Table 1.

Counts of infectious (I), recovered (R) and susceptible (S) gerbils (with proportions in parentheses), where captures were divided into those from a burrow system known to contain one or more infectious gerbils the previous trapping session (relatively rare) and those from burrow systems where there was no evidence of recent infection (Pearson's χ² test: P=0·0027 and 1·8×10⁻⁵ for sites 1 and 2 respectively)