Ecuador has recorded 28,652 confirmed cases of dengue fever in 2026, according to data from the Ministry of Public Health (MSP) available through mid-August. This increase comes as the Aedes aegypti mosquito shows resistance to several insecticides used to control its population.
Data from the Ministry of Public Health, updated through August 15, shows that for 11 consecutive weeks, weekly cases exceeded the 2025 figures for the same period.
In addition, 35 deaths have been reported.
Researchers consulted indicate that environmental conditions may favor the presence of the mosquito. Anita Villacís, a researcher at the Center for Health Research in Latin America, explained that Aedes aegypti is now appearing in areas where conditions were previously less favorable.
“That’s why we’re starting to see these warning signs, because where there are mosquitoes, they will easily proliferate,” Villacís pointed out.
The researcher also links the increase in temperature and rainfall to a greater availability of breeding sites. Jaime Acosta, professor and researcher at SEK International University, also points to the El Niño phenomenon as a factor that can increase areas of stagnant water.
Controlling these areas is important because mosquitoes need containers of water to complete their life cycle. Therefore, eliminating standing water in homes and yards is part of dengue prevention measures.
Another challenge arises in chemical control. The latest bulletin from the National Institute of Public Health Research (INSPI), with information up to June 2025, reported 91.5% resistance to deltamethrin and 62% to temephos in the evaluated Aedes aegypti populations in Ecuador.
Malathion still shows greater susceptibility to mosquito resistance. However, resistance has also increased: it rose from 15.91% in December 2024 to 31.25% in June 2025, according to the cited data from INSPI. Acosta explained the problem this way: “We can’t solve everything with fumigation, and we’re seeing significant resistance rates.” Therefore, the researchers propose combining chemical control with actions to reduce breeding sites.