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Malaria Prevalence among Young Infants in Different Transmission Settings, Africa - Volume 21, Number 7—July 2015 - Emerging Infectious Disease journal - CDC

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Malaria Prevalence among Young Infants in Different Transmission Settings, Africa - Volume 21, Number 7—July 2015 - Emerging Infectious Disease journal - CDC





Thumbnail of Study sites (arrows) in a study of malaria prevalence among young infants in The Gambia, Benin, and Guinea. Inset shows locations of the 3 countries in western Africa.

Figure 1. Study sites (arrows) in a study of malaria prevalence among young infants in The Gambia, Benin, and Guinea. Inset shows locations of the 3 countries in western Africa.

Volume 21, Number 7—July 2015

Research

Malaria Prevalence among Young Infants in Different Transmission Settings, Africa

Serign J. Ceesay, Lamine Koivogui, Alain Nahum, Makie Abdoulie Taal, Joseph Okebe, Muna Affara, Lama Eugène Kaman, Francis Bohissou, Carine Agbowai, Benoit Gniouma Tolno, Alfred Amambua-Ngwa, NFaly Bangoura, Daniel Ahounou, Abdul Khalie Muhammad, Stephan Duparc, Kamal Hamed, David Ubben, Kalifa Bojang, Jane Achan, and Umberto D’AlessandroComments to Author 
Author affiliations: Medical Research Council Unit, Fajara, The Gambia (S.J. Ceesay, J. Okebe, M. Affara, A. Amambua-Ngwa, A.K. Muhammad, K. Bojang, J. Achan, U. D’Alessandro); Institut National de Santé Publique, Conakry, Guinea (L. Koivogui, L.E. Kaman, B.G. Tolno); Centre de Recherches Entomologiques de Cotonou, Cotonou, Benin (A. Nahum, F. Bohissou, C. Agbowai, D. Ahounou); National Public Health Laboratory, Kotu, The Gambia (M.A. Taal); Préfectoral de la santé de Faranah, Guinea (N. Bangoura); Medicines for Malaria Venture, Geneva, Switzerland (S. Duparc, D. Ubben); Novartis Pharmaceuticals Corporation, East Hanover, New Jersey, USA (K. Hamed); London School of Hygiene and Tropical Medicine, London, UK (U. D’Alessandro); Institute of Tropical Medicine, Antwerp, Belgium (U. D’Alessandro)

Abstract

The prevalence and consequences of malaria among infants are not well characterized and may be underestimated. A better understanding of the risk for malaria in early infancy is critical for drug development and informed decision making. In a cross-sectional survey in Guinea, The Gambia, and Benin, countries with different malaria transmission intensities, the overall prevalence of malaria among infants <6 months of age was 11.8% (Guinea, 21.7%; The Gambia, 3.7%; and Benin, 10.2%). Seroprevalence ranged from 5.7% in The Gambia to 41.6% in Guinea. Mean parasite densities in infants were significantly lower than those in children 1–9 years of age in The Gambia (p<0.0001) and Benin (p = 0.0021). Malaria in infants was significantly associated with fever or recent history of fever (p = 0.007) and anemia (p = 0.001). Targeted preventive interventions, adequate drug formulations, and treatment guidelines are needed to address the sizeable prevalence of malaria among young infants in malaria-endemic countries.
Infants are thought to be protected against malaria during the first 6 months of life, largely due to the transfer of maternal antibodies (1) and the presence of fetal hemoglobin (2). Thus, young infants have received little attention in terms of malaria research and treatment guidelines, and this age group has systematically been excluded from clinical trials. As a consequence, young infants are frequently given off-label antimalarial treatments at dosing schedules recommended for older infants and children (3). The lack of attention to case management in this age group is a cause of concern and should be addressed, particularly when considering the widespread use of artemisinin-based combination therapies (ACTs) (4) and ongoing antimalarial drug development.
The true prevalence of malaria in young infants is not well characterized, yet defining the prevalence is critical, especially in light of ongoing epidemiologic shifts in populations at risk for malaria (5). Data on the prevalence and clinical outcomes of malaria in young infants are limited and contradictory: some studies show minimal risk (6–8), and others report that the risk for malaria increases in the first months of life, according to the intensity of transmission (9). A few reports indicate that the prevalence of disease is higher than previously thought and that, after birth, the period of protection against malaria is shorter than the widely quoted 6 months (10,11). However, variations in study designs and challenges related to small sample sizes, lack of details regarding quality control, and varied procedures for sample selection make it difficult to interpret findings from earlier studies (3). A better understanding of the risk for malaria in early infancy is needed to develop antimalarial drugs and inform policy decisions for this age group (4). To improve our knowledge of malaria in young infants, we used standardized methods and more sensitive diagnostics to better characterize the prevalence of malaria among children<6 months of age in different epidemiologic settings.

Mr. Ceesay is a higher scientific officer and research coordinator at the Medical Research Unit, The Gambia. His research interests have focused mainly on the epidemiology of malaria in The Gambia and, more recently, on determining the risk for malaria in early infancy and in different transmission settings.

Acknowledgments

We acknowledge the contribution of the field teams in all 3 countries, and we thank the participants and their families.
This study was funded by Medicines for Malaria Venture and Novartis Pharma AG.

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Figures

Tables

Suggested citation for this article: Ceesay SJ, Koivogui L, Nahum A, Taal MA, Okebe J, Affara M, et al. Malaria prevalence among young infants in different transmission settings, Africa. Emerg Infect Dis. 2015 Jul [date cited]. http://dx.doi.org/10.3201/eid2107.142036
DOI: 10.3201/eid2107.142036

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