In a letter dated March 29, 2006, the Minister of Health and Solidarity tasked the General Inspectorate of Social Affairs and the French Institute for Public Health Surveillance with a joint mission to assess the progression and consequences of the ongoing type 2 dengue epidemic for the health system in French Guiana. The mission’s objectives were: - to identify the factors that allowed the epidemic to develop and to assess the risks of endemicity, as well as the possibilities for eradication; - to evaluate the quality of the vector control system; - to propose appropriate measures to be implemented, taking into account all relevant aspects, particularly communication and the involvement of local authorities. 1. The Current Dengue Epidemic in French Guiana 1.1. A Spreading Arbovirus Disease Dengue is an arbovirus disease (from the English "Arthropod-Borne Virus," a virus transmitted by an arthropod). It is currently the most widespread arbovirus disease in the world. The World Health Organization estimates that dengue affects 100 million people and kills 50,000 each year, mainly in Southeast Asia. This increase is due to the expansion of the geographic range of the four virus types and the mosquito vectors, including Aedes aegypti, the species responsible for the dengue epidemic currently ravaging French Guiana. There are four dengue serotypes (DEN-1 to DEN-4). They were identified between 1940 and 1956. Since 1970, various strains of dengue have circulated in French Guiana, leading to epidemics every 2 to 6 years. This situation is also found in neighboring countries. Brazil, in particular, has experienced the co-circulation of several serotypes in recent years. The states of Amapá and Pará, which border French Guiana, are particularly affected. In Suriname, dengue epidemics caused by all four serotypes occur every 5 years. Venezuela is also in a similar situation. This picture leads to the conclusion that dengue is now endemic in this part of the world. 1.2. A vector particularly well-adapted to humans and benefiting from the socioeconomic conditions of French Guiana The Ae. aegypti mosquito is highly anthropophilic and has strongly domestic habits. Larval breeding sites are either inside or in the immediate vicinity of homes. The urban environment suits it particularly well, and it uses for reproduction all the small pools of water that can be found in this setting (flower pots, saucers, rainwater storage containers, discarded tin cans, tires, and other containers exposed to rain, bathrooms, etc.). These conditions are widespread in French Guiana and are exacerbated, in certain neighborhoods, by the extremely precarious living conditions of an undercounted population resulting from illegal immigration. The department’s situation regarding waste disposal further exacerbates this problem. The development of building codes that incorporate mosquito risk—or the enforcement of existing ones—would be effective in preventing the proliferation of the vector as part of an appropriate mechanical control strategy. Given this situation and the lack of a vaccine or antiviral drugs against dengue, it must be concluded that, for the time being, the eradication of the disease is unrealistic. Vector control remains the only possible means of limiting the spread of the epidemic. 1.3. A responsive health surveillance system, but one that requires long-term strengthening This epidemic has prompted a strong mobilization of all health surveillance partners to rapidly advance dengue surveillance in French Guiana. This adaptation allows for a responsive assessment of the scale and severity of the epidemic across the entire territory. However, the introduction of the NS1 test—intended to speed up diagnosis in the early stages of the disease—has compromised the quality of monitoring for circulating serotypes, and using this test without strictly adhering to the sampling window may lead to false-negative results. This strengthening of epidemiological surveillance of dengue must be sustained on a long-term basis, as the first step toward establishing a responsive and effective public health surveillance system for all diseases deemed a public health priority in French Guiana. 2. The Vector Control Program 2.1. A Program Facing Real Challenges The General Council of French Guiana has been responsible for vector control since the early 1980s, through its Departmental Disinfection Service (SDD). Previously, this mission was carried out by the Pasteur Institute of French Guiana. Today, the relationship with the Pasteur Institute is based solely on a contractual arrangement; the Pasteur Institute makes the expertise of its entomologist available under an agreement that was initially tripartite (State, department, Pasteur Institute) and later two bilateral agreements (State–Pasteur Institute on one side and State–General Council on the other). This relationship is expected to change, as the General Council has recently recruited the entomologist who previously worked at the Pasteur Institute. Another challenge is the sheer size of French Guiana (a territory