Epidemiological Situation

Following an unusually low level of dengue virus circulation in 2017, including during the southern hemisphere winter, the number of dengue cases has been increasing since the beginning of 2018. An intensification of viral circulation has been observed each week since January 29.During the past week (March 26 to April 1), 167 confirmed cases were reported. In the first three months of 2018, 755 cases of dengue were reported on Réunion. Since the beginning of 2017, a total of 849 locally acquired cases and 9 imported cases have been confirmed.

An area of viral circulation has been identified in the north at Ste-Clotilde, whereas until now, the west and south of the island were the only areas affected by active viral circulation. The cases reported last week are mainly located

• in the west in St-Paul, Gare routière, and Etang (37 cases), Bois de Nèfles and La Plaine (35 cases), St-Gilles-les-Bains (16 cases), St-Gilles-les-Hauts (7 cases), La Saline (4 cases), in La Possession (8 cases), Le Port (3 cases), St-Leu (15 cases).

• in the south in St-Pierre (8 cases) and Ravine des Cabris, Bois d'Olives (10 cases)

• in the north: in Ste-Clotilde (2 cases unrelated to known transmission areas)

During the week, isolated cases were also identified; they reside in Saint-Denis/La Montagne (1 case), Sainte-Marie (2 cases), Les Avirons (2 cases), Etang-Salé (3 cases), Saint-Louis (4 cases), Entre-Deux (1 case), Le Tampon (2 cases), and Saint-Joseph (1 case). Ongoing investigations will help identify their presumed place of infection.

Since early 2017, the predominant serotype among locally acquired cases has been DENV-2 (358 genotypes). The other viruses identified are DENV-1 (4 genotypes) and DENV-4 (1 genotype), primarily in imported cases in 2017.