Parasitismo

Parasitismo is a type of biological interaction where one organism, the parasite, lives in or on another organism, the host, and benefits at the host's expense. This relationship is characterized by the parasite deriving nourishment or shelter from the host, often leading to harm or reduced fitness for the host. Parasites can range in size from microscopic organisms like viruses and bacteria to larger, multicellular animals such as ticks, fleas, and certain types of worms. The interaction can occur externally on the host's body surface (ectoparasites) or internally within the host's tissues or organs (endoparasites).

The effects of parasitism on the host can vary greatly. Some parasites cause minimal damage, while others can lead to severe illness, disease, or even death. The host organism often develops defenses against parasites, including immune responses. However, parasites have also evolved sophisticated adaptations to evade or exploit these defenses, leading to a continuous evolutionary arms race between host and parasite. Examples of parasitic relationships are widespread across all domains of life, including plants, animals, fungi, and protists. Understanding parasitism is crucial in fields such as medicine, agriculture, and ecology, as it impacts the health of individuals, populations, and ecosystems.