Protozoans Flashcards
that branch of medical sciences that deals with parasites that cause or transmit disease to man.
Medical Parasitology:
organisms that live in or on a host deriving food and shelter and causing harm to that host.
Parasites:
“Any two organisms living in close association, commonly one living in or on the body of the other,
Symbiosis
One partner benefits but the other is not hurt.
Commensalism:
Both partners benefit.
Mutualism:
One partner harms or lives on the expense of the other
Parasitism:
live within the host causing infection.
Endoparasites:
live on the external surface of the host causing infestation.
Ectoparasites:
only visits the host to get its meal.
Temporary parasite:
always fixed to the host.
Permanent parasite:
produces disease only in immunodeficient hosts.
Opportunistic parasite:
When an organism can live free or establishes a parasitic existence depending on a host.
Facultative Parasitism
When an organism establishes a permanent parasitic existence and is completely dependent on the host.
Obligatory parasitism:
occasionally an organism parasitizes a species other than its usual host.
Accidental or incidental parasitism:
They infect host where they cannot live or develop further.
Abberant or wandering parasite:
in which the adult or sexually reproducing form of the parasite lives.
Definitive host
in which the parasite lives during its larval stage or asexually reproducing form.
Intermediate host:
an animal harboring the same stage of the parasite like in human and represent a potential source of infection to man.
Reservoir host:
“usually an arthropod”: transmits parasites from infected organisms to other hosts.
Vector
Habitat
Small intestine
Large intestine
Blood vessels
Organs; liver, lung, heart, brain,
Muscles
Lymphatics
Reticuloendothelial system
Cells as red blood cells
Transmission Source
Water
Soil
Raw vegetables & fruits
Animals
Fish
Vector [Arthropods]
Blood
Transmission Mode of infection
Ingestion (Oro-fecal)
Inhalation
Penetration of skin & mucous membrane
Bite of vector (vertical transmission)
Direct contact
Congenital transmission
Blood transfusion
Sexual
Trans-mamary
Parasitic toxic products:
produce allergy or necrosis.
Anaemia:
Malarial parasite & Ancylostoma.
Mechanical obstruction:
Ascaris.
Mechanical pressure:
Hydatid cyst.