplasma gondii and causes abortion in a variety of farm animals. This organism was first identified in 1988 as a cause of abortion in dogs and, shortly after a different strain of Neospora was described as causing abortions in dairy cows. Neospora has been found worldwide and is the most common cause of abortions and congenital disease in ruminants. N. caninum has a two-host life cycle in which the infection is acquired through ingestion of coccidial oocysts shed by the definitive host (wild or domestic canids). Antibodies against this agent have been reported in cattle, horses, goats, sheep, deer, hosts. A field evaluation of treatment against N. caninum induced abortions in domestic buffaloes was undertaken in three selected dairy herds of Central Italy (named A,B,C) with a history of high number of abortions. 430 animals, which were serologically negative for BoHV-1, BoHV-4, BVDV, Leptospira hardjo and Chlamydophila abortus were included in the study. In the farm A all animals were treated and sera were collected after 1 year. In the farm B all animals were treated following the same protocol of farm A, but the control sera were collected after six months and, finally, in the farm C only a little group of animals were treated and maintained in the infected farm. Sulphadiazine 200mg/ml and Trimethoprim 40mg/ml was given to the animals at 15mg/kg body weight following different age-depending protocols. Toltrazuril 50mg/ml was also given at 20mg/kg body weight to newborn buffalo and once every three months to the dogs present in the farms. The environment of the farm was disinfected with phenolic disinfectants periodically. A significant reduction of serological values was observed in farms A and B but not in C. Similarly, the percentage of abortions decreased from 24.7 to 3.2 in farm A and from 13 to 1 in farm B (p>0.001), while no difference was observed in farm C. The treatment with Sulphadiazine/Trimethoprim and/or Toltrazuril resulted in drastic reduction in both abortions and seroprevalence since after six months from treatment in farm A and B, while when treated animals were maintained in an infected environment and in contact with infected animals, the proposed therapeutic treatment failed