of Water Treatment Methods

(See the article by Boccia et al. on pages 1679–84) 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 im-munoglobulin 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 i