Abstract:
The multidrug resistance of Plasmodium falciparum to antimalarial drugs is a major public health concern in the
global management of malaria, especially in developing countries. As of today, malaria treatment is primarily dependent
on the sustained efficacy of artemisinin-based combination therapy (ACT). Recent reports indicating decline in efficacy of
ACT and artesunate monotherapy in Southeast Asia are a major threat to global malaria control achievements. Initially,
mutations in Pfmdr1 were associated with chloroquine and amodiaquine resistance only, but there are now emerging field
study reports of Pfmdr1 mutation conferring tolerance to ACT. The current study used Restriction Fragment Length
Polymorphism to evaluate the prevalence of genetic polymorphisms of Plasmodium falciparum multidrug resistance
(Pfmdr1) and Plasmodium falciparum chloroquine-resistant transporter (Pfcrt) gene mutations in Mbita and Nyando field
isolates. The findings report that the prevalence of Pfcrt K76T mutation in Plasmodium falciparum field isolates in Mbita
declined significantly from 76.3% (95% CI 21.0-31.0) in 2008 to 51.9% (95% CI 19.0-25.0) in 2014, a reduction of 24.4% (χ2df
=1 = 4.709, P = 0.0000). In Nyando, prevalence stood at 66.8% (95% CI 12.0-14.0) in 2014 down from 73.7% (95% CI 27.0
48.0), insignificant reduction of 6.9% (χ2df =1 = 17.699, P = 0.0913). Prevalence for Pfmdr1 in Mbita stood at 14.7% (95% CI
44.0-51.0) in 2014 down from 21.9% (95% CI 31.0-49.0) in 2008, a significant reduction of 4.3% (χ2df =1 = 9.011, P = 0.001).
While in Nyando, field isolate samples recorded 16.2% (95% CI 22.0-31.0) in 2014, down from 30.6% (95% CI 12.0-27.0),
insignificant reduction of 1.9% (χ2df =1 = 11.777, P = 0.0591). Our findings confirm a common trend reported by previous
studies: that there has been a small decline in the prevalence of the Pfcrt mutation over a decade since the withdrawal of
Chloroquine as the first line of treatment for uncomplicated cases of malaria in Kenya.
Keywords: polymorphism, resistance, susceptibility, mutation
