He outbreak of dengue in Argentina has so far reached a total of 333,084 cases and 238 deaths, according to the data provided by the Ministry of Health.
This count spans from the end of July 2023 to mid-April 2024, marking this season as a record in terms of infections and deaths. To put the magnitude of this situation in perspective, it is important to note that it significantly exceeds the numbers from the previous year, when there were 130 thousand reported cases and 65 deaths between July 2022 and the same month in 2023.
Currently, according to the latest Epidemiological Bulletin, A gradual downward trend in the number of cases is observed throughout the country since week 13 of 2024, at the end of March. However, although the temperature has dropped in many places in the country, which could influence the decrease in infections, concern about the presence of mosquitoes still persists.
It is crucial to understand what mosquito species are currently active and how to prevent the species Aedes aegypti, that transmits the dengue virus, is “installed” in our homes. As winter approaches, specialists call maintain preventive measures to prevent the reproduction of these vectors, such as eliminating containers with stagnant water and protecting homes with mosquito nets, among others.
In dialogue with Infobae, the doctor Hugo Pizzi, infectious disease doctor, epidemiologist and professor of the National University of Cordoba, contributed: “All epidemiological outbreaks have dynamics, that is, they begin, cases increase rapidly until they reach their peak, then they stabilize and begin to decrease. That is normally what happens in any epidemic outbreak situation. Here, the situation is absolutely transitory. Mosquito activity decreased somewhat when the temperature was cold or relatively cold; tempered. The mosquito not only decreases its activity, but also Leave the surroundings of the house and enter the home.”
Therefore, according to Pizzi, “you have to be very careful in these circumstances, since The mosquito may be behind the curtains or in different places inside the house. So, this doesn’t mean the problem is solved; On the contrary, activity has decreased a little but we are already seeing that cases are increasing again with the return of the heat.”
“There’s a lot female mosquitoes infected with the dengue virus that lay eggs – continued the infectious disease specialist -. Those eggs are already infected with the virus. That is to say that within five or six months, when there are heat strokes, the new mosquitoes will hatch and the infected females will come out with the virus. This will continue to accumulate and increase the negative aspects of any epidemiological outbreak. Therefore, the concept is that there has been a decrease in cases, and it is true that mosquito activity has gone down, but with the return of the heat, cases are starting to increase again.”
“For cases to really decrease in the coming weeks, the temperature must be above below 12°C, because there could be a period of mosquito inactivity. We are compromising our future if we do not adequately care for our environment and, fundamentally, our homes, because The females continue to lay eggs and most of them are infected.”Pizzi advised.
The epidemiology expert from the University of Córdoba added that “that is why it is important clean the patio well, discard stagnant water in the drains, scrub with a rough sponge all the places where the eggs may be, among other things, otherwise, those mosquitoes will appear in August or September.”
For its part, Adrian DiazCONICET researcher at the Institute of Biological and Technological Research (IIByT, CONICET-UNC), pointed out: “We have three abundant species in Argentina: Aedes albopictus, Aedes aegypti and Culex quinquefasciatus, In the south. Of these three species, the first to disappear with the cold is Aedes aegypti because it is a tropical mosquito, although it has adapted to temperate climates. “With sustained temperatures below 14 degrees, they are already dying.”
“The second species that disappears is Culex quinquefasciatuswhich already when we are at more or less 10°C begins to lose activity. Aedes albopictus It is the last to leave because it is a mosquito adapted to temperate climates. Obviously, in the winter in Patagonia there are no mosquitoes. But during the summer and autumn in the southern latitudes it subsists perfectly and we still cannot talk about cold,” said Díaz.
At the same time he remarked: “If we have two days of 13°C or 14°C and then a temperature of 20°C or 22°C comes, the other mosquitoes begin to activate again. The Culex quinquefasciatus With the cold, both the adult and the larvae and eggs die. In the case of Aedes albopictus and Aedes aegypti They are flood mosquitoes and have eggs that resist drought and cold.. Then the larvae and adults disappear, but the eggs remain and resist the winter.”
“He Aedes aegypti It has adapted both to the breeding sites that humans have created for it, as well as to identifying odors and thus perceiving that it is a source of beneficial blood food for them. To prevent them from entering homes, internal breeding sites must be eliminated. If you have vases, they can breed there and the best way to prevent them from entering is to put mosquito nets on the windows and openings. That way we prevent them from entering and we also have to prevent them from breeding inside the home,” suggested the CONICET specialist.
Another professional consulted by Infobae It was the infectious disease specialist Ricardo Teijeiro, who member of the Argentine Society of Infectious Diseases. “Dengue cases in Argentina are going to fluctuate, since these are accumulated cases from previous weeks. This can lead to mortality peaks, given that some cases are patients who are hospitalized and being treated with different outcomes. The current decrease in cases is mainly due to the reduction in the development of the mosquito vector, which does not thrive in cold climates, so it does not reach the adult stage and, therefore, cannot transmit the disease,” said the expert.
And he added: “As cases decrease, so does the possibility of mosquito development. This is a seasonal phenomenon that occurs every year at this time. However, it is important to highlight that During the winter the mosquito does not disappear completely, given that larvae and eggs remain in places where there is accumulation of water. With the arrival of heat, these can develop, representing a new risk for the next season. Therefore, it is crucial work on prevention for the coming year.”
