Epidemiological Situation

A dengue epidemic is currently underway in Réunion. Following an unusually low level of dengue virus circulation in 2017, including during the southern hemisphere winter, the number of dengue cases has been rising since the beginning of 2018. An increase in viral circulation has been observed every week since January 29.

During the past week (April 9–15, 2018), 396 confirmed or probable dengue cases were reported by private and hospital laboratories. A total of 1,388 cases have been reported in Réunion in 2018. Since the beginning of 2017, 1,482 locally acquired cases and 9 imported cases have been confirmed.

Following investigations with Mauritian authorities, no dengue virus circulation was detected. The case reported last week with a suspected link to Mauritius has therefore been reclassified as a locally acquired case.

The cases reported over the past week are primarily located:

• in the west: St-Paul, Gare Routière, and Etang (83 cases), Bois de Nèfles and La Plaine (67 cases), St Gilles-les-Bains (40 cases), St-Gilles-les-Hauts (8 cases), La Saline (7 cases), La Possession (26 cases), Le Port (31 cases), St-Leu (31 cases).

• in the south: St-Pierre (18 cases) and Ravine des Cabris (23 cases)

• in the north: Sainte-Clotilde (1 case) in the known viral circulation zone

Isolated cases have also been identified; they reside in: Saint Denis (2 cases), Saint Paul (Le Guillaume 2 cases), Les Avirons (4 cases), l'Etang Salé (1 case), Saint-Louis (La Rivière 2 cases, Saint-Louis 6 cases), Saint-Joseph (3 cases), Saint-Philippe (1 case), Saint-André (1 case). Ongoing investigations will help identify their presumed place of infection.

Since early 2017, the predominant serotype has been DENV-2 (537 genotypes). The other viruses identified are DENV-1 (4 genotypes) and DENV-4 (1 genotype), primarily in imported cases in 2017.