​Hawaii - Big Island: new testing underway to discern unknown ailment killing wild horses in Waipio Valley

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New testing underway to discern unknown ailment killing wild horses in Waipio Valley

By Max Dible West Hawaii Today mdible@westhawaiitoday.com | Monday, July 23, 2018, 12:05 a.m

KAILUA-KONA ? No one knows how many wild horses in Waipio Valley have perished, or what is killing them.

Dr. Tim Richards, Hawaii County councilman and veterinarian, said the problem appears neurological, but no one looking for answers has ever seen a condition manifest in quite the same way before.

?Not like this clinical presentation,? Richards said. ?It?s weird.?

Horses first present with an abnormal gait as muscles begin to atrophy, starting with the hind limbs. Eventually, the animals are unable to walk at all.
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While the culprit remains unknown, a form of consensus among investigators does seem to be emerging ? that the cause of the unknown illness is correlated with something the horses are eating.

?It most likely looks like a disease caused by mold spore toxins,? Clabaugh said. ?That is not a diagnosis, but it is a high suspicion.?
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Hawaii state Rep. Richard Creagan ? of Hawaii Island?s 5th District, which includes portions of Kona and Ka?u ? said RLD manifests similarly in dogs as what is happening to the horses in Waipio. He said their limbs begin to weaken, typically starting with hind limbs, and their tails don?t wag correctly.
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He added, however, that evidence related to the mysterious ailment killing wild horses in Waipio Valley doesn?t yet point to a zoonotic concern ? an illness that can be passed from animals to the human population.

Confirming that is an important goal of the ongoing testing, Richards said.

http://www.westhawaiitoday.com/2018/07/23/hawaii-news/new-testing-underway-to-discern-unknown-ailment-killing-wild-horses-in-waipio-valley/

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Array of tests zero in on disease afflicting wild horses in Waipio Valley

By Max Dible West Hawaii Today mdible@westhawaiitoday.com | Wednesday, August 8, 2018, 12:05 a.m.
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Many concerned citizens brought up the possibility of rat lungworm (RLW) on social media once they heard of the epidemic.
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Moniz wrote that a ?very low quantity of RLW DNA? was detected in the euthanized horse?s brain, cerebral spinal fluid, heart and lung.

?Correlation with histopathologcial findings are not present at this point,? he said. ?Further histopathological exams will be completed before a final diagnosis will be made.?

Labs also detected sarcocystosis, caused by species of sarcocystis, which can manifest in conditions that involve weight loss and muscle loss in the hind limbs of horses. One type of sarcocystis can cause equine protozoal meyloencephalitis (EPM), but other tests on the animals have ruled out EPM.

?There are other species of Sarcocystis however, one in particular, Sarcocystis fayeri can cause illness similar to what has been seen in the Waipio horses,? Moniz wrote. ?Further evaluation of tissues will be conducted and additional test(s) will be sought out to rule this in or out as a cause of the illness.?
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Other pending tests include those for botulism ...

Test results for the infectious disease dubbed eastern equine encephalitis came back negative...

http://www.westhawaiitoday.com/2018/08/08/hawaii-news/array-of-tests-zero-in-on-disease-afflicting-wild-horses-in-waipio-valley/

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Officials unable to find cause of Big Island horse deaths
The Associated Press
September 17, 2018 09:40 AM

Updated 58 minutes ago

KAILUA-KONA, HAWAII

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.
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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."

https://www.thestate.com/news/article218524425.html