Neospora caninum NC-6 Argentina induces fetopathy in both serologically positive and negative experimentally inoculated pregnant dams

BACIGALUPE, D.; BASSO, W.; CASPE, S. G.; MORÉ, G.; LISCHINSKY, L.; GOS, M. L.; LEUNDA, M.; CAMPERO, L.; MOORE, P. D.; SCHARES G.; CAMPERO, C. M.; VENTURINI, M.C.

PARASITOLOGY RESEARCH

SPRINGER

Lugar: Berlin; Año: 2013 vol. 112 p. 2585 - 2592

0932-0113

Neospora caninum infection is a major cause ofabortion in cattle. The objectives of this study were to geneticallycharacterize the N. caninum NC-6 Argentina isolateusing a multilocus microsatellite analysis approach and tostudy its biological behavior by experimental inoculations intoseronegative and seropositive pregnant cattle, evaluating thehumoral and cellular immune response elicited and the occurrenceof transplacental transmission and fetopathy. Pregnantcows (65 days of gestation) seropositive and seronegativeto N. caninum were intravenously inoculated with tachyzoitesof the NC-6 Argentina N. caninum strain and slaughtered at108±2 days of gestation. Serum samples were analyzed for N.caninum antibodies by indirect fluorescent antibody test. Thecellular immune response was analyzed by detection of gammainterferon (γIFN) production in blood cells. Tissue samplesfrom dams, fetuses, and placental cotyledons wereprocessed by histopathological and immunohistochemicaltechniques and examined for N. caninum DNA by PCR.Positive DNA samples were further analyzed by multilocusmicrosatellite typing for N. caninum. Inoculated animals hadsignificantly higher N. caninum antibody titers and γIFNproduction than control animals. One seropositive inoculatedcow aborted, one seronegative cow had a non-viable fetus,and the remaining fetuses from the experimentally inoculateddams had histopathologic lesions. The PCR was positive in3/4 fetuses from seronegative inoculated cows and in 2/3fetuses from seropositive inoculated cows. Multilocus microsatelliteanalysis revealed that the N. caninum DNA present infetuses and placentas had an identical pattern to NC-6Argentina strain. The NC-6 Argentina strain proved to be ableto cross the placenta and to induce fetopathy in both theseropositive and seronegative dams.