- The spread of the mosquito is not only caused by weather conditions and by a lack of awareness, but by a deep and environmental problem in Brazil.
- Urbanization in Brazil has led to the deforestation of large green areas, destroying the ecosystems in which the mosquitos and its predators used to reproduce.
- An estimated half of the world’s population lives in areas where mosquitoes that can spread Zika are prevalent, and the WHO is concerned the number of cases could jump to four million this year in the Western Hemisphere alone.
For nearly five months now, Liana Azeredo avoids walking the streets of Rio de Janeiro during the day. Even under the intense heat of the city, she also prefers long blouses and pants. Inside her handbag, she’s carrying repellents and colored bracelets with citronella.
The change in her life is due to the fear of Aedes aegypti, the mosquito that transmits diseases such as Dengue, Chikungunya and Zika. Although all three are considered serious diseases, Liana’s biggest fear is being contaminated by the Zika virus, which has been suggested as the cause of microcephaly in babies still in gestation. Liana is pregnant and, like so many other women of Brazil, she feels very vulnerable.
The connection between the Zika virus and cases of microcephaly began to be investigated in the state of Pernambuco, in northeastern Brazil, in the second half of 2015. That’s when an outbreak of malformation in babies first started to be seen, along with a jump in Zika cases. The state, which usually reports about 130 cases annually, is currently investigating more than 4,000.
The World Health Organization (WHO) has declared a global emergency since the virus was detected in more than 50 countries since the first Brazilian cases were reported last year. An estimated half of the world’s population lives in areas where mosquitoes that can spread Zika are prevalent, and the WHO is concerned the number of cases could jump to four million this year in the Western Hemisphere alone.
However, experts consulted by Mongabay stressed that despite strong evidence, it is still not possible to determine the relationship between the disease and microcephaly, although it is “very likely”, as stated by the pediatric neurologist Heloise Viscaino, a professor at the State University of Rio de Janeiro.
New evidence, suspicions, and even conspiracy theories to the cause of microcephaly, though, continue to emerge. A now discredited study from the scientific group “Physicians in the Crop-Sprayed Towns” had made the claim that one of the possible causes was the use of the larvicide Pyriproxyfen, used to kill the Aedes mosquito since 2014 in potable water tanks across Brazil.
And yet some data suggest that other factors could be causing microcephaly in Brazil, since other neighboring countries, like Colombia, have registered thousands of cases (including in over 3,000 pregnant women) without evidence of an increase in microcephaly.
Still, Valcler Rangel of Brazilian institute FioCruz, a leader in mosquito research, insists that although the number of cases are still not enough to determine the causes, the connection between Zika and microcephaly is “very probable.” He says that they have found traces of Zika in the amniotic fluid and in the saliva of infected people.
“The presence of the virus doesn’t indicate that it can be contagious, but it is suspicious. We are getting to know this disease now, the virus. Only after that can we start to make a safe vaccine,” he says.
The only certainty for Rio biologist Mario Moscatelli is that the proliferation of the Aedes aegypti will continue during this year’s long summer, and if a clear connection between Zika and microcephaly is found, the problem will continue on for decades, creating “generations of microcephalies in Brazil.”
According to him and to other experts, this is because the spread of the mosquito is not only caused by weather conditions and by a lack of awareness, but by a deep and environmental problem in Brazil.
“The mosquito has existed for over 120 million years and it is part of a natural balance of the ecosystem. What happens in large cities is a combination of the poor conditions of infrastructure, alongside untreated water, terrible sanitation, deforestation and little awareness in the part of the population,” he says. The fact that mosquitoes can now reproduce in dirty water, for example, clearly shows that their ability to adapt is very large, he adds.
For André Luis Soares da Fonseca, a specialist in tropical diseases at the Universidade Federal do Mato Grosso do Sul, the main cause for the spread of mosquitoes in Brazil is due to a huge environmental imbalance.
“The biggest predators of the mosquitoes are spiders and lizards. But you do not see them much anymore, because pollution and deforestation have cut down their populations,” he explains.
Soares da Fonseca warns that, given the lack of predators, the mosquitoes went to the top of the food chain, creating a major environmental imbalance. For him, public health in Brazil lacks founded criticism of this matter.
“Today the country spends millions in strategies that do not work. The more you use pesticides, the more that aggravates the situation of dengue, because we’re eliminating not only mosquitoes, but their predators,” he criticizes.
According to biologist Mario Moscatelli, the spread of urbanization in Brazil led to the deforestation of large green areas, destroying the ecosystems in which the mosquitos and its predators used to reproduce. Without the protection of the green areas, the overheating of these cities has also contributed to the death of many of the mosquitos’ predators.
For both specialists, the actions currently being taken against mosquitos given the spread of Zika will not have the expected effect until there is a “real environmental revolution” in Brazil.
“If you continue to treat the green areas the way specialists have been doing, if you continue to offer bad solutions to sanitation problems, bad infrastructure –we will face a new problem every summer,” explains Moscatelli.
CORRECTION (02.18.16 at 3:35 pm ET):
In an earlier version of this article, we stated that “studies from the scientific group ‘Physicians in the Crop-Sprayed Towns’ point that one of the possible causes could be the use of the larvicide Pyriproxyfen.” However, this theory has been definitively discredited.
