Risk factors for Plasmodium vivax gametocyte carriage in Thailand.
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.
Nacher
Mathieu
M
Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. m_nacher@lycos.com
Silachamroon
Udomsak
U
Singhasivanon
Pratap
P
Wilairatana
Polrat
P
Phumratanaprapin
Weerapong
W
Fontanet
Arnaud
A
Looareesuwan
Sornchai
S
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
D000962:Antimalarials