Malaria, a disease caused by parasites that are communicated to human beings through mosquitoe bites, started out as a parasite in birds, and then it advanced to colonise bats, and from there it has evolved to affect other mammals, a study has said.
Every year, the disease affects close to 500 million people, but we're not the only ones--different species of malaria can infect birds, bats and other mammals too, it pointed out.
Humans cannot contract malaria directly from birds or bats.
According to lead author Holly Lutz, doctoral candidate at Cornell University in New York, one can't understand how malaria spread to humans until we understand its evolutionary history.
"In learning about its past, we may be better able to understand the effects it has on us," Lutz noted.
For research, published in journal Molecular Phylogenetics and Evolution, researchers took blood samples from several East African birds, bats and other small mammals and screened the blood for the parasites.
After they found malaria, they took samples of parasites' DNA and sequenced it to identify mutations in the genetic code. From there, Lutz was able to perform what is called "phylogenetic analyses" to determine how different malaria species are related.
In examining the genetic codes of the malaria parasites, Lutz found places where the DNA differed from one species to the next. Then, researchers used powerful computing software to determine how the different species evolved and how they're related to each other.
This phylogenetic study relied on large sample sizes and DNA from many different host species of bats and birds, because otherwise the picture would be incomplete.
The analysis revealed that malaria has its roots in bird hosts. It then spread from birds to bats and on to other mammals.