1. Four types of dengue ciruculate in the region

All four dengue virus types (DENV-1 to DENV-4) are present in the Caribbean. Within each type, different genetic versions (called clades) exist. Sometimes one clade replaces another. This can make outbreaks more severe.

2. Clade displacement can change how outbreaks behave

Studies show that these genetic shifts within a dengue type can change how the virus spreads and how serious it becomes. But little is known about how this happens in the Caribbean. More local research is needed.

3. PAHO notes renewed circulation of DENV-3

In early 2025, PAHO (Pan American Health Organization) warned that the DENV-3 serotype is spreading again in parts of the Americas, including the Caribbean. When new virus types arrive in a region, people may have no prior immunity, which increases the risk of severe disease.

4. High dengue cases and mortality among children

Confirmed by PAHO: Children under 15 are most affected by severe dengue. In some countries, they account for up to 70% of dengue-related deaths.

5. Climate change is making it easier for dengue to spread

According to CARPHA (Caribbean Public Health Agency), rising temperatures, rapid urban growth, and poor water management are increasing the risk of dengue outbreaks. They expect dengue to resurgence every 3 to 10 years unless prevention, early warning, and outbreak response systems improve.

Dengue virus comes in four types: DENV-1 to DENV-4. Within each type, there are smaller groups called clades. Sometimes, one clade replaces another, This is called clade displacement.

For example :
DENV-3 Clade A (see image, orange virus) might be the dominant strain for years, until Clade B (see image, yellow virus) takes over due to small genetic changes.

Why it matters:
Your body’s immune system might not recognise the new clade

– This can lead to more severe illness, even if you have had dengue before.

– Vaccines or tests may not work as well

– It may cause bigger, harder to control outbreaks