Healthcare

Brazil hopes UK's GM mosquitoes will fend off Zika virus

My father had Dengue fever. And my brother. And my aunt. And my uncle. Some of the symptoms are high fever, severe headache, vomiting, and pain behind the eyes. You just feel terrible and people have died from Dengue in Brazil. By now, you might be thinking that my family lives in a remote zone of the country, maybe with no access to medical care. But they don’t. They live in Ribeirão Preto, one of the biggest cities of São Paulo state, in one of the most developed and richest parts of Brazil. Dengue is a mosquito-borne viral disease transmitted by the same female mosquito - the Aedes aegypti - that transmits Zika virus, yellow fever and chikungunya. So the spread of the Zika virus in Brazil and 22 other countries in the region is something of a tragedy foretold. 

For Dengue and Zika there is no vaccine and no specific treatment. For both, prevention depends on “effective vector control measures”, as the World Health Organization states. In other words: get rid of the mosquitoes. And Brazil has been fighting against the Aedes aegypti for decades now with no success. The country’s Health Minister, Marcelo Castro, promised that the Army would go to the streets to help in this fight. Brazilian President Dilma Rousseff asked the population in a nationally broadcast speech to unite against the mosquito. No standing water inside our houses and the mosquito cannot lay eggs, she explained. But as reality has been showing us, it is not that simple. You just can’t have access to, and control, every room of every house of the country on a regular basis. The mosquitoes continue to breed and the diseases that they transmit continue to spread.

One possible solution that is attracting a lot of attention in Brazil now is to use a technology based on genetic science and developed by the British company Oxitec, which created genetic-modified (GM) mosquitoes. These GM mosquitoes are designed to die, but in a laboratory with the use of an “antidote” they grow. When they release the GM adult males (only the female bites humans), these mosquitoes mate with wild females and their offspring inherit the special gene added and don’t survive to adulthood. This is the “Friendly Aedes aegypti”, as the company calls its creation. In this cute animation/video, with “exclusive interviews” with the mosquitoes, the technique and the work done by Oxitec, headquartered near Oxford in Abingdon, England, is explained in more detail. 

According to Glen Slade, Director at Oxitec Brazil, results indicated a reduction in wild mosquito larvae by 82% in one neighbourhood of the Brazilian city of Piracicaba, in the state São Paulo. “Today we have 22 employees in Brazil. Most of our team is involved in the Friendly Aedes aegypti Project in Piracicaba, where we produce and release around 800 thousands mosquitoes every week. A great part of the team is allocated to produce these mosquitoes.” 

pupae-emerging

And how does the population react when people see more mosquitoes being released instead of being killed? Slade highlights that the first phase of every Oxitec project is to engage with the community. “In this phase, we work together with personnel from the public health service to explain to the population what it is the Friendly Aedes aegypt,” he says. “This phase lasts between one and two months and only after this is that we start releasing the Friendly Aedes aegypt.”     

The Friendly Aedes aegypti Project was expanded in January in Piracicaba and Oxitec is initiating a new mosquito production facility in the city. Since the beginning of the Zika outbreak, according to Slade, Oxitec has recorded a significant rise in the interest of its technique.

Olympic gains

But, for now, it is only being used in Piracicaba, miles away from the city of Rio de Janeiro, where, from the 5th of August, the first Olympic Games to be held in Latin America will take place. The organizers are betting that the Zika virus spread will decline before the opening of the Games, with the arrival of dry and cool weather. “This is not the rainy period, so historically speaking, the chance to have a wide risk for Zika contamination during the Olympics at this time is not so important”, said João Grangeiro, the Director of Medical Services for the Rio 2016 organizing committee, recently.

Hopefully, he is going to be right. The problem is that evidence from the past doesn’t seem to give us any reassurance. In 2014, just 40 days before the beginning of the World Cup in the country, different cities in Brazil registered, in the middle of autumn, a big rise in the number of cases of Dengue fever. 

 

 

Also read:

Zika: Can a faster sequencing tool help?

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