Institut Louis Malardé

RÉSUMÉTahiti ou le « mythe du Paradis », Bora Bora ou la « Perle du Pacifique ». Qui n’a jamais voulu prendre l’avion et venir se poser sur les plages paradisiaques de la Polynésie, territoire français aux antipodes de la France hexagonale perdu au milieu du Pacifique ? Et pourtant, l’on ne s’imagine pas que 60 % des Polynésiens vivent en dessous du seuil médian de bas revenu métropolitain ou que l’espérance de vie est inférieure à celle de la métropole en raison de l’importante prévalence des maladies cardiovasculaires avec les trois quarts de la population en surpoids.Outre les maladies métaboliques non transmissibles, différentes pathologies communes aux pays tempérés présentent en Polynésie des spécificités dont la prise en charge et le raisonnement médical diffèrent parfois. En effet, en Polynésie où les îles s’étendent sur un territoire grand comme l’Europe, les retards de prise en charge sont fréquents et il peut parfois sembler difficile de renvoyer des patients malades dans leur île isolée. Certaines pathologies autrefois courantes en France comme le rhumatisme articulaire aigu y sévissent toujours, d’autres, comme la goutte, présentent un caractère rarement vu ailleurs en matière de prévalence ou de gravité.Même si l’éloignement géographique l’a préservée de nombre de maladies tropicales dont le paludisme, la rage ou les animaux dangereux, la Polynésie présente un large éventail de maladies infectieuses comme les arboviroses, la leptospirose, la tuberculose, la lèpre ou l’angiostrongylose. Les infections cutanées sont très fréquentes et, avec elles, leur corollaire de complications dont les endocardites et les infections ostéoarticulaires. La mer, qui est omniprésente, expose aussi à quelques dangers comme l’intoxication par la ciguatéra et expose aussi à certains organismes marins.La prise en charge se fait selon les standards modernes de la médecine grâce aux ressources de niveau européen permettant des possibilités diagnostiques et thérapeutiques inexistantes dans les autres états insulaires du Pacifique.L’objectif de ce panorama est d’orienter dans leur pratique quotidienne les soignants en exercice ou voulant venir exercer en Polynésie française et également les praticiens prenant en charge des personnes au retour de Polynésie.

Context The French Pacific Island territories are home to an exceptional terrestrial biodiversity that is threatened by invasive alien rodents causing drastic ecological damage, including the decline of endemic species. Aims This study compiled and analysed rodent eradication efforts in the French Pacific Island territories from 1982 to 2022, focusing on methods, challenges, and results. Methods We compiled data from the Database of Island Invasive Species Eradications and local reports. The dataset included a total of 85 eradication attempts conducted on 77 islands, and for each attempt, we extracted information on island size, targeted species, eradication techniques, and biosecurity measures. An attempt was considered successful if a monitoring carried out at least 2 years after the eradication failed to detect any rodent. Key results In New Caledonia and Wallis, 90% of rodent eradications attempts were successful and concerned quite small island (<60 ha). Eradication attempts in French Polynesia targeted larger islands but showed a lower success rate (56%). Brodifacoum was used in 97% of the operations, and biosecurity measures were uniformly applied, particularly in New Caledonia, where 76% of operations lacked re-invasion prevention protocols. Implications Our findings suggest that future eradication efforts should follow a global or territorial strategy prioritising islands for conservation. A more rigorous protocol, based on reliable data, is essential to success. Improved local stakeholder capacities is vital to safeguard the unique biodiversity of the French Pacific Island territories.

Abstract Ectotherm’s vulnerability to climate change is predicted to increase with temperature variations. Still, translating laboratory observations of organisms’ heat stress responses to the natural fluctuating environment remains challenging. In this study, we used an integrative framework combining insights from the TDT curves and physiological reaction norms, to precisely capturePinctada margaritiferastage -specific thermal tolerance. On a second hand, this study aimed to explore applicability of the model of accumulation of thermal injury, by making in situ predictions at three contrasting sites across French Polynesia. By working with two life stages (early planktonic vs. spat), our study revealed an ontogenetic shift in lethal (CTmax) and sub-lethal (Tc) thermal limits, with higher vulnerability for early larval stages. Cumulative injury calculations resulted in thermal failure (100% injury) for larvae within 12 and 22 h, at the most ‘extreme’ site (Nuku Hiva; T°C > 38°C), and warm lagoon (Reao Atoll), respectively. While substantial damages accumulated in spats, when exposed to consecutive extreme tides (Nuku Hiva) for 8 days. Overall, our results revealed thatP. margarifierais living closer to their upper thermal limits than previously estimated, and inhabit environments where important reduction of settlement and heat stress are already occurring during warmest months.

Estimating the impact of vaccination and non-pharmaceutical interventions on COVID-19 incidence is complicated by several factors, including successive emergence of SARS-CoV-2 variants of concern and changing population immunity from vaccination and infection. We develop an age-structured multi-strain COVID-19 transmission model and inference framework to estimate vaccination and non-pharmaceutical intervention impact accounting for these factors. We apply this framework to COVID-19 waves in French Polynesia and estimate that the vaccination programme averted 34.8% (95% credible interval: 34.5–35.2%) of 223,000 symptomatic cases, 49.6% (48.7–50.5%) of 5830 hospitalisations and 64.2% (63.1–65.3%) of 1540 hospital deaths that would have occurred in a scenario without vaccination up to May 2022. We estimate the booster campaign contributed 4.5%, 1.9%, and 0.4% to overall reductions in cases, hospitalisations, and deaths. Our results suggest that removing lockdowns during the first two waves would have had non-linear effects on incidence by altering accumulation of population immunity. Our estimates of vaccination and booster impact differ from those for other countries due to differences in age structure, previous exposure levels and timing of variant introduction relative to vaccination, emphasising the importance of detailed analysis that accounts for these factors.