Morphological and quantitative analysis of leukocytes in free-living Australian black flying foxes (Pteropus alecto)

PLoS One. 2022 May 25;17(5):e0268549. doi: 10.1371/journal.pone.0268549. eCollection 2022.

Abstract

The black flying fox (Pteropus alecto) is a natural reservoir for Hendra virus, a paramyxovirus that causes fatal infections in humans and horses in Australia. Increased excretion of Hendra virus by flying foxes has been hypothesized to be associated with physiological or energetic stress in the reservoir hosts. The objective of this study was to explore the leukocyte profiles of wild-caught P. alecto, with a focus on describing the morphology of each cell type to facilitate identification for clinical purposes and future virus spillover research. To this end, we have created an atlas of images displaying the commonly observed morphological variations across each cell type. We provide quantitative and morphological information regarding the leukocyte profiles in bats captured at two roost sites located in Redcliffe and Toowoomba, Queensland, Australia, over the course of two years. We examined the morphology of leukocytes, platelets, and erythrocytes of P. alecto using cytochemical staining and characterization of blood films through light microscopy. Leukocyte profiles were broadly consistent with previous studies of P. alecto and other Pteropus species. A small proportion of individual samples presented evidence of hemoparasitic infection or leukocyte morphological traits that are relevant for future research on bat health, including unique large granular lymphocytes. Considering hematology is done by visual inspection of blood smears, examples of the varied cell morphologies are included as a visual guide. To the best of our knowledge, this study provides the first qualitative assessment of P. alecto leukocytes, as well as the first set of published hematology reference images for this species.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chiroptera* / immunology
  • Hendra Virus
  • Leukocytes*
  • Queensland

Associated data

  • Dryad/10.5061/dryad.gb5mkkws0

Grants and funding

RKP was funded by the DARPA PREEMPT program (https://www.preemptproject.org) Cooperative Agreement # D18AC00031, and the U.S. National Science Foundation (https://www.nsf.gov) (DEB-1716698). DH and BEH were funded by the Montana State University Undergraduate Scholars Program (https://www.montana.edu/usp/). BEH was also funded by the Montana State University McNairs Scholar Program (https://www.montana.edu/mcnair/) (Grant #P217A130148). RKP was also funded by the USDA National Institute of Food and Agriculture (https://nifa.usda.gov) (Hatch project 1015891). AJP was supported by an ARC DECRA fellowship (https://www.arc.gov.au/grants/discovery-program/discovery-early-career-researcher-award-decra) (DE190100710).The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.