Brazil Releases Genetically Modified Mosquitoes To Fight Disease Such As Dengue, Zika, Chinkungunya

by Ogo Obudulu MD, MPH Posted on

Rio De Janeiro, Brazil. Sept. 8th. Scientists at the Oswaldo Cruz Foundation (Fiocruz) in Brazil on Thursday released a new batch of genetically-modified mosquitoes in its fight against diseases such as dengue, Zika and chinkungunya. The release of specimens of the aedes aegypti mosquito with the Wolbachia bacterium marks a new stage in the fight against dengue fever in Rio de Janeiro. The bacterium works by interfering with the mosquito’s reproductive capacity, so scientists hope the strategy will eventually eradicate them and the diseases they spread.

Head researcher Luciano Moreira said scientists won’t be able to gauge the effectiveness of the plan for another three to five years. He added residents cannot rely solely on such methods to combat mosquito-borne diseases.

“People must be aware that they have to do their part. It’s really important. Taking care of their yards, eliminating breeding sites, not leaving containers or vessels with water for mosquitoes to breed,” said Moreira.

Scientists plan to gradually expand the area of release, with an initial 10 neighborhoods targeted. By the end of 2018, some 2 million altered mosquitoes are expected to be released.

Dengue, Zika, and chikungunya

Dengue, Zika, and chikungunya are all diseases caused from being bitten by infected Aedes mosquitoes, which are present in many tropical countries, Asia, and the Pacific.

Dengue fever emerged as a worldwide problem in the 1950s, and is becoming more and more widespread. With more than one-third of the world’s population now living in areas at risk of infection, dengue virus is a leading cause of illness in the tropics and subtropics. Up to 400 million people are infected worldwide every year.

Zika and chikungunya spread to Asia and the Pacific in 2013.

How do you catch dengue, Zika, and chikungunya?

You catch these illnesses by being bitten by mosquitoes that live in many popular tourist destinations, such as Southeast Asia and the Pacific Islands. You cannot catch dengue, zika, or chikungunya in Nigeria, and if you have returned to Nigeria with one of these illnesses, you cannot infect other household members.

What are the symptoms of dengue, Zika, and chikungunya?

Dengue fever usually begins with a sudden onset of a high fever and a severe headache. Those affected may also get a skin rash and muscle and joint pain. Nausea, vomiting, and loss of appetite are common. The illness usually lasts up to 10 days, but recovery may take some time, and people can feel tired and depressed for weeks.

Zika and chikungunya cause similar illnesses to dengue, but tend to be milder. However, they can still cause an unpleasant illness with painful joints and skin rashes and zika has recently been linked with severe abnormalities in unborn babies.

How are dengue, Zika, and chikungunya diagnosed?

All are diagnosed by a combination of typical symptoms, and blood tests.

How are dengue, zika, and chikungunya treated?

There is no specific treatment for dengue, zika, and chikungunya, but it is important to take paracetamol rather than aspirin for the fever, headache and muscle pains with dengue, as aspirin can increase the risk of bleeding. People should also rest and drink plenty of fluids. Those who become more unwell may need hospital treatment with fluids into their veins and close monitoring, to make sure they don’t start to bleed or lose too much fluid from their bloodstream.

How can dengue, zika, and chikungunya be prevented?

Aedes aegypti mosquito biting a human hand.

There is no vaccine to protect against dengue, Zika, and chikungunya, and no drugs you can take to prevent them (like you can with malaria). The most effective way to protect against it is to avoid mosquito bites. Please note that these mosquitoes bite during all hours of the day, not just in the evenings:

Apply insect repellent to skin. The most effective repellents are those containing DEET (diethyl toluamide) – at a concentration of between 30% to 50%, or picaridin – at a concentration of 20%. You can apply repellent over sunscreen.

Wear clothing that covers the arms and legs

Wear hats and shoes (rather than sandals)

Apply permethrin insecticide to clothes

Use mosquito nets impregnated with permethrin

Use electric insect-repellent devices, or mosquito coils

When possible, stay in accommodation that has screens on doors and windows, or is air-conditioned.

Can dengue, Zika, and chikungunya be fatal?

There is a severe form of dengue fever – known as dengue haemorrhagic fever – which can cause bleeding and collapse, and can be fatal. This is more common in people who get dengue fever more than once. Dengue haemorrhagic fever is fatal in about five percent of cases, mostly among children and young adults. This risk is important for Pacific peoples who may make a number of visits back to their home country over the years, and so risk repeat infections.


Photo: Aedes aegypti mosquito biting human

Note that Zika virus is not carried by mosquitoes in Nigeria, but it can be carried be carried by people infected elsewhere who travel into the country. Zika virus can be sexually transmitted, hence all men who travel to a Zika affected places and countries with a pregnant partner would be advised to abstain from sexual activity or use barrier methods for the duration of the pregnancy.

What of Malaria?

The Zika virus is typically transmitted by the Aedes aegypti mosquito, but it can also be spread sexually. Aedes aegypti mosquitoes are aggressive daytime biters and officials are warning people of the need to be vigilant, cover up and reapply repellent regularly.

The Asian tiger mosquito (Aedes albopictus) which is also established throughout the United States, and transmits dengue fever and Chikungunya, may also be capable of transmitting the Zika virus.

Chikungunya fever, like Dengue, is transmitted by Aedes mosquitoes, especially Aedes aegypti (the yellow fever mosquito) and Aedes albopictus (the Asian tiger mosquito).

Malaria is caused by parasites, primarily Plasmodium falciparum or Plasmodium vivax. Female Anopheles mosquitoes pick up the parasites by feeding on infected humans. The parasites develop in a mosquito’s body for 10 to 18 days, then is passed on when the mosquito injects saliva while feeding.

Malaria is common in Nigeria because it is the Anopheles mosquitoes that are prevalent in Nigeria

Author

Ogo Obudulu MD, MPH

Ogo Obudulu MD, MPH

A Board Certified Physician (American Board of Internal Medicine) , Dr Obudulu, the Deputy Chief Editor performs editorial supervision and reviews of all health related content in the health and science categories regardless of who authored the post before it is published
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