Investigation of Mutations in the crt-o and mdr1 Genes of Plasmodium vivax for the Molecular Surveillance of Chloroquine Resistance in Parasites from Gold Mining Areas in Roraima, Brazil

Abstract

Plasmodium vivax causes the largest malaria burden in Brazil, and chloroquine resistance poses a challenge to eliminating malaria by 2035. Illegal mining in the Roraima Yanomami Indigenous territory can lead to the introduction of resistant parasites. This study aimed to investigate mutations in the pvcrt-o and pvmdr-1 genes to determine their potential as predictors of P. vivax chloroquine-resistant phenotypes. Samples were collected in two health centers of Boa Vista. A questionnaire was completed, and blood was drawn from each patient. Then, DNA extraction, PCR, amplicon purification, and DNA sequencing were performed. After alignment with the Sal-1, the amplified fragment was analyzed. Patients infected with the mutant parasites were queried in the Surveillance Information System. Among the patients, 98% (157/164) of participants were from illegal mining areas. The pvcrt-o was sequenced in 151 samples, and the K10 insertion was identified in 13% of them. The pvmdr1 was sequenced in 80 samples, and the MYF haplotype (958M) was detected in 92% of them and the TYF was detected in 8%, while the MYL was absent. No cases of recrudescence, hospitalization, or death were found. Mutations in the pvcrt-o and pvmdr-1 genes have no potential to predict chloroquine resistance in P. vivax.

Keywords: Amazon; chloroquine; malaria; mining; pvcrt-o; pvmdr1.

Figure 1

Location map of Roraima, Boa Vista, the urban area of Boa Vista, and sample collection sites.

Figure 2

Distribution of K10 insertions (codon AAG) in the pvcrt-o gene in P. vivax samples, according to probable site of infection (n = 151).

Figure 3

Distribution of pvmdr1 gene haplotypes in P. vivax samples, according to probable site of infection (n = 80).

Figure 4

Percentage of pvcrt-o and pvmdr1 gene alleles in the 79 samples sequenced for both genes.