The influence of haemoglobin phenotype on the susceptibility of sheep to Haemonchus contortus infection in Kenya.
Two flocks of Merino sheep were set-stocked on pastures known to be endemic for Haemonchus contortus. Both flocks included sheep with the three common haemoglobin types (HbAA, HbAB, HbBB). The results of regular monitoring over a two-year period showed a clear relationship between haemoglobin types and susceptibility to haemonchosis. The HbAA sheep experienced fewer deaths, had consistently lower egg counts and exhibited a more frequency and effective self-cure than the HbAB or the HbBB types. Post mortem findings demonstrated that this phenomenon was due to differences in the establishment of adult H contortus and not to suppression of egg laying capacity or an alteration of male to female adult worm ratio.
D000818:Animals; D004198:Disease Susceptibility; D005243:Feces / Q000469:parasitology; D005260:Female; D006188:Haemonchiasis / Q000662:veterinary*; D006454:Hemoglobins / Q000235:genetics*; D007630:Kenya; D008297:Male; D010270:Parasite Egg Count; D010641:Phenotype; D012756:Sheep; D012757:Sheep Diseases / Q000097:blood / Q000235:genetics* / Q000469:parasitology; D014252:Trichostrongyloidiasis / Q000662:veterinary*
D006454:Hemoglobins