as large as Portugal). This forces the SDD to maintain numerous field offices (18, including Cayenne), some of which have extremely limited staff. Supervision of these staff members is provided, aside from the physician in charge of the service and his deputy—both based in Cayenne—primarily by Category C staff, selected based on seniority and who, due to their duties, demand statutory recognition. Lax recruitment standards and severely inadequate training constitute further shortcomings of this service. It would be desirable to establish a more structured recruitment process involving the head of the service (development of job descriptions, participation in candidate selection). Finally, staff should be supported throughout their careers with ongoing training on topics essential to their professional practice (health education, use of insecticides, practical entomology, and worker health protection). 2.2. Areas Requiring Improvement The department has defined an intervention strategy for both malaria and dengue control. However, this strategy appears ill-suited to the situations encountered. For instance, there are excessively long delays between the reporting of a case and the SDD’s response to that case. This situation is partly due to the difficulty the SDD faces in obtaining the exact address of the case. However, the use of mapping software would allow for greater responsiveness and, above all, stronger integration with the health surveillance system, which, in the context of this epidemic, was able to establish a mechanism (reporting of suspected cases by health centers, the network of sentinel physicians, and hospitals) enabling the actual measurement of the scale of the epidemic. 3. Adequate resources to be implemented 3.1. Toward a broader understanding of vector control measures Vector control cannot be limited to the use of chemicals alone. It actually encompasses a wide range of measures that, when combined, can provide complementary solutions. The first of these, community-based control, targets the general population and aims to inform residents about appropriate behaviors to adopt to prevent the proliferation of breeding sites and reduce viral transmission (protection via mosquito nets or repellents in the event of infection to avoid spreading the virus to others). In the specific case of French Guiana, this communication must address the challenge posed by the diversity of written languages and the even greater diversity of spoken languages. To this end, it must be designed with this in mind and convey clear messages that are understandable to everyone, regardless of their level of education. Mechanical control, the only method capable of permanently eradicating a larval breeding site, remains severely inadequate. Clearly, it is already necessary, based on the provisions of the 1964 law, to ensure that the “mosquito” issue is integrated into public procedures. The regional environmental health plan includes an initiative in this regard that should be supported. The issue of waste disposal and wastewater management is a major cause for concern (in Cayenne, one-third of homes lack a separate wastewater/stormwater system and discharge their wastewater directly into open ditches). As for waste disposal, the situation is also very concerning; French Guiana’s sole incinerator, located at the Cayenne hospital, was subject to a prefectural order to cease operations at the time of the mission’s visit. These deficiencies in mechanical waste management pose real public health risks, and dengue is not the only disease to be feared in this context. 3.2. The Necessary Evolution of the Healthcare System This dengue epidemic highlights the chronic difficulties facing French Guiana’s healthcare system, particularly its hospital facilities. Admittedly, an aid mechanism led by the National Directorate of Hospitalization and Healthcare Organization and by the French Guiana Regional Hospitalization Agency has been put in place. This system was necessary to meet the healthcare needs of the French Guiana population and is in line with the republican principle of fraternity, which implies the establishment of solidarity. However, this system cannot be permanent. Moreover, the private medical community located in the coastal area is aging, raising the question of its renewal in the medium term. Furthermore, the Andrée Rosemon Hospital in Cayenne is facing real difficulties in recruiting medical staff. Certain specialties are understaffed (pediatrics) or operate solely with a large number of contract physicians (health centers, for example), exposing the facility to instability. In the context of French Guiana, it would be advisable to examine how, given the attractiveness of the hospital system established for populations along the borders of neighboring states, a portion of the funding could be allocated under international cooperation rather than being solely the responsibility of health insurance. In any case, an assessment of this situation will be necessary so that the appropriate measures it requires can be taken. (R.A.)