1
|
Becker DJ, Chumchal MM, Bentz AB, Platt SG, Czirják GÁ, Rainwater TR, Altizer S, Streicker DG. Predictors and immunological correlates of sublethal mercury exposure in vampire bats. R Soc Open Sci 2017; 4:170073. [PMID: 28484633 PMCID: PMC5414270 DOI: 10.1098/rsos.170073] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/21/2017] [Indexed: 05/21/2023]
Abstract
Mercury (Hg) is a pervasive heavy metal that often enters the environment from anthropogenic sources such as gold mining and agriculture. Chronic exposure to Hg can impair immune function, reducing the ability of animals to resist or recover from infections. How Hg 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. We here quantify total Hg (THg) 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. We examine how diet, sampling site and year, and bat demography influence THg and test the consequences of this variation for eight immune measures. In two populations from Belize, THg concentrations in bats 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 THg. However, relationships between diet and THg were evident only in 2015 but not in 2014, which could reflect recent environmental perturbations associated with agriculture. THg concentrations were low relative to values previously observed in other bat species but still correlated with bat immunity. Bats with higher THg had more neutrophils, weaker bacterial killing ability and impaired innate immunity. These patterns suggest that temporal variation in Hg exposure may impair bat innate immunity and increase susceptibility to pathogens such as bacteria. Unexpected associations between low-level Hg exposure and immune function underscore the need to better understand the environmental sources of Hg exposure in bats and the consequences for bat immunity and susceptibility.
Collapse
Affiliation(s)
- Daniel J. Becker
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
- e-mail:
| | | | | | - Steven G. Platt
- Wildlife Conservation Society, Myanmar Program, Yangon, Myanmar
| | - Gábor Á. Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Thomas R. Rainwater
- Tom Yawkey Wildlife Center and Belle W. Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC, USA
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Center for the Ecology of Infectious Disease, University of Georgia, Athens, GA, USA
| | - Daniel G. Streicker
- Odum School of Ecology, University of Georgia, Athens, GA, USA
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
- MRC-University of Glasgow Centre for Virus Research, Glasgow G61 1QH, UK
| |
Collapse
|