Mercury is a pervasive heavy metal that often enters the environment from anthropogenic sources such as gold mining and agriculture. Chronic exposure to mercury can impair immune function, reducing the ability of animals to resist or recover from infections. How mercury influences immunity and susceptibility remains unknown for bats, which appear immunologically distinct from other mammals and are reservoir hosts of many pathogens of importance to human and animal health. T
his study quantifies mercury in hair collected from common vampire bats (Desmodus rotundus), which feed on blood and are the main reservoir hosts of rabies virus in Latin America. In two populations from Belize, bat hair mercury concentrations were best explained by an interaction between long-term diet inferred from stable isotopes and year. Bats that foraged more consistently on domestic animals exhibited higher mercury. However, relationships between diet and mercury were evident only in 2015 but not in 2014, which could reflect recent environmental perturbations associated with agriculture. Mercury concentrations were low relative to values previously observed in other bat species but still correlated with bat immunity. Bats with higher mercury had more neutrophils, weaker bacterial killing ability, and impaired innate immunity. These patterns suggest that temporal variation in mercury exposure may impair bat innate immunity and increase susceptibility to pathogens such as bacteria. Unexpected associations between low-level mercury exposure and immune function underscore the need to better understand the environmental sources of mercury exposure in bats and the consequences for bat immunity and susceptibility
- Becker DJ, Chumchal MM, Bentz AB, Platt SG, Czirjak GA, Rainwater TR, Altizer S, Streicker DG. Predictors and immunological correlates of sublethal mercury exposure in vampire bats. Royal Society Open Science. [online]