Your Best Shot Against Disease Risk

Travelers heading to remote locales probably know to ask their doctors about preventive measures for such well-publicized health threats as yellow fever, hepatitis and malaria. Yet many are puzzled when a physician asks about the status of their polio or diphtheria immunizations. Such unexpected diseases pose real dangers, however, making protection crucial for certain destinations.

There are also other disease risks that, while remote, can come as a surprise to travelers, including threats posed by meningitis, Japanese encephalitis and heart disease caused by the bite of an ugly beetle known as the kissing bug.

Only a few cases of polio now occur each year in the United States, according to the federal Centers for Disease Control and Prevention in Atlanta. But more than 14,000 polio cases are reported worldwide. Polio struck members of a religious community in the Netherlands in late 1992 and early 1993, for example. The virus was then isolated in some members who traveled back from the Netherlands to Alberta, Canada. Polio is also cited by CDC as a hazard for travelers to North Africa, Middle South Asia and other locales.

The polio virus lives in the throat and intestinal tract of an infected person and some notice no symptoms but still can spread the virus. Others have mild cases, feeling pain and stiffness in the neck, back and legs, along with fever, sore throat, nausea, stomachache and headache. In its most severe form, polio results in paralysis. CDC currently recommends polio vaccinations for healthy children at age 2 months, 4 months, 15 months and before school entry.

As a result of such childhood vaccinations, many adult travelers require only a single booster shot, said Dr. Edward Hanzelik, a Westlake Village internist who specializes in travel medicine. Such boosters are available in two forms: an oral vaccine containing a weakened form of the live virus and an injected vaccine containing an inactivated or killed virus.

Physicians differ in their preferences, with some recommending the live vaccine and others the inactivated. The oral vaccine (recommended by the CDC for healthy children) seems to provide stronger immunity in the intestinal tract, where infection first strikes, according to the CDC. And it is simpler to give. There is, however, a minute risk of paralysis with the oral polio vaccine--a risk estimated by the CDC at 1 in 1.5 million for the first dose and 1 in 40 million for later doses. The oral vaccine is not generally recommended for people who are HIV-positive, those whose immune systems are altered due to disease or treatments and members of their households.

Keeping current on diphtheria vaccinations is also wise for travelers to certain locales. Since 1990, there has been an ongoing outbreak of diphtheria in parts of Russia. As of August, 1993, according to the CDC, nearly 13,000 cases have been reported. An acute bacterial illness, diphtheria causes sore throat and fever and can lead to heart and nerve problems. The CDC recommends healthy children be immunized against diphtheria at age 2 months, 4 months, 6 months, 12 months, 15 months, before school entry and between the ages of 14 and 16. Following that, a tetanus and diphtheria booster is recommended every decade for adults in the United States, so some travelers will already be protected.

There are more remote risks.

Meningococcal meningitis, a serious infection of the membranes lining the brain and spinal cord, is caused by bacteria spread by coughing or sneezing, Hanzelik said. It’s found in sub-Saharan Africa and recent outbreaks have been reported in Kenya, Tanzania and Brazil. A vaccine provides protection for about three years, Hanzelik said.

* Chagas’ Disease occurs throughout much of the Western Hemisphere from Mexico to Argentina and is transmitted by a beetle dubbed the kissing bug, which often infests buildings of adobe, mud or palm thatch.

First symptoms--after contact with the parasite contained within the beetle’s feces--might include swelling of the eyelid, Hanzelik said. Then a traveler might feel weak, be feverish or have swollen lymph glands. The Chagas parasite (trypanosomiasis cruzi) can cause inflammation of the heart muscle and lead to serious complications such as heart problems, many years later. Immediate medical treatment is advised to eliminate the parasite, Hanzelik said.

* Japanese encephalitis, a mosquito-borne disease that strikes most often in summer and autumn, occurs in the temperate regions and northern tropical zones of several countries, including China, India, Japan, Vietnam and eastern Russia. Most infections have no symptoms, but among patients who experience symptoms such as fever, headache, malaise, nausea, vomiting, the fatality rate can be as high as 30%.

Vaccination with the Japanese encephalitis vaccine should be considered, according to CDC guidelines, for those who plan to live in areas where the disease is prevalent or for travelers who will spend time in rural farming areas.

Information on disease risk in specific locations is available from the CDC International Travelers’ Hotline, (404) 332-4559.

The Healthy Traveler appears the second and fourth week of every month.