The rat lungworm is a parasite that can infect rats, snails, slugs, and other animals. While it typically does not cause illness in rats, this worm can have devastating effects when it accidentally infects humans.
The life cycle of the rat lungworm is complex, relying on multiple animal hosts. Adult worms live inside the lungs of rats. The females lay eggs that the rats pass in their feces. Research conducted by the University of Florida explains that “Nematodes can remain relatively quiescent in the third stage for long periods” while awaiting a rat to consume the host snails. Once outside the rat, the eggs hatch into larvae, which are eaten by snails or slugs. Inside these mollusks, the larvae undergo further development.
Humans may become infected by accidentally eating raw or undercooked snails or slugs that contain infectious rat lungworm larvae. For example, this can happen if someone does not wash produce thoroughly before eating. The larvae then penetrate the intestinal wall and travel through the bloodstream to the brain, where they can cause a rare form of meningitis called eosinophilic meningitis.
Symptoms of rat lungworm infection can include a severe headache, stiff neck, tingling or painful feelings in the skin, a low-grade fever, nausea, and vomiting. In severe cases, infected individuals may experience neurological problems like facial paralysis, blindness, coma, or death. There is no specific treatment for the infection, so care focuses on relieving symptoms and preventing complications.
Rat lungworm disease is found in tropical regions around the world, especially Southeast Asia and the Pacific Islands. In the United States, most cases occur in Hawaii, though the worm has also been detected in other states like Louisiana, Florida, and California. The spread of this parasite is linked to the distribution of rats and mollusks that can serve as carriers.
Preventing rat lungworm infection relies on things like washing your hands, cooking your food, and proper food storage. The public should also avoid eating raw or undercooked snails or slugs. The Centers for Disease Control and Prevention (CDC) recommends “thoroughly [washing] fresh produce.” Produce should be washed carefully, especially if grown in a home garden.
While rat lungworm disease is still rare in humans, its devastating neurological effects make this an important parasite to watch. Public health education and smart food preparation can help reduce the risk of infection. With proper precautions, humans can avoid this unwelcome passenger from the rat world.
