Smithsonian's National Zoo scientists have discovered two new malaria species in Washington, D.C. Prior to the discovery, no endemic malaria type was known to appear among American mammals. The newly discovered strains, however, are believed to adapt selectively to white-tailed deer.

An estimated 25 percent of white-tailed deer across the country is alleged to be infected. The scientists were actually searching for a different type of malaria - avian malaria - which is also believed to occur in the U.S.

The team collected and screened mosquitoes at the Smithsonian's National Zoo for a bird project. When they saw a different DNA during the analysis, they looked into more blood samples from one of the mosquitoes and discovered that the parasite present in the blood had fed on a white-tailed deer.

There are about 200 malaria species known across the world but in the U.S., no form was found to exist in American mammals until now. All malaria types depend on two hosts - a vertebrate animal and a flying insect - to complete the life cycle.

The white-tailed deer is one of the closely studied wildlife animal species in North America. Human hunters also prey on white-tailed deer, which in turn, increases hunting licenses. The increase in hunting activities then provides funding for the animal's conservation campaigns.

And yet, despite the time, effort and funding given to the study of the wild-tailed deer, it seems the scientific community failed to see that a malaria type had been present in the animals all this time.

Lead author Ellen Martinsen from the Center for Conservation and Evolutionary Genetics said that one in every four white-tailed deer is infected with malaria. However, the conventional blood sampling analysis fails to detect the infection at low levels wherein the new strains occur.

"The parasite levels in the blood are so low that they are undetectable by traditional techniques with a light microscope," said Martinsen. The accidental discovery was published in the journal Science Advances on Feb. 5.

The deer involved in Martinsen's study were asymptomatic. Co-author and Center for Conservation and Evolutionary Genetics head Robert Fleischer said that health-wise, there seems to be no difference between the deer with the parasite and those without. Fleischer added that the parasites they found could be one of the benign ones that don't evoke much impact on the hosts.

The team documented a total of 21 mosquito species at the Smithsonian's National Zoo. Only the Anopheles punctipennis was found to be a carrier of the two new malaria types.

Photo: Colby Stopa | Flickr

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