The human brain is a marvel of nature, but it’s not invincible. Some tiny invaders can make their way into our heads, causing a range of problems from mild headaches to life-threatening conditions. Let’s explore 16 parasites that can infect the brain, and learn about their sneaky ways of getting in.
Naegleria Fowleri
Naegleria fowleri, often called the “brain-eating amoeba,” lives in warm freshwater. It enters the body through the nose when people swim or dive. Once inside, it travels to the brain and starts destroying tissue. This infection is rare but extremely deadly, with symptoms appearing within days of exposure. Early diagnosis and treatment are crucial for survival.
Toxoplasma Gondii
Toxoplasma gondii is a parasite found in cat feces and undercooked meat. It can cause toxoplasmosis, which often has no symptoms in healthy adults. However, in people with weak immune systems, it can lead to brain inflammation. Pregnant women are at risk of passing it to their unborn babies. Some studies suggest it might affect behavior, but more research is needed.
Taenia Solium
Taenia solium, the pork tapeworm, can cause a condition called neurocysticercosis. People get infected by eating undercooked pork or through poor hygiene. The tapeworm’s eggs hatch in the intestines and the larvae can travel to the brain. There, they form cysts that can cause seizures, headaches, and other neurological problems. It’s a leading cause of adult-onset epilepsy in developing countries.
Acanthamoeba
Acanthamoeba is a tiny, free-living amoeba found in water and soil. It can enter the body through the eyes, nose, or cuts in the skin. While it usually causes eye infections in contact lens wearers, it can sometimes reach the brain. This leads to a rare but serious condition called granulomatous amebic encephalitis. Symptoms include headaches, personality changes, and seizures.
Plasmodium Falciparum
Plasmodium falciparum is the most dangerous malaria parasite. It’s transmitted by mosquito bites. While malaria typically affects the blood, this parasite can sometimes cause cerebral malaria. In this severe form, infected red blood cells stick to blood vessels in the brain. This can lead to swelling, seizures, and even coma. Prompt treatment is essential to prevent long-term damage or death.
Balamuthia Mandrillaris
Balamuthia mandrillaris is another amoeba that can infect the brain. It’s found in soil and can enter through cuts or by breathing in dust. Unlike Naegleria, it causes a slow-progressing disease called granulomatous amebic encephalitis. Symptoms can take weeks or months to appear. They include headaches, personality changes, and seizures. Diagnosis is often difficult, making treatment challenging.
Schistosoma
Schistosoma parasites cause schistosomiasis, also known as bilharzia. People get infected in contaminated freshwater. While these worms usually affect the intestines or urinary tract, their eggs can sometimes travel to the brain. This can cause inflammation and seizures. In rare cases, it may lead to a spinal cord infection. Treatment with antiparasitic drugs is usually effective.
Echinococcus
Echinococcus tapeworms can cause a disease called echinococcosis. Humans become infected by ingesting tapeworm eggs, often from contaminated food or water. The larvae can travel to various organs, including the brain. There, they form cysts that grow slowly over years. These cysts can cause headaches, seizures, and other neurological symptoms. Surgery is often needed to remove them.
Angiostrongylus Cantonensis
Angiostrongylus cantonensis, also known as the rat lungworm, can cause eosinophilic meningitis in humans. People get infected by eating raw or undercooked snails or slugs. The worms normally live in rats, but in humans, they can travel to the brain. This causes inflammation of the brain and spinal cord membranes. Symptoms include severe headaches, neck stiffness, and tingling sensations.
Gnathostoma Spinigerum
Gnathostoma spinigerum is a parasitic worm found in raw or undercooked freshwater fish, eels, and frogs. When humans eat infected meat, the larvae can migrate through the body. If they reach the brain, they cause gnathostomiasis. This can lead to headaches, paralysis, and even death. The worms can move around in the brain, making diagnosis and treatment challenging.
Spirometra
Spirometra tapeworms cause sparganosis, a rare parasitic infection. Humans can get infected by drinking water containing infected copepods or by using raw frog or snake meat as a poultice. The larvae can migrate to various parts of the body, including the brain. There, they form lesions that can cause headaches, seizures, and weakness. Surgery is often necessary to remove the worms.
Paragonimus
Paragonimus, or lung flukes, typically infect the lungs. However, they can sometimes migrate to the brain, causing cerebral paragonimiasis. People get infected by eating raw or undercooked crayfish or crabs. In the brain, these flukes can cause headaches, seizures, and vision problems. The infection can mimic brain tumors or tuberculosis, making diagnosis tricky. Antiparasitic drugs are usually effective for treatment.
Trypanosoma Brucei
Trypanosoma brucei causes African sleeping sickness. It’s transmitted by the tsetse fly. The parasites first multiply in the blood and lymph system. Later, they cross the blood-brain barrier and invade the central nervous system. This leads to confusion, poor coordination, and disrupted sleep patterns. Without treatment, the disease is usually fatal. Early diagnosis and treatment are crucial for recovery.
Baylisascaris Procyonis
Baylisascaris procyonis, the raccoon roundworm, can cause a rare but severe brain infection. Humans get infected by accidentally ingesting eggs from raccoon feces. The larvae can migrate to the brain, causing damage as they move. This can lead to loss of muscle control, blindness, and coma. Prevention through proper hygiene is key, as treatment is often ineffective once symptoms appear.
Onchocerca Volvulus
Onchocerca volvulus is the parasite responsible for river blindness. It’s transmitted by blackfly bites. While it primarily affects the skin and eyes, it can sometimes reach the brain. There, it can cause nodding syndrome, a mysterious neurological condition. This leads to seizures, stunted growth, and cognitive decline. The exact link between the parasite and nodding syndrome is still being studied.
Dirofilaria Immitis
Dirofilaria immitis, known as the dog heartworm, rarely infects humans. When it does, it can sometimes end up in the brain. Mosquitoes spread the parasite from infected dogs to humans. In the brain, the worms can cause headaches and seizures. They may also form lesions that look like tumors on brain scans. Surgery is usually needed to remove the worms.
Katy Willis is a writer, master herbalist, master gardener, and certified canine nutritionist who has been writing since 2002. She’s finds joy in learning new and interesting things, and finds history, science, and nature endlessly fascinating.
