title: A more appropriate white blood cell count for estimating malaria parasite density in Plasmodium vivax patients in northeastern Myanmar.
abstract: The conventional method of estimating parasite densities employ an assumption of 8000 white blood cells (WBCs)/μl. However, due to leucopenia in malaria patients, this number appears to overestimate parasite densities. In this study, we assessed the accuracy of parasite density estimated using this assumed WBC count in eastern Myanmar, where Plasmodium vivax has become increasingly prevalent. From 256 patients with uncomplicated P. vivax malaria, we estimated parasite density and counted WBCs by using an automated blood cell counter. It was found that WBC counts were not significantly different between patients of different gender, axillary temperature, and body mass index levels, whereas they were significantly different between age groups of patients and the time points of measurement. The median parasite densities calculated with the actual WBC counts (1903/μl) and the assumed WBC count of 8000/μl (2570/μl) were significantly different. We demonstrated that using the assumed WBC count of 8000 cells/μl to estimate parasite densities of P. vivax malaria patients in this area would lead to an overestimation. For P. vivax patients aged five years and older, an assumed WBC count of 5500/μl best estimated parasite densities. This study provides more realistic assumed WBC counts for estimating parasite densities in P. vivax patients from low-endemicity areas of Southeast Asia.
authors.affiliation: Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China; Department of Infectious Diseases, The First Affiliated Hospital, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Huaie
authors.initials: H
authors.lastname: Liu
authors.affiliation: Biomedical Engineering Research Center, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Guohua
authors.initials: G
authors.lastname: Feng
authors.affiliation: Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Weilin
authors.initials: W
authors.lastname: Zeng
authors.affiliation: Department of Public Health, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Yao
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Deng
authors.affiliation: Department of Pathology, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Ruan
authors.affiliation: Department of Biochemistry, Kunming Medical University, Kunming, Yunnan Province, China.
authors.forename: James
authors.initials: J
authors.lastname: Morris
authors.affiliation: Eukaryotic Pathogens Innovation Center, Department of Genetics and Biochemistry, Clemson University, SC, USA.
authors.forename: Siman
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Pathogen Biology and Immunology, Kunming Medical University, Kunming, Yunnan Province, China. Electronic address: Zhaoqingy92@hotmail.com.
authors.forename: Zhaoqing
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Entomology, Pennsylvania State University, University Park, PA, USA. Electronic address: Luc2@psu.edu.
authors.forename: Liwang
authors.initials: L
authors.lastname: Cui
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007958:Leukocyte Count / Q000379:methods; D016780:Malaria, Vivax / Q000453:epidemiology* / Q000469:parasitology; D008297:Male; D008875:Middle Aged; D002052:Myanmar / Q000453:epidemiology; D010966:Plasmodium vivax / Q000472:pathogenicity*; D015995:Prevalence; D055815:Young Adult
keywords: Age; Malaria parasite; Parasite density; Parasite species; White blood cell count