Introduction to Parsitology Flashcards
Symbiosis
both partners of the associate benefit from each other
Commensalism
one partner benefits, the other is unaffected
parasitism
one organism benefits at the expense of the other
ectoparasite
live on the surface of their host (ticks and mites)
endoparasite
live within the body of the host
Obligate
must spend at least part of their life cycle in associate with a host
Majority are this
Faculative
are capable of leading both a free and parasitic existence
Vector
insect taht transmits infectious agent from one host to the next
protozoa
unicellular eukaryotic microbe
Helminth
worm
Nematode
roundworm
Cestode
tapeworm
trematode
fluke (complex flatworm)
Which infection causes the most deaths per year
malaria (1.5 million)
How do these infections get to different countries
immuno-suppresed people
travel
4 classes of protozoa
ameba, flagellates, sporozoa, ciliates
Locomotion of ameba
pseudopodia
Locomotion of sporozoa
gliding
Portals of entry
ingestions penetration/inculation direct transmission cogenital transmission transfusions/transplation
Pathological mechanisms of parasitic disease
mechanical damage
damage caused by parasite products
immunopathology
Ways the body fights parasites
neutralizing antibody antibody plus complement antibody plus completment opsoniation activated macrophages CD*+ cytotoxic T cells
Neutralizing antibody
block entry of parasite into host cells
antibody plus complement
lysis of blood dwelling parasites
Antibody plus complement opsonization
phagocytosis
Activatecd macrophages
destruction of intracellular protozoa
CD8+ cytotoxic T cells
lysis of paraiste infected host cells
Size of parasite
larger helminths make them unable to be phagocyosed
Location of parasite
living in the lumen of the gut make it difficult for the immune system to get to
Intracellular sequestration
Numerous protozoan parasites reside for a period of time inside host cells. This will sequester them from destruction by humoral (Ab) defenses.
Formation of cyst
provide impenetrable barrier to the immune system
Avoidance of phago-lysosomal destruction
While most microbes are destroyed by lysosomal enzymes following phagocytosis by macrophages, some parasites can survive and replicate within this inhospitable environment
Antigen variation
having different antigens on different parts of the life cycle
Having successive waves of parasitemia with different antigens
Antigenic masking
coating themselves with host proteins or lipids to mask themselves from the immune system
Immuno-suppresion
make the host more immuno-compromised
Differential toxicity
commonly achieved by preferential uptake of drug by the parasite, metabolic alteration of the drug by the parasite, or differences in the susceptibility of functionally equivalent sites in the parasite and the host.
Antiprotozoals
target rapidly proliferating, metabolically active cells
antihelminthics
Generally, targeted at non-proliferating adult helminthes. Most affect the neuromuscular system, carbohydrate metabolism, or egg (larvae) production of adult worms.