Brazil is one of the 58 countries and territories which to-date report continuing transmission of Zika virus by mosquitoes. While mosquitoes are the primary vectors, a person infected with Zika virus can also transmit the virus to another person through unprotected sex. Zika virus disease usually causes mild symptoms1, and most people will not develop any symptoms. However, there is scientific consensus that Zika virus is a cause of microcephaly (children being born with unusually small heads) and other brain malformations and disorders in babies born to women who were infected with Zika virus during pregnancy, and Guillain-Barré syndrome (a rare but serious neurological disorder that could lead to paralysis and death).
Athletes and visitors to Rio de Janeiro, and other areas where Zika virus is circulating, are being encouraged to:
- follow the travel advice2provided by WHO and their countries’ health authorities, and consult a health worker before travelling;
- whenever possible, during the day, protect themselves from mosquito bites by using insect repellents and by wearing clothing – preferably light-coloured – that covers as much of the body as possible;
- practice safer sex (e.g. use condoms correctly and consistently) or abstain from sex during their stay and for at least 8 weeks* after their return, particularly if they have had or are experiencing symptoms of Zika virus;
- choose air-conditioned accommodation (windows and doors are usually kept closed to prevent the cool air from escaping, and mosquitoes cannot enter the rooms);
- avoid visiting impoverished and over-crowded areas in cities and towns with no piped water and poor sanitation (ideal breeding grounds of mosquitoes) where the risk of being bitten is higher.
Pregnant women continue to be advised not to travel to areas with ongoing Zika virus transmission. This includes Rio de Janeiro. Pregnant women’s sex partners returning from areas with circulating virus continue to be counselled to practice safer sex or abstain throughout the pregnancy3. The Games will take place during Brazil’s wintertime, when there are fewer active mosquitoes and the risk of being bitten is lower.
WHO/PAHO is providing public health advice to the Government of Brazil, the International Olympic Committee and, by extension, and the Rio 2016 Local Organizing Committee on ways to further mitigate the risk of athletes and visitors contracting Zika virus during the Games. An important focus of WHO advice revolves around measures to reduce populations of Aedes mosquitoes which transmit chikungunya, dengue and yellow fever in addition to Zika virus.
WHO/PAHO will continue to monitor the Zika virus transmission and risks in Brazil and in other affected areas to provide updates on how Zika virus outbreaks, risks and prevention interventions develop between now and August and beyond.
 Symptoms include fever, skin rashes, conjunctivitis, muscle and joint pain, malaise, and headache.
*Corrigendum: This sentence was changed on 2 June 2016 to reflect the update in the WHO guidance document, "Prevention of sexual transmission of Zika virus", which was updated on 30 May to the following: "To prevent the onward transmission of Zika and adverse pregnancy and fetal outcomes, all returning travellers should practice safer sex, including through the correct and consistent use of condoms, or abstaining from sex for at least 8 weeks."
Corrigendum: The original version of this statement was modified on 29 May 2016 to remove reference to the fact that WHO/PAHO is providing advice to The International Olympic Committee under a Memorandum of Understanding. The MOU between WHO and the IOC expired in 2015. WHO is currently providing public health advice for the upcoming Olympics through the Rio 2016 task force which was established in 2015. Advice on planning and delivering mass gatherings is undertaken as part of WHO support to host countries with the host country's Ministry of Health.