Occurrence of multiple abortions due to Salmonella enterica serovar abortus equi infection

Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA) and one of the major viral pathogens of horses. EAV is an Arterivirus belonging to the Arteriviridae family in the order Nidovirales. EVA is a respiratory and reproductive disease of horses that occurs worldwide. The vast majority of EAV infections are subclinical, but acutely infected animals may develop a wide range of clinical signs including pyrexia, depression, edema, conjunctivitis and respiratory distress. The direct consequences of EVA outbreaks are financial losses mainly due to abortions of pregnant mares and death of young foals. Following primary EAV infection, up to 70% of the stallions will carry the virus in their reproductive tract sometimes for years and will shed the virus in their semen. Several studies have shown that EAV infection has occurred among horses in North and South America, Europe, Australia, Africa, and Asia. Interestingly, EAV infection prevalence in horses varies between countries and horse breeds. In order to determine equine viral arteritis (EVA) prevalence among the 5000 horses housed in the Vojvodina region of Serbia, 429 sera from non-vaccinated horses have been collected. Serological analysis of equine sera, collected from 2013 and 2014, was performed using virus neutralization test (VNT) as described by the World Organization of Animal Health (OIE). So far sera of 156 horses coming from 10 different stud-farms of the Vojvodina region have been tested. The population tested was composed 86 stallions, aged between 1 and 26 year old, and 70 mares ranged from 1 year old to 23 year old. The mean age of the population tested was 9,9 year old. Our preliminary results indicated that 121 sera were negative (77,60%), thirty three were detected positive (21,15%), two sera were cytotoxic (1,25%). Among the positive sera fifteen (45,45%) exhibit an antibody titer range from 4 to 16, ten ( 30,30%) sera exhibited a titer ranged from 24 to 96 and eight (24,24%) sera had a titer above 128. Moreover, 9 out of 10 stud farms that have been included in this survey exhibited positive horses for EAV showing that EAV is circulating in the horse population kept in the Vojvodina region. So far, only one seropositive stallion has been found positive for the presence of the virus in his semen. Phylogenetic analysis performed on the 3 kb sequence encoding the structural proteins of the virus shows that this isolate seems different from those described in the literature so far.