DISEASE SPREAD: Popular vacation state faced with avian malaria threat
Hawaii's native forest birds on Kauai, Oahu, Maui, and Hawaii Island are facing an escalating threat from avian malaria, a disease caused by protozoa from the same family as human malaria but with bird-specific strains that cannot be transmitted to people.
The illness is spread by mosquitoes, which are not native to the islands. Both native and introduced forest bird species can infect the insects even when carrying small amounts of parasites, allowing mosquitoes to harbor and transmit the disease for months or years. Feeding trials showed that mosquitoes can transmit avian malaria across a wide range of temperatures.
A study published in Nature Communications analyzed blood samples from more than 4,000 birds across 64 sites and found that nearly every forest bird species is now spreading the disease, which appears almost everywhere mosquitoes are present. Researchers from the University of Hawaii at Mānoa, the University of California, and Christa M. Seidl, who conducted the work as part of her PhD at the University of California, Santa Cruz, also ran feeding trials.
The disease has shortened telomeres in affected birds, an element of DNA that influences lifespan, with altered DNA passed to chicks and resulting in shorter lifespans for future generations.
Seidl stated that "avian malaria has taken a devastating toll on Hawaii's native forest birds, and this study shows why the disease has been so difficult to contain. When so many bird species can quietly sustain transmission, it narrows the options for protecting native birds and makes mosquito control not just helpful, but essential."
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The National Park Service has warned that mosquitoes could increase the risk of extinction for Hawaii's forest birds. Historically, the disease contributed to the ʻakikiki, a Hawaiian bird native to Kauai, being declared extinct in the wild, while the Kauai creeper is considered critically endangered or extinct in the wild by some groups.
Scientists noted caveats in the research, including the use of lab-controlled canaries that may not represent all wild species and challenges in measuring mosquito saliva at different temperatures. The findings underscore the need for mosquito control to protect the birds.