An Unprecedented High Incidence of Leptospirosis in Futuna, South Pacific, 2004 - 2014, Evidenced by Retrospective Analysis of Surveillance Data.

Futuna is a small Polynesian island in the South Pacific with a population of 3,612 in 2013. The first human leptospirosis case was confirmed in 1997. Active surveillance started in 2004. Cases were confirmed by PCR or real time PCR, or by serology using MAT or a combination of IgM-ELISA and MAT. A retrospective analysis of surveillance data shows that the disease was endemic with a mean annual incidence of 844 cases per 100,000 over an 11-year period from 2004 to 2014. An epidemic peak as high as 1,945 cases per 100,000 occurred in 2008. Serogroup Australis was predominant until 2007, Icterohaemorrhagiae was dominant afterwards. Cluster analysis revealed different hot spots over time. Lifestyle habits, such as walking barefoot in irrigated taro fields or pig pens probably contributed to contamination from the swine and rodent reservoirs to humans. Severe forms were rare, and the case fatality rate was 0.5%. The medical community and general population were aware of leptospirosis and rapid treatment with amoxycillin was the main treatment, probably contributing to this low fatality rate.

[Pandemic influenza A (H1N1 virus) on Futuna Island in the Pacific, from August to September 2009]. / Pandémie de grippe A (virus H1N1) à Futuna, île du pacifique, d'août à septembre 2009.

OBJECTIVE: The aim of this study is to report the observation of the pandemic of influenza A (H1N1 virus) from August to September 2009 on the island of Futuna, in a context of isolated island that may mimic an environment closed. METHOD: We conducted a prospective observational study of influenza-like illness, from the first confirmed case of influenza A on the island until the end of the epidemic wave. RESULTS: From August 15 to September 20, 2009, 1536 cases of influenza syndrome were identified. The estimate of the overall clinical attack rate was 36 %. The evolution of the epidemic shows an explosion of new cases of influenza A and subsequently a rapid decline of the epidemic. The spread of the infection was made by contiguity, jumping from one city to another. The cumulative number of cases by age group shows that the majority of cases were children and young adults under the age of 20 years. The most frequent symptoms were cough, rhinorrhea, headache, myalgia or asthenia, and fever. CONCLUSION: This study, despite these limitations, shows an explosive epidemic of influenza A, which can be explained by the circulation of virus that has been fostered by gatherings of public and closed environment. Age group classification shows that majority of cases were young, in contrast to seasonal influenza, but the symptoms were alike. This study highlights the difficulties to manage an epidemic surveillance system at high level and given the quick spread of the disease.

Influenza A(H1N1)2009 in the French Pacific territories: assessment of the epidemic wave during the austral winter.

The three French territories in the Pacific (New Caledonia [NC], French Polynesia [FP] and Wallis and Futuna [WF]) have been affected by an outbreak of influenza A(H1N1)2009 during the austral winter of 2009. This wave of influenza-like illness was characterized by a short duration (approximately 8 weeks) and high attack rates: 16-18% in NC and FP, 28% in Wallis and 38% in Futuna. The number of infected patients requiring hospitalization in critical care services and the number of deaths were, respectively, 21 and 10 in NC and 13 and 7 in FP (none in WF). Diabetes, cardiac and pulmonary diseases, obesity in adults, neuromuscular diseases in children, and Oceanic origin were frequently observed among severe cases and deaths. A significant proportion of the population remains susceptible to A(H1N1)2009, making the occurrence of a second wave likely. A state of preparedness and control efforts must be implemented, based on preventive measures (immunization), as well as combined clinical and virological surveillance and health organization.

Multicentre survey of incidence and public health impact of leptospirosis in the Western Pacific.

The objectives of the study were to describe the mode of circulation (endemic or epidemic) of human leptospirosis in various Pacific island states and territories by identifying predominant Leptospira serogroups and the most probable routes of human exposure, and to recommend a feasible laboratory strategy for leptospirosis in the Pacific. From September 2003 to December 2005, 263 leptospirosis suspect patients were recruited by public practitioners on 11 Pacific islands, using the WHO case definition. Diagnosis was confirmed using a three-level serology algorithm and a regional laboratory network. Sixty-nine leptospirosis cases were identified from seven islands: Futuna, Raiatea and the Marquesas Islands where outbreaks were apparent, and Vanuatu, Fiji, Palau and Wallis where sporadic cases indicated at least the presence of the disease. Most patients were men aged 17-40 years. The infection appeared to occur during the course of normal daily activities more often than following specific professional exposure. The dominant presumptive serogroups were Icterohaemorrhagiae and Australis, highly suggestive of a rodent reservoir. This study confirms the widespread presence of leptospirosis in the Pacific region. It should help in the implementation of local leptospirosis control plans and highlights the role of on-site laboratory confirmation.