A dengue type 2 epidemic has been declared in Wallis and Futuna.
Health authorities say they have taken that step after a recent increase in the number of infections to 18.
Dengue type 2 was introduced in the territory in January and is now found mainly in the Hihifo area of Wallis.
Dengue type 1 was already present in the preceding two years, and last November an eight-year-old girl died of the disease.
The public is being advised to eliminate breeding areas of mosquitoes as the wet season has started.
In New Caledonia, which has air links with Wallis, the dengue epidemic was declared over in September after more than 3800 people had contracted dengue type 2.
The disease also spread from New Caledonia to French Polynesia, where hundreds of people have been infected.