Introduction to Parasites Flashcards
What are the three classes of parasites?
Protozoa, helminths and arthropods
Describe the structure of protozoa
Single celled organisms
What is the mode of protozoa transmission?
Intestinal parasites - fecal - oral route
Blood parasites - arthropod vector
What is the species responsible for malaria?
Plasmodium falciparum
What is the vector for malaria?
Anopheles mosquito
What is the life cycle of malaria?
Sporozoites are injected under the skin by the mosquito, they travel through blood and enter the liver, they mature in the liver and re-enter the circulation as merozoites. Merozoites invade red cells, multiply and lyse cells
What is the diagnosis of amoebic dysentery?
Cysts in formed stool - microscopy
Diarrhoea with blood and pus
What type of disease is Amoebic Dysentery responsible for?
Intestinal and extra-intestinal infections
Liver abscess in late disease
What infection is caused by the bite of sandflies?
Leishmaniasis
What is cutaneous or muco-cutaneous leishmaniasis characterised by?
Skin or mucosal ulceration
What is Viceral leishmaniasis caused by?
Fever weight loss and hepato-splenomegaly
How is diagnosis of leishmaniasis achieved?
Histology of biopsy material
What are the different types of helminths?
Nematodes, Cestodes, Trematodes
What are Nematodes?
Round worms
What are Cestodes
Tapeworms
What are trematodes
Flatworms
What is the diagnosis of nematodes?
Press adhesive sellotape against perianal region
What is the lifecycle of Ascaris lumbricoides - nematode?
Ingested eggs hatch in the intestine, larvae carried by circulation to the lungs, swallowed again, adult worms develop in and inhabit small intestine
What are the various methods of ingesting a tapeworm?
Larval cysts ingested in meat, ingest eggs in dog faeces
Where is there a high incidence of Schistosomiasis
Near fresh water, snail is important in the life cycle intermediate host
What accompanies a helminth infection?
Eosinophilia
Elevated IgE
How is diagnosis of a parasite infection achieved?
Microscopy of parasites cysts and ova
Serology - detection of antibodies
Blood films for malaria
Are cultures of parasites possible?
rarely
Schistosomiasis is what kind of parasite?
Flatworm (trematode)
Ascarius lumbricoides is what kind of parasite?
Round worm (nematode)
What kind of parasite infection is leishmaniasis and amoebic dysentry?
Protozoal
