Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 25, Number 4—April 2019
Research Letter

Ross River Virus Antibody Prevalence, Fiji Islands, 2013–2015

Tables
Article Metrics
5
citations of this article
EID Journal Metrics on Scopus
Author affiliations: Institut Louis Malardé, Papeete, French Polynesia (M. Aubry, A. Teissier, T. Mariteragi-Helle, D. Musso, V.-M. Cao-Lormeau); Fiji Centre for Communicable Disease Control, Suva, Fiji (M. Kama); The University of the South Pacific, Suva (M. Kama, K. Christi); Institut Pasteur, Paris, France (J. Vanhomwegen, J.-C. Manuguerra); London School of Hygiene and Tropical Medicine, London, UK (S. Hue, M.L. Hibberd, C.H. Watson, A.J. Kucharski); World Health Organization Division of Pacific Technical Support, Suva (E.J. Nilles); Harvard Medical School and Brigham and Women’s Hospital, Boston, Massachusetts, USA (E.J. Nilles); Harvard Humanitarian Initiative, Cambridge, Massachusetts (E.J. Nilles); Queensland University of Technology, Brisbane, Queensland, Australia (J. Aaskov); Australian National University, Canberra, Australian Capital Territory, Australia (C.L. Lau); Aix Marseille Université, IRD, AP-HM, SSA, VITROME, IHU-Méditerranée Infection, Marseille, France (D. Musso)

Cite This Article

Abstract

A unique outbreak of Ross River virus (RRV) infection was reported in Fiji in 1979. In 2013, RRV seroprevalence among residents was 46.5% (362/778). Of the residents who were seronegative in 2013 and retested in 2015, 10.9% (21/192) had seroconverted to RRV, suggesting ongoing endemic circulation of RRV in Fiji.

Ross River virus (RRV) is an Alphavirus of the family Togaviridae and is transmitted to humans by Aedes and Culex mosquitoes (1). Marsupials are considered important reservoirs of RRV (1). Clinical manifestations of RRV infections include fever, rash, and arthralgia. RRV is endemic to Australia, where it causes ≈5,000 cases of epidemic polyarthritis annually (1). Outbreaks of RRV infection were reported during 1979–1980 in Fiji, the Cook Islands, American Samoa, New Caledonia, and Wallis and Futuna (13). Subsequently, RRV infections were detected in travelers returning from Fiji during 1997–2009 (3) and in patients with suspected dengue in Fiji in 2005 (4).

The Republic of the Fiji Islands comprises 322 islands distributed among 4 administrative divisions (Central, Western, Eastern, and Northern) and has a population of ≈830,000. Apart from RRV, the 4 serotypes of dengue virus were the only mosquitoborne viruses known to circulate in Fiji until the recent emergence of Zika and chikungunya viruses (5). We report evidence of endemic RRV circulation in Fiji on the basis of serologic analysis of blood samples collected in 2013 and 2015.

Our study included 778 participants recruited during September–November 2013 from the Central, Western, and Northern divisions for a community-based serosurvey for leptospirosis and typhoid (6). Among the residents from the Central division who had participated in the 2013 survey, 333 had blood drawn again during October–November 2015, including 311 whose serum sample collected in 2013 was available for testing. We tested all blood samples for RRV IgG by using a recombinant antigen-based microsphere immunoassay (7). We analyzed the data with GraphPad Prism 6.03 using the Fisher or χ2 test. We considered p values <0.05 to be significant.

The prevalence of RRV antibodies among participants in 2013 was 46.5% and was lower in the Central (38.1%) than the Western (58.6%; p<0.0001) and Northern (55.9%; p = 0.0108) divisions (Table). The prevalence of RRV antibodies among the participants sampled in the Central division in 2015 (37.2%) was similar to results from this division in 2013 (38.1%). In 2013, a total of 37.4% of the participants born after 1982 (postoutbreak) had RRV antibodies, and this rate in 2015 (26.9%) was not significantly different (p = 0.0685). The prevalence of RRV antibodies increased with age (p<0.0001 in 2013, p = 0.0020 in 2015) and was higher in rural than in urban (p<0.0001 in 2013, p = 0.0197 in 2015) and periurban areas (p = 0.0060 in 2013). No difference by sex was observed. Among the 311 participants with available serum samples collected in both 2013 and 2015, a total of 21 (10.9%) of the 192 participants who had no detectable RRV antibodies in 2013 had seroconverted to RRV by 2015 (data not shown).

A serosurvey conducted after the RRV outbreak in Fiji in 1979 detected RRV antibodies in 92% of the participants from the Western division (2). In our study, which was conducted in 2013, RRV antibody prevalence in the Western, Central, and Northern divisions ranged from 38.1% to 58.6%, and 37.4% of persons born after 1982 had RRV antibodies, suggesting that RRV circulated in all 3 divisions after the 1979 outbreak. The report of RRV infection in travelers or inhabitants from Fiji during 1997–2009 (3,4), the observations that 10.9% of the seronegative participants in our study seroconverted to RRV during 2013–2015, and the increase in the prevalence of RRV antibodies with age, strongly suggest endemic RRV transmission in Fiji.

The finding that RRV seroprevalence was higher in rural than in urban and periurban environments suggests increased transmission risks in the rural areas, potentially because of higher-risk occupations of rural residents (including farming and outdoor work), greater exposure related to rural housing or other environmental factors, greater animal reservoir density, the possibility that nondomestic mosquito species in Fiji such as Aedes vigilax, Ae. polynesiensis, Ae. pseudoscutellaris, Ae. albopictus, and Culex annulirostris might be more competent vectors of RRV than peridomestic mosquito species such as Ae. aegypti (8).

