Foetal death in naive heifers inoculated with Neospora caninum isolate Nc-Spain7 at 110 days of pregnancy

Authors: ALMERIA, SONIA - Autonomous University Of Barcelona; SERRANO-PEREZ, BEATRIZ - Universitat De Lleida; DARWICH, LAILA - Autonomous University Of Barcelona; DOMINGO, MARIANO - Autonomous University Of Barcelona; MUR-NOVALES, RAMON - Universitat De Lleida; REGIDOR-CERILLO, JAVIER - Complutense University Of Madrid (UCM); CABEZON, OSCAR - Autonomous University Of Barcelona; PEREZ-MAILLO, MONICA - Autonomous University Of Barcelona; LOPEZ-HELGUERA, IRENE - Universitat De Lleida; FERNANDEZ-ALGUILAR, XAVIER - Autonomous University Of Barcelona; PUIG RIBAS, MARIA - Autonomous University Of Barcelona; ORTGEA-MORA, LUIS-MIGUEL - Complutense University Of Madrid (UCM); GARCIA-ISPIERTO, IRINA - Universitat De Lleida; Dubey, Jitender; LOPEZ GATIUS, FERNANDO - Universitat De Lleida

Submitted to: Experimental Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/5/2016
Publication Date: 8/5/2016
Citation: Almeria, S., Serrano-Perez, B., Darwich, L., Domingo, M., Mur-Novales, R., Regidor-Cerillo, J., Cabezon, O., Perez-Maillo, M., Lopez-Helguera, I., Fernandez-Alguilar, X., Puig Ribas, M., Ortgea-Mora, L., Garcia-Ispierto, I., Dubey, J.P., Lopez Gatius, F. 2016. Foetal death in naive heifers inoculated with Neospora caninum isolate Nc-Spain7 at 110 days of pregnancy. Experimental Parasitology. 168:62-69.

Interpretive Summary: Toxoplasmosis, caused by a single celled parasite Toxoplasma gondii continues to be a public health problem worldwide. It causes abortion in livestock and mental retardation and loss of vision in children. Diagnosis of abortion in livestock is difficult because of many causes. Neosporosis, caused by a related parasite, Neospora caninum, is a very important cause of abortion in dairy cattle. N. caninum and T. gondii were considered the same organism until in 1988 ARS researchers developed diagnostic methods to separate these organisms. In the present authors infected cows experimentally at mid gestation (110 day of pregnancy) with N. caninum and followed the pregnancy outcome. All inoculated cows aborted or had dead foetuses when they were euthanized. The diagnostic methods described here will be of interest to parasitologists and pathologists to understand the pathogenic mechanism of parasite-induced abortion.

Technical Abstract: Neospora caninum infection is a leading cause of abortion in cattle worldwide. The pathogenesis of bovine neosporosis, particularly during the second term of gestation, when most abortions occur in naturally infected dams, is poorly understood. In the present study foetal death was observed in 3 of 6 experimentally infected dams at 110 days of gestation after 6 weeks of experimental period. All experimental heifers were febrile between 3 to 5 days post infection (dpi). Inoculated dams seroconverted by 3-4 weeks post infection with higher mean antibody titres in aborting dams compared to non-aborting heifers, although not significantly (p>0.05). Neospora caninum DNA was detected in all infected foetuses and placentas, and three infected foetuses also had N. caninum antibodies. The parasite burden was higher in the brain of dead/aborted foetuses than in live foetuses. Interestingly, high IFN-' production was detected in foetal fluids of a dead foetus found upon euthanasia of its dam, while no IFN-' was observed in amniotic, allantoic and /or foetal fluids in the three infected foetuses that were alive upon maternal euthanasia. The present study confirms that the infection of dams on gestation day 110 with 107 tachyzoites of the Nc-Spain7 isolate causes abortion. The fact that some infected dams aborted and some did not is relevant to to understanding of N. caninum pathogenesis of abortion in naturally infected cows.