Half a million tourists and over 10,000 athletes are expected in Rio de Janeiro for the Summer Olympic Games. This is the first time that the event will be held in South America, and the press has had a lot to say about it. Amid controversies that include health concerns, doubts about the readiness of infrastructure, political turmoil and an economic crisis, Rio will really be a sui generis setting for the Olympics.
A little more than a week before the official opening, we conducted a literature search to map what medical journals are saying about this event. Using the keywords (Olympics OR Olympic games OR Paralympic games) AND (Rio de Janeiro OR Rio OR Brazil) we found 50 articles that addressed some aspect of the competition. 1-55
Papers analyzed the signs of progress in physical activity report and monitoring by several countries since the London Olympics,10 the possibility that scheduling night competitions in the games might hinder athletes’ performances,11 and how genetic variations might influence the result of elite sprinters.14
The levels of air pollution in Rio de Janeiro’s slums and its impact on athletes’ health and performance,28,29 as well as the poor quality of physical activity resources in those areas32 and the appalling lack of sewage treatment contaminating the waters of Guanabara Bay,46,49 have all be closely examined.
Not surprisingly, though, roughly half of those articles focused on the Zika virus epidemic and other arboviruses, their likely consequences, and how athletes, visitors and the population in general should protect themselves.1-8,12,13,16,18,20-27,30,31,36,38,39
As early as 2014, there were already publications covering the health risks involved in travelling to Brazil.50,51,53,54 Gaines et al. searched the peer-reviewed and gray literature to provide travelers coming to the 2014 World Cup and later to the Olympic and Paralympic Games with a list of actions to be taken ahead of the travel.54 The article described the most common diseases in Brazil (including dengue), which vaccines were available, and which precautions should be taken to avoid illnesses.
The recent outbreak of Zika in Brazil brought ample attention to this and other arboviruses. The confirmation that the Zika virus was circulating in the northeast of Brazil happened in March 2015 after the report of several cases of a febrile exanthematic disease that did not fill the parameters for either dengue or chikungunya fever. 56
Detailed data on the incidence of Zika in every state and region can be found for 2016; however, official numbers regarding the impact of the disease in 2015 are still lacking because the mandatory report was only determined last February. The latest epidemiologic bulletin from the government states that between January 3 and June 11 there were 165,932 likely cases of Zika in Brazil, of which 66,180 had been confirmed by tests.9
Burattini et al. used a mathematical formula to calculate the risk of acquiring the Zika virus during the periods of Carnival and the Olympics.39 They used the 27,146 cases of the disease that were reported in 2015 as basis for their calculation. Results showed that the risk of contracting Zika would be 3.6 per 100,000 during Carnival (which is the hottest season and usually the peak of transmission for such diseases) and 1.8 per 1 million during the Olympics (a much drier and cooler season, often the nadir of transmission). However, if the total number of Zika infections in Brazil in 2015 was really 1.5 million cases (anecdotal information, as yet unconfirmed), then the respective risks would 1.3 per 1,000 and 3.2 per 100,000.
Another mathematical calculation was performed to evaluate the risk of contracting dengue fever during the Olympic Games.2 This stochastic model took into consideration all historic data on the disease from 2000 to 2015. The calculations predict that in the worst-case scenario (based on the worst month of August 2007) incidences of 5.75 symptomatic and 51.5 asymptomatic cases per 100,000 individuals will be expected. That would result in 23 and 206 cases, respectively.
Most authors did not support the postponement of the games, particularly because delaying the event would place it in the middle of summer, the hottest and most humid season when mosquito populations increase all over the country.21,35,36,38 An extensive review of data regarding mass gatherings around the world (sports-related or religious) summarized the lessons learned and the implications for the Olympics in Brazil.1 The virus is present in over 60 countries, and the risk of infection is real with or without the Olympics. The authors reinforced that any potential risks caused by mass gatherings can be lessened when they are previously recognized and planned for and emphasized that other events already occurred in the country without significant international spread.
