Mosquito army
1
October 27, 2016 MOSQUITO ARMY Scientists have been creating spe- cially modified mosquitoes. They plan to release millions of these insects in parts of Colombia and Brazil. It is hoped that this “mos- quito army” will reduce the chanc- es of people being infected with viruses carried by mosquitoes. These include: Zika, dengue fever and chikungunya. A mosquito called Aedes aegypti spreads these viruses. This mosqui- to originally lived in Africa. With human help, it has spread to most of the world’s tropical, or warmer, regions. This mosquito can be easily recognized by the white markings on its legs and upper body. Only female mosquitoes suck blood. They need it to produce their eggs. If a mosquito bites a person who has the Zika, dengue or chi- kungunya virus in their blood, it becomes infected. These viruses do not harm the mosquitoes. Yet the in- sects can spread them to others. If the mosquitoes bite and feed on oth- er people, the virus can enter their bloodstream. Once this happens, the virus starts to replicate. People infected with dengue or chikungunya become very ill. They suffer from headaches and fevers. These illnesses are rarely fatal. However, they can affect a person’s health for many years. The Zika vi- rus causes a different problem. Re- searchers are now sure that this vi- rus causes a birth defect, or disorder, called microcephaly. Aedes aegypti mosquito People most at risk from the Zika virus are expectant mothers. If a woman gets the virus while pregnant, her child may have the disorder. New-born babies with mi- crocephaly have small heads and less developed brains. Some babies with the defect die at a young age. Others grow up with smaller heads, but seem to be unaffected. However, as they age, many suffer from learn- ing troubles, speech difficulties and health problems. There is no cure for microcephaly. The Zika virus was first discov- ered in Africa nearly 70 years ago. It was found in monkeys that lived in Uganda’s Zika Forest. In 1954, a person in Nigeria got the virus. This was the first time that it had been found in a human. Over the years, the virus began to appear in other countries. It does not make people very ill. It was therefore thought to be less serious than other mosquito- carried diseases. The Zika virus was first recorded in Brazil 18 months ago. Virolo- gists, or scientists who study virus- es, tracked it. During the following six months, the virus rapidly spread throughout most of South America and the Caribbean islands. Now, Zika is present in over 50 countries. Since 2015, 2,200 babies have been born with microcephaly associated with the Zika virus. Most, or 2,033, are in Brazil. The scientists have worked out how to infect the Aedes aegypti mosquito with a bacterium called Wolbachia. This bacterium is found in many other insect species. It does not harm humans. Wolbachia seems to improve a mosquito’s immune system. It also competes with any viruses inside the insect. This means that the virus- es cannot replicate so easily. There- fore they are less likely to be passed to humans. When a mosquito with Wolbachia breeds, the bacterium is passed onto its offspring. Experiments, or trials, have been carried out in small areas of Aus- tralia, Vietnam, Indonesia, Colom- bia, and Brazil. These have reduced the spread of dengue fever. The scientists’ mosquito army will be re- leased in large urban areas of Brazil and Colombia early next year. Preparatoria 1o.
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Transcript of Mosquito army
October 27, 2016
MOSQUITO ARMY
Scientists have been creating spe-cially modified mosquitoes. They plan to release millions of these insects in parts of Colombia and Brazil. It is hoped that this “mos-quito army” will reduce the chanc-es of people being infected with viruses carried by mosquitoes. These include: Zika, dengue fever and chikungunya.
A mosquito called Aedes aegypti spreads these viruses. This mosqui-to originally lived in Africa. With human help, it has spread to most of the world’s tropical, or warmer, regions. This mosquito can be easily recognized by the white markings on its legs and upper body.
Only female mosquitoes suck blood. They need it to produce their eggs. If a mosquito bites a person who has the Zika, dengue or chi-kungunya virus in their blood, it becomes infected. These viruses do
not harm the mosquitoes. Yet the in-sects can spread them to others. If the mosquitoes bite and feed on oth-er people, the virus can enter their bloodstream. Once this happens, the virus starts to replicate.
People infected with dengue or chikungunya become very ill. They suffer from headaches and fevers. These illnesses are rarely fatal. However, they can affect a person’s health for many years. The Zika vi-rus causes a different problem. Re-searchers are now sure that this vi-rus causes a birth defect, or disorder, called microcephaly.
Aedes aegypti mosquito
People most at risk from the Zika virus are expectant mothers. If a woman gets the virus while pregnant, her child may have the disorder. New-born babies with mi-crocephaly have small heads and less developed brains. Some babies with the defect die at a young age. Others grow up with smaller heads, but seem to be unaffected. However, as they age, many suffer from learn-ing troubles, speech difficulties and health problems. There is no cure for microcephaly.
The Zika virus was first discov-ered in Africa nearly 70 years ago. It was found in monkeys that lived in Uganda’s Zika Forest. In 1954, a person in Nigeria got the virus. This was the first time that it had been found in a human. Over the years, the virus began to appear in other countries. It does not make people very ill. It was therefore thought to be less serious than other mosquito-carried diseases.
The Zika virus was first recorded in Brazil 18 months ago. Virolo-gists, or scientists who study virus-es, tracked it. During the following six months, the virus rapidly spread throughout most of South America and the Caribbean islands. Now, Zika is present in over 50 countries. Since 2015, 2,200 babies have been born with microcephaly associated with the Zika virus. Most, or 2,033,
are in Brazil.The scientists have worked out
how to infect the Aedes aegypti mosquito with a bacterium called Wolbachia. This bacterium is found in many other insect species. It does not harm humans.
Wolbachia seems to improve a mosquito’s immune system. It also competes with any viruses inside the insect. This means that the virus-es cannot replicate so easily. There-fore they are less likely to be passed to humans. When a mosquito with Wolbachia breeds, the bacterium is passed onto its offspring.
Experiments, or trials, have been carried out in small areas of Aus-tralia, Vietnam, Indonesia, Colom-bia, and Brazil. These have reduced the spread of dengue fever. The scientists’ mosquito army will be re-leased in large urban areas of Brazil and Colombia early next year.
Preparatoria 1o.
