Zika Virus and the over-50 Traveler

If you think Zika virus should only be a concern of travelers of childbearing age, you’re mistaken. 

Mosquito bites can be itchy, annoying, and unsightly but the aftereffects are usually short-term and inconsequential. Although far less common, mosquitoes also spread serious diseases like malaria, dengue, chikungunya, West Nile fever, and Zika virus disease.

What is Zika?

Zika is a mosquito-borne virus. The symptoms of Zika virus infections typically include fever, rash, joint pain, general malaise or red eyes (conjunctivitis) that resolves in a few days or a week. Some people who are infected have no symptoms at all.

However, the effects of the virus on an unborn fetus of a pregnant woman can be devastating. These may include microcephaly and other severe fetal brain abnormalities such as eye defects, hearing loss and impaired growth.

Even though Zika virus was discovered and named in 1947 and first detected in humans in 1952, there are still many gaps in our knowledge about the disease.

There is no existing vaccine to prevent Zika and no specific antiviral treatment. Current treatment is limited to addressing its symptoms (e.g. with rest, fluids, acetaminophen.)

As the number of confirmed Zika cases has escalated around the world since 2007, physicians, scientists and the public are slowly beginning to learn more about the disease. We now know that although most often spread by infected mosquitoes, Zika can also be transmitted through sexual contact. Additionally, the Food and Drug Administration (FDA) recommended last month that all blood donations be routinely tested for the virus to prevent transmission through blood transfusions.

In terms of travel, the Centers for Disease Control (CDC) in Atlanta has issued a Level 2 Travel Notice urging precautions for travelers headed to destinations where mosquitoes are known to spread Zika.

Older folks: Should we worry?

New evidence suggests that older people who contract the Zika virus may be at increased risk for Guillain-Barré syndrome (GBS).

Symptoms of GBS include weakness of the arms and legs and in some severe cases, paralysis, which can even affect muscles that control breathing. Most people recover after weeks or months but others are left with permanent muscle damage.

Doctors believe GBS occurs when the body’s immune system attacks part of the peripheral nervous system. According to the CDC, the disorder is rare (1-2 cases for every 100,000 people in the U.S.) and its causes unclear. True clusters of cases are very unusual.

The association between Zika and Guillian-Barré Syndrome

Several countries that recently experienced Zika outbreaks have reported corresponding increases in Guillian-Barré syndrome (GBS). The CDC website notes:

“Current CDC research suggests that GBS is strongly associated with Zika; however, only a small proportion of people with recent Zika virus infection get GBS.”

NBC News reported on a letter in the New England Journal of Medicine noting that rates of GBS have risen dramatically with the spread of Zika, and that even asymptomatic Zika infections can lead to GBS.

NBC News science writer Maggie Fox wrote: 

“From April 1, 2015, to March 31, 2016, a total of 164,237 confirmed and suspected cases of Zika virus disease and 1,474 cases of the Guillain-Barré syndrome were reported in Bahia, Brazil; Colombia; the Dominican Republic; El Salvador; Honduras; Suriname; and Venezuela.”

“The reported incidence of the Guillain-Barré syndrome was 28 percent higher among males than among females and consistently increased with age, findings that are in line with previous reports.” 

While there are still gaps in what we know: 

• There appears to be an established link between Zika and GBS.

• Although the incidence of GBS is rare, its prevalence is rapidly increasing in countries with reported Zika epidemics.

• The incidence of GBS is greater in males than females, and increases with age.

The bottom line for over-50 travelers

In making travel decisions to Zika-prone areas, older individuals need to evaluate and weigh their own risks in consultation with their physician. Until more is known about the causes, treatment and prevention of Zika, it seems prudent for older travelers to:

• Review the growing list of countries included in the CDC travel notice on the Center’s Zika Travel Information
• Keep abreast of emerging Zika-related information and research in the media.
• Use an Environmental Protection Agency (EPA)-registered insect repellent when traveling to areas prone to mosquito infestations. (The CDC website provides brand-name examples.)
• Whenever possible, cover up with long sleeve shirts and pants and opt for stays in places with air-conditioning and window screens.

A review in the medical journal Lancet concludes:

“While clinical research and the funding debate continues, protection from the Zika virus will depend largely on avoiding the mosquitoes that carry it.”

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Useful Information & Resources

• CDC Zika Virus Update Page
• CDC Feature: Avoid Mosquito Bites
• CDC Mosquito Bite Prevention for Travelers
• American Medical Association (AMA) Zika Virus Resource Center

Recently on Reuters: For one Zika patient, lingering symptoms and few answers

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