September 25-October 1, 2014 Current Events Lesson Plan
Current Event: For Once, Scientists Encourage Mosquito Breeding
Brazilian scientists recently released thousands of specially modified mosquitoes in a region around the city of Rio de Janeiro in an effort to combat the spread of mosquito-borne dengue fever. The scientists hope that the special mosquitoes will breed and eventually become the majority population in the region. Modifying the mosquitoes involves infecting them with a microbe that prevents the dengue virus from multiplying. Once infected, the insects cannot transmit the disease to humans when they bite. If successful, the mosquito program may also be used to help control other diseases, including yellow fever and malaria. Dengue fever, which is only transmitted by mosquitoes, causes headaches, eye aches, and severe pain in the muscles and joints, in addition to a high fever. Global health officials estimate that about 390 million people get dengue each year. Although it is seldom fatal, the debilitating illness is an enormous burden on the economy and health care systems of many developing countries. There is no known cure for the disease.
Objective:
Mosquitoes are slender insects that feed on blood and other liquids. The mosquito is the world’s deadliest animal, by a landslide. Some people estimate that mosquitoes kill from 1 million to 3 million people each year, mainly in Africa and Asia. People control mosquitoes in many ways. Chemical insecticides kill adult mosquitoes when sprayed in homes, garages, and other buildings. Mosquito-control agencies spray thin mists of insecticides into fields, forests, and gardens when the threat of disease becomes high. The best traditional approach to mosquito control involves destroying the places where mosquitoes breed. Mosquitoes lay their eggs in marshes, swamps, and pools of still water, as well as in tree holes, discarded tires and containers, and yard and garden ornaments that contain standing water. Such objects and places may be drained, filled in, or covered with thin layers of oil or insecticides. The Behind the Headlines news story and related World Book articles explore mosquitoes and other insects.
Words to know:
Discussion Topics:
1. Ask your students what they know about Brazil. (Students might say that it is the largest country in South America in terms of both area and population; Rio de Janeiro and Sao Paulo are the country’s two largest cities, and Brasilia is its capital; about two-thirds of the Amazon rain forest is in the country; the country was a Portuguese colony for hundreds of years.)
2. Ask your students to debate “Because insecticides can cause environmental harm or even poison people when they are inappropriately applied or overused, they should be banned.”
Ask your students to use World Book’s Timelines feature to view or add to the Advances in Medicine timeline. (Students may wish to use the “History” section of World Book’s Medicine article for help.)