title: Airborne dust and high temperatures are risk factors for invasive bacterial disease.
abstract: BACKGROUND
  The Sahel region of West Africa has the highest bacterial meningitis attack and case fatality rate in the world. The effect of climatic factors on patterns of invasive respiratory bacterial disease is not well documented.
  
  
  OBJECTIVE
  We aimed to assess the link between climatic factors and occurrence of invasive respiratory bacterial disease in a Sahel region of Niger.
  
  
  METHODS
  We conducted daily disease surveillance and climatic monitoring over an 8-year period between January 1, 2003, and December 31, 2010, in Niamey, Niger, to determine risk factors for bacterial meningitis and invasive bacterial disease. We investigated the mechanistic effects of these factors on Streptococcus pneumoniae infection in mice.
  
  
  RESULTS
  High temperatures and low visibility (resulting from high concentrations of airborne dust) were identified as significant risk factors for bacterial meningitis. Dust inhalation or exposure to high temperatures promoted progression of stable asymptomatic pneumococcal nasopharyngeal carriage to pneumonia and invasive disease. Dust exposure significantly reduced phagocyte-mediated bacterial killing, and exposure to high temperatures increased release of the key pneumococcal toxin pneumolysin through increased bacterial autolysis.
  
  
  CONCLUSIONS
  Our findings show that climatic factors can have a substantial influence on infectious disease patterns, altering density of pneumococcal nasopharyngeal carriage, reducing phagocytic killing, and resulting in increased inflammation and tissue damage and consequent invasiveness. Climatic surveillance should be used to forecast invasive bacterial disease epidemics, and simple control measures to reduce particulate inhalation might reduce the incidence of invasive bacterial disease in regions of the world exposed to high temperatures and increased airborne dust.
authors: Centre de Recherche Médicale et Sanitaire, Niamey, Niger.
authors: Jean-François
authors: JF
authors: Jusot
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom. Electronic address: d.neill@liverpool.ac.uk.
authors: Daniel R
authors: DR
authors: Neill
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom.
authors: Elaine M
authors: EM
authors: Waters
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom; European Public Health Microbiology Training Programme (EUPHEM), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
authors: Mathieu
authors: M
authors: Bangert
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom.
authors: Marisol
authors: M
authors: Collins
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom.
authors: Laura
authors: L
authors: Bricio Moreno
authors: Direction de la Météorologie Nationale, Niamey, Niger.
authors: Katiellou G
authors: KG
authors: Lawan
authors: Direction de la Météorologie Nationale, Niamey, Niger.
authors: Mouhaiminou Moussa
authors: MM
authors: Moussa
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom.
authors: Emma
authors: E
authors: Dearing
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi.
authors: Dean B
authors: DB
authors: Everett
authors: Centre de Recherche Médicale et Sanitaire, Niamey, Niger.
authors: Jean-Marc
authors: JM
authors: Collard
authors: Department of Clinical Infection, Microbiology and Immunology, Institute of Infection & Global Health, University of Liverpool, Liverpool, United Kingdom. Electronic address: kadioglu@liverpool.ac.uk.
authors: Aras
authors: A
authors: Kadioglu
mesh_terms: D000293:Adolescent; D000393:Air Pollutants; D000818:Animals; D002675:Child, Preschool; D004391:Dust; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016920:Meningitis, Bacterial / Q000453:epidemiology*; D051379:Mice; D009548:Niger / Q000453:epidemiology; D011008:Pneumococcal Infections / Q000276:immunology; D012307:Risk Factors; D013296:Streptococcus pneumoniae; D013696:Temperature
chemical_list: D000393:Air Pollutants; D004391:Dust
keywords: Meningitis; Neisseria meningitidis; Streptococcus pneumoniae; climate; dust; pollution