Serosurveys conducted in American Samoa in 2010 (1), in French Polynesia during 2011–2013 (9) and 2014–2015 (7), and our study in Fiji during 2013–2015 suggest that endemic circulation of RRV in the Pacific region continued, or recommenced, after 1979–1980. These data provide further evidence for endemic transmission of RRV in areas where marsupials are absent (10). Because of extensive travel between Australia and the Pacific Islands, it is plausible that RRV is repeatedly seeded into the Pacific region. Whether this plays an important role in perpetuating local transmission in the Pacific Islands is unknown. As previously illustrated with Zika and chikungunya viruses, a risk exists for emerging arboviruses to be imported from the Pacific to other parts of the world, and RRV could be the next unexpected threat.

Dr. Aubry is a research scientist at the Institut Louis Malardé, Papeete, French Polynesia. Her research interests include the prevalence, epidemiology, and genetic evolution in the Pacific region of various arboviruses, such as dengue, Zika, chikungunya, and Ross River viruses.

Top

Acknowledgments

This work was part of ISID-Pacific and R-ZERO Pacific programs funded by the French Ministry for Europe and Foreign Affairs (Pacific Funds nos. 06314-09/04/14, 12115-02/09/15, 03016-20/05/16, and 04917-19/07/17). The study also received support from the Embassy of France in the Republic of the Fiji Islands. The study was supported by the French Government’s Investissement d’Avenir Program (Labex IBEID no. ANR-10-LABX-62-IBEID). C.L.L. was supported by an Australian National Health and Medical Research Council Fellowship (no. 1109035). Fieldwork in 2013 was funded by the World Health Organization Western Pacific Region and by the Chadwick Trust. C.H.W. was supported by the UK Medical Research Council (grant no. MR/J003999/1). A.J.K. was supported by a Sir Henry Dale Fellowship, jointly funded by the Wellcome Trust and the Royal Society (grant no. 206250/Z/17/Z).

The study was approved by the Fiji National Health Research Ethics Review Committee (FNRER/no. 2015.114.NW and FNRER/no. 2015.45.MC), the University of the South Pacific (FSTER/2015/10/Research Proposal Approval), and the London School of Hygiene and Tropical Medicine Observational Research Ethics Committee (approval nos. 6344 and 10207).

Top

References

  1. Lau  C, Aubry  M, Musso  D, Teissier  A, Paulous  S, Desprès  P, et al. New evidence for endemic circulation of Ross River virus in the Pacific Islands and the potential for emergence. Int J Infect Dis. 2017;57:736. DOIPubMedGoogle Scholar
  2. Aaskov  JG, Mataika  JU, Lawrence  GW, Rabukawaqa  V, Tucker  MM, Miles  JA, et al. An epidemic of Ross River virus infection in Fiji, 1979. Am J Trop Med Hyg. 1981;30:10539. DOIPubMedGoogle Scholar
  3. Lau  C, Weinstein  P, Slaney  D. Imported cases of Ross River virus disease in New Zealand - a travel medicine perspective. Travel Med Infect Dis. 2012;10:12934. DOIPubMedGoogle Scholar
  4. Ngwe Tun  MM, Inoue  S, Thant  KZ, Talemaitoga  N, Aryati  A, Dimaano  EM, et al. Retrospective seroepidemiological study of chikungunya infection in South Asia, Southeast Asia and the Pacific region. Epidemiol Infect. 2016;144:226875. DOIPubMedGoogle Scholar
  5. Cao-Lormeau  V-M, Musso  D. Emerging arboviruses in the Pacific. Lancet. 2014;384:15712. DOIPubMedGoogle Scholar
  6. Lau  CL, Watson  CH, Lowry  JH, David  MC, Craig  SB, Wynwood  SJ, et al. Human leptospirosis infection in Fiji: an eco-epidemiological approach to identifying risk factors and environmental drivers for transmission. PLoS Negl Trop Dis. 2016;10:e0004405. DOIPubMedGoogle Scholar
  7. Aubry  M, Teissier  A, Huart  M, Merceron  S, Vanhomwegen  J, Roche  C, et al. Ross River virus seroprevalence, French Polynesia, 2014–2015. Emerg Infect Dis. 2017;23:17513. DOIPubMedGoogle Scholar
  8. Mitchell  CJ, Gubler  DJ. Vector competence of geographic strains of Aedes albopictus and Aedes polynesiensis and certain other Aedes (Stegomyia) mosquitoes for Ross River virus. J Am Mosq Control Assoc. 1987;3:1427.https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=2849637&dopt=Abstract
  9. Aubry  M, Finke  J, Teissier  A, Roche  C, Broult  J, Paulous  S, et al. Silent circulation of Ross River virus in French Polynesia. Int J Infect Dis. 2015;37:1924. DOIPubMedGoogle Scholar
  10. Stephenson  EB, Peel  AJ, Reid  SA, Jansen  CC, McCallum  H. The non-human reservoirs of Ross River virus: a systematic review of the evidence. Parasit Vectors. 2018;11:188. DOIPubMedGoogle Scholar

Top

Table

Top

Cite This Article

DOI: 10.3201/eid2504.180694

Original Publication Date: February 28, 2019

Table of Contents – Volume 25, Number 4—April 2019

EID Search Options
presentation_01 Advanced Article Search – Search articles by author and/or keyword.
presentation_01 Articles by Country Search – Search articles by the topic country.
presentation_01 Article Type Search – Search articles by article type and issue.

Top

Comments

Please use the form below to submit correspondence to the authors or contact them at the following address:

Van-Mai Cao-Lormeau, Institut Louis Malardé, PO Box 30, 98713 Papeete, Tahiti, French Polynesia

Send To

10000 character(s) remaining.

Top

Page created: March 17, 2019
Page updated: March 17, 2019
Page reviewed: March 17, 2019
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.
file_external