Comparison of the numbers of free (surface) macrophages in the respiratory systems of three species of birds in an urban and a rural area of South Africa

Steyn, Lindi; Maina, John N.

doi:10.1007/s10336-015-1209-2

Cited by 15 publications

(4 citation statements)

References 41 publications

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“…Global population growth contributes to the destruction, modification and fragmentation of wildlife habitat, reduced genetic diversity, threats from pathogens, the spread of exotic and invasive species, air, noise and light pollution, alteration in natural hydrologic and fire regimes, and a rapidly changing climate [33–37]. The consequences of these environmental changes for most species include a reduced ability to forage, reduced prey or food availability, altered immune function, and diminished breeding success [38–45]. Changes to any of these life traits can compromise the persistence of native fauna populations in the wild.…”

Section: Introductionmentioning

confidence: 99%

The impact of human activities on Australian wildlife

et al. 2019

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Increasing human population size and the concomitant expansion of urbanisation significantly impact natural ecosystems and native fauna globally. Successful conservation management relies on precise information on the factors associated with wildlife population decline, which are challenging to acquire from natural populations. Wildlife Rehabilitation Centres (WRC) provide a rich source of this information. However, few researchers have conducted large-scale longitudinal studies, with most focussing on narrow taxonomic ranges, suggesting that WRC-associated data remains an underutilised resource, and may provide a fuller understanding of the anthropogenic threats facing native fauna. We analysed admissions and outcomes data from a WRC in Queensland, Australia Zoo Wildlife Hospital, to determine the major factors driving admissions and morbidity of native animals in a region experiencing rapid and prolonged urban expansion. We studied 31,626 admissions of 83 different species of native birds, reptiles, amphibians, marsupials and eutherian mammals from 2006 to 2017. While marsupial admissions were highest (41.3%), admissions increased over time for all species and exhibited seasonal variation (highest in Spring to Summer), consistent with known breeding seasons. Causes for admission typically associated with human influenced activities were dominant and exhibited the highest mortality rates. Car strikes were the most common reason for admission (34.7%), with dog attacks (9.2%), entanglements (7.2%), and cat attacks (5.3%) also high. Admissions of orphaned young and overt signs of disease were significant at 24.6% and 9.7%, respectively. Mortality rates were highest following dog attacks (72.7%) and car strikes (69.1%) and lowest in orphaned animals (22.1%). Our results show that WRC databases offer rich opportunities for wildlife monitoring and provide quantification of the negative impacts of human activities on ecosystem stability and wildlife health. The imminent need for urgent, proactive conservation management to ameliorate the negative impacts of human activities on wildlife is clearly evident from our results.

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Section: Introductionmentioning

confidence: 99%

The impact of human activities on Australian wildlife

et al. 2019

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“…This indicates that squirrels in this area are responding to external airborne agents. In wild populations, exposure to urban air pollution has been shown to increase the number of circulating alveolar macrophages (Lorz & López, 1997;McArn et al, 1974;Steyn & Maina, 2015), also lower the number of lung lamellar bodies (Lorz & López, 1997) and have no effect on lung oxidative damage in birds (Isaksson et al, 2009). Experimental exposure to TRAP also reduced Tcell mediated immune response in the skin of European starlings (Sturnus vulgaris, (North et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…Activated macrophages release inflammatory mediators which attract other immune cells to the site, and these elevated numbers of macrophages provide an excellent indicator of immuneactivation and inflammation due to TRAP (Kulkarni et al, 2006). A study by Steyn & Maina (2015) (Steyn & Maina, 2015) of wild populations of house sparrows (Passer domesticus), Cape glossy starlings (Lamprotornis nitens) and laughing doves (Spilopelia senegalensis) in South Africa found higher numbers of alveolar macrophages present in the lungs of urban birds exposed to high TRAP levels. As well as lung exposure and responses to air pollution, TRAP exposure can also potentially alter lung DNA methylation levels.…”

Section: Introductionmentioning

confidence: 99%

Impact of exposure to urban air pollution on grey squirrel (Sciurus carolinensis) lung health

Torres‐Blas

Horsler

Paredes

et al. 2023

Environmental Pollution

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“…Powered flight allows birds rapidly to vacate harsh or polluted habitats, and to relocate to more hospitable ones. Volancy makes birds a reliable bioindicator (sentinel) animal group for environmental health (Temple & Wiens, 1989; Dyke, 2009; Roché et al ., 2010; Amat & Green, 2010; Morelli, Jerzak & Tryjanowski, 2014; Steyn & Maina, 2015; Alexandrino et al ., 2016; Egwumah, Egwumah & Edet, 2017; Dutta, 2017; Hartfield et al ., 2018). For a particular habitat, the species abundance and diversity of birds signals environmental health (O'Connell, Jackson & Brooks, 2000; Stolen, Breininger & Frederick, 2005; Butler, Renwick & Norris, 2012; Wade et al ., 2014; Valerio et al ., 2016; Mekonen, 2017; Basile, Storch & Mikusiński, 2021; Atikah et al ., 2021; Kamal & Deepak, 2022; Dvořáková et al ., 2022; Asmare, Derebe & Tamer, 2023).…”

Section: Introductionmentioning

confidence: 99%

A critical assessment of the cellular defences of the avian respiratory system: are birds in general and poultry in particular relatively more susceptible to pulmonary infections/afflictions?

Maina

2023

Biological Reviews

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In commercial poultry farming, respiratory diseases cause high morbidities and mortalities, begetting colossal economic losses. Without empirical evidence, early observations led to the supposition that birds in general, and poultry in particular, have weak innate and adaptive pulmonary defences and are therefore highly susceptible to injury by pathogens. Recent findings have, however, shown that birds possess notably efficient pulmonary defences that include: (i) a structurally complex three‐tiered airway arrangement with aerodynamically intricate air‐flow dynamics that provide efficient filtration of inhaled air; (ii) a specialised airway mucosal lining that comprises air‐filtering (ciliated) cells and various resident phagocytic cells such as surface and tissue macrophages, dendritic cells and lymphocytes; (iii) an exceptionally efficient mucociliary escalator system that efficiently removes trapped foreign agents; (iv) phagocytotic atrial and infundibular epithelial cells; (v) phagocytically competent surface macrophages that destroy pathogens and injurious particulates; (vi) pulmonary intravascular macrophages that protect the lung from the vascular side; and (vii) proficiently phagocytic pulmonary extravasated erythrocytes. Additionally, the avian respiratory system rapidly translocates phagocytic cells onto the respiratory surface, ostensibly from the subepithelial space and the circulatory system: the mobilised cells complement the surface macrophages in destroying foreign agents. Further studies are needed to determine whether the posited weak defence of the avian respiratory system is a global avian feature or is exclusive to poultry. This review argues that any inadequacies of pulmonary defences in poultry may have derived from exacting genetic manipulation(s) for traits such as rapid weight gain from efficient conversion of food into meat and eggs and the harsh environmental conditions and severe husbandry operations in modern poultry farming. To reduce pulmonary diseases and their severity, greater effort must be directed at establishment of optimal poultry housing conditions and use of more humane husbandry practices.

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Comparison of the numbers of free (surface) macrophages in the respiratory systems of three species of birds in an urban and a rural area of South Africa

Cited by 15 publications

References 41 publications

The impact of human activities on Australian wildlife

The impact of human activities on Australian wildlife

Impact of exposure to urban air pollution on grey squirrel (Sciurus carolinensis) lung health

A critical assessment of the cellular defences of the avian respiratory system: are birds in general and poultry in particular relatively more susceptible to pulmonary infections/afflictions?

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