Pathohistological changes in aborted foetuses of cows due to neosporosis: Evidence from Ukraine

Neosporosis is a parasitic disease characterized by abortions and the birth of weak offspring in cows. The causative agent of Neospora caninum is an obligate, protozoan parasite that belongs to the type Apicomplexa. The relevance of the study is conditioned upon the adverse impact of neosporosis on the economy of Ukraine (loss of productivity, veterinary and diagnostic costs). Furthermore, the issue of neosporosis is understudied. In this regard, the purpose of this study was to establish pathohistological changes in aborted foetuses and the foetal part of placentas and to confirm the involvement of the parasite (Neospora caninum) in cases of abortions recorded in different regions of the country. Two methods were used to investigate this problem: histological and real-time polymerase chain reaction. In aborted foetuses positive for N. caninum, the following pathohistological changes were most often detected: focal gliosis and perivascular mononuclear infiltrates in the brain; focal or diffuse mononuclear infiltration in the heart and skeletal muscles; periportal mononuclear infiltrates in the liver; focal necrosis of the mucous membrane and mononuclear infiltration in the foetal part of the placenta. Changes were less often detected in the lungs – mononuclear infiltration of the interstitium and diffuse lymphocytic alveolitis, and in the kidneys – diffuse interstitial mononuclear infiltration. No changes were found in the spleen. Neospore-like cysts were found in one out of twelve foetuses. Lesions established of foetal organs and placentas are inherent in neosporosis. The results of histological studies substantially complement the data of other authors, confirm the involvement of N. caninum in the occurrence of abortions in cows in certain regions of Ukraine, and also represent practical value for the diagnosis and control of neosporosis in cattle