The Aedes aegypti mosquito is part of history and has been spreading around the world since the colonization period

The mosquito that transmits dengue originates in Egypt, Africa, and has been spreading throughout the tropical and subtropical regions of the planet since the 16th century, the period of the Great Navigations. It is admitted that the vector was introduced in the New World, in the colonial period, through ships that trafficked slaves. It was scientifically described for the first time in 1762, when it was named Culex aegypti. The final name Aedes aegypti � was established in 1818, after the description of the genus Aedes. Reports by the Pan-American Health Organization (PAHO) show that the first dengue epidemic on the American continent occurred in Peru, at the beginning of the 19th century, with outbreaks in the Caribbean, United States, Col... mbia and Venezuela.

In Brazil, the first reports of dengue date from the end of the XNUMXth century, in Curitiba (PR), and the beginning of the XNUMXth century, in Niterói (RJ).
At the beginning of the 1955th century, the mosquito was already a problem, but not because of dengue -- at the time, the main concern was the transmission of yellow fever. In XNUMX, Brazil eradicated the Aedes aegypti as a result of measures to control yellow fever. At the end of the 1960s, the relaxation of the measures adopted led to the reintroduction of the vector into national territory. Today, the mosquito is found in all Brazilian states.

According to data from the Ministry of Health, the first occurrence of the virus in the country, clinically and laboratory documented, happened in 1981-1982, in Boa Vista (RR), caused by the viruses DENV-1 and DENV-4. Years later, in 1986, there were epidemics in Rio de Janeiro and in some capitals in the Northeast. Since then, dengue has been occurring in Brazil on an ongoing basis.

Research from 1908 already described characteristics of the A. aegypti
The summer of 1908 let the populationiocon alert due to the risk of yellow fever. It was in this context that Antonio Gon�alves Peryass�, a researcher at the then Instituto Soroter�pico Federal, which would be named Instituto Oswaldo Cruz (IOC) that same year, made discoveries about the life cycle, habits and biology of the A. aegypti. His studies were fundamental for the eradication of the mosquito in the national territory in the following decades and still today guide research on vector control.

In a monograph with more than 400 pages, entitled Os Culicídeos do Brasil, the entomologist described the habits of the A. aegypti and a series of other mosquitoes of the same family, showing aspects of their biology never seen before. For two years, Peryass� carried out a series of experiments with the A. aegypti. His study provided valuable information on aspects such as resistance to desiccation of the mosquito egg, which can remain up to a year without contact with water. He also made observations regarding the productivity of breeding sites, an issue still debated today, stating that, in general, large water reservoirs are the most productive foci of the vector.

Image reproduction of the book Os Anophel�neos do Brasil, by Ant�nio Peryass�

Several characteristics of Aedes aegypti observed by the researcher Antonio Peryass� (in the center, wearing a pallet, during field work) continue to be studied until today

Among his most interesting discoveries are also the relationship between the mosquito and temperature and population density. When carrying out the first detailed survey of mosquito infestation in Rio de Janeiro, the researcher associated the greater presence of the A. aegypti to the increase in population density in certain areas of the city and also showed the similarity between the insect population concentration map and the occurrence of yellow fever cases. His observations also showed that the drop in ambient temperature to less than 20^oC interferes with the development and reproduction of the mosquito, which are drastically reduced, leading to a reduction in cases.

Peryass�'s discoveries gave even more strength to the campaign led by public health doctor Oswaldo Cruz to eliminate the mosquito, which was controlled in the 1920s in Rio de Janeiro and considered to have been eradicated from Brazil a little over a year ago. thirty years later. Most of the points raised in his research remain on the scientific agenda of specialists who today seek to develop strategies to control the mosquito that transmits dengue.

*All contents were reviewed by researchers at Instituto Oswaldo Cruz (IOC/Fiocroz)