Airborne dust and high temperatures are risk factors for invasive bacterial disease

Abstract

BackgroundThe 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.ObjectiveWe aimed to assess the link between climatic factors and occurrence of invasive respiratory bacterial disease in a Sahel region of Niger.MethodsWe 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.ResultsHigh 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.ConclusionOur 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.

An Evaluation of the CHIMERE Chemistry Transport Model to Simulate Dust Outbreaks across the Northern Hemisphere in March 2014

“…Sea salt emissions are mostly influenced by wind speed and the resulting concentrations are obviously high over the North Pacific and Atlantic oceans where the low-pressure systems are still active in early spring, the order of magnitude is in agreement with observational data as reported on coastal areas [88,89]. 10 concentrations are located over the arid and semi-arid regions and also over the most populated areas in Asia. High PM levels are simulated in the southwest of the USA.…”

“…As shown in Figure 26, the ratio PM coarse /PM 10 exceeds 50-60% during the previous identified episode; this threshold is usually mentioned to identify a mineral dust outbreak [16]. On average, the model captures quite well the evolution of PM concentrations over the Beijing area in March 2014 (Figure 27), the correlation is close to 0.8 for most of stations either for PM 2.5 and PM 10 concentrations with a very low bias. However, the coarse fraction seems underestimated by the model (Figure 26).…”

“…In this paper, SIA, SOA, DUST, SALT, and TPPM, respectively, refer to Secondary Inorganic Aerosol (sum of nitrate, sulfate and ammonium), Secondary Organic Aerosols (anthropogenic and biogenic in origins), natural mineral dust, sea salt and Total Primary Particle Matter (total primary anthropogenic carbonaceous and non-carbonaceous species). The attribute "−10", "−25" or "coarse" are affected, respectively, for the PM 10 , and PM 2.5 and the coarse (PM 10 -PM 2.5 ) fractions. "Total dust" (sum over all bins including the bin above 10 µm) is a terminology sometimes used in this study; the "coarse" fraction can include the last bin in some analyses.…”

“…The impact of pollutants on health, ecosystems and climate were clearly highlighted by many studies. The main sources of pollutants are anthropogenic and biogenic in origin and in the two last decades, particulate matter (PM) were identified as a vector of toxics particularly the fine fractions PM 10 and PM 2.5 (respectively, the mass of particles with diameter below 10 and 2.5 µm). According to the World to 1 or 2 km over large domains [29] showing the added value of finer resolutions to analyze the evolution of anthropogenic pollution plumes issued from source areas.…”

“…• Atmospheric composition data from the US IMPROVE network are also available with PM 2.5 , PM 10 and Soil PM concentrations based on calcium measurements [82]. Daily data are available every three days and available at http://vista.cira.colostate.edu/Improve/improve-data/.…”