General Parasitology
Parasite is a living organism, which lives in or upon another organism (host) and derives nutrients directly from it, without giving any benefit to the host.
Parasites may be Classified as
- Ectoparasite: Inhabits the surface of the body of the host without penetrating into the tissues (e.g. fleas or ticks). Invasion by the ectoparasite called as infestation.
- Endoparasite: Lives within the body of the host. Invasion by the endoparasite is called as infection.
- Obligate parasite: Cannot exist without a parasitic life in the host
- Example: Plasmodium spp.)
- Facultative parasite: Can live a parasitic life or free-living life.
- Example: Acanthamoeba sp
Read And Learn More: Micro Biology And Immunology Notes
- Accidental parasite: Infects an unusual hos
- Example: Echinococcus granulomas infect humans accidentally).
- Aberrant parasite or Wandering parasite: It cannot develop further when infects an unusual host (larva migrans such as Toxocara in humans).
- HOST: Harbors the parasite and provides nourishment and shelter.
- Definitive host: Sexual cycle takes place.
- Intermediate host: Asexual cycle takes place.
- Reservoir host: Harbors and serves as an important source of infection to other susceptible hosts.
- Paramedic host: It functions as a transport or carrier host. The parasite lives, but it cannot develop further, and the host is not essential for its life cycle
- Example: Freshwater prawn for Angiostrongylus cantonensis, big suitable fish for plerocercoid larva of Diphyllobothrium latum, and Freshwater fishes for Gnathostoma spinigerum).
Unusual/Rare Mode of Transmission
- Parasites transmitted by sexual route: Trichomonas, Entamoeba, Giardia, Enterobius
- Parasites transmitted by Transplacental/Perinatal route: Plasmodium, Toxoplasma, Trypanosoma
- Parasites transmitted by blood transfusion: Plasmodium, Babesia, Toxoplasma, Leishmania & Trypanosoma
- Parasites entering through conjunctiva: Acanthamoeba spp.
Tropical Parasitic Diseases
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