Parasite prevalence and sample size: misconceptions and solutions.

Parasite prevalence (the proportion of infected hosts) is a common measure used to describe parasitaemias and to unravel ecological and evolutionary factors that influence host-parasite relationships. Prevalence estimates are often based on small sample sizes because of either low abundance of the hosts or logistical problems associated with their capture or laboratory analysis. Because the accuracy of prevalence estimates is lower with small sample sizes, addressing sample size has been a common problem when dealing with prevalence data. Different methods are currently being applied to overcome this statistical challenge, but far from being different correct ways of solving a same problem, some are clearly wrong, and others need improvement.