Vol 27 No 2 December - The Indian Society for Parasitology

JPD : Vol. 27 (2), 2003
Parasitic infections in travelers
77
of morbidity and mortality among visiting and documented that of 1000 travelers to developing
returning travelers around the wortd. History is countries, 15% traveled for business, 12% for teaching
witness to the numerous outbreaks of parasitic or study and 3% for missionary activity. The most
diseases like malaria and sleeping sickness among popular countries visited were Kenya (27%), India
laborers and soldiers. Ancient caravanners recognized (19%), Nepal (13%), Thailand (10%), Hong Kong,
the signs of sleeping sickness that had often been Tanzania or Peru (9%) and the people's republic of
observed in travels to southern kingdoms of Africa. In China (7%). The median duration of travel was 21 days
the summer of 1828 "swamp fever" (or malaria) broke while 5% had longer than 1-year travel period (Hill,
out along the construction route of the Rideau Canal in 1988).
Canada. The "malaria", according to most experts was
In a study of 171 cases at the tropical disease unit in
not native to North America but had been introduced
Spain it was found that the commonest diagnoses were
by infected British soldiers who had returned from
malaria (34 cases), amoebiasis (8 cases), giardiasis (6
India. During the American Civil War (1861-65), one
cases), and cutaneous larva migrans (5 cases). The
half of the white troops and 80% of the black soldiers
origin areas were Africa (84 cases), Central America
of the Union Army got malaria annually. Therefore, it
(49 cases), South America (23 cases) and Asia (15
is clear from the lessons of history that the hazards of
cases). Among the patients, 72 were tourists and 49
traveling have taken its toll from early times. Newer
were immigrants (Zubero Sulibarria et al, 2000).The
innovations in mass transport system, changes in
steady growth of intercontinental travel has caused an
humanity's way of life have altered the dynamics of
increasing incidence of tropical diseases in many parts
man's interaction with the environment leading to an
of Europe, including continental Europe. Malaria and
enhanced exposure of various diseases, including
amebiasis deserve special attention, due to their
parasitic diseases (Desowitz, 1996).
frequency and potential fatality (Hassig, 1999).
Travelers visiting tropical countries: facts and
Travelers' diarrhea is the most frequent health problem
figures
encountered by travelers in the tropics (Nettleman,
In recent years, international travel has increased 1996). Twenty to 50% of the 35 million people who
enormously. With greater movement of people, there travel from industrialized countries each year are
has been an increased encounter with a wide variety of affected by traveler's diarrhea (Lima, 2001). Travelers
parasitic diseases. The jet age travel, globalization of experience a high rate of diarrhea caused by a wide
food and agricultural market, and the incubation variety of enteric pathogens acquired by ingestton of
period being longer than the travel period, the diseases contaminated food or water. A single or a combination
may not be identified as travel-related ones. There is a of palhogen(s) can be found in the stool of a majority
greater need of information for travel related medical of ill individuals. Important risk factors regarding
care to meet the challenges of travel-associated tropical diarrhea in travelers include the point of origin
sickness. Worldwide statistics on travelers indicate and destination of the traveler, host factors, and
that 1.4 million people cross international borders exposure to contaminated food and water. The most
everyday (Freedman, 1999). Each year 12 million-35 common parasitic causes of traveler's diarrhea in
million persons travel from an industrialized country adults in developing countries include infection with
to a developing country in the tropics or subtropics Entamoeba histolytica, Giardia lamblia,
(Black, 1990; Lima, 2001). In a study of almost 8000 Cryptosporidium parvum and Cyclospora
travelers to developing countries, Steffen and cayetanensis (Black, 1990; Lima, 2001). Although
colleagues have reported that 15% of them had health intestinal protozoa account for a minority of cases of
problems, 8% consulted a doctor and 3% were unable acute traveler's diarrhea, but they are the common
to work for an average of 15 days. (Steffen, 1987) They pathogens in travelers who experience protracted
also reported that the problems were more common in diarrhea during or after travel (Okhuysen' 2001). It
younger individuals, those who had significant was observed that diarrhea is not only the most
contact with people especially in rural areas and those common health hazard during travel in the tropics but
who had a prolonged stay. In another study, it has been also the most frequent condition which prompts