SAN FRANCISCO, Agusan del Sur (MindaNews / 29 March) — When Rogelio Timbal tends his one-hectare rice field in Barangay Caimpugan, the thick, knee-deep mud makes every step a struggle. His boots, meant to protect him, only slow him down, making him sink deeper into the sludge with each step. "Hubuon ko na lang ang botas kay malangan ang trabaho. Makabug-at sa akong tikang," he lamented. (I just have to take off my boots because they slow me down; they just make each step heavier.) For 11 years, this has been his routine, wading barefoot through the waterlogged paddies, his feet constantly soaked in mud. “It’s just part of the job,” he said. But in 2023, the exposure took its toll. At first, it was just dizziness and headaches. Then, the left side of his body started feeling numb. He ignored it, thinking it was exhaustion from long hours in the field. But when the symptoms worsened, he went to a clinic and discovered he had schistosomiasis. A disease long associated with poverty, schistosomiasis remains a constant threat to farmers like Timbal, whose livelihoods depend on the very conditions that put them at risk. According to the World Health Organization (WHO), schistosomiasis is an acute and chronic disease caused by parasitic blood flukes of the genus Schistosoma. Classified as a neglected tropical disease (NTD), it mostly affects poor rural communities in Asia, the Middle East, Africa, and South America. The article Management and Control of Schistosomiasis in Agusan del Sur, Philippines: A Modeling Study highlighted that schistosomes require both a mammalian definitive host and a freshwater snail intermediate host to complete their life cycle. Schistosomiasis, first reported in the Philippines in 1906, is caused by Schistosoma japonicum, a zoonotic parasite that infects humans and over 40 mammalian species, including carabaos, dogs, pigs, cats, rats, and goats. The Oncomelania snail serves as the parasite’s intermediate host. Definitive hosts become infected when the larval form of the parasite, known as cercariae, penetrates the skin during direct contact with infested water. Once inside, the cercariae shed their tails and transform into schistosomulae, which travel through the bloodstream before settling in the hepatic portal vein leading to the liver, where they mature into adult worms and begin laying eggs, which are excreted in the host’s stool. Upon exposure to freshwater, the eggs hatch into miracidia, which infect snails. Inside the snails, the miracidia multiply asexually into sporocysts and later develop into cercariae, continuing the cycle when these newly developed cercariae penetrate the skin of another mammalian host. The rice paddies where Timbal works daily are in schistosomiasis-endemic areas, farmlands that were once natural habitats for snails carrying schistosomiasis, according to the Department of Health Caraga. In the Philippines, these snails originally thrived in floodplain forests and swamps, many of which have been converted into agricultural lands. While farming has altered these environments, the snails have adapted, finding new homes in irrigation canals, abandoned or minimally farmed rice fields, and even roadside ditches, allowing them to persist and continue the cycle of schistosomiasis transmission. The still unpublished study “Prevalence, Clinical Profile, and Outcomes of Admitted Cases of Schistosomiasis Japonicum in Agusan del Sur from 2012 to 2022” conducted by Dr. Annie Abordo-Dioso initially recorded 620 cases after analyzing admissions in nine hospitals across the province, but after filtering out non-residents and those with incomplete records, only 449 cases remained. Most of those affected were men, particularly farmers like Timbal. The study Schistosomiasis in the Philippines: A Comprehensive Review of Epidemiology and Current Control stated that the most susceptible groups in agricultural transmission hotspots are farmers and irrigation workers, as they labor in contaminated fields and irrigation canals, exposing themselves to infectious cercariae. Farming, a male-dominated occupation, has been identified as a high-risk cohort due to greater exposure, explaining the higher prevalence of schistosomiasis among men compared to women. The highest number of cases came from municipalities near the Agusan River, including San Francisco, Talacogon, Prosperidad, San Luis, and Bunawan. Sibagat, a town at a higher elevation with fewer bodies of water and rice paddies, had no recorded hospital admissions for schistosomiasis. Dr. Dioso noted that schistosomiasis remains underreported, with hospital admissions increasing over the years, even during the COVID-19 pandemic. The most common form found among admitted patients was hepatosplenic schistosomiasis, affecting the liver, with symptoms ranging from liver cysts and vomiting to severe cases of abdominal swelling and internal bleeding. Some patients also suffered from neuroschistosomiasis, a rarer but severe form that leads to seizures. However, these numbers likely represent only the tip of the iceberg, as many residents accept schistosomiasis as a “normal” disease. Dioso emphasized that patient education and encouragement are critical, as many fear side effects from treatment, preventing them from seeking care. Symptoms vary based on the severity and duration of the disease. Acute schistosomiasis, seen in newly exposed individuals, includes swimmer’s itch, fever, chills, body pain, abdominal pain, diarrhea, cough, and difficulty breathing. Chronic schistosomiasis, prevalent in endemic areas like Agusan del Sur, causes hepatosplenic complications, liver cirrhosis, gastrointestinal bleeding, abdominal swelling, jaundice, anemia, and malnutrition. In severe cases, it may affect the nervous system, leading to seizures or pneumonia. Data from the Department of Health’s Field Health Services and Information System for the period 2013–2023 showed a significant economic impact of schistosomiasis, citing its public health burden and associated loss of productivity. The WHO’s World Health Observatory estimated the disability-adjusted life year (DALY) for schistosomiasis in the Philippines in 2021 at 22,300. Endemic communities in Leyte estimate that illness due to schistosomiasis results in the loss of 45.4 productive days per infected person per year, reduced to just four days after treatment. Farmers also face risks from animal transmission. Carabaos, essential agricultural aides, often wallow in rice paddies, increasing the risk of exposure. Carabaos have been established as crucial in maintaining the parasite life cycle, with each infected carabao releasing hundreds of thousands of eggs into the environment. Flooding further increases the risk, as floodwaters expose communities to schistosomiasis. A review by Guo et al. noted that flooding damages water conservancy infrastructure, leading to fecal contamination and increased water contact, raising the risk of infection. Flooding may also carry snails to previously snail-free areas, expanding their habitats and increasing transmission risk. The Department of Health’s interventions include Mass Drug Administration (MDA) using praziquantel, but challenges like MDA fatigue, where people resist taking the medication due to side effects, persist. Dr. Annie Abordo-Dioso emphasized the need for a One Health approach, involving multi-sectoral collaboration to achieve better health outcomes. The WHO’s road map for 2021-2030 aims to eliminate schistosomiasis as a public health problem globally, but achieving this goal by 2030 is challenging. Strengthening partnerships with the Department of Agriculture and Veterinary Offices is crucial, as is implementing Zero Open Defecation (ZOD) programs to reduce transmission. Out of 314 barangays in Agusan del Sur, 207 have already achieved ZOD status, including Barangay Caimpugan. Timbal, who has been taking praziquantel since 2023, reported no symptoms by 2024 but continues annual treatment as a precaution. Despite health center recommendations to wear protective boots, he refuses, saying they are an added burden. “I’ll just take the medication along with my family to prevent schistosomiasis. Exposure is unavoidable since I work in the rice fields, and I can’t stop farming because it’s our livelihood,” he said.
