Researchers at the University of Auburn studied sentinel wild fowl in Kauai, Hawaii as environmental indicators of the parasite Toxoplasma gondii or T. gondii, which is spread by cats. The parasite is a leading cause of death in endangered species, including the monk seal, and can cause serious neurological symptoms in humans. The study by Auburn researcher Kayleigh Chalkowski focused on the prevalence of T. gondii in the research area’s chicken population. Shown is an active door trap used to trap chickens in Opaekaa Falls Vista, Kauai, Hawaii. Photo credit: Auburn University at Montgomery
Kayleigh Chalkowski, PhD student at Auburn University School of Forestry and Wildlife Sciences, leads a research study that will make important discoveries about the extent of the disease caused by a deadly parasite spread by wildcat populations – not just in Kauai, Hawaii, where the study took place – but worldwide.
The study recently published in Pacific Conservation Biology has implications for public health policies wherever feral cats are found.
Researchers looked at sentinel wild chickens in Kauai as environmental indicators of the parasite Toxoplasma gondii or T. gondii, which is spread by cats. The parasite is a leading cause of death in endangered species, including the monk seal, and can cause serious neurological symptoms in humans.
While the effects are on feral cats and other animals, Chalkowski’s study focused on the prevalence of T. gondii in the research area’s chicken population.
“In our study, we found that almost 40% of the chickens were positive for this parasite, and there were positive chickens with a positive correlation to proximity to the coast in almost every area examined,” said Chalkowski.
“Our results from positive chickens in community centers and public beach parks suggest a risk to public health, and our results from positive chickens in nature reserves and coastal areas suggest exposure to endangered birds and marine mammals.”
Chalkowski spent years in Kauai doing local conservation work. The island’s extensive topography, the variety of ecosystem types and the abundance of wild chickens provide optimal model systems for studying the prevalence of the parasite. The wild chicken is an ideal sentinel species for this research. Recent evidence that T. gondii is contributing to the local decline in endemic bird and mammal species in Hawaii.
Chris Lepczyk, professor at the School of Forestry and Wildlife Sciences, co-authored the study.
“Kauai and the Hawaiian Islands in the broader sense are really a central point in the world for understanding how the parasite spreads across the landscape and how it affects ecosystem health,” Lepczyk said.
Chalkowski’s extensive field experience in the Hawaiian Islands resulted in a strong appreciation for effective predator control and an interest in diseases that affect both endangered species and humans. Identifying this and other environmental factors that predict or influence exposure to T. gondii is important to reduce the risk of disease.
The year-long project included working with the Kauai Invasive Species Committee, the Fish and Wildlife Service and the collaborative expansion of the University of Hawaii College of Agriculture and Human Resources.
“Given the dual interests of all these organizations in public outreach and either public health agriculture or wildlife health, I think this has been a good example of how partnerships can develop to understand a problem, the concern in terms of conservation and public health, “she said.
Next steps to mitigate harm
There is still a long way to go in research before the health effects of T. gondii are mitigated. And then a change in health policy will be necessary.
“Our study is absolutely not the final step in the process of mitigating the health effects of this parasite,” she said. “Recognizing and understanding how parasites like these can vary based on environmental and landscape features is important to inform and guide mitigation efforts, but of course changing the policy is a critical next step.
“We hope this study not only guides containment efforts, but also increases awareness of how widespread and widespread this parasite is in public land use areas.”
She and her team also hope that this widespread awareness will lead to greater public support for animal control measures, such as banning wildcat feeding anywhere on the island because the parasite is widespread – not site-specific or grouped in specific locations – and trapping efforts to control feral cats increases.
“Stricter cat ownership legislation would also help: stricter fines for dumping or abandonment, requirements for spay or neuter, and firstly improving access for spay and neutral services,” she said.
Health risks far beyond the islands
These health policy implications are becoming increasingly evident on islands like Kauai, but are hardly confined to this part of the world.
“Could these control efforts benefit other regions? Definitely,” said Chalkowski. “T. gondii is not only a problem in Hawaii. This parasite is spread by domestic cats – which can be found pretty much anywhere that humans can be found – and can infect any bird or mammal. This parasite can be found on any continent can be found, literally even Antarctica in marine mammals.
“That sounds crazy – there are clearly no cat populations in Antarctica – but it’s an example of this parasite’s ability to move through the environment and through host chains.
“It’s both fascinating and terrifying, given how little we know about the health effects of this parasite on many species,” she said. “This parasite is a problem worldwide, there are a lot that we are new to, and efforts to control or understand this parasite in one area can be very helpful elsewhere.”
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Kayleigh Chalkowski et al. Spatial epidemiology of the seroprevalence of Toxoplasma gondii in sentinel wild fowl (Gallus gallus) in Kaua’i, Hawaii, Pacific Conservation Biology (2020). DOI: 10.1071 / PC20045
Provided by Auburn University in Montgomery
Quote: Researcher makes significant discoveries on the extent of the disease, parasite spread by wild cats (2021, February 17), accessed February 17, 2021 from https://phys.org/news/2021-02-significant-discoveries- scope-disease-parasite. html
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