Dengue is an infection caused by four distinct viral serotypes htat are transmitted by the female mosquito of the genus Aedes. The disease was reintroduced in Brazil during the early 1980s and became a widespread problem by the mid-1990s. Nowadays, the country has the highest number of dengue infections worldwide, with more than 7 million reported cases.57 Up to 6% of travelers who visit Brazil and report febrile sickness on return are affected by it.50
Dengue has a usual pattern of outbreaks during the year, with most of the cases concentrated during the hot and humid months of summer, when the proliferation of mosquitoes and their vectorial capacity are higher.52
Symptoms include mild, nonspecific febrile syndrome with headache and myalgia. About 5% of patients may present hemorrhagic dengue, a severe and life-threatening condition. As a new dengue vaccine58 is being introduced and monitored in countries where dengue is most prevalent, the general recommendation for infected patients is supportive treatment with rest and fluid ingestion and avoidance of non-steroidal anti-inflammatories and aspirin. Preventive measures to avoid the infection are the same described for Zika below.
Zika fever is another disease cause by an arbovirus (flavivirus) transmitted mainly by Aedes mosquitoes bites (Aedes aegypit and Aedes albopictus) but also via sexual intercourse, perinatal or in utero to the newborn, and likely by blood transfusion.6 The virus was first identified in 1947 on rhesus monkeys in the Zika forest in Uganda. From the first case in humans in 1952 until the present day, outbreaks of Zika occurred in 2007 in Micronesia, 2010 in Cambodia and 2013-2014 in French Polynesia.24 The latter affected 11% of the population (28,000 infected) and was marked an excessive number of Guillain-Barré syndrome cases.6 The virus might have been brought to Brazil during the 2014 World Cup or later that same year during the Va’a World Sprint Championship canoe race, in which teams from the Pacific Island competed.43
One in five infected people will develop symptoms after two to 14 days of incubation. The disease often presents with a pruritic, descending and maculopapular rash, arthralgias, conjunctival injection, fatigue, malaise, retro-orbital pain, paresthesia, headache, myalgia, and lymphadenopathy. Most cases are mild and can last up to seven days.24,37
There is an increased incidence of Guillain-Barré Syndrome among Zika patients, although most patients fully recover. This neurological condition presents as ascending motor weakness and paralysis (sometimes requiring ventilatory support) lasting for days or weeks.37 Another potential complication of Zika is the development of microcephaly and other neurological abnormality in newborns when the infection occurs during pregnancy.
There is not a specific therapy. Because Zika is usually self-limited with mild symptoms, rest, hydration and acetaminophen are recommended. Nonsteroidal anti-inflammatories and aspirin should be avoided because they increase the risk of hemorrhage in dengue cases (differential diagnosis).
Prevention of Zika and Dengue
The key way to prevent Zika and dengue is to avoid mosquito bites.8 So, the Centers for Disease Control and Prevention recommends the following actions to athletes, visitors and the general population:
- Personal protection: Wear long-sleeved shirts and long pants, use insect repellents, and treat clothing and gear with permethrin.23,37
- Safe sex: Because the Zika virus can be spread through semen during all stages of the disease, the use of condoms should be considered for male athletes who have been diagnosed or had symptoms (for at least six months), those who traveled to an endemic area but did not have symptoms (at least eight weeks after returning), and those who live in such an area. 23,37
- Environmental precautions: Stay in places with air conditioning or that use window and door screens to keep mosquitoes outside, sleep under a mosquito net, and avoid places with stagnant water (tires, flower pots, containers, etc.) because these are breeding grounds for larvae and mosquitoes.23,37
- Zumla A, McCloskey B, Bin Saeed AA, et al. What is the experience from previous mass gathering events? Lessons for Zika virus and the Olympics 2016. International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 2016.
- Ximenes R, Amaku M, Lopez LF, et al. The risk of dengue for non-immune foreign visitors to the 2016 summer olympic games in Rio de Janeiro, Brazil. BMC infectious diseases. 2016;16(1):186.
