Researchers led by the study led by the University of Adelaide and The Australian National University claim that Australia’s Ross River Virus (RRV) could be the next mosquito-borne global epidemic. The virus has been circulating in areas experts were not aware of previously.

Initially, the virus was believed to only be present in Australia and Papua New Guinea. However, experts found that it has been circulating silently in the South Pacific.

In the study, which has been published in the journal International Journal of Infectious Diseases, the researchers explain that the virus is harbored by kangaroos and wallabies. The virus has not killed anyone, the team explains.

“When humans arrived, first Aboriginal Australians and then Europeans, they were bitten by the same mosquitoes and became infected: they had all of the sore joints, fever, rash, and fatigue that we associate with the disease today. Although RRV has never killed anyone, it can be extremely debilitating for several months, and up to years in a few unlucky individuals,” says Professor Phil Weinstein, Professorial Research Fellow with the University of Adelaide’s School of Biological Sciences.

In 1979, an epidemic in the Pacific Islands Countries and Territories made the authorities believe that the virus escaped from its usual territory. This became better the year after. However, it has been found that recent tourists from New Zealand and Canada got diagnosed with the RRV. These tourists came from the South Pacific, not Australia.

The Australian team and their French colleagues have tested the blood samples of American Samoans. They concluded that the virus is now harbored by local animals instead of marsupials in these areas.

“We were surprised to find that of those who were born after the 1979-1980 epidemic and had lived in American Samoa their whole lives, a massive 63% had antibodies to RRV, strongly suggesting local transmission of the virus after 1980,” says researcher Colleen Lau, NHMRC Research Fellow in ANU’s College of Medicine, Biology and Environment. “There are no marsupials in American Samoa, so the only reasonable conclusion is that the virus was able to circulate in local mammals rather than marsupials. If RRV can circulate in non-marsupials in the South Pacific, then it can find a home anywhere in the world.”

Lau adds that isolating the virus from non-marsupials will help them prove that the RRV can become the next global disease. Weinstein also states that it would be possible that the virus can become the next Zika given the right conditions.

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