Information and Inspiration, London 2005

By Philip R. Fischer MD, DTM&H

Dr. Fischer is Professor of Pediatrics, Division of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN

Dr. Fischer reports no consultant, stockholder, speaker’s bureau, research, or other financial relationship with any company having ties to this field of study.

Gray skies, warm collegiality, professional education, and personal inspiration—it was all available in London. On November 10-11, 2005, 150 travel medicine practitioners from 30 countries gathered at the Royal College of Surgeons for a travel medicine conference sponsored by the Journal of Travel Medicine and Infectious Disease. Detailed proceedings will be published by the Journal in an upcoming issue, and should include key reviews of information resources, vaccination, tick-borne diseases in travel medicine, pediatric travel, emerging infections, and urban risks of travel. In the meantime, however, discussion of several other important points is already of interest to Travel Medicine Advisor readers.

Update on Regulations

Since 1969, the World Health Organization’s International Health Regulations has governed vaccine requirements for foreign travelers. The goal of this legal document is to limit the spread of disease. (Evidence-based recommendations to guide clinical care are found in another WHO publication, International Travel and Health.) Now, a new edition of the Regulations has been approved.

What changes can be anticipated as the new document and its regulations are implemented in 2007? There will still be yellow fever vaccine centers, but there will be fewer restrictions on who can provide the vaccine and accompanying certificate. The certificate will also be reformatted to allow entry of more customized vaccine information, and health workers other than physicians will be permitted to officially sign the document. However, unvaccinated individuals, even if vaccine was contraindicated, can potentially be quarantined for 6 days upon arrival from a yellow fever endemic area.

Immunizations

Hajj: Two million Muslims from 140 countries converge on Mecca each year in fulfillment of one of the pillars of Islam. Scheduled by the lunar calendar, Hajj trips are currently winter-time expeditions. There has been considerable recent press about the need for quadrivalent meningococcal vaccine and polio vaccine coverage for travelers going on the Hajj. A British health group working both in the UK and Saudi Arabia identified a high rate of respiratory infections among several hundred British pilgrims during the 2005 Hajj. Studies in clinics and tent camps, though somewhat biased toward those who were symptomatic, identified influenza in 14% of individuals (influenza A in 10% and influenza B in 4%). In addition, 3% had RSV. Influenza vaccine should be strongly considered for travelers of any age going on the Hajj.

Rotavirus: Children with diarrhea in Botswana were tested for various viral pathogens from 1999 to 2002. Of 595 individuals, 13% had rotavirus (89% of these were less than 2 years of age) and 3% had astrovirus. New rotavirus vaccines are looming on the horizon, and clinical indications have not been fully determined. If vaccination is not universal for children in North America, one wonders if foreign travel might become an indication for vaccination of traveling children.

Hepatitis A: In the Netherlands, outbreaks of hepatitis A are typically seen following the summer holiday when children of Dutch immigrant families return from family visits to the countries of their ancestral origin (often Morocco and Turkey). During the past 8 years, pre-holiday vaccination campaigns have resulted in a 50% drop in the overall incidence of reported cases of hepatitis A in Amsterdam. (Concurrently, at least one American advisory group has suggested that hepatitis A vaccination be provided to all American 1-year-olds.)

Traveler’s Diarrhea

Population-Based Data: For years, we have heard that traveler’s diarrhea is common (30-40%) among travelers to developing countries. How important is this to local populations? Reviewing 30 general practices involving 215,000 residents of Wales over 3 years, a population-based study showed that traveler’s diarrhea prompted medical consultation in 15 people per 100,000 population each year.

Resistant Campylobacter: Does the presence of blood in stool affect diagnostic thinking? Should it? In a Spanish travel disease facility, 6% of patients presenting with diarrhea over 19 months had bloody stools. Campylobacter was the most frequently identified pathogen overall and, was similarly, frequently seen whether the diarrhea was bloody or not. However, ciprofloxacin resistance was more frequently noted when the Campylobacter came from a patient without bloody stools (97% vs only 40% of those with bloody stools).

Malaria

Got Prophylaxis? Malaria is still commonly seen among travelers returning to Portugal. Of 109 cases in one hospital, most had not taken prophylactic medications, and had falciparum malaria following travel to Africa. Fortunately, no deaths were noted in this series.

Common Things are Still Common: Post-mortem samples from 5 patients were sent to the CDC for analysis of presumed bacterial infection or viral hemorrhagic fever. Using novel technology and samples of heart, lung, and brain tissue, a post-mortem diagnosis of malaria was made in 4 of the 5 patients. Even when initial evaluation for malaria is negative, critically ill febrile patients returned from malarial areas should still be suspected of having malaria.

No Resistance: Genetic testing of cytochrome B mutations in P. falciparum from the Thai-Myanmar border area was negative in 27 patients. Despite the increased use of atovaquone-proguanil in this area, atovaquone resistance does not seem to have emerged yet.

Poor Compliance > Resistance: In France, analysis of 10 cases of apparent atovaquone-proguanil-resistant malaria turned out to reveal true resistance in just 2—others had failed to respond to treatment due to poor compliance, vomiting, or poor absorption. When resistance was identified, it emerged with drug pressure—thus later recurrence of symptoms should prompt consideration of emerging mutations with resistance.

Eat Fat? A case of presumed resistance to artemether-lumefantrine in Belfast turned out to be due to inadequate absorption. It was postulated that taking this combination treatment with fatty foods would improve absorption and outcomes.

Conversation Starters

Warthogs: A study of Tanzanian animals showed that 10% of warthogs were infected with sleeping sickness, whereas only 1% of cows were infected. Watch out for sharing tsetse flies with warthogs!

Compliance: A case of Japanese encephalitis in an American student following travel in Thailand prompted a review of compliance with pre-travel advice in the case individual’s 22 co-travelers. Only half had been advised by a health care provider to avoid insect bites prior to the trip. Nonetheless, 75% used repellents at least some of the time. Rare cases might serve to fortify our pre-travel advice and, potentially, travelers’ compliance with advice.

Inspiration?

A keynote speaker reminded conference participants that 19th century literary figure WB Yates said that "Education is not the filling of a pail, but the lighting of a fire." Participants at the London travel medicine conference did indeed get their information pails filled. At the same time, however, they networked and interacted in ways that could light their fires for the ongoing practice of travel medicine at their home sites.