- Wilson ME, Schlagenhauf P. Aedes and the triple threat of DENV, CHIKV, ZIKV--Arboviral risks and prevention at the 2016 Rio Olympic games. Travel medicine and infectious disease. 2016;14(1):1-4.
- Vancini RL, Dos Santos Andrade M, Vancini-Campanharo CR, Barbosa DELCA. Dengue and the olympic and paralympic games in Rio 2016: what do athletes, coaches and visitors need to know? The Journal of sports medicine and physical fitness. 2016.
- Trilla A, Trilla-Aymerich G. [Zika virus: travel, mosquitoes and Olympic Games]. Medicina clinica. 2016;147(3):113-115.
- Toresdahl BG, Asif IM. Update on Zika Virus: Considerations for the Traveling Athlete. Sports health. 2016.
- Shadgan B, Pakravan A, Zaeimkohan H, Shahpar FM, Khodaee M. Zika and Rio Olympic Games. Current sports medicine reports. 2016;15(4):298-300.
- Shadgan B, Khodaee M. Smart Clothing is the Best Protection Against Zika During Rio Olympic and Paralympic Games. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine. 2016;26(4):345-346.
- Secretaria de Vigilância em Saúde (SVS), Ministério da Saúde (MS). Monitoramento dos casos de dengue, febre de chikungunya e febre pelo vírus Zika até a Semana Epidemiológica 23, 2016. Secretaria de Vigilância em Saúde (SVS);2016.
- Sallis JF, Bull F, Guthold R, et al. Progress in physical activity over the Olympic quadrennium. Lancet (London, England). 2016.
- Rosa JP, Rodrigues DF, Silva A, et al. 2016 Rio Olympic Games: Can the schedule of events compromise athletes' performance? Chronobiology international. 2016;33(4):435-440.
- Petersen E, Wilson ME, Touch S, et al. Rapid Spread of Zika Virus in The Americas--Implications for Public Health Preparedness for Mass Gatherings at the 2016 Brazil Olympic Games. International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases. 2016;44:11-15.
- Patel D, Field V, Schlagenhauf P. Countdown to the 2016 Olympic Games: A travel medicine checklist. Travel medicine and infectious disease. 2016;14(3):173-176.
- Papadimitriou ID, Lucia A, Pitsiladis YP, et al. ACTN3 R577X and ACE I/D gene variants influence performance in elite sprinters: a multi-cohort study. BMC genomics. 2016;17(1):285.
- Nali LH, Fujita DM, Salvador FS, et al. Potential measles transmission risk in mass gatherings: Are we safe for the Olympic games-Rio 2016? Journal of travel medicine. 2016;23(4).
- Massad E, Coutinho FA, Wilder-Smith A. Is Zika a substantial risk for visitors to the Rio de Janeiro Olympic Games? Lancet (London, England). 2016;388(10039):25.
- Malina RM. Reflections on the Olympic Games in Rio - from the Elite to the Majority. Annals of human biology. 2016:1-8.
- Lewnard JA, Gonsalves G, Ko AI. Low Risk for International Zika Virus Spread due to the 2016 Olympics in Brazil. Annals of internal medicine. 2016.
- Kubosch EJ, Kosel J, Steffen K, et al. Upcoming Paralympic Summer Games in Rio. What did the German medical team learn from the London Games? The Journal of sports medicine and physical fitness. 2016.
- Korzeniewski K, Juszczak D, Zwolinska E. Zika - another threat on the epidemiological map of the world. International maritime health. 2016;67(1):31-37.
- Kmietowicz Z. Olympic Games are likely to be free of Zika cases, say officials. BMJ (Clinical research ed.). 2016;353:i3233.
- Kekule A. [How dangerous is the Zika virus?]. Deutsche medizinische Wochenschrift (1946). 2016;141(13):969-972.
- Igreja RP. Olympics fans must take Zika precautions before travelling. BMJ (Clinical research ed.). 2016;353:i3255.
