Pathophysiology of single and challenge infections of Haemonchus contortus in Merino sheep: studies on red cell kinetics and the "self-cure" phenomenon.

摘要: Abstract The alterations in red cell kinetics and iron metabolism occuring sheep infected with 10,000 Haemonchus contortus larvae similarly reinfected 7–8 weeks later were monitored by radio-isotopic methods the results obtained correlated clinical course of anaemia development parasite populations. It is suggested that there are essentially three stages sheep. first, occurring during initial 3 weeks, characterized a progressive fall PCV, negative or low faecal egg count, normal serum level, attributable both to blood-sucking activities developing young adults latency response host's erythropoietic system. second stage, which may not, at least initially, involve further reduction PCV nonetheless accompanied continuous abomasal haemorrhage marked stimulation erythropoiesis achieved expense animal's stores. final dramatic concentration, signals exhaustion synthetic machinery due frank deficiencies possibly available protein. nature timing underlying changes worm activity following re-infection add support concept experimental ‘self-cure’ immunological origin.