Parasitism is a relationship between two organisms in which one of them (called the parasite) lives off of the other organism (called the host). However, unlike in symbiosis, the relationship is not beneficial for both of the organisms. Only the parasite benefits in this relationship and uses the body and bodily functions of the host organism, which will either get infected with some disease or may ultimately die. Unlike predation, parasitism is a slow process. Parasitism takes places in human beings, animals, plants, and even parasites themselves. Some examples are:
- Aphid insects eat the sap of the host plant
- Downy mildew fungus harms fruits and vegetables
- Tapeworms live in the intestines of cattle and live on partially digested food, thereby depriving the host animal of nutrition
- Cryptosporidium: a parasite that causes Crytposporidiosis in human beings, a gastrointestinal sickness
- Pinworms cause Enterobiasis in human beings
- Leeches consume the blood of their host
Hope this helps.