DHFR and infection: In contrast, the prevalence of dhfr triple and dhfr/dhps quadruple mutants (dhfr triple mutant plus dhps A437G in the same infection) remained stable over a one-year period as IPTi-SP was implemented in Mali in 2006–2007, with no differences in marker prevalences between 11 IPTi implementation zones and 11 control zones [79].