A wild bonobo in the Democratic Republic of Congo. Credit: Sean M. Lee
Key points:
- A new study sheds light on how bonobos respond to malaria.
- An immune gene variant in bonobo that is similar to humans appears to protect from developing severe and deadly malaria.
- Better understanding of the variant could lead to an additional source of treatment or vaccination for humans.
A new study by researchers at Washington University in St. Louis provides a better understanding of how malaria affects wild African apes.
Previously, scientists knew little about what malaria infection looked like in apes, especially bonobos. What they do know, however, is that malaria infection is widespread across the geographic ranges of wild chimpanzees and gorillas. In fact, previous studies show African great apes harbor at least 12 different Plasmodium species, seven of which are closely related to the human parasite that causes about 95% of human deaths. But, that level of detail for bonobos was previously unavailable as bonobos seemingly escaped infection in all but two locations where researchers have studied them in the wild.
In one “infected” location, 38% of bonobos had detectable parasite DNA in their feces. According to the study published in Nature Communications, in areas where malaria infection was detected, bonobos were more likely to have particular variants of an immune gene (Papa-B). The bonobo variants are very similar to a human variant (HLA-B*53) associated with protection from developing severe disease. This suggests that similar immune defense mechanisms may be used in these two species.
“Seeing infected populations differ from uninfected populations in this immune trait suggests that it is because bonobos experience increased mortality or costs to their reproductive success because of their infection,” said Emily Wroblewski, an assistant professor of biological anthropology at Washington University in St. Louis. “The differences between the bonobo populations provide the first evidence of any kind, albeit indirect, that a great wild ape suffers any consequences from their infection.”
The scientists say they are particularly intrigued to see that the immunogenetic pattern observed in infected bonobos is very similar to what is observed among human populations experiencing malaria infection in Africa.
“This is notable because these immune genes evolve very rapidly while trying to keep up with rapidly evolving pathogens,” said Wroblewski. “Because of this, it is very unusual to observe a pattern that is shared between humans and their closest living relatives.”
The research team hopes future investigations examine how the Papa-B/HLA-B*53 immune gene variant protects individuals—both bonobo and human. Understanding that mechanism could lead to an additional source of treatment or vaccination for humans.