Recruitment and Population Characteristics
The study analyzed data from short-term visitors to developing countries, with a high response rate to the questionnaire showing that the majority of travelers are aware and concerned about possible medical problems. The mean age of the travelers was 39.9 years, and the mean duration of stay was 2.8 weeks. Health problems were significantly more frequent in young adults, visitors to West Africa, people on adventure tours, and those who lived with natives or worked abroad.
Illness and Accidents in Travelers
Malaria was found to be one of the most frequent health problems among travelers from every region, with 11 of the 12 definite or possible cases originating in Africa. Hepatitis A and non-A, non-B hepatitis affected 291.6 per 100,000 visitors to developing countries in the 2.8-week stay. Chronic diarrhea was found in 73 (0.9%) travelers, with the highest rate (1.8%) noted upon return from West Africa and after journeys through various regions of the Far East. Accidents affected 38 (0.5%) travelers, with the most severe cases resulting from traffic accidents or assaults.
Malaria was imported from Africa at a rate of 97.6 per 100,000 travelers, with an attack rate of 108.0 per 100,000 in US travelers to Kenya. Increasing distribution of chloroquine-resistant parasites and growing concern about adverse reactions to prophylactic medication could lead to diminished protection and a further increase in malaria incidence.
The hepatitis incidence rate was significantly higher than in retrospective surveys, and it occurred exclusively in travelers who had not received prophylactic immunoglobulin. Prophylactic immunoglobulin might be suggested for each traveler to a developing country to prevent hepatitis A.
Typhoid Fever and Cholera
No cases of typhoid fever or cholera were reported in the study, indicating that typhoid vaccination should only be recommended for travelers “off the usual tourist itinerary” and those visiting certain high-risk countries. Cholera vaccination should be restricted to those visiting countries still requiring a certificate despite World Health Assembly recommendations.
Only 8.5% of all travelers suffered from “severe” diarrhea, focusing on chronic or incapacitating forms. Higher infection rates are possible due to asymptomatic courses and spontaneous eradication of certain parasitic and bacterial intestinal infections. Diarrhea occurring after return home tended to last longer and become chronic compared to cases occurring while abroad.
Serious accidents were rare, with only 1% of travelers requiring hospitalization. However, travelers should be reminded to wear shoes while swimming over coral reefs and disinfect any laceration. These measures would avoid a significant proportion of cases with subsequent inability to work.
Differences between Travelers to Developing Countries and Control Group
In the control group consisting of travelers to the Greek or Canary Islands, far fewer serious health problems were reported. No cases of severe infection were confirmed, and only dermatological problems and accidents occurred slightly more frequently in the control group.
This study provides a comprehensive and updated analysis of the health risks faced by short-term travelers to developing countries. The results highlight the importance of destination-specific and age-related differences in the risk of illness and accidents. High-risk travelers require more detailed medical recommendations, and prophylactic measures should be tailored accordingly.