Zika worries go global

Mosquito-borne virus spreading through the Americas may cause birth defects

Zika map

Mosquitoes carrying Zika virus have infected people in more than 20 countries and territories. The World Health Organization says the recent wave of cases is “a public health emergency of international concern.”


The recent wave of birth defects and brain disorders linked to Zika virus is an international “public health emergency,” according to the World Health Organization (WHO). The agency is part of the United Nations. It tries to control the spread of disease around the world. It declared the emergency February 1.

The Zika virus is spread by mosquitoes. It has struck hard in Brazil and spread into Central America and Mexico. In a press conference, Margaret Chan, who heads the WHO, says the link between the virus and birth defects has not been proven. But experts strongly suspect Zika infection in pregnant women can cause babies to be born with abnormally small heads. That condition is called microcephaly.

Chan said people, including pregnant women, can still travel to countries hit by Zika. But women should try to avoid mosquito bites. They can do that by wearing long sleeves and trousers, she said. They can also use bug spray and mosquito nets. 

As of January 23, Brazil has reported 4,180 suspected cases of microcephaly since October. 

Power Words

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infection  A disease that can spread from one organism to another.

Latin America  Nations in the Americas south of the United States, most of which now speak Spanish as their native tongue. The major exception within this region: Brazil, which speaks Portuguese.

microcephaly  A condition that leaves babies with abnormally small heads and partially developed brains.

virus  Tiny infectious particles consisting of RNA or DNA surrounded by protein. Viruses can reproduce only by injecting their genetic material into the cells of living creatures. Although scientists frequently refer to viruses as live or dead, in fact no virus is truly alive. It doesn’t eat like animals do, or make its own food the way plants do. It must hijack the cellular machinery of a living cell in order to survive.

World Health Organization  An agency of the United Nations, established in 1948, to promote health and to control communicable diseases. It is based in Geneva, Switzerland. The United Nations relies on the WHO for providing international leadership on global health matters. This organization also helps shape the research agenda for health issues and sets standards for pollutants and other things that could pose a risk to health. WHO also regularly reviews data to set policies for maintaining health and a healthy environment.

Zika virus  A virus that can be transmitted to humans via mosquitoes. About 20 percent of infected people get sick. Symptoms include a slight fever, rash and pinkeye and usually fade quickly. A growing body of evidence suggests that the virus could also cause a devastating birth defect — microcephaly. Evidence suggests it may also cause neurological conditions such as Guillain-Barré syndrome.

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