Travel-associated Illness Trends and Clusters, 2000–2010

Longitudinal data examining travel-associated illness
patterns are lacking. To address this need and determine
trends and clusters in travel-related illness, we examined
data for 2000–2010, prospectively collected for 42,223 ill
travelers by 18 GeoSentinel sites. The most common destinations
from which ill travelers returned were sub-Saharan
Africa (26%), Southeast Asia (17%), south-central Asia
(15%), and South America (10%). The proportion who traveled
for tourism decreased significantly, and the proportion
who traveled to visit friends and relatives increased.
Among travelers returning from malaria-endemic regions,
the proportionate morbidity (PM) for malaria decreased;
in contrast, the PM trends for enteric fever and dengue
(excluding a 2002 peak) increased. Case clustering was
detected for malaria (Africa 2000, 2007), dengue (Thailand
2002, India 2003), and enteric fever (Nepal 2009).
This multisite longitudinal analysis highlights the utility of
sentinel surveillance of travelers for contributing information
on disease activity trends and an evidence base for travel
medicine recommendations.