Peace Corps Volunteers, Tuberculosis and Causes for Fatalities
Abstract and Commentary
By Lin Chen, MD
Dr. Chen is Assistant Clinical Professor, Harvard Medical School Director, Travel Medicine Center, Mt. Auburn Hospital, Cambridge, MA.
Dr. Chen reports no financial relationships related to this field of study.
Synopsis: Peace Corps Volunteers can be exposed to tuberculosis depending on the country of service, and the highest rates of PPD conversion and acute TB occur in the Africa region. However, unintentional injury was the major cause of death among Peace Corps Volunteers from 1984 to 2003.
Source: Jung P, Banks RH. Tuberculosis risk in US Peace Corps Volunteers, 1996 to 2005. J Travel Med 2008;15(2):87-94. Nurthen NM, Jung P. Fatalities in the Peace Corps: a retrospective study, 1984 to 2003. J Travel Med 2008;15(2):95-101.
Jung and Banks reported PPD conversions and acute TB cases from the Peace Corps Epidemiological Surveillance System and post-service claims data between 1996 and 2005. PPD conversions to positive occurred at a rate of 1.283 per 1000 Volunteer-months, and acute TB cases occurred at 0.057 per 1000 Volunteer-months (1540 and 68.9 per 100,000 Volunteer-years, respectively). The authors analyzed PPD conversion and acute TB cases based on regions. The highest risk region for PPD conversion is Africa with a rate of 1.467 cases per 1000 Volunteer-months. The European region is second with a rate of 1.442. Asia is third with a rate of 1.364. Central America has a rate of 1.272. The rates for the Caribbean, South America, and the Pacific Islands are 0.994, 0.739, and 0.547 per 1000 Volunteer-months, respectively.
For active TB, the African region also has the highest rate at 0.089 cases per 1000 Volunteer-months. The Pacific Islands are second with a rate of 0.071, followed by Central America (0.065), Europe (0.039), the Caribbean (0.021), Asia (0.019), and South America (0.013).
The authors also compared their rates to the high-risk countries as identified by the World Health Organization. These are: Bangladesh, Botswana, China, Congo, Ethiopia, Haiti, Kenya, Lesotho, Malawi, Mozambique, Namibia, Philippines, Russia Far East, Russia Western, South Africa, Tanzania, Thailand, Uganda, Zambia, Zimbabwe. These high-risk countries have a PPD conversion and active TB at rates of 1.436 and 0.084 cases per 1000 Volunteer-months. For individual countries that host Peace Corps Volunteers (PCVs) and whose rates are available, Ethiopia has the highest PPD conversion rate at 3.384 and also the highest active TB rate at 0.677 per 1000 Volunteer-months.
Compared to the U.S. population that has a TB rate of 4.8 per 100,000 person-years, the Peace Corps Volunteers have a higher TB rate. However, the PPD conversion rate is lower than data from other studies on travelers, which reported 2.8 per 1000 person-months.
The second study on Peace Corps Volunteers reported on fatalities that occurred between 1984 and 2003. Sixty-six deaths occurred during this period, with a death rate of 54.3 deaths per 100,000 Volunteer-years. The major causes were injury (45), homicide (11), medical illness (9), and suicide (1). The death rate is lower than the previous Peace Corps report from 1961 and 1983, where death occurred at 110.4 per 100,000 Volunteer-years.
Unintentional injuries included motor vehicle accidents (22; 48.9%), most commonly in automobiles (11; 24.4%), but injuries also occurred in buses, trucks, taxis, and minibus taxis. Only 1 of the automobile deaths occurred during confirmed seat belt use, and 5 had a confirmed lack of seat belt use. There were 2 motorcycle deaths (3%), 6 drownings (13.3%), including 4 in volunteers who knew how to swim.
The homicides included 6 women and 5 men, and occurred in Africa (6), Eastern Europe (1), Asia (2), Latin America (2). Among the medical illnesses that led to death, heart disease was the major cause (5), cancer (2), cerebral malaria (1), and sepsis (1). Age group of 25 to 34 had the highest number of deaths (28), although death rates were highest in the 65- to 74-year-old group (185 deaths per 100,000 Volunteer-years).
