A large outbreak of hepatitis E among a displaced population in Darfur, Sudan, 2004: the role of water treatment methods.
BACKGROUND
The conflict in Darfur, Sudan, was responsible for the displacement of 1.8 million civilians. We investigated a large outbreak of hepatitis E virus (HEV) infection in Mornay camp (78,800 inhabitants) in western Darfur.


METHODS
To describe the outbreak, we used clinical and demographic information from cases recorded at the camp between 26 July and 31 December 2004. We conducted a case-cohort study and a retrospective cohort study to identify risk factors for clinical and asymptomatic hepatitis E, respectively. We collected stool and serum samples from animals and performed a bacteriological analysis of water samples. Human samples were tested for immunoglobulin G and immunoglobulin M antibody to HEV (for serum samples) and for amplification of the HEV genome (for serum and stool samples).


RESULTS
In 6 months, 2621 hepatitis E cases were recorded (attack rate, 3.3%), with a case-fatality rate of 1.7% (45 deaths, 19 of which involved were pregnant women). Risk factors for clinical HEV infection included age of 15-45 years (odds ratio, 2.13; 95% confidence interval, 1.02-4.46) and drinking chlorinated surface water (odds ratio, 2.49; 95% confidence interval, 1.22-5.08). Both factors were also suggestive of increased risk for asymptomatic HEV infection, although this was not found to be statistically significant. HEV RNA was positively identified in serum samples obtained from 2 donkeys. No bacteria were identified from any sample of chlorinated water tested.


CONCLUSIONS
Current recommendations to ensure a safe water supply may have been insufficient to inactivate HEV and control this epidemic. This research highlights the need to evaluate current water treatment methods and to identify alternative solutions adapted to complex emergencies.
Guthmann
Jean-Paul
JP
Epicentre, Paris, France. jguthmann@epicentre.msf.org
Klovstad
Hilde
H
Boccia
Delia
D
Hamid
Nuha
N
Pinoges
Loretxu
L
Nizou
Jacques-Yves
JY
Tatay
Mercedes
M
Diaz
Francisco
F
Moren
Alain
A
Grais
Rebecca Freeman
RF
Ciglenecki
Iza
I
Nicand
Elisabeth
E
Guerin
Philippe Jean
PJ
D000293:Adolescent; D000328:Adult; D000375:Aging; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks; D005260:Female; D016751:Hepatitis E / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D012367:RNA, Viral; D012307:Risk Factors; D013397:Sudan / Q000453:epidemiology; D018508:Water Purification / Q000379:methods*
D012367:RNA, Viral