The Aedes is still beating humans and this must be changed
By Vicente Amato Neto and Jacyr Pasternak The authors are high education professors, specialized in infectious and parasitic diseases’ clinics. The Aedes is a very competent mosquito to transmit viral diseases to humans. The list of diseases transmitted is long: dengue, Chikungunya, Mayaro, Zika and yellow fever. All of them wonder through our country, and […]14/02/2018
By Vicente Amato Neto and Jacyr Pasternak
The authors are high education professors, specialized in infectious and parasitic diseases’ clinics.
The Aedes is a very competent mosquito to transmit viral diseases to humans. The list of diseases transmitted is long: dengue, Chikungunya, Mayaro, Zika and yellow fever. All of them wonder through our country, and not having urban yellow fever is a true miracle. Yes, since cases of it among monkeys still happen and increasingly people invade wild animals ecological space. In fact, all it takes is a truck driver, for example, to acquire wild yellow fever, drive into a large city during incubation period, be bitten by the Aedes, which is in large amounts, hungry. This way, disaster is set. It has not happened yet because among other diseases spread by the Aedes, yellow fever can be prevented by an excellent vaccine, widely used to restrain the diseases areas. However we are concerned by the possibility of the virus spreading to cities, unarranged and covered with places where conditions for the mosquitos proliferation are almost ideal and out of reach of the several governments. There are places where even the police are unable to enter, what to say about sanitary surveillance members.
Since the Aedes is the vector of all viral diseases quoted above, fighting it would mean to limit all of them. With male transgenic mosquitos, that when mating with infected females lead to a defective offspring, being able to cause large outages in mosquito populations. Some field experiences took place with mosquitos produced by Oxytec. We could produce them in industrial scale and control Aedes populations, but recently the company withdrew the idea of building a facility in Brazil.
The National Agency of Sanitary Surveillance (ANVISA) cannot decide whether obtaining transgenic mosquitos is or not under its competence and, as the best of Brazilian bureaucratic traditions, the process was left to rot deep inside a drawer. The National Biosafety Tech Commission (CTNBio) had already approved the use of these mosquitos. We try, but we cannot understand how national sanitary bureaucracy remains, depriving Brazilians from a biological method that seems so efficient to control Aedes, and at the same time, all viruses it transmits.
Dengue, Chikungunya, Mayaro and Zika have similar symptoms, with slight variations. During all acute phases, the only way to perform accurate diagnostic is by laboratory tests. The immune tests are not difficult to perform, but are now always available when they should be. Moreover, while the viruses remain circulating they develop mutations that could have clinical relevance: one single change made it able to lead to all those cruelties in fetuses leading to microcephaly. Besides diagnostic, we must be equipped to assist the many children with after-effects, which is not an easy task and the Unified Health System (SUS) admits its weakness is rehabilitation.
Other things can control Aedes: infecting it with bacteria, making them less susceptible to the several viruses and acting vertically or selecting those naturally resistant to viral infections. Now that new resources are known, as the genome of any species, it would be possible to move towards genetic engineering. However, this requires research investments and for a long time. It will not happen suddenly. Our investments in research are not going very well. The resources are little and distributed under, many times, unclear criteria. Or, frankly, just wasted. The use of public resources to study a drug that never proved its efficiency against cancer, just because some lawmakers thought it was worth. Of course, it resulted in nothing, but we have noticed that some founding parents, that know absolutely nothing about research, requesting further studies because no one ever proved the drug does not work, recalling that in science we never prove the negative.
We require efficient confrontation against the Aedes. To argue that this is not simple, alleging among other facts that the enormous territorial extension of our country and shortfalls of funds are representative difficulties of strong obstacles. It is not quite this way. Priority and governmental will are essential to stop these harms. Relevant is to not allow money to escape, currently available, only needing to retake from corrupt politicians, robbers of national goods. Likewise, it is indispensable to prevent from the looting they perform.
Considering the evil, perverse and toxic consequence, the Aedes leads to, the need to combat it soon and effectively is evident. Now, it seems they are waiting the weakening of the vector, due to something unexpected but concrete. If it happens, we will all be happy, and wish success. However, it is reasonable not to accommodate. Therefore, it urges to fight since now, in a wide, well-planned and permanent way these unwanted and abundant transmitters. Occasional and limited acts are insufficient.
We insist the best way to control the Aedes is using transgenic mosquitos as we stated above. We cannot understand the difficulty implanting this use, which lead the company producing them to withdrawal doing it in Brazil. There is no chance of spreading these genes here, and the only species similar to the Aedes, the Aedes albopictus, which could eventually breed with the Aedes aegypti is another plague. Both are exotic fauna that did not exist before slave trade. By the way, this attitude against transgenics ignores the fact that humans have abused natural selection for a long time, long before the genomic tricks we have today, but with the same result. Other biological arrangements as finding an Aedes-larvae-eating bacterium are being studied, but for now, we do not have them.
*Vicente Amato Neto is a former professor of Infectious and Parasitic Diseases at the University of São Paulo and Jacyr Pasternak, with a DSc degree at Universidade de Campinas in Infectious Diseases, is currently at the Albert Einstein Hospital in São Paulo. Both are writers.…