Scientists have recently discovered two new relatives of rubella, aka “German measles,” previously the only known member of the virus family Matonaviridae. One of the two newfound relatives infects bats in the forests of Uganda, while the other was found spreading between animals at a zoo in Germany.
Understandably, mysterious new viruses being discovered in bats and zoo animals might trigger some concerns given the current pandemic, but the researchers say there’s no evidence the new viruses can infect people yet. They do say, however, that the research sheds light on the origins of the rubella virus, suggesting it originated in animals before spreading to people, much like many other viruses that infect humans.
Reported in the journal Nature this week, scientists from the US and Germany detail the discovery of the two new members of the Matonaviridae family and the first known relatives of the rubella virus: the ruhugu virus and the rustrela virus.
The ruhugu virus was discovered in 10 out of 20 oral swabs taken from seemingly healthy cyclops leaf-nosed bats in Kibale National Park, Uganda. Somewhat ironically, the Ugandan team discovered the virus while looking for coronaviruses carried by bats before the Covid-19 pandemic.
Meanwhile in Germany, the researchers first discovered the rustrela virus in the brain tissue of three different animals – a donkey, a capybara, and a Bennett’s tree-kangaroo – that fell acutely sick at a zoo in Germany with severe neurological diseases. The same novel virus was then detected in the brain tissues of eight out of 16 mice found within 10 kilometers (just over 6 miles) of the zoo, clearly showing the pathogen managed to jump from species-to-species.
The two new relatives are genetically close to the rubella virus and appear to share many traits, along with a fair number of key differences. Rubella, also known as German measles, is a highly infectious airborne viral infection that causes a distinctive red rash and a flu-like illness. It is especially dangerous for pregnant women and can lead to miscarriages, stillbirth, or profound birth defects. The disease has been largely eradicated thanks to an effective vaccine, notably the MMR vaccine, although some pockets of the world continue to have outbreaks. Unlike rubella, it currently doesn't look like the new viruses can infect humans.
“There is no evidence that ruhugu virus or rustrela virus can infect people, yet if they could, it might be so consequential that we should consider the possibility,” Tony Goldberg, a University of Wisconsin-Madison professor of epidemiology at the School of Veterinary Medicine, who led the American arm of the research, said in a statement.
“We know that in Germany, rustrela virus jumped among species that are not at all closely related. If either of these viruses turns out to be zoonotic, or if rubella virus can go back into animals, that would be a game-changer for rubella eradication,” Goldberg added.
If there’s any good news to draw from the research, it’s that this discovery could help to further our understanding of rubella. As the team explains, rubella has not been found in animals, so scientists do not have an animal model to carry out research on. Since the rustrela virus is known to reside in mice, a common lab animal, this could open up the study of rubella-like viruses.