- Hajra A, Bandyopadhyay D, Hajra SK. Zika Virus: A Global Threat to Humanity: A Comprehensive Review and Current Developments. North American journal of medical sciences. 2016;8(3):123-128.
- Grills A, Morrison S, Nelson B, Miniota J, Watts A, Cetron MS. Projected Zika Virus Importation and Subsequent Ongoing Transmission after Travel to the 2016 Olympic and Paralympic Games - Country-Specific Assessment, July 2016. MMWR. Morbidity and mortality weekly report. 2016;65(28):711-715.
- Gautret P, Mockenhaupt F, Grobusch MP, et al. Arboviral and other illnesses in travellers returning from Brazil, June 2013 to May 2016: implications for the 2016 Olympic and Paralympic Games. Euro surveillance : bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin. 2016;21(27).
- Ganczak M. Zika--an emerging infectious disease. The risk assessment from Polish perspective. Przeglad epidemiologiczny. 2016;70(1):1-6, 93-97.
- Furlow B. Olympics shine a light on slums and pollution in Rio. The Lancet. Respiratory medicine. 2016.
- Fitch K. Air pollution, athletic health and performance at the Olympic Games. The Journal of sports medicine and physical fitness. 2016;56(7-8):922-932.
- Elachola H, Gozzer E, Zhuo J, Memish ZA. A crucial time for public health preparedness: Zika virus and the 2016 Olympics, Umrah, and Hajj. Lancet (London, England). 2016;387(10019):630-632.
- Eberhardt KA, Vinnemeier CD, Dehnerdt J, Rolling T, Steffen R, Cramer JP. Travelers to the FIFA world cup 2014 in Brazil: Health risks related to mass gatherings/sports events and implications for the Summer Olympic Games in Rio de Janeiro in 2016. Travel medicine and infectious disease. 2016;14(3):212-220.
- de Sousa-Mast FR, Reis AC, Vieira MC, Sperandei S, Gurgel LA, Puhse U. Does being an Olympic city help improve recreational resources? Examining the quality of physical activity resources in a low-income neighborhood of Rio de Janeiro. International journal of public health. 2016.
- de Sousa-Mast FR, Reis AC, Sperandei S, Gurgel LA, Vieira MC, Puhse U. Physical activity levels of economically disadvantaged women living in the Olympic city of Rio de Janeiro. Women & health. 2016;56(5):595-614.
- Daniel P, Gist R, Grock A, Kohlhoff S, Roblin P, Arquilla B. Disaster Olympics: A Model for Resident Education. Prehospital and disaster medicine. 2016;31(3):237-241.
- Coombes R. Call to cancel 2016 Olympics because of Zika risk is not backed by WHO guidance. BMJ (Clinical research ed.). 2016;353:i2899.
- Codeco C, Villela D, Gomes MF, et al. Zika is not a reason for missing the Olympic Games in Rio de Janeiro: response to the open letter of Dr Attaran and colleagues to Dr Margaret Chan, Director - General, WHO, on the Zika threat to the Olympic and Paralympic Games. Memorias do Instituto Oswaldo Cruz. 2016;111(6):414-415.
- Centers for Disease Control and Prevention (CDC), National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Division of Vector-Borne Diseases (DVBD). Zika Virus - CDC. 2016; https://http://www.cdc.gov/zika/index.html. Accessed August, 3, 2016.
- Castro MC. Zika virus and the 2016 Olympic Games - Evidence-based projections derived from dengue do not support cancellation. Travel medicine and infectious disease. 2016.
- Burattini MN, Coutinho FA, Lopez LF, et al. Potential exposure to Zika virus for foreign tourists during the 2016 Carnival and Olympic Games in Rio de Janeiro, Brazil. Epidemiology and infection. 2016;144(9):1904-1906.
- Blauwet CA, Lexell J, Derman W, et al. The Road to Rio: Medical and Scientific Perspectives on the 2016 Paralympic Games. PM & R : the journal of injury, function, and rehabilitation. 2016.
