Malaria Parasite Found in Nearly 1 in 4 White-Tailed Deer

Deer
A new type of malaria parasites has been found in white-tailed deer in the United States. Mike Segar / REUTERS

A newfound species of malaria parasite has been found in one-quarter of the white-tailed deer living the eastern United States.

The news comes as a surprise since deer are one of the better-studied wild animals; they are some of the more populous mammals and very popular game species for hunting, and they are often surveyed for disease.

A team of researchers found the parasite accidentally when they were looking at DNA within the blood of mosquitoes at the Smithsonian’s National Zoo. In a mosquito engorged with deer blood, they noticed the presence of genetic material that they didn’t recognize. Further analysis revealed that the genetic material came from a protozoan in the genus Plasmodium. The results of the study were published last Friday in the journal Science Advances.

Species in the genus Plasmodium are known as malarial parasites. The genus includes several species that spread malaria in humans; other varieties infect nonhuman mammals, birds and reptiles. There are about 200 species worldwide in this genus.

In the recent study, scientists sampled blood from deer in 17 states and found 41 infected animals in 10 states; nearly 25 percent of the deer from Virginia and West Virginia had the parasite. None of these deer seemed to have any symptoms, however. It’s unclear yet if the new species could affect people, but it seems unlikely, Ellen Martinsen, lead author of the paper and a postdoctoral fellow, told Smithsonian.com.

Although there was one scientific record of a malarial parasite found in a deer’s spleen in 1967, this is the first proof of a widely established malaria parasite in New World mammals, and it expands scientists’ knowledge of the malarial family tree.