Eri Togami1, Narayan Gyawali2, Oselyne Ong2, Mike Kama3, Van-Mai Cao-Lormeau4, Maite Aubry4, Albert I Ko5, Eric J Nilles6, Julie M Collins-Emerson7, Gregor J Devine2, Philip Weinstein8, Colleen L Lau9. 1. Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06510, USA. Electronic address: eri.togami1@gmail.com. 2. QIMR Berghofer Medical Research Institute, 300 Herston Road, Brisbane City, Queensland 4006, Australia. 3. Centre for Communicable Disease Control, Ministry of Health, 88 Amy Street, Toorak P.O. Box 2223, Government Buildings Suva, Fiji. 4. Institut Louis Malardé, P.O. Box 30, 98713 Papeete, Tahiti, French Polynesia. 5. Yale School of Public Health, Department of Epidemiology of Microbial Diseases, 60 College Street, New Haven, CT 06510, USA; Instituto Gonçalo Moniz, Fundação Oswaldo Cruz/MS, Rua Waldemar Falcão, 121, 40296-710 Salvador, Bahia, Brazil. 6. Harvard Humanitarian Initiative, 14 Story Street, Fl Second, Cambridge, MA 02138, USA; Harvard Medical School, Brigham & Women's Hospital, 75 Francis Street, Boston, MA 02115, USA. 7. Hopkirk Research Institute, Massey University School of Veterinary Science, Palmerston North 4410, New Zealand. 8. The University of Adelaide, School of Public Health, North Terrace Campus, 5005 South Australia, Australia. 9. Research School of Population Health, College of Health & Medicine, Australian National University, Canberra ACT 0200, Australia.
Abstract
BACKGROUND: Ross River virus (RRV) is a zoonotic alphavirus transmitted by several mosquito species. Until recently, endemic transmission was only considered possible in the presence of marsupial reservoirs. METHODS: RRV seroprevalence was investigated in placental mammals (including horses, cows, goats, pigs, dogs, rats, and mice) in Fiji, where there are no marsupials. A total of 302 vertebrate serum samples were collected from 86 households from 10 communities in Western Fiji. RESULTS: Neutralizing antibodies against RRV were detected in 28% to 100% of sera depending on the species, and neutralization was strong even at high dilutions. CONCLUSIONS: These results are unlikely to be due to cross-reactions. Chikungunya is the only other alphavirus known to be present in the Pacific Islands, but it rarely spills over into non-humans, even during epidemics. The study findings, together with a recent report of high RRV seroprevalence in humans, strongly suggest that RRV is circulating in Fiji in the absence of marsupial reservoirs. Considering that all non-human vertebrates present in Fiji are pan-global in distribution, RRV has the potential to further expand its geographic range. Further surveillance of RRV and access to RRV diagnostics will be critical for the early detection of emergence and outbreaks.
BACKGROUND:Ross River virus (RRV) is a zoonotic alphavirus transmitted by several mosquito species. Until recently, endemic transmission was only considered possible in the presence of marsupial reservoirs. METHODS:RRV seroprevalence was investigated in placental mammals (including horses, cows, goats, pigs, dogs, rats, and mice) in Fiji, where there are no marsupials. A total of 302 vertebrate serum samples were collected from 86 households from 10 communities in Western Fiji. RESULTS: Neutralizing antibodies against RRV were detected in 28% to 100% of sera depending on the species, and neutralization was strong even at high dilutions. CONCLUSIONS: These results are unlikely to be due to cross-reactions. Chikungunya is the only other alphavirus known to be present in the Pacific Islands, but it rarely spills over into non-humans, even during epidemics. The study findings, together with a recent report of high RRV seroprevalence in humans, strongly suggest that RRV is circulating in Fiji in the absence of marsupial reservoirs. Considering that all non-human vertebrates present in Fiji are pan-global in distribution, RRV has the potential to further expand its geographic range. Further surveillance of RRV and access to RRV diagnostics will be critical for the early detection of emergence and outbreaks.
Authors: Tanya L Russell; Paul F Horwood; Humpress Harrington; Allan Apairamo; Nathan J Kama; Albino Bobogare; David MacLaren; Thomas R Burkot Journal: PLoS Negl Trop Dis Date: 2022-02-10