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Table 2 Main features of major trichostrongylid nematodes of sheep and environmental influences on survival; adapted from[28]

From: Impact of gastrointestinal parasitic nematodes of sheep, and the role of advanced molecular tools for exploring epidemiology and drug resistance - an Australian perspective

Nematode species

Life cycle stage

   
 

Unembryonated egg

Embryonated egg

Pre-infective larvae

Infective larvae

H. contortus

High susceptibility to cold and desiccation. High mortality at < 10°C.

Susceptible to cold and desiccation. Low hatching in the abscence of moisture and/or at < 10°C.

High susceptibility to cold and desiccation.

Optimum survival under warm and moist conditions. Poor survival in dry climates (warm or cool) and sub-freezing winter.

T. colubriformis

Intermediate susceptibility to cold and desiccation. High mortality at < 5°C.

Intermediate susceptibility to cold. Low susceptibility to desiccation.

Susceptible to cold and desiccation. High mortality at < 5°C.

Optimum survival under warm or cool moist conditions. Poor survival over sub-freezing winters.

Te. circumcincta

Low susceptibility to cold. Intermediate susceptibility to desiccation. High egg viability at 0-10°C.

Low susceptibility to cold and desiccation. Hatching at < 5°C.

Intermediate susceptibility to cold. Susceptible to desiccation.

Optimum survival under cool moist conditions and sub-freezing winters. Poor survival under warm, dry conditions.