In a survey examining the causes of travellers' diarrhoea
treated in Tokyo between July 1986
and December 1995, Aeromonas species were isolated from 1265
(5·5%) of 23215 travellers
returning from developing countries. Aeromonas species were the
fourth most frequent
enteropathogen isolated, following enterotoxigenic E. coli
(8·5%), Salmonella spp. (7·6%) and
Plesiomonas shigelloides (5·6%). Aeromonas
species were found in 1191 (5·6%) of 21257
patients with diarrhoea and in 74 (3·8%) of 1958 healthy
individuals without diarrhoea. Mixed
infection was observed in 512 (40·5%) cases. No significant
difference in the prevalence of
Aeromonas by year, season, age distributions, or sex was observed,
but a slight difference was
noted depending on the country where the travellers visited. Of the 1265
Aeromonas isolates,
893 strains (70·6%) were A. veronii biovar sobria, 330
(26·1%) were A. hydrophila, and 42
(3·3%) were A. caviae. The clinical symptoms of patients
from
whom Aeromonas species was
isolated as the only potential enteric pathogen were almost similar, which
were watery
diarrhoea (about 60%), abdominal cramps (43%), fever (around 15%), and
nausea or
vomiting (13%). Although the severity of illness was milder than that of
enterotoxigenic E. coli
alone, these data suggest that Aeromonas species are important
enteric pathogens in travellers' diarrhoea.