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For more than 6 years, the Brazilian city of Rio de Janeiro has been preparing for the 2016 Olympics, which will be held August 5-21,[1] followed by the Paralympics, which are scheduled for September 7-18.[2]
Regardless of which games you choose to experience or whether you will be caring for individuals after their return from Brazil, disease awareness and appropriate preparation along with knowledge of clinical recommendations may keep you and your patients healthy during and after the trip.
Are you ready for Rio?
Topographic map courtesy of Sam Shlomo Spaeth. Right images courtesy of Molekuul: dengue virus (top right); Mrfiza: Aedes mosquito feeding (center right); and Decade3d: malaria viruses in a red blood cell (bottom right)—all via Dreamstime.
Awareness and preparation is everything with global travel—especially when there is involvement with an international host country and the influx of athletes and spectators from all over the world. Standard precautions must include ensuring that all travelers are updated on routine vaccinations (eg, measles/mumps/rubella, tetanus/diphtheria/pertussis, tetanus/diphtheria, varicella, polio, flu), with additional consideration for vaccination for hepatitis A, typhoid, yellow fever, and/or rabies.[3]
Depending on anticipated travel locations in Brazil and within South America, medicine for travelers' diarrhea and malaria prophylaxis may be indicated.[3]
The Centers for Disease Control and Prevention (CDC) provides specific health information for travelers to Brazil. It is essential for travelers to ensure they have an adequate supply of all routine medications and a travel health kit, as well as enroll in the Smart Traveler Enrollment Program (STEP).[3]
Adapted infographic courtesy of the CDC.
Zika virus is spread to people primarily through the bite of an infected Aedes species mosquito (eg, A aegypti, A albopictus),[4,5] the same mosquito that transmits dengue and chikungunya viruses.[4] Transmission in the Americas has markedly increased since May 2015, when the Pan American Health Organization issued an alert for Brazil.[6,7] This has been a topic of concern for Olympians and travelers alike with regard to the upcoming Games, as there is currently an ongoing Zika virus outbreak in Brazil.
The most common signs/symptoms of Zika virus infection are fever, rash, joint pain, and conjunctivitis, which typically begin 2-7 days after being bitten by an infected mosquito.[4,5] Signs/symptoms are usually mild, lasting several days to 1 week, and they are most commonly managed without hospitalization with supportive care.[4,5]
No vaccine currently exists to protect against Zika virus infection[4]; treatment typically includes supportive measures.[4,5]
The map shows countries and territories in the Americas and the Pacific with active Zika virus transmission as of July 14, 2016.
Image courtesy of the CDC.
Zika virus infection has been linked to serious birth defects; therefore, special precautions have been recommended for pregnant women, women who are trying to become pregnant (shown), and any sexual partners of these women.[4,8,9]
NOTES: (1) The CDC does not recommend pregnant women in any trimester travel to areas with active Zika outbreaks, including Brazil.[3,8] (2) The CDC reported the first suspected case of female-to-male sexual transmission of the virus in New York City on July 15, 2016. Barrier protection or abstinence is recommended for any sexual partner of men and/or women traveling to areas with active Zika virus transmission.
In addition to pregnancy, concerns exist regarding an association between Guillain-Barré syndrome—an autoimmune system response that damages the nervous system and causes progressive muscle weakness and, sometimes, paralysis[10]—and the Zika virus.[5,6]
Keep in mind that the geographic range of the Aedes species mosquitoes that can become infected with and spread the Zika virus, as well as the chikungunya and dengue viruses, does include the US mainland.[11]
Adapted table courtesy of the CDC.
Prevention of mosquito bites
Mosquitoes may sometimes be impossible to avoid. However, personal efforts towards defense can be very effective.
Key protective measures include wearing light-colored clothing that covers as much exposed skin as possible,[12,13] applying DEET (N,N-diethyl-meta-toluamide)–containing insect repellents to vulnerable areas, sleeping under mosquito nets, and donning a net hood in areas where mosquitoes teem.
Travelers should be mindful of their immediate surroundings and remember that mosquitoes are present during the day and night. The ears will often detect a mosquito before it is close enough to bite.
Adapted table courtesy of the CDC.
Dengue is a febrile illness spread to people through the bite of an infected Aedes species mosquito, the same mosquito that transmits the Zika virus.[4,5,14,15] This condition is commonly found in Latin and Central America, as well as the Caribbean.[14]
Although most patients are asymptomatic, those with signs/symptoms commonly present with high fever, and/or headache, nausea, vomiting, rash, and muscle/joint pain.[14,15] Signs/symptoms typically develop within 2 weeks of exposure (incubation: 4-10 days) and last up to 7 days.[14,15]
In rare cases, severe dengue may be associated with dengue hemorrhagic fever—with bleeding from the gums and other mucosa, severe abdominal pain, persistent vomiting, and respiratory difficulty—or dengue shock syndrome, both of which may be fatal.[14,15]
There is currently no vaccine for prevention of dengue, and treatment is supportive.[14,15] Avoiding mosquito bites is essential.[14,15]
The map shows the distribution of dengue in the Americas and the Caribbean.
