A mysterious illness is killing the wild horses of Waipio Valley, on the Big Island of Hawaii. Struggling horses were first spotted in June. Initially, the horse’s gait becomes abnormal and as their muscles atrophy they are unable to walk at all. To date 11 wild horses have died.
The neurological presentation is unique, nothing that veterinarians or officials have previously seen. Domestic horses have not presented with symptoms leading officials to speculate that the condition may derive from something the horses are ingesting.
Veterinarians and officials from Hawaii’s Department of Agriculture have tested and ruled out several neurological diseases including Rhino, West Nile, EPM and influenza. Tissue samples from a recently deceased horse are currently being tested by the Department of Agriculture and Cornell University, renown for their expertise in equine toxicology. Officials hope these more extensive tests will yield an answer, and means of treatment. Results are expected by mid August.
The exact number of wild horses living in the valley is unknown but guesstimated at several dozen. The horses derive from domestic horses turned lose by their owners following a 1946 tsunami that contributed to many residents leaving the area.

Photography Courtesy Aramat Equine Services.