Study on outbreak ofNeospora caninum-associated abortion in dairy cows in Tabriz (Northwest Iran) by serological, molecular and histopathologic methods

摘要

Objective:To determineNeospora caninum(N. caninum) as a cause of bovine abortion in dairy cows byELISA,PCR andPathological methods inTabriz,Northwest ofIran.Methods:For study of outbreak of neosporosis, blood samples were collected from76Holstein aborted dairy cows in Tabriz(NorthwestIran).Antibodies to N. caninum were assayed by using a commerciallyELISA kit(IDEXX,USA).IgG againstN. caninum were found in14(18.4%) cases.Aborted fetuses of these seropositive dams were proposed for histopathological and molecular investigations.Brains, spinal cords and placentas of the fetuses were fixed in10% buffered formalin for histopathology. Also5-10 g of brain tissue was sampled forDNA extraction.In6 out of14(42.8%) fetuses, brain tissue was positive inPCR.All dams of these fetuses were serologically seropositive inELISA test. Results:Histopathologically, the lesions consistent withN. caninumwere observed in brains, spinal cords and placenta of all fetuses.Lesions inCNS included severe congestion, perivascular and perineuronal edema, status spongiosis, perivascular cuffing, focal gliosis, nourophagy and focal necrosis.There were someNeospora-like cysts in brain.In placentas, severe congestion, perivascular infiltration of mononuclear cells, vascular thrombosis, focal placentitis and necrotic foci in cotyledons were noticed.Conclusions:The results of present study agreed the results of similar studies about serological, histopathological and molecular results of other studies about neosporosis and it seems to support the outbreak ofN. caninum-associated abortion in dairy cows inTabriz(NorthwestIran).