KAILUA-KONA — Veterinarians have been unable to determine the cause of a mysterious disease linked to the deaths of more than a dozen wild horses on the Big Island, officials said.
The team of veterinarians and researchers from the state Department of Agriculture and multiple universities tried to determine why wild horses in Waipio Valley exhibited neurological problems that eventually resulted in their deaths, West Hawaii Today reported .
About 13 horses showed symptoms during the summer that first appeared in their hind limbs, altering the animals’ gaits. The disease eventually made the animals unable to move.
“This disease investigation into the cause of the deaths of these wild horses is one of the most extensive in Hawaii in my recollection,” said Jason Moniz, manager of the department’s Animal Disease Control Branch. “In addition to the veterinarians, laboratories and researchers who worked on this case, we appreciate the help of Waipio Valley taro farmers who provided assistance, observations, information and feedback and who showed sincere concern for these horses.”
About 50 to 60 wild horses live in the valley on the island’s north side, forming five separate bands, according to the department. All the horses found sick were from the same band on the west side of the valley. No other horses were affected.
“It was noted that infectious diseases were not the cause of the deaths and that the incident may be attributed to possible exposure to a toxicological event,” the department said in a statement last week.
Veterinarians tested for an array of possible causes for the disease, sending blood and tissue samples to labs across the country. Testing for infectious equine diseases produced negative results. They also ruled out rat lungworm disease, finding that the horses’ brain and spinal cord changes were not consistent with an infection.
Testing revealed that parasites might have contributed to the state of the horses’ overall health, but were not the cause of the disease.
“Blood tests indicated there was damage to the horse’s liver and muscles and there was evidence of liver damage consistent with intestinal parasite migration,” the department said. “A microscopic parasite, Sarcocystis spp., was found sporadically in various muscles. Further testing is ongoing to determine the species of this parasite so its significance can be determined.”
Information from: West Hawaii Today, http://www.westhawaiitoday.com