Hematological Indices in Malian Children Change Significantly During a Malaria Season and with Increasing Age: Implications for Malaria Epidemiological Studies.
Standard hematological indices are commonly used in malaria epidemiological studies to measure anemia prevalence and calculate blood parasite densities. In Africa, few studies have investigated how these indices change during a malaria transmission season and with increasing age. To address these knowledge gaps, we collected blood from 169 healthy Malian children aged 3-12 years before (May 2010) and after (January 2011) a transmission season. Red blood cell (RBC) count, hemoglobin (Hb) level, hematocrit (Ht), white blood cell (WBC) count, and WBC subsets were measured in paired blood samples, and the data were stratified by month (May, January) and age group (3-5, 6-8, and 9-12 years). From May to January, RBC count (4.53-4.70 × 10(6)/μL; P < 0.0001), Hb level (11.5-11.9 g/dL; P < 0.0001), and Ht (37.1-39.2%; P < 0.0001) increased, and WBC count (6.46-5.96 × 10(3)/μL; P = 0.0006) decreased. From May to January, the prevalence of WBC subsets also changed: 35-43% neutrophils, 6.5-7.6% monocytes, and 53-45% lymphocytes (P < 0.001). These seasonal changes were not associated with the number of malaria episodes experienced in the interim or the presence of RBC polymorphisms. In May, Hb (11.2, 11.4, and 11.8 g/dL; P = 0.0013) and Ht (36.5%, 36.7%, and 38.1%; P = 0.0154) increased and WBC count (8.04, 6.43, and 5.76 × 10(3)/μL; P < 0.0001) decreased with age group; similar differences were observed in January. These data suggest that season- and age-based reference values for hematological indices are needed to better estimate anemia prevalence and parasite density in malaria epidemiological studies.
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali. mdiakite@icermali.org mdiakite65@icermali.org.
Mahamadou
M
Diakite
Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
Kazutoyo
K
Miura
Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
Ababacar
A
Diouf
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali.
Drissa
D
Konate
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali.
Abdoul S
AS
Keita
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali.
Saibou
S
Doumbia
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali.
Seidina
S
Diakite
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali.
Karim
K
Traore
Faculty of Medicine, Pharmacy, and Odontostomatology (FMPOS), Malaria Research and Training Center (MRTC), University of Sciences, Techniques, and Technologies of Bamako (USTTB), Bamako, Mali.
Mory
M
Doumbouya
Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
Jennifer M
JM
Anderson
Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
Rick M
RM
Fairhurst
Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland.
Carole A
CA
Long
D000367:Age Factors; D000740:Anemia / Q000097:blood* / Q000453:epidemiology* / Q000469:parasitology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004909:Erythrocyte Indices; D005260:Female; D006400:Hematocrit; D006801:Humans; D007958:Leukocyte Count; D016778:Malaria, Falciparum / Q000097:blood* / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission; D008297:Male; D008302:Mali / Q000453:epidemiology; D018512:Parasitemia / Q000097:blood* / Q000453:epidemiology* / Q000469:parasitology / Q000635:transmission; D015995:Prevalence; D012424:Rural Population; D012621:Seasons