Image courtesy of the CDC.
Chikungunya virus (CHIKV) is an RNA alphavirus (family Togaviridae) that spreads in humans via the bite of infected female A aegypti/A albopictus mosquitoes.[16,17] The first described outbreak occurred in Southern Tanzania in 1952; since then, outbreaks have occurred in Africa, Asia, Europe, and nations in the Indian and Pacific Oceans (shown).[16,18] In 2013, chikungunya was found for the first time in the Americas in the Caribbean islands.[17,18]
Although the Zika virus has garnered more attention recently, chikungunya remains active in Brazil.[19] In general, the incubation period is 3-7 days, with fever and arthralgia the main signs/symptoms.[16,17] Headache, myalgia, rash, and/or nausea/vomiting may also occur.[16,17] Most signs/symptoms resolve quickly (7-10 days), but arthralgia may persist for months. Serious complications are uncommon.
Those at risk for more severe disease include perinatally infected newborns, older adults (≥65 y), and people with comorbidities (eg, diabetes, cardiovascular disease).[16]
Differentiating chikungunya from dengue can be a clinical challenge due to overlap of geographic and clinical features.[16,17] However, therapy remains supportive for both diseases.
The map shows countries and territories where chikungunya cases have been reported, as of April 22, 2016.
Image courtesy of the CDC.
The day-and-night activity of the mosquito vectors and the proximity of their breeding sites to human habitation are significant risk factors for CHIKV infection.
Key elements of prevention and infection control are eliminating/reducing the number of artificial water-filled containers and natural habitats that act as mosquito breeding grounds and avoiding Aedes mosquito bites (eg, wear permethrin-treated clothing that minimizes skin exposure; use insect repellents that contain DEET, picaridin, oil of lemon eucalyptus/p-menthane 3,8-diol [PMD], or ethyl butylacetylaminopropionate [IR3535]; use window/door screens and bed nets).[17,20]
There is no commercial vaccine or specific drug to treat CHIKV infection; prevention is the best countermeasure.[17,20] Supportive care includes rest, adequate hydration, and use of antipyretics/analgesics.[17]
The main image shows a rash on a foot of a Filipino patient infected with CHIKV; the inset image is that of CHIKV particles.
Image of foot courtesy of Wikimedia Commons/Nsaa; micrograph (inset) courtesy of the CDC/Cynthia Goldsmith.
Malaria is caused by the parasite Plasmodium via the bites of infected female Anopheles mosquitoes.[21,22] Sometimes, infection occurs via blood transfusions, organ transplantation, needle sharing, or congenital transmission.[21] Common signs/symptoms include high fever, chills, headache, vomiting, myalgia, and anemia; they usually appear within 14 days after the mosquito bite.[21,22] However, some patients may present as late as months after exposure.[21]
For participants in and visitors to the Rio Olympics, the risk of malaria (and yellow fever) vary depending on the location of the events. On the basis of the risk assessment, travelers should use specific malaria prevention measures (eg, protective clothing, insect repellents, insecticide-treated bed nets, antimalarial agents).[21,22] Awareness and preparation based on precaution and/or prophylaxis requirements may minimize the likelihood of transmission.[21,22] No licensed vaccine currently exists.[22]
Blood smears are the gold standard to confirm the diagnosis of malaria; other tests include antigen detection, polymerase chain reaction (PCR), and serology.[21]
The map shows malaria transmission areas in Brazil.
Image courtesy of the CDC.
Clinicians should be alert to potential malaria infection in (1) travelers to Brazil and/or other regions in the tropics—particularly malaria-endemic areas—(2) those who have received a blood transfusion, and/or (3) individuals who develop a fever and other flulike signs/symptoms.[21,22] Delayed or lack of treatment may be fatal.
The type of antimalarial agent used depends on the region, and the treatment depends on the disease severity. In many parts of the world, the parasites have developed resistance to a number of antimalarial agents.[21,22] Chloroquine has been the drug of choice, but owing to widespread resistance to this agent, other therapeutic medications should be considered.[21,22]
Medical care, including intravenous fluids and respiratory support, may be needed for some infected patients. In most cases, the outcome is expected to be good with treatment.[21,22] However, severe malaria (especially P falciparum disease) is a medical emergency that requires urgent intervention; malaria disrupts the blood supply to vital organs and can result in seizures, mental confusion, kidney failure, acute respiratory distress syndrome, coma, and death.[21]
CDC guidelines for treatment of malaria are available at: http://www.cdc.gov/malaria/diagnosis_treatment/treatment.html.
The image depicts the malaria parasite life cycle.
Image courtesy of the CDC.
