Parasite prevalence and statistical analysis
Mean comparisons were made with t -tests for two independent means, with α = 0.05. The maximum possible prevalence of infection, interpreted as the maximum prevalence (for each pathogen) that could be present in a population but not observed (i.e. with all tested samples negative), was calculated with three confidence levels (90, 95 and 99%) with an unknown population size using WinEpi 2.0 (Thrusfield, Ortega, de Blas, Noordhuizen, & Frankena, 2001).