Parasitology Exam 2 - Epidemiology Flashcards
predominant factors that contribute to parasite transmission
environmental contamination
development/survival of infectious stages
alteration in host susceptibility
susceptible to shock
infection into clean environment
environmental contamination examples
biotic potential
stock management
hypobiosis/diapause
developmental/survival of infectious stages
microhabitat
diet
pregnant/lactating animals
immunosuppressed animals
biotic potential
success by fecundity
Haemonchus contortus and Ascaris suum have thousands of eggs that enter the environment while Trichostrongylus only produces a few hundred eggs; this is an example of what?
biotic potential
Lucilia sericata (blowfly) or Ixodes ricinus (tick) has high egg production while Glossina spp. have few offspring; this is an example of what?
biotic potential
parasites can also multiply within an intermediate host or final host, such as…
Galbae (Lymnaea) infected w/ one miracidium of Fasciola hepatica and give rise to several hundred
Eimeria multiply exponentially due to merogony and gametogenic and can quickly contaminate environment
these are examples of what
biotic potential
stock management
what species is this important in? why?
influences environmental contamination
cestodes and nematodes for which no multiplication takes place outside final host and also for ectoparasite transmission (e.g. lice and mites)
crowded cattle yards or sow to offspring at nursing is an example of what
stock management
what parasite is commonly known as husbandry and management disease? why?
Coccidiosis
oocyst contamination of the environment can be high in situations such as lambs gathered around feed troughs
hypobiosis
give examples.
arrested development of nematode larvae within the host
occurs seasonally, especially in adverse conditions - too cold; resumption of development occurs when conditions are improved and leads to increased environmental contamination
Ostertagia/Teladorsagia (seasonal) or Hyostrongylys spp. In pigs
Trichonema sp. In horses
diapause
provide an example
hypobiosis in arthropods, it’s an adaptive mechanism
occurs in adverse conditions which cause cessation in growth/metabolism in certain life stage
Hydrotoea irritans
microhabitat
moderate temps/high humidity favor development
cold temps prolong survival
rotational cropping reduces parasites
high groundwater promotes transmission of other parasites
provide an example of a parasite in ruminants thats prevalence increases with warmer wetter weather/higher ground water
Fasciola hepatica
how does diet affect development/survival of infectious stages
adequately fed animals tolerate parasitism better
