TBL 12 Helminths and Protozoa Flashcards
There are 2 main types of parasites that we look at in detail.
Protozoa: Unicellular
Metazoa: Multicellular (e.g. worms)
Protozoa and metazoa are (eukaryotes/prokaryotes).
Eukaryotes - genome encased within nucleus with complex organelles in cytoplasm
Protozoa (causes/does not cause) eosinophilia (increase in non-blood tissue eosinophils), whereas metazoa (causes/does not cause) eosinophilia.
protozoa - no eosinophilia
metazoa - causes eosinophilia
_______ host is the host in which parasite undergoes sexual reproduction.
Definitive
_______ host is one which harbours the larval stages of the parasite or an asexual cycle of development
Intermediate
_______ host is one in which a parasite cannot complete its life cycle. (unsuitable)
Aberrant
________ host is a host in which the parasite is not commonly found, but still suitable for its development.
Accidental
A _______ is a living carrier which transports a pathogenic organism from an infected to a non-infected host.
vector
Compare between infection and disease.
Infection refers to the invasion and multiplication of pathogenic microorganisms within or on the body and does not necessarily mean disease.
Disease is illness characterised by specific signs and symptoms and damage to the host.
________ is the presence of microorganisms in or on the body without causing damage to the host.
Commensals
4 types of protozoa that are clinically important:
- Amoeba
- Apicomplexa
- Flagellates
- Ciliates
2 main pathogenic amoeba are:
- E. histolytica
2. Naegleria fowleri
Infective form of amoebas are _________.
infective cysts
(After ingestion of mature cysts, the encysted parasite passes through the gut and excystation takes place in the small intestine, releasing trophozoids.
Naegleria fowleri is a free-living _______ found mostly in warm water, and is a rare cause of disease primary amoebic meningo-encephalitis (PAM).
It enters through the _______ when host comes into contact with contaminated water, and proceeds to invade the ____ and cause brain damage.
amoeba
enters through the nasal cavity, invades the CNS
There are 3 main types of apicomplexans (protozoa/metazoa).
Protozoa
- Plasmodium spp
- Toxoplasma
- Cryptosporidium