Yellow fever, named for the jaundice that affects some patients, is a single-stranded RNA arbovirus (genus Flavivirus),[23,24] that is transmitted to humans via the bite of infected Aedes or Haemagogus mosquitoes, which are common in most of Central and South America, including Brazil.[23,24]
The vectors acquire the virus by feeding on infected primates (human/nonhuman) and then transmit it to other primates.[23] There are three transmission cycles (sylvatic [jungle], intermediate [savannah], urban), as well as three disease stages (infection, remission, intoxication).[23,24]
Most infected persons are asymptomatic, or they have only a mild illness (incubation, 3-6 days) and improve 3-4 days after the initial onset.[23,24] Early signs/symptoms include sudden fever/chills, severe headache, back pain, myalgia, nausea/vomiting, and fatigue/weakness. After a brief remission of hours to a day, about 15% of patients develop a more severe form of the disease that is characterized by high fever, jaundice, bleeding and, eventually, shock and multisystem organ failure; up to 50% of these patients die within 10-14 days.[23,24]
The map shows yellow fever vaccine recommendations in Brazil.
Image courtesy of the CDC.
Yellow fever is difficult to diagnose, especially during the early stages. This disease can be confused with severe malaria, dengue or other hemorrhagic fevers, leptospirosis, viral hepatitis, and other conditions, as well as poisoning.[24] Diagnostic tests include serology and viral isolation or nucleic acid amplification.[23,24]
There is no specific treatment for yellow fever, but supportive and life-saving therapy is used to manage dehydration, respiratory failure, and fever[23,24]; antibiotics should be used to treat bacterial infections.[24] Unfortunately, such measures are rarely available in poorer regions.
As discussed earlier for Zika, dengue, CHIKV, and malaria infection, mosquito avoidance precautions are critical for disease prevention.[23,24] In addition, a live-attenuated vaccine exists that is very effective against yellow fever and confers lifelong protection.[23,24] All individuals aged 9 months or older should take the vaccine at least 10-14 days before travel to endemic areas such as Brazil.
Adapted table courtesy of the CDC.
Hepatitis A is a highly contagious picornavirus that is commonly transmitted by the fecal-oral route, either through consumption of contaminated food or water, or by person-to-person contact.[25,26] This disease is common in developing nations with poor sanitary and hygienic conditions and practices[25,26]; Central and South America, including Brazil, are considered intermediately endemic areas.[25]
The typical incubation period is 4 weeks.[25,26] Signs/symptoms often occur abruptly and may include fever, nausea, vomiting, abdominal pain, jaundice, dark urine, clay-colored stool, joint pain, and fatigue.[25-27] These generally last less than 2 months, although 10%-15% of affected individuals may experience prolonged or relapsing symptoms over 6-9 months.[25,27] Treatment consists of supportive measures.[25,26]
Although hepatitis A is a self-limited disease without long-standing chronic infection, receiving appropriate prophylactic protection before travel to the Rio Olympics is recommended.[19] For healthy individuals, the Advisory Committee on Immunization Practices (ACIP) recommends one dose of single-antigen hepatitis A vaccine at any time before travel[28]—with simultaneous immune globulin administration at a separate injection site for older adults or those with chronic medical conditions.[25,27]
Image courtesy of Medscape. IgG = immunoglobulin G; IgM = immunoglobulin M.
Typhoid fever most often results from infection with the bacterium Salmonella enterica serotype typhi (ie, S typhi).[29] The disease is transmitted through contaminated food or water,[29,30] moving from the intestines into the bloodstream and then to other parts of the body, including the lymph nodes, gallbladder, liver, and spleen.[30]
Typhoid fever is common in developing countries, as in Asia, Africa, and Latin America.[29,30] Signs/symptoms typically occur 1-3 weeks after the bacterium has been ingested, characterized initially by sustained fever and abdominal pain.[30] As the disease progresses, the fever rises higher (102°-104°F [38°-40°C]) and severe diarrhea develops. Small, red spots (rose spots) (shown) appear on the chest and abdomen of some patients.[29,30]
Typhoid fever may include the following constellation of symptoms[29,30]:
Image courtesy of the CDC.
Treatment for typhoid fever includes antibiotics; in addition, fluid and electrolytes may be administered intravenously.[30] However, in patients who have symptoms of typhoid fever within 60 days of having returned from a region where the disease is endemic or who have consumed food prepared by a known S typhi carrier, broad-spectrum empiric antibiotics should be administered prior to confirming the diagnosis. More specific antibiotic treatment can be prescribed once the diagnosis has been made.[30]
The CDC recommends typhoid vaccination for travelers to Brazil.[19] Vaccines against typhoid fever include the oral vaccine Ty21a (which uses live, attenuated cells of S typhi strain Ty21a) and the injectable Vi capsular polysaccharide vaccine (ViCPS vaccine).[29] However, even when a vaccine is available and administered, it is essential to maintain appropriate food and water precautions because both vaccines are only 50%-80% effective.[29]
The images show diffuse terminal ileal ulceration and angiomal formation with oozing hemorrhage from the ulcers in a child with rare complications from typhoid fever. The patient had life-threatening bleeding from Dieulafoy lesions of the ileum.
Images courtesy of Ezzat RF, Hussein HA, Baban TS, Rashid AT, Abdullah KM. J Med Case Rep. 2010;4:171. [Open access.] PMID: 20525295 PMCID: PMC2887901.
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