New viruses identified in bats in China

Scientists in China have discovered a host of never-before-seen viruses in bats that live near humans. These viruses include two that are closely related to the deadly Nipah and Hendra viruses, which can cause severe brain inflammation and respiratory disease in humans.

The work, published June 24 in the journal PLOS Pathogens, highlights the importance of keeping a close eye on bats and other animals that live near human populations, and avoiding contact with them as much as possible.

Bats are natural reservoirs for many pathogens that can cause disease in humans, but the full extent of the bacteria, viruses and other potentially infectious agents they harbor is not known. Most previous studies have focused on bat feces rather than on internal organs, mainly because it is easier to collect. However, that tells us only about the viruses that make their way into feces.

To investigate the pathogens present in bat kidneys, a team led by Yun Feng of the Yunnan Institute of Endemic Disease Control and Prevention sampled the kidneys of 142 bats from 10 species collected from China's Yunnan province. Genetic sequencing revealed 22 viruses, 20 of which had never been seen before, as well as a new protozoan parasite and two kinds of bacteria, one of which was new to science.

Study co-author Edward Holmes, a virologist at the University of Sydney in Australia, said focusing on the kidneys is important because they provide a window into what viruses might be excreted in urine, and urine is one way humans might be infected by bat viruses.

"Bats peeing into date-palm collecting bowls was how Nipah virus first spread from bats to humans," Holmes told Live Science. Because the bats in this study were living close to orchards near human villages, there is a risk that contaminated fruit could allow these pathogens to jump to livestock or people.

Although two of the new viruses are closely related to Nipah virus and Hendra virus (together known as henipaviruses), they are not cause for concern, Holmes said.

"These newly discovered viruses have not yet been found in humans, and there is currently no evidence that they will ever infect or emerge in humans," he said. "In theory, they could pose a threat, but as there are no human cases, there is no need to be concerned."

However, the discoveries do highlight the importance of sampling animals like bats that live near human populations. It would also be helpful to monitor human populations that might be exposed to these animals, to identify potential viral threats before they emerge.

"It is this increasingly porous animal-human interface that leads to pandemics," Holmes said. "Pandemics always reflect how humans disturb natural environments. Better surveillance is always the key."