Epidemiological and molecular features of dengue virus type-1 in New Caledonia, South Pacific, 2001-2013.

Myrielle Dupont-Rouzeyrol (1) , Maïté Aubry (2) , Olivia O'Connor (1) , Claudine Roche (2) , Ann-Claire Gourinat (1) , Aurélie Guigon (1) , Alyssa Pyke (3) , Jean-Paul Grangeon (4) , Eric Nilles (5) , Suzanne Chanteau (1) , John Aaskov (6) , Van-Mai Cao-Lormeau (2)

1 Institut Pasteur de Nouvelle-Calédonie
2 ILM - Institut Louis Malardé [Papeete]
3 Queensland Health Forensic and Scientific Services
4 Direction des Affaires Sanitaires et Sociales
5 OMS / WHO - Organisation Mondiale de la Santé / World Health Organization Office
6 QUT - Queensland University of Technology [Brisbane]

BACKGROUND: The epidemiology of dengue in the South Pacific has been characterized by transmission of a single dominant serotype for 3-5 years, with subsequent replacement by another serotype. From 2001 to 2008 only DENV-1 was reported in the Pacific. In 2008, DENV-4 emerged and quickly displaced DENV-1 in the Pacific, except in New Caledonia (NC) where DENV-1 and DENV-4 co-circulated in 2008-2009. During 2012-2013, another DENV-1 outbreak occurred in NC, the third DENV-1 outbreak in a decade. Given that dengue is a serotype-specific immunizing infection, the recurrent outbreaks of a single serotype within a 10-year period was unexpected. FINDINGS: This study aimed to inform this phenomenon by examining the phylogenetic characteristics of the DENV-1 viruses in NC and other Pacific islands between 2001 and 2013. As a result, we have demonstrated that NC experienced introductions of viruses from both the Pacific (genotype IV) and South-east Asia (genotype I). Moreover, whereas genotype IV and I were co-circulating at the beginning of 2012, we observed that from the second half of 2012, i.e. during the major DENV-1 outbreak, all analyzed viruses were genotype I suggesting that a genotype switch occurred. CONCLUSIONS: Repeated outbreaks of the same dengue serotype, as observed in NC, is uncommon in the Pacific islands. Why the earlier DENV-1 outbreaks did not induce sufficient herd immunity is unclear, and likely multifactorial, but the robust vector control program may have played a role by limiting transmission and thus maintaining a large susceptible pool in the population.

Domaines: Maladies infectieuses

Myrielle Dupont-Rouzeyrol, Maïté Aubry, Olivia O'Connor, Claudine Roche, Ann-Claire Gourinat, et al.. Epidemiological and molecular features of dengue virus type-1 in New Caledonia, South Pacific, 2001-2013.. Virology Journal, 2014, 11 (1), pp.61. ⟨10.1186/1743-422X-11-61⟩. ⟨pasteur-00971442⟩