The study, published today in PLOS ONE, caps a multi-year effort to determine the cause of the disease, which has been observed in parrots from this flock since at least 1999.
"The investigation, inspired and funded by Mickaboo, required a team of veterinarians, pathologists and researchers. It is only because the poisoned birds were feral parrots that the condition was so thoroughly investigated," said first author Fern Van Sant, whose clinic, For the Birds, in San Jose, California, provided care for many of the affected parrots. "The findings offer us an opportunity to assess the true risk of this rodenticide to pets and feral animals and to clarify the risk of potential soil and water contamination."
Study - Parrots - Set - Signs - Veterinarians
The study focused on four parrots that presented in 2018 with a set of characteristic neurologic signs that attending veterinarians say most affected birds exhibit to varying degrees: ataxia, circling, seizures and tumbling. Three of these parrots, like many before them, were euthanized when their condition worsened and they could no longer self-feed.
The study team looked for bromethalin, or its active metabolite desmethyl-bromethalin, based on their findings in 15 historic cases from 2013 through 2017. The historic cases lacked evidence of viruses known to cause neurologic disease in parrots, as well as of exposure to lead or other toxins. But pathologists found consistent lesions in the central nervous system that suggested bromethalin poisoning.
Bromethalin - Living - Animals - Birds - Assays
Bromethalin is difficult to detect, especially in living animals, and particularly in free-ranging birds. Some assays have successfully detected bromethalin in fat tissue of animals, but birds typically do not have surplus fat from which samples can be drawn and tested. In their study, the UGA-led team screened fecal samples from live birds, as well as liver and brain samples from deceased parrots. Co-author Sayed M. Hassan, director of the UGA Laboratory for Environmental...
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