Antimalarial drug resistance markers in human immunodeficiency virus (HIV)-positive and HIV-negative adults with asymptomatic malaria infections in Port Harcourt, Nigeria.

We found evidence of continued chloroquine use among HIV-positive individuals. Selection for the pfmdr1 86N after artemether-lumefantrine treatment was observed, indicating a possible threat to antimalarial efficacy in the study area. The complexity of pfdhps haplotypes emphasises the need for careful monitoring of anti-folate susceptibility in Nigeria.