Parasites in humans

In short: Parasites are organisms that live on or in a host and feed at its expense, often without killing it immediately. In humans, known parasites range from tiny single-celled organisms to tapeworms several metres long.

In more detail: Unlike predators, parasites usually live together with their host for an extended time and have an evolutionary interest in its survival.

Note: Not a substitute for medical advice.

In detail

• Ectoparasites: Lice, fleas, and ticks live on the body surface, feeding on blood or skin flakes of the host.
• Endoparasites: Tapeworms, roundworms, and single-celled pathogens like malaria parasites live inside the body, often in the gut or bloodstream.
• Transmission routes: Parasites spread through contaminated water, insufficiently cooked meat, direct bodily contact, or blood-sucking insects.
• Symptoms: Depending on the parasite, symptoms range from mild itching to digestive complaints to severe systemic illness.
• Development cycles: Many parasites go through complex life cycles with multiple host changes before completing their development stage.
• Prevention: Good hygiene, thoroughly cooking food, and protection against blood-sucking insects significantly reduce infection risk.
• Global significance: Parasitic diseases like malaria are among the most significant infectious diseases worldwide, especially in tropical regions with limited access to medical care (bakterien-und-viren-unterschied, symbiose-und-parasitismus).