Travel medicine knowledge essential in age of globalization
LAS VEGAS – Thanks to globalization, 20 million North Americans travel to developing countries every year. Worldwide, that number is 50 million. Nancy Ivansek, PA-C, a clinician in the infectious disease department at the Cleveland Clinic Foundation, lives vicariously through her globetrotting patients. Of course, travel is not always glamorous.
Approximately 50% of those travelling to developing countries will develop some sort of illness, Ivansek told audiences at the American Academy of Physician Assistants 39th Annual PA Meeting. This is because only a very small portion of people will seek medical care before traveling. The majority of people who do, however, go to their primary-care providers.
“A little bit of knowledge goes a long way,” Ivansek said. “People who see a clinician who is familiar with travel medicine can reduce their risk of becoming ill by sevenfold.”
The pre-travel visit is really a specialty visit that incorporates wellness promotion, general safety for the traveler, as well as disease prevention, she explained. “The travel shots are just the tip of the iceberg; or as they say in Africa, the eyes of the hippopotamus.”
Travel health experts have to be knowledgeable about a wide variety of health topics including food and safety information, traveler's diarrhea information, vaccines, malaria and mosquito-borne illness information and useful tips for the traveler. Ivansek discussed some of the most common travel illnesses at the meeting.
Hepatitis A is by far the number-one vaccine that travelers receive. The incubation period for hepatitis A infection ranges anywhere from 15 to 50 days, and the disease has a very abrupt clinical course that includes fever, malaise, nausea, abdominal pain, dark urine and jaundice.
Hepatitis A is endemic in Africa, Central and South America, the Middle East, Asia and Western Pacific regions. By the age of 12 years, about 70% of people native to these areas have had the disease. Transmission is primarily through contaminated food and water, but it can be transmitted from person to person. The young and the old are more vulnerable.
“The hepatitis A vaccine is a great vaccine,” Ivansek said. Given in a series of two shots, the second shot is administered six to 12 months after the first and grants lifelong immunity, eliminating the need for more follow up vaccines later in life.
Hepatitis B is transmitted through contact with blood and bodily fluids and kills 250,000 people worldwide every year. “It is a ferocious virus,” Ivansek said.
The hepatitis vaccine first became available in 1981 as a pooled-virus vaccine. In 1986, a recombinant vaccine was introduced and found to be incredibly effective. The first of three shots are given initially, followed by the second at one month, and the third at six months. No boosters are recommended.
“You have to ask about close contact with the local populace,” Ivansek said. “If somebody starts asking about HIV post-exposure prophylaxis, you better start questioning their hepatitis A and B series.”
Hepatitis C and E
There is no vaccine for hepatitis C or E. Hepatitis C is a blood-borne disease and hepatitis E is food-borne. “When it looks like hep A, and it smells like hep A, but it doesn't test out as hep A, think about hep E and test for it,”Ivansek advised.
Typhoid comes from food and water contaminated with Salmonella typhi. Morality can be as high as 30%, and most cases occur from those traveling to India and South America. The incubation period for typhoid can vary from one week to 30 days.
Typhoid has a rather insidious onset that goes from high fever, malaise, headache and macular rash to a very sick individual. Complications include intestinal hemorrhage and intestinal perforation.
Typhoid is very hard to culture, but if you are suspicious for it, it can be treated. Ciprofloxacin is generally used, but resistance is increasing, so ceftriaxone (Rocephin, Hoffmann-LaRoche) is the treatment of choice.
There is a vaccine for typhoid, but immunization rates are at 80% at best. There are two vaccines available. One is an oral, live-attenuated vaccine given once every other day for one week (four pills in total) and confers immunity for five years. The second type, an intramuscular vaccine, is given once and immunity lasts for two years.
Yellow fever is a viral illness transmitted to humans by mosquitoes. There is a wide range of symptoms, and the disease can be fatal. Yellow fever occurs in sub-Saharan Africa and tropical South America.
The yellow fever vaccine must be administered with caution to immunocompromised individuals (e.g. those with HIV, rheumatoid arthritis or undergoing chemotherapy). Complications to the vaccine include viscerotropic illnesses and neurologic diseases, which can be severe.
Carried by Anopheles mosquitoes, malaria kills 2 million people worldwide annually. Every 30 seconds, a child dies from this disease. There is no vaccine to date for malaria. Prevention includes insect repellents and clothing. Advise patients against wearing darker colored clothing in endemic areas, as this attracts mosquitoes, whereas lighter colors do not.
Also become familiar with antimicrobial resistance patterns in different parts of the world. “Know where antimalarials work,” Ivansek said. “Don't send your patient to India with chloroquine. There's resistance.”
She said that atovaquone is a great antimalarial that works very well with few side effects.
Repellent with 30% to 50% DEET is by far the best insect repellent, according to Ivansek. Anything more is overkill and may be associated with some level of toxicity.
Ivansek N. “Preventive health measures and travel vaccine update for the primary care provider.” Presented at: American Academy of Physician Assistants' 39th Annual PA Meeting. 2011; Las Vegas, Nevada.