Birds around the world suffer and die from one species of malaria, and while these strains are not infectious to humans, they are spreading rapidly through global transmission hotspots.
An international team, including Dr. Nicholas Clark, of the University of Queensland, did research to understand where and why the disease is spreading so quickly.
“Bird malaria affects an average of 13 to 14 percent of all wild birds worldwide today,” said Dr. Clark.
“It is caused by a group of blood parasites – so-called hemosporidian parasites – and, like human malaria, is transmitted via blood-sucking insects such as mosquitoes.
“It cannot harm humans, but it is known to have significant effects on the bird population.”
For example, when avian malaria was introduced to Hawaii in the late 19th through early 20th centuries, it was a major contributor to the extinction of about a third of the 55 known species of Hawaiian honey tree creepers.
“We discovered that there are hotspots that transmit these parasites all over the world,” he said.
“The most important hotspot was in the Sahara Arab region, with local hotspots in North America, Europe and Australia, depending on different parasite variants.
“In fact, some of these blood parasites here in Australia are causing high rates of infection in our songbirds, including silver-eyes – Zosterops lateralis – and many kinds of honeyeater – the Meliphagidae Family.”
With more than 53,000 wild birds examined, the research team created and analyzed what is probably the largest data set on wild bird infections with avian malaria parasites.
They combined infection data with remotely collected environmental data such as climate or forest conditions and information on bird life history such as body size and migration patterns in computer models to identify which factors best describe the risk of infection with avian malaria parasites.
Dr. Konstans Wells, director of the Biodiversity and Health Ecology Research Group at Swansea University, said predicting what conditions will favor the infection of wild birds with avian malaria is critical to understanding the dangers of infectious diseases.
“Since every bird species is unique in its ecological niche and disease-transmitting insects are exposed differently during the breeding and migration phases, the risks of infection for different bird species are not the same,” he said.
“Conditions that allow infection in different areas of the world are completely context dependent.
“For example, on some continents migratory birds were more likely to be infected over long distances, but less likely on others.
“With so many factors there is no easy answer, but we will continue research to find out how we can best protect the world’s birds from this deadly disease.”
The study was published in Global ecology and biogeography (DOI: 0.1111 / GEB.13390).
Top left picture: pied flycatcher. Photo credit: Dr. Nicholas Clark
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