Intro to parasitology Flashcards
Definition of parisitology
Association b/w two species, smaller is physiologically dependent on host. Parasite has higher reproductive potential than host and potential to harm host.
Types of parasites
Ecto- (surface) and endoparasite (includes inside GI tract)
Types of hosts
Intermediate - parasite multiplies asexually (in larva) and definitive - parasite multiplies sexually (in adult)
Types of vectors for parasites
Vector is an invertebrate which transports parasite. Mechanical and biological
Forms of parasites
Infective form (environmentally hardy, protected (cyst, egg)) and Invasive form (vulnerable naked cell, responsible for invasion (trophozoite, larva)
Single host parasites
Transmission determined by environmental viability. Direct (vegetative form) and Indirect (cyst, egg - infective form). Distribution determined by hygiene, sanitation
Multiple host parasites
Transmission requires more than one host. Distribution determined by second host’s ecological niche.
Protozoa
Unicellular (nucleus, cytoplasm), Locomotion (pseudopodia, flagella), Multiplication: asexual and sexual (cysts)
Helminths
Multicellular; specialized, differentiated organs; sexual reproduction (eggs)
Immunity to parasitic infections
Can be acquired with many diseases, but less immunity to subsequent infections than viruses/bacteria b/c their antigens are so complex and change so much. Absolute immunity rare with protozoa, never with helminths. Stimulate both cell-mediated and humoral.
Eosinophilia
High eosinophil count. NOT specific to parasites (can be allergies, connective tissue disorders, neoplasms). Produced by helminths and only when tissue invasion), not protozoa.
Parasite effect on host
Tissue damage, competition for nutrients, use host’s non-nutrient resources (suck blood), mechanical interference, poisons and secretions, abnormal tissue responses.
