Skip to main content

Table 3 The results of the final linear models to estimate each life history trait of the parasitic phase of H. contortus

From: Meta-analysis of the parasitic phase traits of Haemonchus contortus infection in sheep

Life history traits Explanatory factors Estimation of means SE P
Larval establishment rate (proportion of ingested larvae that develop into immature or adult worms)
Infection duration     0.04
4–9 dpi 0.09 0.08  
12–16 dpi 0.27 0.05  
21–30 dpi 0.23 0.03  
Infection dose     0.004
4000–5000 L3 0.25 0.05  
10,000 L3 0.22 0.03  
16,000–20,000 L3 0.05 0.07  
30,000 L3 0.26 0.08  
Host age     0.007
2.5–5 months 0.29 0.06  
5.5–10 months 0.21 0.02  
12–36 months 0.08 0.07  
Adult mortality rate (Proportion of adult worms that die per day)
Host GIN resistance status     0.003
Susceptible 0.039 0.009  
Resistant 0.065 0.011  
Unknwon 0.048 0.009  
Isolate status     0.005
Susceptible to anthelmintics or non-adapted to sheep resistance isolate of H. contortus 0.044 0.009  
Isolate adapted to sheep resistancea 0.069 0.033  
Isolate resistant to anthelmintics 0.062 0.012  
Unknown 0.026 0.003  
Host age     0.005
1.2–3 months 0.045 0.009  
4.5–8 months 0.059 0.010  
11–12 months 0.047 0.009  
Previous host exposure     < 0.001
Immunologically naive 0.049 0.009  
Suspected natural pre-infection 0.039 0.010  
Experimental abbreviated pre-infection 0.063 0.009  
Female fertility (number of eggs/female/day)
Host GIN resistance status     < 0.001
Susceptible 4545.2 310.0  
Resistant 2740.9 361.5  
Unknown 3465.6 513.1  
Infection duration     < 0.001
27–30 dpi 2136.5 308.9  
41–50 dpi 2270.6 204.3  
70 dpi 6344.7 821.2  
Previous exposure of host     < 0.001
Immunologically naive host 4626.8 372.0  
Experimental pre-infection 2541.0 377.8  
Population level fecundity (number of eggs/gram of faeces)b
Host GIN resistance status     < 0.001
Susceptible 13536.8 1429.1  
Resistant 4837.4 918.8  
Unknown 9563.8 992.7  
Infection duration     0.002
27–28 dpi 5032.6 1034.9  
30 dpi 18032.4 2575.9  
41–49 dpi 4873.0 415.6  
  1. aBy serial passages in resistant host
  2. bThe host age was not included in the models for this trait due to a limited dataset
  3. Abbreviation: SE standard error