Extensive testing of malarial DNA revealed that malaria spread from birds to bats and on to other mammals
A file photo of a mosquito through a microscope. Malaria is caused by parasites that are transmitted to people through the bites of infected female mosquitoes.
The origins of malaria have been under scrutiny for years as researchers tried to find the roots of the disease. A new study now throws light on the evolution of malaria and found that the disease has its roots in birds.
Extensive testing of malarial DNA found in birds, bats and other small mammals from five East African countries revealed that malaria spread from birds to bats and on to other mammals, said the study published this week in the journalMolecular Phylogenetics and Evolution.
“We can’t begin to understand how malaria spread to humans until we understand its evolutionary history,” said lead author Holly Lutz, a doctoral candidate in the fields of ecology and evolutionary biology and population medicine and diagnostic sciences at Cornell University.
“In learning about its past, we may be better able to understand the effects it has on us,” said Lutz.
After drawing blood samples from hundreds of East African birds, bats, and other small mammals, researchers screened the blood for the malarial parasites. When they found malaria in the blood samples, they took samples of the parasites’ DNA and sequenced it to identify mutations in the genetic code. After that, the researchers assessed how different malaria species are related, based on differences in their genetic code.
“Trying to determine the evolutionary history of malaria from just a few specimens would be like trying to reconstruct the bird family tree when you only know about eagles and canaries,” explained Lutz.
Malaria, which affected 214 million people worldwide in 2015, is caused by parasites that are transmitted to people through the bites of infected female mosquitoes. The most deadly malarial parasite, P. falciparum, is most prevalent in Africa, where malaria cases and deaths are heavily concentrated.
“Malaria is notoriously adaptive to treatment, and its DNA holds a host of secrets about how it’s able to change and evolve. Having a better understanding of its evolutionary history could help scientists anticipate its future,” said co-author and Field Museum curator of mammals Bruce Patterson.