As travelers gear up to cross oceans and countries during the summer season, threats of illness – the highly publicized Zika virus, gastrointestinal or respiratory illnesses, even malaria – can turn anticipation into anxiety. At the latest installment of Frontiers in Medicine, a lecture series designed to connect members of the Washington, D.C. community with health care experts, however, would-be adventurers learned how to stay healthy.
“[Tonight’s topic, ‘Healthy Traveling: What You Need to Know to Prepare for This Vacation Season’] is timely because you can’t pick up a newspaper without reading about Zika,” said moderator Alan Wasserman, M.D., professor and chair of the Department of Medicine, and Eugene Meyer Professor of Medicine at the GW School of Medicine and Health Sciences (SMHS).
The culprit of the virus, explained speaker Aileen Chang, M.D., M.S.P.H., assistant professor of medicine at SMHS, is the Aedes aegypti mosquito, a day-biting, urban-dwelling insect. The latter aspect of the mosquito – its preference for urban areas – is particularly important, she said.
“The world is becoming more urbanized,” Chang explained. “In Brazil, for example, in the last 70 years, it’s gone from 20 percent of the population living in urban areas to 80 percent, so that may actually have been a factor in the Zika outbreak and why the Zika outbreak was so severe.”
High incidence of the illness in Brazil, she added, may have started as early as 2013 and 2014, but it wasn’t publicized; it was only when babies started being born with microcephaly, a condition that results in an abnormally small head and potential brain damage, that the virus started to gain traction in the media. Microcephaly has increased 20-fold in the South American country. In Colombia, Guillain-Barré Syndrome, a rare autoimmune disorder that affects the central nervous system, has also been linked to the virus, and it has increased three-fold.
So, what can travelers do to avoid infection?
“The most important thing you’d want to walk with from tonight are the travel recommendations,” she said. “They’re pretty simple.”
Chang recommends visiting the Centers for Disease Control and Prevention (CDC) website, which suggests pregnant women avoid Zika-endemic areas. For travelers – those pregnant and those not – who do have to go, they should wear 20 percent DEET insect repellant.
“It’s not always possible [to avoid being bitten], and it’s also not always possible to cancel trips, especially if they’re related to work,” Chang said. “So, there are things like permethrin-embedded clothing (chemical treatments you can spray on your clothing), [and wearing] long sleeves and long pants.”
At home, Chang cautions against having excessive plants or standing water around flower pots as the Aedes aegypti feeds on plant nectar; female mosquitos only feed on humans when they need blood for egg production.
Because the virus can also be transmitted sexually, the CDC recommends men use condoms when their partners are pregnant, or they should abstain. Additionally, Chang said, if a man has Zika virus, he should consider using condoms for six months, or if he has been exposed to the virus, use them for eight weeks.
If someone has been exposed – as travelers to Brazil for the 28th Summer Olympic Games are likely to be, according to Chang – the virus tends to be asymptomatic. When symptoms do appear, they’re non-specific (a rash, a fever, conjunctivitis, joint pain, or a headache), and they typically last for several days.
What’s critical, as well, is distinguishing between Zika and other Flaviviruses, like dengue and chikungunya, all of which are transmitted by the same mosquito and share clinical features. The best recourse, if it’s unclear which virus a patient has contracted, is to treat for dengue, as it tends to be the riskiest.
Malaria, on the other hand, said speaker David Parenti, M.D., professor of medicine at SMHS, is transmitted by a different mosquito entirely, Anopheles, a dusk-to-dawn biter. Like Zika, dengue, and chikungunya, though, travelers can use the same prevention practices: wearing insect repellant like DEET or picardin on top of sunscreen; treating clothing, tents, or other fabrics with permethrin; and using bed nets. Additionally, there are preventive medications like Malarone and Doxycycline available for malaria.
Travelers should also be wary of schistosomiasis, a widely disseminated disease resulting from an infection from parasites.
“Don’t swim in fresh water,” Parenti warned, adding that lakes, such as Lake Victoria in Uganda and Lake Malawi, pose some risks, though oceans are safe.
Aside from viruses, gastrointestinal and respiratory illnesses are common for travelers, particularly on cruise ships. Parenti encourages avoiding two items at the dinner table: “Lettuce and hot sauce.”
Lettuce, he said, is hard to clean and there’s no guarantee that the water used to clean it is safe, while hot sauce has been shown to carry a variety of bacteria. He also suggests drinking bottled water or using a water filter.
Overall, however, Parenti’s biggest piece of advice at the conclusion of the Frontiers in Medicine Lecture echoed Chang’s: “Use your insect repellant!”