Survivors of the recent earthquake in Nepal are now facing a “very high” risk of a hepatitis E virus (HEV) outbreak in the upcoming monsoon season, which could be especially dangerous to pregnant women. So warns a consensus statement published by top international infectious disease experts in the Lancet, reports.

The document, signed by a panel of seven researchers, states that the devastation of the April quake that killed 8,800 people and injured more than 23,000 has created ideal conditions for hep E to spread. There are large populations of displaced people with limited access to clean drinking water or proper sanitary facilities. The health care infrastructure in the country is overburdened with injured and sick survivors.

Hep E is a viral liver disease that is primarily spread via feces and contaminated water sources. It affects an estimated 20 million people worldwide every year. HEV is rarely deadly and usually runs its course with few long-term complications. However, pregnant women are an exception—the virus kills up to 25 percent of pregnant women who contract it.

Researchers estimate that up to 500 pregnant women could die in Nepal over the next few months if precautionary steps are not taken, with many more sickened. An effective HEV vaccine is available, but it is only licensed in China. The Lancet statement recommends that the Nepalese Ministry of Health initiate a request for the vaccine and build up a stockpile for monsoon season, which runs from July through September.