Effect of NC-1 strain of Neospora caninum inoculated experimentally in pregnant buffaloes (Bubalus bubalis)

KONRAD, J.L.; CRUDELI, G.; CASPE, G.; MOORE, D.; LISCHINSKY, L.; LEUNDA, M.; ODEÓN, A.; CAMPERO, C.M.

Buenos Aires

Congreso; World Association for the Advancement of Veterinary Parasitology (WAAVP); 2011

Neospora caninum is an Apicomplexan parasite which has shown a high seroprevalence in buffaloes in Argentina. While there are descriptions of lesions in bovine fetuses produced by experimental inoculation with N. caninum, there is little information in buffaloes fetuses. The aim of this study was to characterize the pathogenic effect of NC-1 strain of N. caninum in fetus when inoculated in pregnant buffaloes. 12 Mediterranean pregnant buffaloes, seronegative to indirect immunofluorescent (IFI) were used for this purpose. Ten cows were inoculated with 10 8 viable NC-1 strain tachyzoites´ intravenously, and two control cows were inoculated with placebo. Pregnant cow buffaloes were challenged at 70 (n=3) and 90 (n=7) days of pregnancy (DOP), and then slaughtered. The genital tract was recovered, 98 DOP and 28 days post inoculation (DPI) (n=3), 118 DOP and 28 DPI (n=3), 132 DOP and 42 DPI days (n=4). Control fetuses were 98 and 118 DOP. Twelve fetuses were recovered; one of them was dead at the time of slaughtering. It belonged to an inoculated female buffalo of 70 DOP and slaughtered 28 DPI. The fetus showed an advanced degree of autolysis and a small size (length=9 cm). At necropsy, samples from placenta, central nervous system (CNS), heart, lung, liver, kidney, the skeletal muscle, tongue and the intestine were fixed in 10% buffered formalin and stained with hematoxylin and eosin. There were no macroscopic changes in organs or tissues of viable fetuses.Multiple mononuclear inflammatory foci were observed in different fetuses´ organs from inoculated mothers: peribronchiolar interstitial pneumonia in 10/10, myocarditis in 3/10, epicarditis in 6/10, interstitial nephritis in 6/10, interstitial myositis in 6/10, hepatitis periportal in 7/10. CNS lesions were focal gliosis 1/10, meningitis 1/10 and focal necrosis 2/10.Placental lesions (9/10) were moderated mononuclear infiltration in the placentoma and allantoides. Control fetuses showed neither macroscopic nor microscopic alterations.The histopathological lesions observed in this work were similar to those identified in bovine fetuses of similar age; however, the lesions were less severe. The finding of a dead fetus inside the inoculated buffaloes shows the susceptibility of this species when inoculated early in pregnancy.