Divulgação, Notícias

Controlling dengue will become interesting when it hits rich and poor evenly, ironizes entomologist

The specialist claims little attention is still given to basic santiation, education and the needs of the population, still struggling to survive in our country


Dr. Marcondes says the A. aegypti takes advantage on the Brazilian cities disorganization, including poor drinkable water supply and large garbage production and dispertion to proliferate

Entomologist Carlos Brisola Marcondes believes that while controlling the Aedes aegypti mosquito, Brazil is still cutting corners, i.e., taking palliative actions facing the problem. Without disguising his words, the researcher believes the interest in controlling this insect will only happen when dengue evenly strikes the poor and the rich.

The hope to one day controlling [the mosquito] is that it evenly strikes the masses and the people at the Elysium (fictional place where the rich people depicted in the homonymous film live), what could increase the interest in the control, says the researcher.

The concern controlling the disease has its reasons, once the numbers reveal an increasingly smaller care through the years.

I witnessed, in 1996, the former Health Minister Adib Jatene launch a wide campaign against the mosquito, which included adequate garbage disposal and many other measures. I remember leaving Embratel, where I watched the presentation, shaking my head, not believing this could really be seriously done. Later then, the minister was changed, control was lowered, and from 200 thousand annual cases, we rose to the current 1.6 million cases, criticized Dr. Marcondes.

He evaluates the A. aegypti takes advantage on Brazils disorganization – as poor drinkable water supply and the large garbage production and dispersion – to proliferate. According to the entomologist, the measures to control the breeding sites, as tires and bottles, can only be effective if conducted extremely efficiently. This is because the mosquitos females place their eggs in several breeding sites and widen their flight area when adequate places are not found.

In short, we are still cutting corners, because little attention is given to basic sanitation, education and the needs of the population, concerned in surviving in a such unfair Country, he explains.

Doctor Marcondes highlights that in times where politicians only talk about cutting costs, we must be wise knowing what to cut; millions of people rely on the governments adequate measures to maintain their health. It is impossible to do for some privileged people what Dr. King proposed for Washington – surrounding it with an enormous net to protect it from mosquitoes.

For the researcher, controlling mosquitoes and the severe diseases brought by them cannot be done based on the thought lets wait the fire to break out to hire and train the firemen. He argues that each year the panic routine repeats itself, followed by drastic measures, which includes hiring young inexperienced people to walk by every house, putting the Army in the streets and the Media showing litter scattered on the streets, then, the number of cases drops and the matter is forgotten until a few months later. Can we control in an uneven and improvised way? he questions while saying this must be done in an organized way, and without politicizing the matter. It is worth remembering that one of Oswaldo Cruzs demands to President Rodrigues Alves was that he, an experienced and decent man, had total power over the campaigns nominations and activities. “Was his way of acting keept after that? Who certainly knows what to do has had his/hers opinions respected and power to act?” the expert questions.

He also alerts it is convenient to observe how the efficient campaigns to control malaria-gambiae and erradicating Aedes aegypti were conducted. Dr. F. L. Soper said only authoritary governments can control endemic diseases. I personally disagree, but only with organization, continutiy and responsability it is possible to control any endemic disease, he stresses.

Even new control methods must be very well evaluated for costs and efficiency, according to Dr. Marcondes. Among them, sterile or transgenic mosquitoes and the use of the Wolbachia bacteria fighting the mosquito.

Strong capacity of adaptation

One of the main issues fighting the A. aegypti is its great adaptation ability, especially in urban environments. It is hard to tell if it has modified in the past or if the opportunities that came up with the disordered growth of our cities have provided conditions for it to develop its full potential, he explains.

Proving its versatility, a study conducted in the semiarid region in North Minas Gerais showed the proportion of eggs laid directly over water increases in the drier months. Despite having a large mortality of eggs laid on surfaces, great part can survive for several months allowing them to hatch and proliferate as soon as rainfall begins, says the researcher.

The dengue transmitter mosquito was originally addapted to the wild environments, developing its immature forms especially in holes and rocks.

However, the insects ability to resist drought for several months and its adaptability to several types of breeding sites allowed it to follow humans in their displacements, including those by ship. As water traffic intensified, especially by the end of the 15th century, it was certainly very easy for the A. aegypti to be transported to the Americas in barrels and other recipients accumulating water, including rain water.

Dengue virus, according to the researcher, was brought from Asia and took advantage of the mosquitos presence in the Americas to disperse throughout the continent.

Recommended reading:

Aedes aegypti (L.) The yellow fever mosquito: its life history, bionomics and structure, Cambridge University Press, 739 pp.