Schistosomiasis in the Philippines
Dear Dr. Jen,
Schistosomiasis was first reported in the Philippines in 1906, and as of 1921, an estimated 25,000 to 30,000 people were infested. During 1944 to 1945, 1,700 cases were reported among American and Australian military personnel serving in the Philippines.
An estimated 300,000 Filipinos were infested as of 1948. By 1970, the disease was known to be in epidemic proportion in 24 provinces; and as of 1975, five million persons were considered at risk and approximately one million infected. By 2002, an estimated 800,000 were infested and 6.7 million at risk; and as of 2010, an estimated 560,000 were infested.
In recent years, cases have been reported from Mindoro Oriental and Sorsogon in Southern Luzon; the provinces of North, East and Western Samar; Leyte; Bohol in Eastern Visayas; all of Mindanao with the exception of Misamis Oriental, Davao Oriental and Maguindanao.
Schistosomiasis is most common among males, and individuals ages 19 years old and above.
Notable outbreaks were reported in Davao del Sur in 2000 (222 cases as of October – most in Digos-Igpit, Colorado, and Matti barangays); and in Palo, Leyte in 2011 (99 cases). Just last week, the Secretary of Health announced the declaration of schistosomiasis epidemic in several areas in Metro Manila.
Infestation by Schistoma japonicum is common among dogs, field water buffaloes (carabao) and rats on Leyte. The local snail Oncomelania hupensis quadrasi is a known carrier of the disease. The more recent schistosomiasis outbreaks in the country’s urban centers is said to have been caused by urine of rodents infested with the virus mixing with floodwaters.