PALO, Leyte — Nearly 900,000 people in Eastern Visayas are exposed to schistosomiasis, a chronic parasitic disease, the Department of Health (DOH) has warned.

The exposed population in the region’s 876 villages is being targeted as a priority group in this year’s mass treatment to be launched this January as the country observes “Schistosomiasis Awareness Month”.

The disease is also known as snail fever as people become infected when larval forms of the parasite – released by freshwater snails – penetrate the skin during contact with infested water.

Agnes Cuayzon, DOH regional schistosomiasis program manager, said these villages are hosts to 1,718 freshwater snail colonies.

“An area is considered endemic and people are susceptible if there is presence of indigenous cases and presence of infected snails,” Cuayzon said in a mobile phone interview on Friday.

In the national listings, four of the region’s six provinces – Leyte, Northern Samar, Samar, Eastern Samar – are categorized as high endemic areas.

Of the 878,777 exposed populations, 338,842 are in Leyte; 113,175 in Samar; 206,043 in Eastern Samar; and 220,717 in Northern Samar.

The health department has already sent anti-schistosomiasis drugs to rural health units in these areas for free treatment.

The health department has no available data on the number of persons infected with schistosomiasis but they claimed there has been deaths due to the disease every year.

“The focus is massive treatment of persons under the age bracket of 5 to 65 years old to protect them from the severe consequences of schistosomiasis. We have been reducing disease through periodic, large-scale population treatment with praziquantel,” Cuayzon added.

Although the drugs are free, there’s still resistance from susceptible persons for fear of side effects, according to the DOH.

The target is to cover at least 85 percent of the exposed population every year.

The most common symptoms of the disease are abdominal pain, diarrhea, bloody stool, and liver enlargement.

Transmission occurs when people suffering from schistosomiasis contaminate freshwater sources with their feces containing parasite eggs, which hatch in the water.

The first epidemic of schistosomiasis in the region occurred among Americans and allied forces after landing in Leyte during World War II in 1944. (PNA)