One Health: the case of human exposure to cyanobacterial toxins in natural and built environments
Authors: Chatziefthimiou Aspassia D. , Metcalf James S. , Powell James , Powell James , Glover J. W. Broc , Banack Sandra A. , Cox Paul A. , Richer Renee 
Published: April 2015

One Health is the combination of multidisciplinary efforts and expertise from the fields of medicine and science to determine environmental factors that affect human, animal, plant and microbial health in natural and built environments. The One Health initiative has gained momentum in recent decades, yet it has its roots of inception at the beginning of Western medicine when Hippocrates realized that human and ecosystem health are intrinsically connected and should not be considered in isolation.Our studies focus on cyanobacteria and how their abundance and toxin production are affected by unique climatological attributes of the desert, as well as anthropogenic influences and practices. We have determined that cyanobacterial crusts and mats can cover up to 87% of the terrestrial and coastal surface of Qatar, contributing to ecosystem health by preventing soil and coastal sediment erosion and enhancing rain water retention allowing for plant proliferation.Cyanobacteria negatively impact human and ecosystem health through the production of a range of toxins known or suspected to produce liver damage, promote tumors, cause paralysis, and potentially trigger neurodegenerative disease in humans and other animals. We have discovered that toxin-producing cyanobacterial species and cyanotoxins are present in both terrestrial crusts and coastal mats of Qatar.In the current paper, we present our results on cyanotoxin transmission and exposure routes to humans through air, drinking water and foodstuffs. We have observed that the annual natural phenomenon of dust storms experienced in the Arabian Peninsula leads to airborne cyanobacteria and cyanotoxins, and that in areas impacted by anthropogenic infrastructure development there is an increased rate of airborne exposure. Interestingly, local dress of gutras and sheilas act as natural filters against inhalation, minimizing exposure to cyanobacterial cells and cyanotoxins in controlled lab experiments.Another feature unique to desert life is the transportation and storage of desalinated water, kept in impoundments for drinking. We have tested water contained in such tanks in both rural and urban desert settings. Visible growth of cyanobacteria was observed in the majority of the tanks, with the neurotoxin AEG present in 90% of rural tanks, and 30% of urban tanks had concentrations of the hepatotoxin microcystin exceeding the World Health Organization’s Provisional Guideline value for lifetime health protection.Finally, we have performed biomagnification studies in the marine food chain of the gulf, choosing marine species based on consumer preferences of the local population.Neurotoxins were found in marine species at all trophic levels, attributed to the bottom up influence of toxins present in cyanobacterial mats or to top down effects of localized cyanobacterial blooms potentially caused by discharge of ballast water into the gulf.Our studies have shed the light on an unexplored biological desert system. Our findings may be used for conservation of this vital biota and for improving the design of built environments, construction procedures and water transportation and storage practices to minimize human exposure to cyanobacteria and their toxins through air and water.