Long-term persistence of monotypic dengue transmission in small size isolated populations, French Polynesia, 1978-2014

Yoann Teissier (1, 2) , Richard E. Paul (3) , Maite Aubry (1) , Xavier Rodó (4, 5) , Carlos Dommar (5) , Henrik Salje (6) , Anavaj Sakuntabhai (3) , Bernard Cazelles (7, 8, 9) , Van-Mai Cao-Lormeau (1)

1 ILM - Institut Louis Malardé [Papeete]
2 UFR Sciences Fondamentales et Biomédicales [Sciences] - Université Paris Cité
3 Génétique fonctionnelle des maladies infectieuses - Functional Genetics of Infectious Diseases
4 Department of Experimental and Health Sciences - ICREA Infection Biology Laboratory
5 ISGlobal - Instituto de Salud Global - Institute For Global Health [Barcelona]
6 Modélisation mathématique des maladies infectieuses - Mathematical modelling of Infectious Diseases
7 UMMISCO - Unité de modélisation mathématique et informatique des systèmes complexes [Bondy]
8 iGLOBES - Interdisciplinary and Global Environmental Studies
9 IBENS - Institut de biologie de l'ENS Paris

Understanding the transition of epidemic to endemic dengue transmission remains a challenge in regions where serotypes co-circulate and there is extensive human mobility. French Polynesia, an isolated group of 117 islands of which 72 are inhabited, distributed among five geographically separated subdivisions, has recorded mono-serotype epidemics since 1944, with long inter-epidemic periods of circulation. Laboratory confirmed cases have been recorded since 1978, enabling exploration of dengue epidemiology under monotypic conditions in an isolated, spatially structured geographical location. A database was constructed of confirmed dengue cases, geolocated to island for a 35-year period. Statistical analyses of viral establishment, persistence and fade-out as well as synchrony among subdivisions were performed. Seven monotypic and one heterotypic dengue epidemic occurred, followed by low-level viral circulation with a recrudescent epidemic occurring on one occasion. Incidence was asynchronous among the subdivisions. Complete viral die-out occurred on several occasions with invasion of a new serotype. Competitive serotype replacement has been observed previously and seems to be characteristic of the South Pacific. Island population size had a strong impact on the establishment, persistence and fade-out of dengue cases and endemicity was estimated achievable only at a population size in excess of 175 000. Despite island remoteness and low population size, dengue cases were observed somewhere in French Polynesia almost constantly, in part due to the spatial structuration generating asynchrony among subdivisions. Long-term persistence of dengue virus in this group of island populations may be enabled by island hopping, although could equally be explained by a reservoir of sub-clinical infections on the most populated island, Tahiti.

Domains: Emerging diseases

Yoann Teissier, Richard E. Paul, Maite Aubry, Xavier Rodó, Carlos Dommar, et al.. Long-term persistence of monotypic dengue transmission in small size isolated populations, French Polynesia, 1978-2014. PLoS Neglected Tropical Diseases, 2020, 14 (3), pp.e0008110. ⟨10.1371/journal.pntd.0008110⟩. ⟨hal-02747286⟩