Send to

Choose Destination
Parasitology. 1990 Oct;101 Pt 2:309-16.

The population biology of the free-living phase of Haemonchus contortus.

Author information

University of Pennsylvania, School of Veterinary Medicine, New Bolton Center, Kennett Square, PA 19348.


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).

[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center