A rice farmer went to an emergency department after a one-minute episode of shaking in the right arm and leg. The MRI showed linear enhancement and a cluster of enhancing nodules with surrounding swelling in the left frontal lobe, the part of the brain that controls movement on the body's right side. The diagnosis was cerebral schistosomiasis, a parasitic worm infection that had reached the brain.
The case appeared as an Images in Clinical Medicine report in the New England Journal of Medicine from doctors at Jose R. Reyes Memorial Medical Center in Manila. The patient's job matters as much as the scan. The case was published after 2025, the year the Department of Health set for ending transmission in every endemic community, yet the parasite is still reaching people who work in flooded fields.
A Patient Who Works Where the Parasite Lives
Schistosomiasis spreads through water. According to the World Health Organization, people are infected when larvae released by freshwater snails burrow through the skin during routine contact with water. For a rice farmer, wading through paddies is part of the job.
The Philippines has its own species, Schistosoma japonicum, which also infects animals. A 2025 review in Tropical Medicine and Infectious Disease by Tabilin and colleagues noted that domestic animals, particularly bovines such as the carabao, the water buffalo still used on many farms, are persistently infected in endemic areas. Their infected stool returns parasite eggs to the water, which keeps the cycle going in the fields.
The CDC notes that eggs can lodge outside their usual sites, and that the brain is the typical site for S. japonicum. It describes central nervous system lesions as rare. A 29-patient study from Philippine General Hospital in Acta Medica Philippina cited estimates that brain involvement occurs in as many as 2% to 5% of S. japonicum infections. Seizures were the most common symptom in that series.
A 2025 Deadline Comes and Goes
The Department of Health's Schistosomiasis Control and Elimination Program set a goal to "eradicate the transmission and incidence" of the infection "in all endemic barangays by 2025." It estimates that about 12.4 million Filipinos are at risk and 2.7 million are directly exposed.
The 2025 review counted 28 of the country's 81 provinces as endemic, mostly in the Visayas and Mindanao, with 4.8% prevalence in village-level surveys from 2014 to 2018. Progress has been slow in places: the review noted that Zamboanga del Norte, Bohol, and Davao Oriental were already considered near elimination as early as 1995.
The authors concluded that the disease "necessitates integrated, multisectoral efforts that address its complex epidemiology," because people are not the only hosts keeping it alive.
In June, lawmakers pushed for a probe into the country's fight against schistosomiasis, the Daily Tribune reported.
The Treatment Exists, Reaching People Is Harder
The medicine is not the problem. CDC says praziquantel is effective against all major Schistosoma species, and WHO calls it "effective, safe and low-cost." The harder part is reaching everyone who needs it. Globally, at least 253.7 million people needed preventive treatment in 2024, and only about 100.5 million were treated, according to WHO.
That gap helps explain why cases like this one still turn up. A mass treatment program works only if people take the tablets year after year. Farmers return to the same water, and the snails and carabao keep the parasite present in the environment.
One image report cannot show how common brain involvement is in any province. But it shows what the infection can do when it travels beyond the liver and gut, where it usually causes harm.
A Diagnosis Worth Remembering in Farm Country
For clinicians, the takeaway is simple: a new seizure in someone who works in freshwater in an endemic area should raise the possibility of a parasite, not only a tumor or a stroke. Diagnosis usually starts with finding eggs in stool, according to the CDC.
That history matters most at the start. A cluster of enhancing nodules with swelling around it can look like a brain tumor on a scan, and the treatments for the two conditions are very different. Asking about work, home province, and contact with rivers, ponds, or rice paddies can point to the right diagnosis earlier.
For people living in endemic provinces, the DOH program and local health units remain the main source of testing and preventive treatment. Anyone with a new seizure, sudden weakness, or a severe headache should seek emergency care right away.
For travelers, the CDC's prevention advice is not to swim, wade, or bathe in freshwater in regions where schistosomiasis is common. The agency notes that the ocean and chlorinated pools are safe.
Key Questions Answered
What did the NEJM report describe?
A rice farmer with a one-minute episode of right-sided arm and leg shaking whose MRI showed enhancing nodules and swelling in the left frontal lobe, diagnosed as cerebral schistosomiasis.
Why are rice farmers at higher risk?
The parasite's larvae live in freshwater and penetrate skin. Farmers who spend long hours in paddies where infected snails and carabao are present have repeated exposure.
How often does schistosomiasis reach the brain?
CDC calls it rare. A Philippine hospital study cited estimates of 2% to 5% of S. japonicum infections.
Did the Philippines meet its 2025 goal?
The DOH aimed to end transmission in all endemic barangays by 2025. A 2025 review still counted 28 endemic provinces, and lawmakers pushed for a probe in June 2026.
Is there a treatment?
Yes. Praziquantel is effective against all major species, but in 2024 fewer than half of the people worldwide who needed preventive treatment received it.
Are travelers at risk?
Only with freshwater contact in endemic areas. CDC advises travelers not to swim, wade, or bathe in freshwater where schistosomiasis is common.
Published by Medicaldaily.com
