ENDEMIC. People living near freshwater, like this river in Burauen, Leyte with water discharge from nearby rice fields, are vulnerable to schistosomiasis, a chronic parasitic disease. A Department of Health-Eastern Visayas report Monday (Nov. 21, 2022) said some 973,400 exposed in the region will be prioritized in the annual mass vaccination in January next year. (PNA photo by Sarwell Meniano)

TACLOBAN CITY – As the country tries to purchase drugs to combat schistosomiasis, nearly 1 million people in Eastern Visayas remained exposed this year to the chronic parasitic disease, the Department of Health (DOH) reported.

The projected 973,406 exposed in the regions are included in the priority group during the annual mass treatment in January when the country observes “Schistosomiasis Awareness Month”.

Agnes Cuayzon, DOH regional schistosomiasis program manager, said that since August this year, thousands of residents in endemic areas have been looking for praziquantel, a drug used to treat infections caused by certain parasites.

“The last time we received supplies of praziquantel was in 2019. There was no delivery from our central office from 2020 to 2022 since resources have been concentrated on battling the pandemic. We expect deliveries by December in time for the mass treatment activities in January next year,” Cuayzon said in a phone interview on Monday.

The medicines up for delivery nationwide are still being analyzed by the Food and Drug Administration main office in Metro Manila, according to Cuayzon.

The DOH regional office usually requests medicines four times the requirement of the most vulnerable communities.

In Eastern Visayas, the disease, which is also known as snail fever, is endemic in 897 villages in 63 towns and cities.

These villages are hosts to 1,718 freshwater snail colonies based on the 2015 survey.

People become infected with schistosomiasis when larval forms of the parasite, released by freshwater snails, penetrate the skin during contact with infested water.

“An area is considered endemic and people are susceptible if there is presence of indigenous cases and presence of infected snails,” Cuayzon added.

In the national listings, four of the region’s six provinces are categorized as high endemic areas -- 338,842 are in Leyte; 113,175 in Samar; 206,043 in Eastern Samar; and 220,717 in Northern Samar.

“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,” she added.

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

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)