Land use, season, and parasitism predict metal concentrations in Australian flying fox fur

Cecilia A Sánchez; Michael T Penrose; Maureen K Kessler; Daniel J Becker; Adam McKeown; Madeline Hannappel; Victoria Boyd; Melinda S Camus; Ticha Padgett-Stewart; Brooklin E Hunt; Amelia F Graves; Alison J Peel; David A Westcott; Thomas R Rainwater; Matthew M Chumchal; George P Cobb; Sonia Altizer; Raina K Plowright; Wayne S J Boardman

doi:10.1016/j.scitotenv.2022.156699

Land use, season, and parasitism predict metal concentrations in Australian flying fox fur

Sci Total Environ. 2022 Oct 1:841:156699. doi: 10.1016/j.scitotenv.2022.156699. Epub 2022 Jun 14.

Authors

Cecilia A Sánchez¹, Michael T Penrose², Maureen K Kessler³, Daniel J Becker⁴, Adam McKeown⁵, Madeline Hannappel⁶, Victoria Boyd⁷, Melinda S Camus⁸, Ticha Padgett-Stewart⁹, Brooklin E Hunt⁹, Amelia F Graves⁹, Alison J Peel¹⁰, David A Westcott⁵, Thomas R Rainwater¹¹, Matthew M Chumchal⁶, George P Cobb², Sonia Altizer¹², Raina K Plowright⁹, Wayne S J Boardman¹³

Affiliations

¹ Odum School of Ecology, University of Georgia, Athens, GA, USA; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA. Electronic address: sanchez@ecohealthalliance.org.
² Department of Environmental Science, Baylor University, Waco, TX, USA.
³ Department of Ecology, Montana State University, Bozeman, MT, USA.
⁴ Department of Biology, University of Oklahoma, Norman, OK, USA.
⁵ CSIRO Land & Water, Atherton, QLD, Australia.
⁶ Department of Biology, Texas Christian University, Fort Worth, TX, USA.
⁷ Commonwealth Scientific and Industrial Research Organisation (CSIRO), Health and Biosecurity Business Unit, The Australian Centre for Disease Preparedness (ACDP), Geelong, VIC, Australia.
⁸ Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
⁹ Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, USA.
¹⁰ Centre for Planetary Health and Food Security, Griffith University, Nathan, QLD, Australia.
¹¹ Tom Yawkey Wildlife Center and Belle W. Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC, USA.
¹² Odum School of Ecology, University of Georgia, Athens, GA, USA; Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA.
¹³ School of Animal and Veterinary Sciences, University of Adelaide, SA, Australia.

PMID: 35710009
DOI: 10.1016/j.scitotenv.2022.156699

Abstract

Urban-living wildlife can be exposed to metal contaminants dispersed into the environment through industrial, residential, and agricultural applications. Metal exposure carries lethal and sublethal consequences for animals; in particular, heavy metals (e.g. arsenic, lead, mercury) can damage organs and act as carcinogens. Many bat species reside and forage in human-modified habitats and could be exposed to contaminants in air, water, and food. We quantified metal concentrations in fur samples from three flying fox species (Pteropus fruit bats) captured at eight sites in eastern Australia. For subsets of bats, we assessed ectoparasite burden, haemoparasite infection, and viral infection, and performed white blood cell differential counts. We examined relationships among metal concentrations, environmental predictors (season, land use surrounding capture site), and individual predictors (species, sex, age, body condition, parasitism, neutrophil:lymphocyte ratio). As expected, bats captured at sites with greater human impact had higher metal loads. At one site with seasonal sampling, bats had higher metal concentrations in winter than in summer, possibly owing to changes in food availability and foraging. Relationships between ectoparasites and metal concentrations were mixed, suggesting multiple causal mechanisms. There was no association between overall metal load and neutrophil:lymphocyte ratio, but mercury concentrations were positively correlated with this ratio, which is associated with stress in other vertebrate taxa. Comparison of our findings to those of previous flying fox studies revealed potentially harmful levels of several metals; in particular, endangered spectacled flying foxes (P. conspicillatus) exhibited high concentrations of cadmium and lead. Because some bats harbor pathogens transmissible to humans and animals, future research should explore interactions between metal exposure, immunity, and infection to assess consequences for bat and human health.

Keywords: Contaminant; Ectoparasite; Fruit bat; Haemoparasite; Metal exposure; Pteropus.

MeSH terms

Animals
Australia
Chiroptera*
Mercury*
Metals
Seasons

Substances

Metals
Mercury