Ross River Virus (RRV), a small ARBO virus in Togaviridae was found to be much more prevalent in the American Samoa than previously predicted, leaving researchers wondering if RRV could someday become the new global virus to watch out for.
Ross River Virus originated in marsupials in Australia, and is spread by mosquito vectors to marsupial and human hosts. In 55-75% of hosts, the virus is asymptomatic. But for others, the vector is characterized by joint pain, fever, rash, myalgia, and swollen lymph nodes. For an unfortunate few, the arthritis can continue for months or years, and can be incredibly painful and debilitating.
From 1979-1980 a large epidemic of Ross River Fever broke out in Pacific Island Countries and Territories. The epidemic is thought to have been caused by an infected Australian who travelled to Fiji, and it was known that for a short period of time, the virus could be sustained between non-marsupial hosts and spread with mosquito vectors. It was thought that the virus could not survive being spread from human to human for long, and since the 1980 outbreak, RRV has not been routinely seen in people in these regions.
However, in a recent serological study into individuals in the American Samoa it was found that 74% had IgG antibodies for RRV, a much higher rate than could have existed had people only been infected with the virus during its epidemic outbreak. This suggests that RRV has a much larger geographical spread than has previously been recognized, and also that it can be sustained in areas without marsupial hosts. It is possible that non-human mammals like dogs, mice, or cats are perpetuating the virus, although animal studies have not yet been performed.
This study could mean that Ross River Virus has the ability to become a virus endemic in areas that researchers never before expected. It is easy to draw a thread between this virus and Zika, another virus that until recently was seen as obscure and a non-threat to global human health. It is likely that this finding will spur many more studies into the virulence and possible consequences of a large RRV outbreak.
Elisa Hofmeister ’18
Colleen Lau, Maite Aubry, Didier Musso, Anita Teissier, Sylvie Paulous, Philippe Desprès, Xavier de-Lamballerie, Boris Pastorino, Van-Mai Cao-Lormeau, Philip Weinstein. New evidence for endemic circulation of Ross River Virus in the Pacific Islands and the potential for emergence. International Journal of Infectious Diseases, 2017; DOI: 10.1016/j.ijid.2017.01.041