Desert Dust, Aerobiology and Human Implications

 In recent years, the natural environment and human health have become increasingly associated. De Longueville et al (2010) reveal that around 30% of global diseases can be attributed to environmental dynamics. As we have discussed already, aeolian activity in deserts because of the extreme erosivity and erodibility can result in extensive entrainment of fine particles, and in some cases, long-distance transport on various trajectories. Transoceanic and transcontinental (in the case of Asian deserts) dust loadings are now known to facilitate the dispersal of pathogens. The biogeographical range of pathogens is consequently increased in significant dust events and the considerable health implications of allergens and pathogens means such occurrences are being increasingly investigated (Kellogg and Griffin, 2006).  

There are a number of ways in which dust particles can affect humans and ecological patterns and processes. At the most basic of levels, mineral dust can have a significant effect on horizontal visibility and air quality. More worryingly, perhaps, evidence has been presented of the long distance transfer of aerosolised microbiota around the globe. Moreover, the concentrations of such microorganisms have been confirmed as higher during dust events, although the magnitudes of concentrations are still to be verified (Kellogg and Griffin, 2006). Aspergillus fumigatus, Aspergillus niger, Staphylococcus gallinarum and Gordonia terrae have all been found in African dust. There are various hypotheses linking African dust transport to episodes of coral reef morbidity and Caribbean basin mortality with the discovery of the fungus Aspergillus sydowii in Sahelian soil (Rypien, 2008). Many of the bacteria found are spore-formers, making them more resistant to desiccation, increasing the potential of successful long distance transport.

Global  transport of microorganisms and toxic compounds in clouds of desert dust (USGS)

With humans no doubt adding to the production of dust by breaking down crusts, removing vegetation, overgrazing, vehicular use and construction activity, the potential for dust-borne pathogens to be transported to regions of high population density or ecological significance is ever increasing. Study is this discipline is in its relative infancy but will surely receive more attention because of the threat posed to human societies.