Lessons raised by the major 2010 dengue epidemics in the French West Indies.

Dengue fever has been endemo-epidemic in the whole Region of America. In 2010, Guadeloupe and Martinique experienced historical epidemics, with an estimated attack rate of 10% in two islands. When considering the temporal evolution of epidemiological indicators, an unusual increase in the number of dengue cases could be detected very early. Two main factors might have facilitated the settlement of a viral transmission despite the dry season: a low immunity of the population against the circulating serotype and particular climatic conditions, notably very high temperatures which could have improved both virus and vector efficiency. This unusual situation was considered as a warning sign, and indeed led to major outbreaks in both islands a few weeks later. This event underlines that follow-up of epidemiological indicators is necessary to detect the unusual situations as soon as possible. Furthermore, development of biological and modelling tools should be promoted, as well as integrated management strategies for dengue prevention and control.

[Epidemic of influenza A(H1N1) 2009 in the French overseas territories of the Americas: epidemiological surveillance set up and main results, April 2009-January 2010]. / L'épidémie de grippe A(H1N1) 2009 dans les territoires français des Amériques: dispositif de surveillance mis en place et principaux résultats, avril 2009-janvier 2010.

Guadeloupe, French Guiana, Martinique, St. Martin and St. Barthelemy were the French territories most exposed to the new influenza A(H1N1)v, and adequate epidemiological surveillance tools were promptly developed in order to detect its emergence. The first stage, "containment phase", consisted in detection and management of individual cases. Then, when an autochthonous A(H1N1)v circulation was confirmed, its evolution has been monitored within the whole population, mainly through data collected from sentinel doctors' networks and virological surveillance. This allowed to detect very early the occurrence of epidemics, and to follow their evolution until they were over. Like all the other Caribbean countries, the five French overseas territories were hit by an outbreak of influenza A(H1N1)v. Although they had globally similar characteristics, each epidemic had its specificity in terms of scale and severity. They started between August and September 2009 in four of the five territories, while the last one, St. Barthelemy, was not affected until the end of the year. Attack rate estimates varied from 28 to 70 per 1000 inhabitants according to the territory, and hospitalisation rate varied from 4.3 to 10.3 per 1000 cases. Severity rate didn't reach 1 per 1000 cases in any of the territories. Compared to metropolitan France, the surveillance system presented several strengths, including the pre-existence of both an active sentinel network and an expert committee on emerging diseases in each territory. On the other hand, specific difficulties appeared, notably linked with logistical aspects of virological surveillance and the co-circulation of dengue virus in Guadeloupe and St. Barthelemy. Despite these difficulties, the different tools allowed early detection of the epidemics and follow-up of their evolution. All of them lead to very concordant results, suggesting that they are completely appropriate to monitor a potential new epidemic wave.

[Control of intestinal schistosomiasis in Martinique island]. / Le contrôle de la schistosomose intestinale de l'île de la Martinique.

The presence of schistosomiasis mansoni is known in Martinique since the beginning of the XXth century. A general survey of the distribution of the disease was carried out in 1977 and showed a mean prevalence of 12% (coprology and serology taken together) in the whole of the island. Following this survey, an integrated control programme associating sanitary education, detection and treatment of patients and improved sanitation, was developed. In addition, a biological control programme against the intermediate snail host, Biomphalaria glabrata using the competitor snail, Melanoides tuberculata, was developed in the transmission sites. The decline of snail populations and of its parasite, as well as a strong reduction of the prevalence in humans were recorded between 1977 and 1996. At the present time, only few cases corresponding to older infections are detected. This epidemiological situation is quite different from that in Guadeloupe island where, in spite of an excellent control programme which was achieved on the Basse-Terre district, an important focus is still functioning on Grande-Terre district with the black rat as host reservoir. Such foci do not exist on Martinique island.