Rapid shifts between periods of drought and heavy rainfall can increase the risk of dengue outbreaks in regions where the disease is already common, according to an international study based on data from Latin America, Southeast Asia, the Philippines, and Australia.
The investigation analyzed the relationship between abrupt changes in weather conditions and the occurrence of dengue outbreaks. The authors identified a frequent association between rapid transitions from dry to humid periods and from humid to dry periods and the emergence of outbreaks within a short time frame.
Episodes of transitions from humid to dry conditions were, in particular, the ones that most often preceded dengue outbreaks. According to the researchers, these abrupt changes can create conditions favorable to the proliferation and transmission of the mosquito that carries the virus, especially in regions where factors such as high temperatures and poverty already contribute to the disease’s circulation.
Dengue is a viral disease transmitted mainly by mosquitoes of the Aedes genus. Environmental conditions influence the life cycle of these insects and, consequently, the possibility of virus transmission.
The results suggest that it is not only the occurrence of drought or heavy rainfall that should be considered in risk assessment. The speed with which weather conditions change may also play an important role.
For the authors, identifying these patterns may help improve early warning systems and enable health authorities to strengthen surveillance and preventive measures in the periods following abrupt changes between dry and humid conditions.
In the context of climate change, the greater frequency or intensity of extreme weather events could make this relationship particularly relevant for regions that already present conditions favorable to dengue transmission.
