title: Clonal outbreak of Plasmodium falciparum infection in eastern Panama.
abstract: Identifying the source of resurgent parasites is paramount to a strategic, successful intervention for malaria elimination. Although the malaria incidence in Panama is low, a recent outbreak resulted in a 6-fold increase in reported cases. We hypothesized that parasites sampled from this epidemic might be related and exhibit a clonal population structure. We tested the genetic relatedness of parasites, using informative single-nucleotide polymorphisms and drug resistance loci. We found that parasites were clustered into 3 clonal subpopulations and were related to parasites from Colombia. Two clusters of Panamanian parasites shared identical drug resistance haplotypes, and all clusters shared a chloroquine-resistance genotype matching the pfcrt haplotype of Colombian origin. Our findings suggest these resurgent parasite populations are highly clonal and that the high clonality likely resulted from epidemic expansion of imported or vestigial cases. Malaria outbreak investigations that use genetic tools can illuminate potential sources of epidemic malaria and guide strategies to prevent further resurgence in areas where malaria has been eliminated.
authors.affiliation: Department of Immunology and Infectious Diseases.
authors.forename: Nicanor
authors.initials: N
authors.lastname: Obaldia
authors.affiliation: Department of Immunology and Infectious Diseases.
authors.forename: Nicholas K
authors.initials: NK
authors.lastname: Baro
authors.affiliation: Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama City, Panama.
authors.forename: Jose E
authors.initials: JE
authors.lastname: Calzada
authors.affiliation: Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama City, Panama.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Santamaria
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University.
authors.forename: Rachel
authors.initials: R
authors.lastname: Daniels
authors.affiliation: Department of Immunology and Infectious Diseases.
authors.forename: Wesley
authors.initials: W
authors.lastname: Wong
authors.affiliation: Department of Epidemiology, Harvard School of Public Health.
authors.forename: Hsiao-Han
authors.initials: HH
authors.lastname: Chang
authors.affiliation: Department of Immunology and Infectious Diseases.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Hamilton
authors.affiliation: Centro de Investigación Científica Caucaseco/Centro Latino Americano de Investigación en Malaria, Cali, Colombia.
authors.forename: Myriam
authors.initials: M
authors.lastname: Arevalo-Herrera
authors.affiliation: Centro de Investigación Científica Caucaseco/Centro Latino Americano de Investigación en Malaria, Cali, Colombia.
authors.forename: Socrates
authors.initials: S
authors.lastname: Herrera
authors.affiliation: Department of Immunology and Infectious Diseases Broad Institute, Cambridge, Massachusetts.
authors.forename: Dyann F
authors.initials: DF
authors.lastname: Wirth
authors.affiliation: Department of Organismic and Evolutionary Biology, Harvard University.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Hartl
authors.affiliation: Department of Immunology and Infectious Diseases.
authors.forename: Matthias
authors.initials: M
authors.lastname: Marti
authors.affiliation: Department of Immunology and Infectious Diseases Simmons College, Boston Broad Institute, Cambridge, Massachusetts.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Volkman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000962:Antimalarials / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000494:pharmacology*; D016000:Cluster Analysis; D003105:Colombia; D058893:DNA Barcoding, Taxonomic; D004196:Disease Outbreaks; D004351:Drug Resistance / Q000235:genetics*; D005260:Female; D056426:Genetic Loci / Q000235:genetics; D006239:Haplotypes; D006801:Humans; D016778:Malaria, Falciparum / Q000453:epidemiology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D010176:Panama / Q000453:epidemiology; D010963:Plasmodium falciparum / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D020641:Polymorphism, Single Nucleotide; D015800:Protozoan Proteins / Q000235:genetics; D055815:Young Adult
chemical_list: D000962:Antimalarials; D015800:Protozoan Proteins; D002738:Chloroquine
keywords: Plasmodium falciparum; drug resistance; molecular surveillance; outbreak, epidemic; tropical diseases