The determination of the pfmdr1 copy number in samples collected after 2008 could provide a useful complement for the assessment of potential resistance to artemether and lumefantrine. The observed low genetic diversity www.selleckchem.com/products/BAY-73-4506.html of the P. falciparum population does probably reflect the context of an island country, where gene flow may be restricted. This low diversity was compared with observations in PNG [24]. In contrast to the SI situation, where mutations associated with antimalarial drug resistance tended to be fixed, the diversity was higher in PNG with various SNP patterns present in the P. falciparum population. However, the most dominant SNP pattern related to CQ resistance seen in PNG between 1992 and 2002 [37] was composed of mutations pfcrt K76T, A220 S, N326 D and I356L, which corresponds to the dominant haplotype observed in the SI.

Regarding SP resistance, the dominant SNP pattern in PNG was the pfdhfr C59R+S108N double mutant, which also corresponds to the dominant haplotype in SI. Parasite populations in SI and PNG show similarities that can be explained by their close geographical vicinity. However, the pronounced insularity and remoteness of the SI differs from PNG and this may be reflected in the lower genetic diversity observed in the SI. The absence of mutations in pfdhps in the SI, which are already present in PNG, is a possible illustration of such low gene flow. A meta-population analysis on the diversity of genes encoding P. falciparum vaccine antigens also reported that biogeographic characteristics of island nations in the Pacific constitute a barrier to gene flow [38].

Restricted gene flow is also reflected in the low mean multiplicity of infection in the SI (1.39 concurrent infections in parasite positive samples). For comparison, in a coastal location in PNG having similar geographical characteristics, the multiplicity of infection was slightly higher (1.54), and the msp2 PCR-based P. falciparum prevalence was also higher than in the SI (32% versus 25%, respectively) [39]. An additional explanation for limited diversity in the considered study site could be the vector control measures. Field evaluations have shown that insecticide-impregnated bed nets and indoor residual spraying together with educational activities significantly reduced malaria transmission in north Guadalcanal Province and contributed to a slow decrease of malaria incidence in the SI since 1992 [40].

To further validate the hypothesis of restricted gene flow in the SI in contrast to PNG, the diversity of various Brefeldin_A microsatellites which are not under selection pressure could be tested. In conclusion, the present data provide baseline information on the prevalence of P. falciparum drug resistance-associated SNPs and highlight the low level of genetic diversity in the P. falciparum population in the Guadalcanal Province of the SI.