title: The participation of secondary clinical episodes in the epidemiology of vivax malaria during pre- and post-implementation of focal control in the state of Oaxaca, Mexico.
abstract: The participation of vivax malaria secondary clinical was researched in a retrospective cohort of 33,414 confirmed cases occurring between 1994 and 2005 in the state of Oaxaca, Mexico. Secondary episodes occurred in 23.4% of all primary cases. An increase in secondary episodes was associated with primary cases occurring during the dry seasons (risk ratio [RR] = 1.68, 95% CI: 1.45-1.96). The incidence of secondary episodes peaked at an older age, occurred similarly in men and women mostly during low mosquito abundance, and had a uniform distribution among localities. A reduction in secondary episodes was associated with the administration of an increased dose and early administration of primaquine (RR = 0.32, 95% CI: 0.26-0.38). However, limitations to distinguish relapses from re-infections impede assessment of the new treatment effect on relapses and its contribution to malaria control in the area. These findings highlight the need for new therapeutic schemes to radical cure of P. vivax infections and operational research aimed at parasite pool elimination.
authors.affiliation: Center for Research in Infectious Diseases, National Institute of Public Health, Cuernavaca, Morelos, Mexico. mhenry@insp.mx
authors.forename: Mario H
authors.initials: MH
authors.lastname: Rodriguez
authors.forename: Angel F
authors.initials: AF
authors.lastname: Betanzos-Reyes
authors.forename: Juan E
authors.initials: JE
authors.lastname: Hernández-Avila
authors.forename: Jorge F
authors.initials: JF
authors.lastname: Méndez-Galván
authors.forename: Rogelio
authors.initials: R
authors.lastname: Danis-Lozano
authors.forename: Armando
authors.initials: A
authors.lastname: Altamirano-Jiménez
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000962:Antimalarials / Q000008:administration & dosage / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D002738:Chloroquine / Q000008:administration & dosage / Q000627:therapeutic use; D015331:Cohort Studies; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D016780:Malaria, Vivax / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D009032:Mosquito Control / Q000379:methods; D011319:Primaquine / Q000008:administration & dosage / Q000627:therapeutic use; D012189:Retrospective Studies; D012621:Seasons; D055815:Young Adult
chemical_list: D000962:Antimalarials; D002738:Chloroquine; D011319:Primaquine