The Prevalence of Norovirus in returning international travelers with diarrhea

Background: There is a high incidence of diarrhea in traveling
populations. Norovirus (NV) infection is a common cause of diarrhea
and is associated with 7% of all diarrhea related deaths in the US.
However, data on the overall prevalence of NV infection in
traveling populations is limited. Furthermore, the prevalence of NV
amongst travelers returning to Europe has not been reported. This
study determined the prevalence of NV among international travelers
returning to Germany from over 50 destinations in and outside
Europe. Methods: Stool samples of a total of 104 patients with a
recent (< 14days) history of international travel (55 male, mean
age 37 yrs.) were tested for the presence of NV genogroup (GG) I
and II infection using a sensitive and well established
quantitative RT PCR method. 57 patients experienced diarrhea at the
time of presentation at the Department of Infectious Diseases &
Tropical Medicine. The remaining 47 patients had no experience of
diarrhea or other gastrointestinal symptoms for at least 14 days
prior to their date of presentation at our institute. Results: In
our cohort, NV infection was detected in 15.7% of returning
travelers with diarrhea. The closer to the date of return symptoms
appeared, the higher the incidence of NV, ranging as high as 21.2%
within the first four days after return. Conclusions: In our
cohort, NV infection was shown to be frequent among returning
travelers especially in those with diarrhea, with over 1/5 of
diarrhea patients tested positive for NV within the first four days
after their return to Germany. Due to this prevalence, routine
testing for NV infection and hygienic precautions may be warranted
in this group. This is especially applicable to patients at an
increased risk of spreading the disease, such as healthcare
workers, teachers or food-handlers.