"Digging a latrine for every 20 people and providing 20lts of water a day per person saves more lives than any of our fancy medical programmes. It's up there with measles vaccinations in terms of a priority but just has not been done", complained Greg Elder who heads MSF's aid work in the region.

Earlier this week, there were reports of an outbreak of hepatitis E at three of the camps for displaced people in Darfur Sudan. This outbreak, which has been active for some weeks now, further complicates the Darfur emergency and is a direct result of a constant and widespread inadequate level of both water and sanitation.

The disease is particularly dangerous to pregnant women - the mortality rate is one in five.

WHO has released statistics showing more than 1,000 cases and 27 dead. In Mornay, the MSF teams dealt with 443 cases in seven weeks, and 11 people have died - including 8 pregnant women.

Cases were also declared in Kerenik and Habilah. Hepatitis E is spread fecally-orally, with water or food contaminated by faeces. The symptoms characteristic of hepatitis E are similar with those of hepatitis A: abdominal jaundice, anorexia, pains, nauseas, vomiting or fever.

Three questions with Doctor Mercedes Tatay of MSF.

In what way was this epidemic unexpected? There have been warnings about possible malaria outbreaks as well as risks of an epidemic of bloody diarrhoea or cholera. Was an epidemic of hepatitis E expected?

No, and one could not expect it. It is a rather rare disease, and it is the first time that we have been faced with this during our interventions. Nevertheless, when we noted cases of jaundice and anorexia among pregnant women, we immediately thought of hepatitis E, even if we would have to wait for more than a month before biological examinations could confirm our diagnoses. If the total mortality figures related to hepatitis E is not very high - compared to an epidemic of measles or cholera - pregnant women are particularly vulnerable, since hepatitis E in this group has an extremely high mortality of 20%. In the future, we will have to work to prevent thus make in kind prevent the appearance of this disease.

Does one know how the epidemic started?

There are several assumptions: perhaps the disease is endemic to the area and the shortage out of water and the very poor sanitary arrangements in the camps launched the epidemic. As for the Mornay camp, it seems that the epidemic started after a 48 hours rupture in the supply of drinking water in one of the camp sectors. The displaced people would then have had no other choice than to get water from the wadi (the river). However, because there are not enough latrines in the camp, a segment of people do their toilet "in nature" and the water in the wadi is then contaminated.

How does one treat hepatitis E and what should be done to end the epidemic? Is there exist a vaccine?

There is no cure to hepatitis E; one can only relieve the symptoms. For example, rehydrating the patients who are suffering from vomiting. But it is not a chronic disease. At the end of an infection, if the patient survives, the disease is re-absorbed, the virus disappears and the liver recovers to function normally.

As for prevention, no vaccine is available now. There is a vaccine that is currently in the test phase, but it is not on the market yet. When this vaccine is available, we will be able to plan in the context of massive groups of the population to vaccinate the pregnant women, like what is done now against measles for children.

In the absence of a vaccine, above all it is advisable to improve both the quantity and quality of the supply water. That means chlorinating drinking water systematically, either in the tanks or in the buckets and jerry cans that the displaced use when they are supplied unchlorinated water via pumps. In addition, it is necessary to install more latrines and to improve the drainage of used water. Finally, to break the chain of contamination, we distribute soap at the same time of blanket feedings (distribution of family feed rations to the children below a certain size).