Abortion in Donkeys Associated with Salmonella Abortus Equi Infection

Background: Salmonella enterica subspecies enterica serovar abortus equi (S. abortus equi) is well known as the aetiological agent of equine abortion. However, abortion caused by S. abortus equi has not been previously described in donkeys.

Objectives: To investigate whether S. abortus equi was correlated with an abortion outbreak consisting of 61 abortions.

Study Design: Investigation of the clinical cases using pathoanatomical, bacteriological, serological and molecular approaches.

Methods: Autopsies on nine aborted foetuses were performed. Tissue specimens from seven aborted foetuses and two mares were cultured and subjected to detection of equine herpesvirus 1 (EHV-1), equine herpesvirus 4 (EHV-4) and equine arteritis virus (EAV) by polymerase chain reaction. The isolates were serotyped according to the Kaufmann-White scheme and analysed by multi-locus sequence typing (MLST). Detection of EHV and EAV antibodies was performed in all pregnant mares.

Results: No obvious gross lesions were observed in the foetuses. Nine Gram-negative isolates were obtained from all nine tissue samples and were identified as Salmonella spp. All of the isolates belonged to the B group, the O antigen epitope was 4, 12 and H antigen was not obtained. The isolates of Salmonella were characterised as sequence type (ST) 251. Detection of EHV-1, EHV-4 and EAV was negative.

Main Limitations: The mechanism that causes abortion in donkeys needs further study and the lack of histological examination.

Conclusion: Salmonella abortus equi was isolated as the single agent and was responsible for the abortions. Equine practitioners should be aware of S. abortus equi infection as a cause of abortion in donkeys.