By Sarah Carey
While participating in a summer research project in Thailand in 2018, a University of Florida graduate student discovered a rarely diagnosed and often fatal infection, known as melioidosis, in a dog, and helped veterinarians develop a protocol to successfully treat the animal.
One year later, the 11-year-old Pomeranian mixed-breed dog continues to be doing well, said Pacharapong Khrongsee, D.V.M., a master’s student who studies melioidosis with his mentor, tropical disease expert Apichai Tuanyok, Ph.D., an assistant professor in the UF College of Veterinary Medicine’s department of infectious diseases and immunology.
Their findings were reported in September in the journal Veterinary Sciences.
The dog had run away from home at night and was found by its owner a day later with large wounds around its neck and back. After unsuccessful treatment at a local animal clinic, the dog was referred to the veterinary teaching hospital at Prince of Songkla University for further care and diagnostics.
It just so happened that Khrongsee worked in the same building as the teaching hospital, and he learned of the case when he was consulted by the laboratory that received the dog’s test results.
“The laboratory tests showed that this dog had bacteremic melioidosis,” Khrongsee said.
Veterinarians there do not typically look for the disease, said Tuanyok, who also is affiliated with UF’s Emerging Pathogens Institute.Melioidosis, a serious bacterial infection that affects humans and several species of animals, is caused by a soil bacterium, Burkholderia pseudomallei. Roughly 40% of the cases reported in people lead to death. In Thailand, the disease is required to be reported to governmental authorities, meaning that any treatment may only be undertaken with their permission. The disease is common in Southeast Asia and many tropical countries, but there has never previously been a dog reported with the disease in Thailand.
Because there is no known protocol for treating melioidosis in dogs, once the disease was diagnosed, veterinarians at the teaching hospital gave the dog’s owner their standard recommendation: humane euthanasia.
“No one had ever reported how to treat the disease, and the publications out there recommend euthanizing the dog, as the disease can affect humans,” Tuanyok said. “Scientists are concerned about environmental contamination as well.”
But the owner, who was very attached to her dog, did not want to euthanize it.
Khrongsee, whose research focuses on the biology of viruses that live in the environment — including those known to infect the bacteria that causes melioidosis — knew there was a protocol for treatment of the disease in humans, and contacted Tuanyok to discuss possible options.
“This is an intracellular bacteria, which means most antibiotics can’t get in and cure the bacteria, so it would survive,” Khrongsee said. “Apichai and I came up with the idea of using a specific antibiotic, the best one used in human protocols. But we still didn’t know what the proper doses would be in a dog.”
The two researchers continued investigating to come up with the best approach.
“The first thing was, we needed to save the dog, which was going to soon die from bacteremia, or septic shock, so we looked at antibiotics that could cure the bacteria in blood,” Tuanyok said. “We gave it 14 days.”
During that time, dog was housed in isolation facilities, its blood checked every three days for bacteria. At the end of the 14-day period, the dog appeared to be bacteria-free. But the researchers knew the bacteria could still hide in certain cells, so they recommended a protocol of oral antibiotics, to be administered over 20 weeks, or four months.
“After the first two months, the dog got better,” Khrongsee said. “The wounds healed, and over time, all of its fur came back.”
He performed regular blood tests on the dog every month for almost a year to ensure the bacteria had not returned. It never did.
“We couldn’t see any bacteria or any infection,” Khrongsee said. “Now we know how to treat a dog, so next, we’re going to look at developing guidelines for treating companion animals diagnosed with this disease, as well as a possible vaccine.”
The project Khrongsee is working on is part of UF’s One Health initiative.