An Uncommon Medical Case

A woman suddenly experienced uncontrolled shaking in her right arm and leg, even though she had been feeling fine just moments before. She wasn’t suffering from headaches, confusion, or any weakness. Yet, for about a minute, half of her body trembled uncontrollably.

This woman, who works as a rice farmer in the Philippines, went to the emergency room. After a physical examination, doctors didn’t find anything unusual. They then conducted a brain scan, which showed a bright cluster of nodules surrounded by fluid in her left frontal lobe. It didn’t take long for the doctors to suspect parasite eggs.

In a recent case report featured in the New England Journal of Medicine, the medical team theorized that the woman was suffering from neuroschistosomiasis. This rare condition arises from an infection with a parasitic worm known as Schistosoma, or blood fluke. S. japonicum is the most prevalent variety in the Philippines, but it also exists in China and parts of Indonesia. Interestingly, it has been eradicated from Japan.

A Complex Parasitic Life Cycle

S. japonicum has a notably intricate life cycle, which begins when its eggs are released through the urine or feces of various hosts, including humans. Under favorable conditions, these eggs hatch into larvae that seek out specific aquatic snails, where they will inhabit and develop through two stages. Eventually, the mature larvae burst out, grow a forked tail, and swim in search of an animal host. Known as cercariae, these tailed larvae can penetrate unbroken skin and venture through the bloodstream, stopping by the lungs, heart, and then the liver to mature into adults.

In their mature form, male and female worms live together, often with the slender female nestled within a groove of the bulkier male. These adult worms typically migrate to large blood vessels in the abdomen that connect the liver to the intestines. From this cozy spot, they continuously release eggs, which ultimately exit the body through feces and urine.