Temporal Variation in Physiological Biomarkers in Black Flying-Foxes (Pteropus alecto), Australia

Abstract

Bats of the genus Pteropus (Pteropodidae) are recognised as the natural host of multiple emerging pathogenic viruses of animal and human health significance, including henipaviruses, lyssaviruses and ebolaviruses. Some studies have suggested that physiological and ecological factors may be associated with Hendra virus infection in flying-foxes in Australia; however, it is essential to understand the normal range and seasonal variability of physiological biomarkers before seeking physiological associations with infection status. We aimed to measure a suite of physiological biomarkers in P. alecto over time to identify any seasonal fluctuations and to examine possible associations with life-cycle and environmental stressors. We sampled 839 adult P. alecto in the Australian state of Queensland over a 12-month period. The adjusted population means of every assessed hematologic and biochemical parameter were within the reported reference range on every sampling occasion. However, within this range, we identified significant temporal variation in these parameters, in urinary parameters and body condition, which primarily reflected the normal annual life cycle. We found no evident effect of remarkable physiological demands or nutritional stress, and no indication of clinical disease driving any parameter values outside the normal species reference range. Our findings identify underlying temporal physiological changes at the population level that inform epidemiological studies and assessment of putative physiological risk factors driving Hendra virus infection in P. alecto. More broadly, the findings add to the knowledge of Pteropus populations in terms of their relative resistance and resilience to emerging infectious disease.

Time of year, age class and body condition predict Hendra virus infection in Australian black flying foxes (Pteropus alecto)

“…The statistical association between positive RNA status and lower BCS in the animal-level analysis (but not the urine- or serum-level analyses) is of unknown biological significance. It may simply reflect correlation, with the probability of infection temporally coincident with seasonal weight loss [46]; alternatively, it could reflect causation, with individuals in poorer body condition more likely to become infected, or at least, more likely to excrete virus. The latter could plausibly include a scenario of recrudescing infection and viral shedding as body condition declines [21, 47].…”

Physiological stress and Hendra virus in flying-foxes (Pteropus spp.), Australia

“…poliocephalus was observed in March each year. At the Boonah roost, 95% adult females were palpably pregnant from June onwards in both 2013 and 2014 [ 33 ], and visibly pregnant from August to October. First pups were observed in September, dependent pups observed from September to April, and independent juveniles first observed in April.…”

Optimizing dissection, sample collection and cell isolation protocols for frugivorous bats

“…Here we characterized sample collection and utilization of almost all tissues from fruit bats. While multiple groups have used bats in in vivo scientific studies for physiology (Chen, Zhu, Jones, Zhang, & Sun, 2013;Harrison & Roberts, 2000;Suarez, Hanna, & Herrera, 2009;Suarez, Welch, Hanna, & Herrera, 2009b), metabolism (Arévalo, Pérez-Suárez, & Lóapez-Luna, 1991;Bell, Price, Balthes, Cordon, & Wormell, 2019;Brunet-Rossinni, 2004;Foley et al, 2018;Funakoshi & Kunisaki, 1991;Healy et al, 2014;Hernández-Arciga et al, 2018;McMichael et al, 2016McMichael et al, , 2015Peng et al, 2017;Podlutsky, Khritankov, Ovodov, & Austad, 2005), evolution (Currie, Stawski, & Geiser, 2018;Moreno-Santillán, Machain-Williams, Hernández-Montes, & Ortega, 2019;Pollard et al, 2019;Seim et al, 2013;Shen et al, 2010) or immunological/virological studies (Aguilar-Setién et al, 2008;Ahn et al, 2019;Aída, Herrera, Flores-Martínez, & Welch, 2016;Allen, Sims, & Singht, n.d.;Barr et al, 2012;Chakravarty & Paul, 1987;Halpin et al, 2011;Davis et al, 2005;Cabrera-Romo et al, 2014;Hughes et al, 2006;Jones et al, 2015;Kandeil et al, 2019;Mackie et al, 2017;Obregón-Morales et al, 2017;…”

“…Here we characterized sample collection and utilization of almost all tissues from fruit bats. While multiple groups have used bats in in vivo scientific studies for physiology (Chen, Zhu, Jones, Zhang, & Sun, ; Harrison & Roberts, ; Suarez, Hanna, & Herrera, ; Suarez, Welch, Hanna, & Herrera, ), metabolism (Arévalo, Pérez‐Suárez, & Lóapez‐Luna, ; Bell, Price, Balthes, Cordon, & Wormell, ; Brunet‐Rossinni, ; Foley et al, ; Funakoshi & Kunisaki, ; Healy et al, ; Hernández‐Arciga et al, ; McMichael et al, , ; Peng et al, ; Podlutsky, Khritankov, Ovodov, & Austad, ), evolution (Currie, Stawski, & Geiser, ; Moreno‐Santillán, Machain‐Williams, Hernández‐Montes, & Ortega, ; Pollard et al, ; Seim et al, ; Shen et al, ) or immunological/virological studies (Aguilar‐Setién et al, ; Ahn et al, ; Aída, Herrera, Flores‐Martínez, & Welch, ; Allen, Sims, & Singht, n.d.; Barr et al, ; Chakravarty & Paul, ; Halpin et al, ; Davis et al, ; Cabrera‐Romo et al, ; Hughes et al, ; Jones et al, ; Kandeil et al, ; Mackie et al, ; Obregón‐Morales et al, ; Paweska et al, ; Perea‐Martínez et al, ; Sarkar & Chakravarty, ; Sullivan, Grimes, Eads, Menzies, & Irons, ; Swanepoel et al, ; Tong et al, ; Watanabe et al, ; Weise, Czirják, Lindecke, Bumrungsri, & Voigt, ; Yob et al, ), there is no detailed description of the methods required for efficient processing. Consistent, fast, methodology will benefit comparative biology studies on bats across multiple disciplines.…”