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Parasitic Gastroenteritis (view source)
Revision as of 18:08, 26 December 2008
, 18:08, 26 December 2008→Host Immunity
Host immunity often reduces egg production by female worms. This results in a stereotyped pattern of worm egg output, regardless of the level of infection.
Host immunity often reduces egg production by female worms. This results in a stereotyped pattern of worm egg output, regardless of the level of infection.
'''Factors Adversely Affecting Host Immunity''':
a) ''Nutrition'':
Gross deficiency; mineral/trace element deficiency, e.g. cobalt.
b) ''Reproductive status'':
"Periparturient relaxation in immunity" (PPRI) seen in breeding ewes and sows. Due to impaired cell-mediated immune response - associated with an increase in blood prolactin levels/shift of IgA from gut mucosa to mammary gland around parturition?
c) ''Drug treatment'':
e.g. repeated anthelmintic and corticosteroid treatment.
d) ''Concurrent infection'':
e.g. pathogenic effects of ''Nematodirus'' infection exacerbated by coccidia in lambs.
e) ''Previous experience of a parasite'':
e.g. hypersensitivity reaction to ''Haemonchus'' in some ewes.