title: Risk factors for Plasmodium vivax gametocyte carriage in Thailand.
abstract: To study the risk factors for Plasmodium vivax gametocyte carriage, the presence or absence of gametocytes was determined in 2,125 patients with P. vivax malaria participating in clinical trials at the Hospital for Tropical Diseases in Bangkok, Thailand. Stepwise logistic regression models were used to determine which variables were significantly related to gametocyte carriage. On admission, 615 patients (29%) had detectable gametocytes (before treatment). After treatment had started, an additional 245 patients (11%) developed patent gametocytemia. The variables retained by multivariate analysis were highest observed temperature (adjusted odds ratio [AOR] per degrees C increase = 0.82, 95% confidence interval [CI] = 0.71-0.94, P = 0.006), asexual parasitemia > 9,200/muL (AOR = 2.8, 95% CI = 1.9-4.2, P < 0.0001), erythrocyte counts (AOR = 0.8/million/muL increase, 95% CI = 0.67-0.95, P = 0.01), monocyte percentage (AOR = 0.93 per % increase, 95% CI = 0.89-0.96, P < 0.0001), lymphocyte percentage (AOR = 0.98 per % increase, 95% CI = 0.97-0.99, P = 0.006), albumin (AOR = 0.67 per 10 g/mL increase, 95% CI = 0.5-0.9, P = 0.007), and anion gap (AOR = 1.1 per unit increase, 95% CI = 1.02-1.14, P = 0.009). The possible significance of these observations is discussed.
authors.affiliation: Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. m_nacher@lycos.com
authors.forename: Mathieu
authors.initials: M
authors.lastname: Nacher
authors.forename: Udomsak
authors.initials: U
authors.lastname: Silachamroon
authors.forename: Pratap
authors.initials: P
authors.lastname: Singhasivanon
authors.forename: Polrat
authors.initials: P
authors.lastname: Wilairatana
authors.forename: Weerapong
authors.initials: W
authors.lastname: Phumratanaprapin
authors.forename: Arnaud
authors.initials: A
authors.lastname: Fontanet
authors.forename: Sornchai
authors.initials: S
authors.lastname: Looareesuwan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000962:Antimalarials / Q000627:therapeutic use; D002353:Carrier State / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008018:Life Cycle Stages; D016780:Malaria, Vivax / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D018512:Parasitemia / Q000097:blood; D010966:Plasmodium vivax / Q000254:growth & development; D012307:Risk Factors; D013785:Thailand / Q000453:epidemiology; D013997:Time Factors
chemical_list: D000962:Antimalarials