Sero-epidemiological study of major infectious abortive diseases in dairy cattle in Morocco

Abstract

In order to determine the importance of abortions and the seroprevalence of six abortive infections namely brucellosis, leptospirosis, neosporosis, Q fever, salmonellosis and bovine herpesvirus 4 (BoHV-4) infection in dairy cows in Morocco, a sero-epidemiological survey was conducted in five large farms in the Fez and Gharb regions of Morocco, where abortions have often been reported. A total of 252 sera were collected from females of different ages and a retrospective survey, based on questionnaires and farm records, was carried out on a total of 4144 females between 2018 and 2022. Antibodies to the pathogens studied were detected by indirect ELISA tests in 75.7% of the samples tested, with an overall seroprevalence of 46% for Leptospira hardjo, 25% for Neospora caninum, 43% for Coxiella burnetii, 50% for BoHV-4. As for Salmonella, antibodies against serovar Dublin were identified in two farms with an average seroprevalence of 2%. Serological indicators of co-infections were frequently observed. The absence of evidence of non-infectious factors epidemiologically linked to abortions suggests that the agents studied should be considered as important risk factors in the dynamics of the observed syndrome, even if further investigations are necessary to identify the causes of abortion.

Keywords: Abortive diseases, brucellosis, leptospirosis, neosporosis, Q fever, salmonellosis, bovine herpesvirus 4, Morocco