The symptoms of parasitic infections depend on the parasite. Here are a few examples:
Giardia infection (giardiasis) infection can cause symptoms such as diarrhea, abdominal cramping and bloating, gas, nausea, fatigue, and weight loss. Not everyone with the infection shows symptoms though, and they may pass the infection on to others unknowingly.
Chagas disease: Most people who contract Chagas disease may not have symptoms for the first few weeks or months. If they do, they may experience mild swelling at the infection site, low fever, body aches and pains, skin rash, headache, nausea and vomiting, diarrhea, and swollen glands, among other symptoms. The infection then moves into the chronic phase. This is when signs and symptoms may start for those who did not have any during the acute phase. They may include an irregular heartbeat, congestive heart failure, swollen esophagus that makes it hard to swallow, and abdominal pain or constipation. The infection could also cause a cardiac arrest.
Tapeworm: Symptoms of tapeworm may not be noticed right away, beginning only about 8 weeks after the tapeworms have developed in the intestine. The symptoms may be mild and non-specific, including nausea, diarrhea, constipation, and abdominal pain. Untreated tapeworms can live for years, and can lead to malnutrition. Long-term complications could include headaches, blindness, and seizures.
