Pairwise likelihood-ratio test chi-square values comparing the fit of dose-response relationships.

aDF: Degrees of freedom.bThe degree of measurement error is summarized by parameter k of the negative binomial distribution, which is an inverse measure of extra-Poisson variation in the distribution of microfilarial counts measured per individual.cPoisson measurement errors.dMeasurement error estimated from published data [43].eArbitrarily large measurement error.