Question

Explain how humans can act as both definitive and intermediate hosts?

Answer 1

Explain how humans can act as both definitive and intermediate hosts?

The wide evolutionary strategies of parasites helps in keeping their hosts in an equally wide range of relationships. The host–parasite coevolution assisting the maintenance of gene polymorphisms in the host implies the parasitism. It helps in host developing the resistance to a parasite. Types of host includes:

Definitive host: Also called as primary host. It is the final host where the parasite reproduce s@xually and matures in the same host. Human acts as the definitive host for some obligate parasites. Some examples are: pneumococcus bacteria, group B streptococcus bacteria, and mycoplasma bacteria.

Intermediate host: Otherwise called as secondary host. It acts as a vector of the parasite through which the parasite reaches the definitive host. It harbors the immature parasite and helps in completing its life cycle. In intermediate host, the parasite lives for shorter period and go through several asexual stages. Humans became accidental intermediate host for pork tapeworm called as Taenia solium. The cysticercus is the larvel form of T.solium which causes infection called cysticercosis in the intermediate host. Swine was the usual intermediate host and humans were the definitive host. They became unusual intermediate host due to the ingestion of infectious ova that are sticky and acquire via the fecal-oral route .