The population biology of the free-living phase of Haemonchus contortus.
A deterministic model for the demography of the free-living stages of Haemonchus contortus is described. The model consists of three compartments: the pre-infective stages, comprising the eggs and first- and second-stage larvae combined; third-stage larvae in the faeces; and third-stage larvae on the pasture. The mortality (mu j) of each of these stages was a function of temperature (K, where K = (degrees Celsius + 30)/100) of the form, mu j = a j exp [alpha j K] + b j exp [-beta j K]. The minimum time to second moult (tau) and the moulting rate thereafter (sigma) were also functions of temperature (ln [1/tau] = c1 + c2[1/K], and sigma = d1 exp [d2 K] respectively). The rate at which L3 larvae migrated out of the faeces was treated as a constant (0.165/larva/day).
Smith
G
G
University of Pennsylvania, School of Veterinary Medicine, New Bolton Center, Kennett Square, PA 19348.
D000818:Animals; D005243:Feces / Q000469:parasitology; D006189:Haemonchus / Q000254:growth & development*; D006813:Humidity; D008954:Models, Biological; D009026:Mortality; D012987:Soil; D013696:Temperature; D014867:Water
D012987:Soil; D014867:Water