Definitive Host
host in which the adult parasite lives and reproduces
A definitive host is a term used in parasitology to describe an organism that houses the adult, sexually mature stage of a parasite. This is the host in which the parasite completes its life cycle and reproduces.
For example, in the case of the human intestinal parasite, Ascaris lumbricoides, humans are the definitive host. The adult worms reside in the small intestine of humans, where they mate and lay their eggs. The eggs are then passed out of the human host in feces and can contaminate the soil, where they can develop into the infective stage for the next host, typically a pig, which becomes the intermediate host.
In some cases, a parasite might require multiple definitive hosts. For example, the tapeworm Diphyllobothrium latum requires humans as its primary definitive host, but also requires a secondary definitive host, typically a carnivorous fish, which consumes the intermediate host containing the tapeworm larvae.
It is important to identify the definitive host of a parasite as it can help in understanding the epidemiology and potential for transmission of the parasite, leading to more targeted prevention and control efforts.
More Answers:
Understanding the Direct Life Cycle: Examples in Plants, Invertebrates, and VertebratesUnderstanding the life cycle: stages of growth and development in organisms
Understanding Intermediate Hosts: The Role of Parasite Development and Life Cycle in Disease Transmission