Virginia confirms strangles case in Loudoun County horse

A confirmed strangles case in Loudoun County has put Virginia equine practitioners on alert after a 4-year-old Morgan mare tested positive on March 2. The mare, reported through EDCC Health Watch and published by The Horse, developed fever, nasal discharge, cough, and lethargy on Feb. 25, and eight horses on the farm were identified as exposed. (thehorse.com)

The timeline in the report points to a familiar outbreak pattern: movement of a horse with a recent respiratory history, followed by delayed recognition of disease after arrival. According to The Horse, the mare’s illness began about two to three weeks after a new horse came to the farm from Georgia. That incoming horse had previously shown respiratory signs, but those signs were believed to have resolved before transport. (thehorse.com)

That matters because strangles remains one of the most contagious equine respiratory diseases, caused by Streptococcus equi subsp. equi. AAEP guidance says horses with fever, nasal discharge, or lymphadenopathy should be treated as potentially infected and isolated immediately. The organization also advises quarantining new arrivals for three weeks with temperature monitoring, and notes that guttural pouch evaluation can be part of preventing introduction of silent carriers into a resident population. EDCC-linked background reports add an important practical point: horses without obvious clinical signs can still harbor and spread the organism, and recovered horses may remain contagious for at least six weeks, helping explain why apparently resolved illness before transport does not eliminate risk. (aaep.org)

The Virginia case also fits a broader pattern of sporadic strangles activity tracked by the Equine Disease Communication Center. Recent EDCC-linked reports have included a Feb. 25 Maryland case involving a 17-year-old Oldenburg gelding at a boarding facility in Washington County; the horse developed fever and nasal discharge on Feb. 22 and was quarantined. Another Virginia report described a quarantined strangles case at a boarding facility in Prince William County. Outside the region, Oregon recently reported 10 confirmed positives—nine in Harney County and one in Linn County—along with additional suspected and exposed horses. EDCC’s broader reporting has also highlighted that disease reporting requirements vary by state, which can affect how quickly practitioners and facilities receive formal notice of cases. (equinediseasecc.org)

Expert guidance is consistent on the operational response. AAEP says biosecurity should be an active, written part of equine practice, not an ad hoc measure once a horse is already sick. Supporting reports from The Horse and EquiManagement note that strangles spreads through direct horse-to-horse contact and contaminated surfaces, that PCR testing of a nasal swab, wash, or abscess sample is commonly used for diagnosis, and that most horses recover in three to four weeks. Those reports also note that antibiotics are generally reserved for more severe cases, because overuse can interfere with development of immunity. AAEP’s strangles vaccination guidance describes the vaccine as appropriate for premises with persistent endemic disease or horses at elevated risk of exposure, while the broader vaccination guidelines classify strangles as risk-based; other source material similarly notes that available vaccines are not always effective, underscoring the need for individualized protocols rather than one-size-fits-all recommendations. (aaep.org)

The broader Virginia disease picture is also worth noting as spring movement increases. Separate EDCC-linked reporting from The Horse said 10 horses in Louisa County, Virginia, tested positive for EHV-1, 25 horses were exposed, one horse was euthanized, and the premises was quarantined. While EHV-1 is a different pathogen, the overlap in early signs such as fever, cough, depression, decreased appetite, and nasal discharge reinforces the value of prompt isolation, careful differential diagnosis, and routine cleaning and disinfection at equine facilities. The same report noted that current EHV-1 vaccines may reduce viral shedding but do not protect against the neurologic form, again putting the emphasis on prevention and day-to-day biosecurity. (thehorse.com)

Why it matters: For veterinary professionals, this is less about a single positive horse and more about the management gaps that cases like this can expose. A transported horse with apparently resolved respiratory signs may still warrant caution, especially at boarding barns, lesson programs, and other facilities with frequent movement on and off the property. The case reinforces the value of intake screening, isolation capacity, daily temperature logs, clear client communication, and rapid testing when compatible signs emerge. It’s also a useful conversation starter with pet parents and barn managers about why “looks fine now” isn’t always enough to relax biosecurity. (thehorse.com)

What to watch: The next signal will be whether any of the eight exposed horses develop clinical signs or test positive, and whether Virginia posts additional linked alerts in the coming days or weeks. More broadly, practitioners should watch for renewed emphasis on pre-arrival screening, quarantine compliance, environmental hygiene and disinfection, and risk-based vaccination discussions as spring horse movement picks up. (thehorse.com)