Parasitic infections occur when parasites invade the body, often leading to illness. These parasites can be organisms like protozoa, worms, or ectoparasites such as lice and fleas. They typically enter the body through contaminated food, water, or direct contact with infected individuals or animals. Symptoms of parasitic infections vary widely and may include fever, fatigue, digestive issues, and skin rashes. Treatment often involves medications that target the specific type of parasite. Preventive measures include practicing good hygiene, ensuring safe food and water consumption, and using protective measures against insect bites.