Streptococcus equi subsp. zooepidemicus: High molecular diversity of Argentinian strains isolated from mares with endometritis.

Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) is a mucosal commensal of the lower genital tract in horses and is the most isolated bacterium causing endometritis in mares. The aim of this study was to determine the molecular diversity of S. zooepidemicus obtained from endometritis in mares in Buenos Aires province, Argentina. Thirty isolates obtained from the uterus of mares in 2005 and 2017 were studied. The MLST scheme was applied to identify the Argentinian genotypes and the clonal relationships and patterns of evolutionary descent were identified using the eBURST algorithm - goeBURST. Twenty six different Sequence types (STs) were identified, being only 11 of them previously reported in horses and also, from several host species and tissues. The other 15 STs were reported in Argentinian reproductive strains of mares in our study for the first time. The genotypes obtained from uterus in Argentina were not evenly distributed when all the published S. zooepidemicus STs were analysed, thus, it was not possible to establish that the same lineage circulates in our equine population. The fact that the identified genotypes were also reported in other countries, diverse samples and host species suggest that there is not a host, and an anatomical niche adaptation. Finally, the isolation of the same genotype in the vagina/clitoris and the uterus of the same mare highlights the versatility of S. zooepidemicus and its role as an opportunistic pathogen.

Serological evidence of equine infectious anaemia, West Nile fever, surra and equine piroplasmosis in a herd of horses in northern Argentina.

Northern Argentina hosts equine populations living under preserved natural areas and extensive breeding conditions, with limited access to veterinary care. Horses can be in contact with i) wildlife considered to be a potential reservoir of horse pathogens (e.g. capybara, coatis and pampas deer) and/or ii) potential disease vectors such as ticks, horse flies, Culicidae and vampire bats. In this context, the aim of this study was to assess the exposure of horses from a herd in northern Argentina to different vector-borne pathogens. Serum samples were collected from 20 horses on a farm in Chaco province. Most of these horses were in good health, but a few showed clinical signs such as fever, neurological signs or emaciation. Potential vectors (ticks, horse flies and Culicidae) were present and a fresh bite of a vampire bat (Desmodus rotundus) was observed on one horse. This serological survey revealed that 100% (20/20) were positive for equine infectious anaemia (EIA), 100% (18/18) for West Nile fever (WNF), 53% (10/19) for surra and 45% (9/20) for equine piroplasmosis (Babesia equi). Among these horses, four were found seropositive for all four infections. On the other hand, all the tested horses were seronegative for equine viral arteritis (EVA), Eastern equine encephalomyelitis (EEE), Venezuelan equine encephalitis (VEE), Western equine encephalomyelitis (WEE) and glanders. The data from this survey conducted on a small number of animals illustrate the need for an effective application of surveillance programmes and control measures for equine diseases in northern Argentina and constitute, to our knowledge, the first report of horses simultaneously seropositive for EIA, WNF, surra and equine piroplasmosis.