There are some terrifying parasites out there that can infect humans and lead to severe health issues like blindness, large swellings, cysts in organs, rotting flesh, and more. Below are five of the worst infections caused by these parasites. They’re particularly dangerous because they can be deadly and tough to diagnose and treat.
### Chagas Disease
This disease is spread by Triatomine bugs, also known as kissing bugs, which carry Trypanosoma parasites in their feces. People get infected when these bugs defecate on their skin or food, or through contaminated blood transfusions. Initially, the symptoms are mild or non-existent, with possible signs like fever, fatigue, or headache. If left untreated, it becomes chronic, causing severe problems like heart swelling, irregular heartbeat, cardiac arrest, swallowing difficulties, and abdominal pain. The main issue is that many people don’t know they’re infected until serious symptoms arise years later when it’s much tougher to treat.
### Malaria
Malaria is caused by the Plasmodium parasite, which is transmitted through the bite of an Anopheles mosquito. The parasites first multiply in the liver and then infect red blood cells, disrupting blood flow to vital organs. Symptoms, which appear 10 to 15 days after the mosquito bite, include high fever, vomiting, and headache. Without prompt treatment, malaria can quickly turn life-threatening. The World Health Organization estimates around 655,000 people die from malaria each year.
### Raccoon Roundworm
The Baylisascaris procyonis parasite found in raccoon feces can cause severe disease if its eggs are ingested. People don’t need to eat raccoon feces to get infected; they just need to touch their mouths with hands contaminated with dirt containing the eggs. Young children are especially at risk since they’re more likely to have dirty hands. Once inside the body, this parasite can cause drowsiness, confusion, vision loss, decreased muscle control, and other neurological symptoms. Severe cases can lead to permanent brain damage, blindness, or death.
### The Brain-Eating Amoeba
Naegleria fowleri, commonly known as the brain-eating amoeba, thrives in soil and warm freshwater bodies like lakes, rivers, and hot springs. It can even be found in contaminated tap water. Infection occurs when the contaminated water enters the nose, allowing the amoeba to travel to the brain and cause meningoencephalitis. Initial symptoms include fever, headache, nausea, and vomiting, followed by a stiff neck, seizures, confusion, hallucinations, coma, and death. Although rare, this infection is typically fatal.
### Visceral Leishmaniasis
Leishmania parasites are transmitted to humans through sandfly bites. While they usually cause severe skin lesions (cutaneous leishmaniasis), in some cases, they lead to visceral leishmaniasis, a more dangerous form of the disease. This results in fever, weight loss, enlargement of the liver and spleen, anemia, bleeding, and a higher risk of other infections. Without treatment, visceral leishmaniasis is almost always fatal.