Hundreds of pregnant women in Nepal are at risk of dying from hepatitis E, as the onset of the monsoon season could trigger an outbreak of the virus in the earthquake-hit country, experts warned. Tens of thousands of survivors of the South Asian country’s worst disaster on the record are at a “very high” risk of facing an outbreak of the liver disease, which spreads through water contaminated with feces, researchers said in the Lancet medical journal. Hepatitis E affects an estimated 20 million people around the world each year. For most people, the infection runs its course with a few long-term complications, but the mortality rate for pregnant women is about 25 percent. The experts said that an outbreak in Nepal could kill more than 500 pregnant women. “Hepatitis E is a neglected virus that isn’t well understood, but we are now seeing that it is likely a major cause of maternal deaths in countries where it is common,” Alain Labrique of Johns Hopkins University and co-author of the document said in a statement. The earthquakes that struck Nepal on April 25 and May 12 killed about 8,800 people and injured 22,000 others. Disaster-affected areas present a “perfect storm” of factors – such as large displaced populations with little access to water, sanitation, and life-saving medicines – that can lead to the spread of disease, the experts said. An effective vaccine for the virus is currently only licensed for use in China. The World Health Organization (WHO) said it needs more safety and efficacy data before recommending routine use of the vaccine, but added that it “should be considered” to mitigate or prevent outbreaks and to alleviate consequences in high-risk groups such as pregnant women. The experts said there have been a number of large hepatitis E outbreaks in Nepal, including one in 2014 that sickened more than 10,000 people. They urged Nepalese health authorities to conduct surveillance to identify cases of the disease and to request the vaccine and build a stockpile. According to the WHO, typical hepatitis symptoms include jaundice, dark urine, and pale stools, abdominal pain and tenderness, nausea and vomiting, fever, and an enlarged, tender liver. Nepal’s monsoon season runs from July to September.