Parasitology Flashcards
What is a parasite?
A parasite is an organism that lives on or in a host organism and gets its food from or at the expense of its host
State the 3 main classes of parasites which cause disease in humans?
- Protozoa
- Helminths
- Ectoparasites
What are protozoa?
- Microscopic, single-celled organisms that can be free-living (living within the environment) or parasitic in nature
- Are able to multiply in humans allowing serious infections to develop from a single infection
Describe how transmission occurs for protozoa if living in the human intestine and blood/tissues?
- Protozoa living in the human intestine can be transmitted by the fecal-oral route
- Protozoa living in blood or tissues are transmitted by an arthropod vector
- Arthropod vectors include mosquitoes, flies, biting midges, ticks, mites, fleas, bugs, lice, and other arthropods that carry and transmit disease-causing organisms, or pathogens, from one host to another.
What are Protozoa classified by?
Protozoa are classified by their mode of movement
State the 4 types with examples for each one?
- Amoeba, e.g.Entamoeba: Finger-like projections of protoplasm
- Flagellates, e.g.Giardia, Leishmania: Flagella
- Ciliates e.g. Balantidium: Cilia
- Sporozoa: organisms whose adult stage is not motile: e.g.Plasmodium,Cryptosporidium
State 9 medically important protozoa infections?
- Entamoeba histolytica
- Giardia lamblia
- Trichomonas vaginalis
- Malaria (Plasmodium spp.)
- Toxoplasma gondi
- Cryptosporidium
- Leishmania spp.
- Trypansomacruzi
- Trypansomabrucei (gambiense/rhodesiense)
What are helminths?
- Helminths are large, multicellular organisms (worms) generally visible to the naked eye in their adult stages.
- In their adult form, helminths cannot multiply in humans.
State the 3 main classes of helminths which are human parasites?
- Nematodes (roundworms)
- Trematodes (flukes)
- Cestodes (tapeworms)
Nematodes
State 3 types of medically important nematodes?
- Soil transmitted helminths
- Filarial parasites: Transmitted by biting flies and mosquitos
- Others
State 4 examples for soil-transmitted helmniths
- Ascaris lumbricoides
- Trichuris trichiura
- Hookworm spp.
- Enterobius vermicularis
State 4 examples for filarial parasites?
- Wuchereria bancrofti
- Loa loa
- Onchocerca volvulus
- Dracunculus medinensis
State 2 examples for the other category of nematodes
- Toxocaracanis/cati
- Trichinella spiralis
Trematodes
State 4 examples of medically important trematodes?
- Schistosoma mansoni/haematobium/japonicum
- Clonorchissinensis
- Fasciolahepatica
- Paragonimusspp
Cestodes
State 3 examples of medically important cestodes?
- Tania saginata
- Taenia solium
- Echinococcus granulosus