- Barwise-Munro L. Jumping into equine practice. The Veterinary record. 2016;179(5):i-ii.
- Al-Tawfiq JA, Gautret P, Benkouiten S, Memish ZA. Mass Gatherings and the Spread of Respiratory Infections. Lessons from the Hajj. Annals of the American Thoracic Society. 2016;13(6):759-765.
- Zanluca C, Melo VC, Mosimann AL, Santos GI, Santos CN, Luz K. First report of autochthonous transmission of Zika virus in Brazil. Memorias do Instituto Oswaldo Cruz. 2015;110(4):569-572.
- Vilani RM, Machado CJ. The impact of sports mega-events on health and environmental rights in the city of Rio de Janeiro, Brazil. Cadernos de saude publica. 2015;31 Suppl 1:39-50.
- Veneroso CE, Ramos GP, Mendes TT, Silami-Garcia E. Physical performance and environmental conditions: 2014 World Soccer Cup and 2016 Summer Olympics in Brazil. Temperature (Austin, Tex.). 2015;2(4):439-440.
- The Lancet Infectious D. Concerns raised over water quality at the Rio Olympics. The Lancet. Infectious diseases. 2015;15(9):987.
- Mujika I, Orbananos J, Salazar H. Physiology and training of a world-champion paratriathlete. International journal of sports physiology and performance. 2015;10(7):927-930.
- Loturco I, Winckler C, Kobal R, et al. Performance changes and relationship between vertical jump measures and actual sprint performance in elite sprinters with visual impairment throughout a Parapan American games training season. Frontiers in physiology. 2015;6:323.
- Fistarol GO, Coutinho FH, Moreira AP, et al. Environmental and Sanitary Conditions of Guanabara Bay, Rio de Janeiro. Frontiers in microbiology. 2015;6:1232.
- Wilson ME, Chen LH, Han PV, et al. Illness in travelers returned from Brazil: the GeoSentinel experience and implications for the 2014 FIFA World Cup and the 2016 Summer Olympics. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. 2014;58(10):1347-1356.
- Wilson ME, Chen LH. Health risks among travelers to Brazil: implications for the 2014 FIFA World Cup and 2016 Olympic Games. Travel medicine and infectious disease. 2014;12(3):205-207.
- Liu-Helmersson J, Stenlund H, Wilder-Smith A, Rocklov J. Vectorial capacity of Aedes aegypti: effects of temperature and implications for global dengue epidemic potential. PloS one. 2014;9(3):e89783.
- Iliaki E, Chen LH, Hamer DH, et al. Travel to Brazil: analysis of data from the Boston Area Travel Medicine Network (BATMN) and relevance to travelers attending world cup and olympics. Journal of travel medicine. 2014;21(3):214-217.
- Gaines J, Sotir MJ, Cunningham TJ, et al. Health and safety issues for travelers attending the World Cup and Summer Olympic and Paralympic Games in Brazil, 2014 to 2016. JAMA internal medicine. 2014;174(8):1383-1390.
- Demarzo MM, Mahtani KR, Slight SP, Barton C, Blakeman T, Protheroe J. [The Olympic legacy for Brazil: is it a public health issue?]. Cadernos de saude publica. 2014;30(1):8-10.
- Oliveira WK, Henriques CMP. Nota Informativa Nº 6/2015 CIEVS/DEVIT/SVS/MS. In: Departamento de Vigilância das Doenças Transmissíveis - DEVIT, ed2015:4.
- Teixeira MG, Siqueira JB, Jr., Ferreira GL, Bricks L, Joint G. Epidemiological trends of dengue disease in Brazil (2000-2010): a systematic literature search and analysis. PLoS neglected tropical diseases. 2013;7(12):e2520.
- Villar L, Dayan GH, Arredondo-Garcia JL, et al. Efficacy of a tetravalent dengue vaccine in children in Latin America. The New England journal of medicine. 2015;372(2):113-123.