As concerns about the mosquito borne Zika virus continue to grow, the Olympic organizing committee in Rio de Janeiro has announced that it will charge the various nations to place window screens in team housing, Fox News reported Feb. 29. The committee will have screens in place “where required” in common areas but individual national Olympic committees must pay for screening athletes’ rooms. The Summer Olympics begin in Rio on Aug. 5 and end Aug. 21.
The Brazilian government has been battling a number of viral illnesses carried from person to person by mosquitoes. Zika viral illnesses were first discovered in the country in the spring of 2015. All four dengue viruses and the chikungunya virus were already present at that time.
The vector for Zika and these other viruses is the Aedes mosquito. In Brazil, Aedes aegypti and Aedes albopictus are the two species transmitting these arboviruses, according to the Pan American Health Organization. The female mosquitoes of both species use human blood as part of their reproductive process.
Aedes aegypti, the Yellow Fever mosquito, lives in and around humans, including indoors at times. Aedes albopictus, the Asian Tiger mosquito, may feed on other animals as well as humans. Both species can breed is as little as a few ounces of fresh water.
August is the dry season in Rio de Janeiro. Weather.com reports that the average precipitation for the city is 2 inches of rain for the month. This means good weather for the outdoor events at the Olympics but it also means that the most common species of mosquito in the region may be out in force.
Culex quinquefasciatus mosquitoes are 20 times more common in Brazil than are the Aedes species, as reported by Outbreak News. Studies have shown that a drought or dry spell can greatly impact their population, causing a Culex population explosion. These mosquitoes breed in stagnant, sometime polluted water as described by the Illinois Department of Public Health.
The Culex mosquito is the primary vector of the West Nile virus worldwide. The illness is avian, and humans are “incidental” hosts. In humans, up to 80 percent of those infected are asymptomatic and never know that they were ill.
Brazil does not have the West Nile virus in circulation at this time. With the arrival of hundreds of thousands of people for the Olympic Games, that could change. An increase in the Culex population in Rio due to the dry season combined with the almost certain arrival of individuals infected with West Nile suggests the potential of the virus being introduced. The Zika virus is believed to have been introduced to Brazil during the World Cup competition in 2014.
Another viral illness spread by the Culex mosquito is Sindbis. It is endemic in Northern Europe, the European Centre for Disease Prevention and Control (ECDC) states. Tourists and teams from the Scandinavian countries could carry this virus to the Olympics.
The risks of contracting dengue, chikungunya or Zika viral illnesses could be lower during the Olympics due to Rio’s dry season. The chances of a new mosquito borne illness being introduced to Brazil may be increased by that same dry season. Window screens could be a key preventative measure, regardless of who pays for their installation.