The Bureau of Land Management (BLM) is voluntarily closing the Bruneau Wild Horse Off-Range Corrals (ORC), in Idaho, to horses entering or leaving the facility due to a strangles outbreak, the agency announced July 19.

Individual infected animals are being tested to confirm the diagnosis, but the horses have developed clinical signs indicative of strangles.

Caused by the bacteria called Streptococcus equi, strangles causes respiratory problems, nasal discharge, and large pus-filled abscesses in horses’ throats and necks, among other issues. Although horses usually recover, this disease is highly contagious, spreads from direct or indirect contact between horses, and can lead to more serious complications in some horses. It also can cause persistent infections in populations of asymptomatic carrier horses.

The closure could delay the shipment of the wild horses gathered from three Wyoming herd management areas—Adobe Town, Salt Wells Creek, and Great Divide Basin—to BLM facilities and events nationwide to be placed into private care