The African Sahel, an area that stretches from Senegal in the west to Ethiopia in the east, is known as the 'meningitis belt'. Over the past ten years, there have been about one million cases of bacterial meningitis, resulting in some 100,000 deaths. Caused by Streptococcus pneumoniae, it can result in an often-lethal inflammation of the lining of the brain.
Most people carry the bacteria that causes meningitis in their nasal passages, but researchers think that sand and other airborne debris people breathe in during a sandstorm carries the bacteria high into the respiratory tract where it is more likely to develop into the deadly infection. When combined with extremely hot temperatures, the bacteria release toxins that make it hard for the immune system to fight off infection.
Investigators measured periods of visibility during the storms. They found that the lower the visibility - where people could see for no more than three meters - the more cases of meningitis were reported.
Researchers suggest that people should cover their faces during a sandstorm or dust storm, but that may hardly be a helpful suggestion, because the airborne particles may be so small that they may penetrate almost any cover.
 Jusot et al: Airborne dust and high temperatures are risk factors for invasive bacterial disease in Journal of Allergy and Clinical Immunology – 2016