Plasmodium falciparum Drug-Resistant Haplotypes and Population Structure in Postearthquake Haiti, 2010

Abstract

Abstract. Chloroquine (CQ) remains the first-line treatment of malaria in Haiti. Given the challenges of conducting in vivo drug efficacy trials in low-endemic settings like Haiti, molecular surveillance for drug resistance markers is a reasonable approach for detecting resistant parasites. In this study, 349 blood spots were collected from suspected malaria cases in areas in and around Port-au-Prince from March to July 2010. Among them, 121 samples that were Plasmodium falciparum positive by polymerase chain reaction were genotyped for drug-resistant pfcrt, pfdhfr, pfdhps, and pfmdr1 alleles. Among the 108 samples that were successfully sequenced for CQ resistant markers in pfcrt, 107 were wild type (CVMNK), whereas one sample carried a CQ-resistant allele (CVIET). Neutral microsatellite genotyping revealed that the CQ-resistant isolate was distinct from all other samples in this study. Furthermore, the remaining parasite specimens appeared to be genetically distinct from other reported Central and South American populations.

Plasmodium falciparumK76TpfcrtGene Mutations and Parasite Population Structure, Haiti, 2006–2009

“…These observations of highly related and clonal parasites that endure across years are consistent with decreasing transmission and potential inbreeding among the parasite population in Haiti. They are also consistent with the population structure analysis of Morton et al ( 14 ). …”

“…The observation that increasing use of chloroquine after the earthquake in 2010 did not select for or increase the prevalence of these mutations among the parasite population as described by Morton et al ( 14 ) is consistent with the lack of resistant forms of pfcrt among the population sampled in 2006 and 2009 in Haiti. Although a 2011–2012 study conducted by Okech et al raises concerns regarding drug efficacy related to the persistence of parasites in some patients treated with chloroquine, the resistance mutation was not detected ( 17 ).…”

“…In Haiti, identification of specific parasite genetic types may suggest importation of parasites related to humanitarian efforts or population migration; in addition, the identification of hot spots of transmission of specific parasite types can direct precise application of control efforts, particularly when resources are limited. Our equivocal detection of only 2 patients potentially harboring low-level populations of chloroquine resistance alleles despite screening >900 samples collected during 4 years supports the contention that the sustained propagation of CQR parasites was not occurring in Haiti during the study period; the possibility is raised by Morton et al that reported cases are of exogenous origin ( 14 ). The finding of low genetic diversity in the P. falciparum population in Haiti is also consistent with that of Morton et al and others ( 7 , 14 , 20 ).…”

“…The earthquake destroyed health infrastructure in the country, including the Ministry of Health and Population, killed >220,000 people, and left >1.5 million homeless. In the aftermath of this catastrophe, major efforts were deployed to establish enhanced surveillance systems to detect and prevent the transmission of disease in the affected population ( 13 , 14 ). …”

Malaria Surveillance — United States, 2015

“…Monitoring chloroquine resistance markers is recommended ( 76 – 80 ), and health care providers should contact CDC to assist with the evaluation of potential chloroquine failures identified after travel to Hispaniola. Seven samples from patients with infections acquired in the Dominican Republic in 2015 were tested for molecular resistance markers, and none contained a genotype associated with chloroquine resistance.…”