Effect of 8-Br-cGMP or 8-Br-AMP on midgut infections of T. b. brucei in male G. m. morsitans. Flies were infected at their first feed, the bloodmeal containing 8-Br-cGMP or 8-Br-AMP dissected 10 days later and midguts examined for trypanosome presence by microscopy. Control flies were received saline in their bloodmeal. Data presented as the mean S.E.M. from three experiments. Significance: *** p < 0.001 versus the corresponding control value.