Bats can be hosts to a host of dangerous viruses, such as Ebola, SARS, Marburg, Nipah and Hendra. Now researchers in the Proceedings of the National Academy of Sciences report that bats are reservoirs of relatives of the hepatitis C virus, one of the main causes of liver transplantation in the United States.
The hepatitis C virus infects roughly 3 percent of the world population, and there is currently no vaccine against it. Although it was discovered more than 20 years ago, its origin remains unknown. Hepatitis C virus and its distant relative, GB virus B, are known as hepaciviruses; other GB viruses, such as GB virus A, C and D, are known as pegiviruses.
Now molecular virologist Phenix-Lan Quan at Columbia University and her colleagues find that bats are naturally hosts to a highly diverse group of hepaciviruses and pegiviruses. After investigating 1,673 bat specimens from 58 species from Guatemala, Cameroon, Nigeria, the Democratic Republic of the Congo, Kenya, Mexico, and Bangladesh, the researchers discovered 83 novel hepaciviruses and pegiviruses in bats.
Evolutionary analyses revealed that all known hepaciviruses and pegiviruses, including those previously seen in humans and other primates, fall within the phylogenetic diversity of the novel bat-derived viruses—essentially, within their family tree.
“The broad prevalence, unprecedented diversity and worldwide distribution of these novel viruses suggest that bats are a major and ancient reservoir for both hepaciviruses and pegiviruses, and provide insights into the evolutionary history of hepatitis C virus and human pegiviruses,” Quan said.
Nearly 60 percent of emerging infectious diseases in humans are zoonotic, meaning they came from animals. However, Quan cautioned there is currently no evidence these bat hepaciviruses and pegiviruses are transmitted directly to humans.
Quan and many other researchers have emphatically noted that attempts to eradicate bats would do more harm than good. “Bats are extremely important for the ecosystems. They play a major role as pollinators and insect predators. Their ecological benefits far outweigh their potential for zoonotic disease transmission,” Quan said.
Future research may answer whether hepaciviruses and pegiviruses originated in bats. Researchers can also investigate how people might not encroach upon or damage the natural habitats of these bats, so as to not potentially set off spillover infections, Quan said.