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Brazil Zika crisis: Over 200,000 deployed in massive mitigation operation ahead of Rio Olympics

By By Kevin Byrne, Staff Writer
April 20, 2016, 1:28:38 AM EDT

This coming August, hundreds of thousands of visitors will descend upon Rio de Janeiro for the 2016 Summer Olympics, the first time in history South America will host the event.

As health officials around the world continue to combat the outbreak of the mosquito-borne Zika virus, Olympic organizers have stated that the World Health Organization (WHO) has not recommended any changes to travel plans for the summer games, with the exception of pregnant women or women thinking about becoming pregnant.

On Wednesday, April 13, the Centers for Disease Control (CDC) confirmed a link between the virus and abnormal birth defects, including microcephaly, which can affect head size and brain development. This comes a few days after Brazilian scientists uncovered a new brain disorder associated with Zika infections in adults, Reuters reported.


With no sign of the health threat diminishing anytime soon, entomologists, public health officials, vector control specialists, as well as other experts convened for a summit in Maceió, Alagoas, Brazil, last month. The purpose of the summit was to bring knowledge leaders together to identify immediate steps needed to create long-term and sustainable solutions for effective control of the Aedes aegypti mosquitoes, which are known to carry the Zika virus.

For mosquito breeding areas, the ideal conditions would be moist or wet with nighttime temperatures around 75-80 degrees Fahrenheit, according to Dr. Grayson Brown, director of the Public Health Entomology Laboratory at the University of Kentucky. Brown attended the summit in Brazil last month, where he served as a co-chair of the Aedes aegypti Steering Committee.

One of the reasons that Olympics officials have publicly expressed optimism for being able to hold the games despite the threat of Zika is that they will take place during Brazil’s winter season, when rain is less frequent and temperatures are lower, causing a reduced mosquito presence.

From July through August, normal high temperatures in Rio are around 75 F (24 C), with normal low temperatures in the same time frame around 63 F (17 C), according to AccuWeather Senior Meteorologist Rob Miller.

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“Humidity levels are slightly lower than in the summer, but it’s still considered a tropical climate, and therefore it can still be classified as being humid most days,” Miller said.

However, even though it will be Brazil’s winter, temperatures will remain high enough for mosquitoes to complete development, according to Brown.

Even the smallest amounts of water can still bring mosquitoes. The Aedes aegypti larvae can complete development in less than a teaspoon of water, experts say.

Miller said that rainfall is at a minimum in July in Rio and only slightly higher in August, typically increasing toward the end of the month.

“Rainfall averages only about 3.5-4 inches (approximately 90-100 mm) during those two months combined,” Miller said.

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If that amount of rain were to fall during this July and August, that total would increase the number of Aedes aegypti because it's ideal rainfall for that species, according to Brown.

“The rain levels affect not just the number of mosquitoes but also the composition of the species and consequently the disease threat,” Brown said.

To minimize the risk of having visitors come into contact with mosquitoes, the Brazilian government is deploying more than 200,000 personnel to help educate the population and assist them by cleaning areas of stagnant water, which is where mosquitoes lay their eggs, the Rio Organizing Committee said.

“We remain strongly confident that Rio will organize excellent Games with memorable celebrations and we look forward to welcoming you all here this August and September, or before for test events and pre-Games preparations,” the committee said in a letter.


Many communities in the disease zones have inadequate sanitation that allow frequent trash piles and open sewers to serve as mosquito breeding and feeding grounds, according to the final outcome statement from the Aedes aegypti summit last month.

In February, the United States Olympic Committee (USOC) reportedly told athletes scheduled to participate in the games that they should consider not attending if they are fearful of contracting the virus, according to Reuters.

The USOC has organized an Infectious Disease Advisory Group that will help identify best practices that will prepare athletes and staff attending the games on what issues could arise.

“The health and safety of our athletes, and our entire delegation, is our top priority,” USOC CEO Scott Blackmun said in a statement. “I’m grateful to the diverse group of medical experts that have agreed to provide Team USA with the information and resources necessary to stay healthy and compete successfully.”

The games will take place from Aug. 5-21, but athletes are expected to arrive several weeks earlier.

U.S. women’s national soccer team goalie Hope Solo told Sports Illustrated on Thursday that she is planning to attend the games despite her concerns about the outbreak.

While Brown was in Brazil, he said the mosquitoes were “everywhere,” flying around in high population densities. He cautioned that spectators should avoid being outdoors late in the afternoon in crowded, low-lying areas, although there shouldn’t be any trouble with sitting up high in a stadium.

Brown added that people will encounter more mosquitoes wherever the air is the stillest.

Beach areas will likely be fine, but busy shopping areas as well as areas around plants and in shaded areas are where a lot of mosquitoes will be encountered, he added.

There is no vaccine or medicine for Zika, so the best precaution is to prevent mosquito bites. For travelers planning to head to areas where Zika has been widely reported, the CDC lists several prevention methods.

1. Protect exposed skin by wearing long-sleeved shirts and long pants.

2. Use EPA-registered insect repellents containing DEET, picaridin, oil of lemon eucalyptus.

3. Stay in places with air conditioning and window and door screens to keep mosquitoes outside.

4. Sleep under a mosquito net if rooms are not air conditioned or protected with window and door screens.

Source: CDC

Several AccuWeather meteorologists and staff writers contributed content to this article.

Have questions, comments, or a story to share? Email Kevin Byrne at, follow him on Twitter at @Accu_Kevin. Follow us @breakingweather, or on Facebook.

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