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Age-dependent sex bias in clinical malarial disease in hypoendemic regions.
- Source :
-
PloS one [PLoS One] 2012; Vol. 7 (4), pp. e35592. Date of Electronic Publication: 2012 Apr 25. - Publication Year :
- 2012
-
Abstract
- Background and Objectives: Experimental models show a male bias in murine malaria; however, extant literature on biases in human clinical malaria is inconclusive. Studies in hyperendemic areas document an absence of sexual dimorphism in clinical malaria. Data on sex bias in clinical malaria in hypoendemic areas is ambiguous--some reports note a male bias but do not investigate the role of differential mosquito exposure in that bias. Moreover, these studies do not examine whether the bias is age related. This study investigates whether clinical malaria in hypoendemic regions exhibits a sex bias and whether this bias is age-dependent. We also consider the role of vector exposure in this bias.<br />Methods: Retrospective passive clinical malaria datasets (2002-2007) and active surveillance datasets (2000-2009) were captured for the hypoendemic Mumbai region in Western India. To validate findings, passive retrospective data was captured from a primary malaria clinic (2006-2007) in hypoendemic Rourkela (Eastern India). Data was normalized by determining percent slide-positivity rates (SPRs) for males and females, and parasite-positivity distributions were established across age groups. The Mann-Whitney test, Wilcoxon Signed Rank test, and Chi-square analysis were used to determine statistical significances.<br />Results: In both the Mumbai and Rourkela regions, clinical malaria exhibited an adult male bias (p<0.01). A sex bias was not observed in children aged ≤10. Post-puberty, male SPRs were significantly greater than females SPRs (p<0.01). This adult male bias was observed for both vivax and falciparum clinical disease. Analysis of active surveillance data did not reveal an age or sex bias in the frequency of parasite positivity.<br />Conclusion: This study demonstrates an age-dependent sex bias in clinical malaria in hypoendemic regions and enhanced incidence of clinical malaria in males following puberty. Possible roles of sex hormones, vector exposure, co-infections, and other factors in this enhanced susceptibility are discussed.
- Subjects :
- Adolescent
Adult
Age Factors
Animals
Child
Child, Preschool
Disease Vectors
Endemic Diseases
Female
Humans
India epidemiology
Malaria, Falciparum parasitology
Malaria, Vivax parasitology
Male
Middle Aged
Phylogeography
Plasmodium falciparum physiology
Plasmodium vivax physiology
Retrospective Studies
Sex Factors
Anopheles physiology
Behavior, Animal physiology
Malaria, Falciparum epidemiology
Malaria, Vivax epidemiology
Population Surveillance
Subjects
Details
- Language :
- English
- ISSN :
- 1932-6203
- Volume :
- 7
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- PloS one
- Publication Type :
- Academic Journal
- Accession number :
- 22558172
- Full Text :
- https://doi.org/10.1371/journal.pone.0035592