Comparison with prior PCV data found significant decreases, with major declines in motorcycle accidents and medical illness. When compared with U.S. death rates, PCVs have lower death rates probably due to the overall younger age of PCVs. When deaths in only the 20- to 39-year-old age group were compared, there were fewer deaths in PCVs. When compared to U.S. resident overseas deaths (1799 between October 2002 and December 2004), PCVs have a higher proportion of deaths due to injury and lower proportions from homicide and suicide.
Commentary
The World Health Organization estimated that in 2006, tuberculosis caused 9.2 million new infections and 1.7 million deaths.1 About 30% of the world population carried Mycobacterium tuberculosis in 2000.2 A Dutch study from 1994-1996 that assessed tuberculosis exposure in travelers returning from highly endemic areas (annual incidence rate ≥ 1%) after 3-12 months of travel found that 0.15% (12/656) of the returning travelers had a PPD skin test with induration ≥ 10 mm.3 The overall incidence rate was estimated to be 3.5 per 1000 person-months of travel. Health care workers were more likely to have TB exposure, with a PPD conversion rate of 7.9 per 1000 person-months of travel compared to 2.8 per 1000 person-months among the others.
These two reports summarize important health issues in PCVs, one particular group of long-term travelers. They are more likely to have exposure to TB when serving overseas when compared to the U.S. population,4 but their TB risk appears to be lower than Dutch travelers who traveled for 3-12 months.3 Cobelens had concluded previously that the risk of TB associated with travel was similar to that occurring in the local population.3 The table summarizes the estimated rates of PPD conversion and acute TB in this study, for the U.S. population, and for Dutch travelers.
Some PCVs die during their service, but their death rates are lower than the U.S. population, even when matched by age. The major cause of death is unintentional injury, especially automobile accidents. However, accidents associated with public transportation, motorcycles, and trucks, as well as drowning have also contributed a significant numbers of deaths. The death rate has declined from earlier periods of Peace Corps programs, possibly due to regulations on motorcycle use and improved health screening and maintenance for the volunteers.
Peace Corps Volunteers gain meaningful experience through their service. A longitudinal study that interviewed volunteers during their service in the Philippines and 20 years later indicated that the program was a life-changing experience for many.5 The volunteers face physical and emotional challenges in developing countries. Although infectious diseases constituted the most common health problems that PCVs develop,6,7 the main causes of fatality have been unintentional injury, medical illness, homicide, and suicide in the volunteers as reported in 1985.8 The recent analysis by Nurthen and Jung suggest that policy change and health screening instituted by Peace Corps after the earlier report may have reduced some deaths. Similar to other studies on deaths overseas, unintentional injury remains a major cause of death in U.S. travelers.9,10 While not statistically significant, the number of homicides has increased. Therefore, safety during travel continues to be a concern and travelers would benefit from reminders about personal safety during their sojourns. Data from these two studies illustrate exposure to tuberculosis in travelers as well as to underscore the importance of injury prevention in travelers, in particular among long-term travelers.
References
- WHO. Global tuberculosis control: surveillance, planning, finance: WHO report 2008. Geneva, World Health Organization. Available at http://www.who.int. Accessed May 7, 2008.
- Corbett EL, Watt CJ, et al. The Growing Burden of Tuberculosis. Arch Intern Med 2003;163:1009-1021.
- Cobelens FG, Deutekom H, et al. Risk of Infection with Mycobacterium tuberculosis in travelers to areas of high tuberculosis endemicity. Lancet 2000;356:461-465.
- CDC. Trends in tuberculosis—United States, 2007. MMWR 2008;57(11):281-285.
- Starr JM. Peace Corps service as a turning point. Int J Aging Hum Dev. 1994;39(2):137-61.
- Bernard K, Graitcer PL, van der Vlugt T, et al. Epidemiological surveillance in Peace Corps Volunteers: a model for monitoring health in temporary residents of developing countries. Int J Epidemiol 1989;18(1):220-226.
- Leutscher PDC, Bagley SW. Health-related challenges in United States Peace Corps Volunteers serving for two years in Madagascar. J Travel Med 2003;10(5):263-267.
- Hargarten SW, Baker SP. Fatalities in the Peace Corps. A retrospective study: 1962 through 1983. JAMA 1985;254:1326-1329.
- McInnes RJ, Williamson LM, Morrison A. Unintentional injury during foreign travel: a review. J Travel Med 2002;9:297-307.
- Hargarten SW, Baker TD, Guptill K. Overseas fatalities of United States citizen travelers: an analysis of deaths related to international travel. Ann Emerg Med 1991;20:622-626.
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