Ahr. Stich et al., Foci of Schistosomiasis mekongi, Northern Cambodia: II. Distribution of infection and morbidity, TR MED I H, 4(10), 1999, pp. 674-685
In the province of Kracheh, in Northern Cambodia, a baseline epidemiologica
l survey on Schistosoma mekongi was conducted along the Mekong River betwee
n December 1994 and April 1995. The results of household surveys of highly
affected villages of the East and the West bank of the river and of school
surveys in 20 primary schools are presented. In household surveys 1396 peop
le were examined. An overall prevalence of infection of 49.3% was detected
by a single stool examination with the Kato-Katz technique. The overall int
ensity of infection was 118.2 eggs per gram of stool (epg). There was no di
fference between the population of the east and west shore of the Mekong fo
r prevalence (P = 0.3) or intensity (P = 0.9) of infection. Severe morbidit
y was very frequent. Hepatomegaly of the left lobe was detected in 48.7% of
the population. Splenomegaly was seen in 26.8% of the study participants.
Visible diverted circulation was found in 7.2% of the population, and ascit
es in 0.1%. Significantly more hepatomegaly (P = 0.001), splenomegaly (P =
0.001) and patients with diverted circulation (P = 0.001) were present on t
he west bank of the Mekong. The age group of 10-14 years was most affected.
The prevalence of infection in this group was 71.8% and 71.9% in the popul
ation of the West and East of the Mekong, respectively. The intensity of in
fection was 172.4 and 194.2 epg on the West and the East bank, respectively
. In the peak age group hepatomegaly reached a prevalence of 88.1% on the w
est and 82.8% on the east bank. In the 20 schools 2391 children aged 6-16 y
ears were examined. The overall prevalence of infection was 40.0%. ranging
from 7.7% to 72.9% per school. The overalls mean intensity of infection was
110.1 epg (range by school: 26.7-187.5 epg). Both prevalence (P = 0.001) a
nd intensity of infection (P = 0.001) were significantly higher in schools
on the east side of the Mekong. Hepatomegaly (55.2%), splenomegaly (23.6%),
diverted circulation (4.1%), ascites (0.5%), reported blood (26.7%) and mu
cus (24.3%) were very frequent. Hepatomegaly (P = 0.001), splenomegaly (P =
0.001), diverted circulation (P = 0.001) and blood in stool (P = 0.001) we
re significantly more frequent in schools of the east side of the Mekong. B
oys suffered more frequently from splenomegaly (P = 0.05), ascites (P = 0.0
5) and bloody stools (P = 0.004) than girls. No difference in sex was found
for the prevalence and intensity of infection and prevalence of hepatomega
ly On the school level prevalence and intensity of infection were highly as
sociated (r = 0.93, P = 0.0001). The intensity of infection was significant
ly associated only with the prevalence of hepatomegaly (r = 0.44, P = 0.05)
and blood in stool (r = 0.40, P = 0.02). This comprehensive epidemiologica
l study documents for the first time the public health importance of schist
osomiasis mekongi in the Province of Kracheh, Northern Cambodia and points
at key epidemiological features of this schistosome species, in particular
the high level of morbidity associated with infection.