Experimental infection of domestic canaries (<i>Serinus canaria domestica</i>) with<i>Mycoplasma gallisepticum</i>: a new model system for a wildlife disease

Hawley, Dana M.; Grodio, Jessica L.; Frasca, Salvatore; Kirkpatrick, Laila T.; Ley, David

doi:10.1080/03079457.2011.571660

Cited by 61 publications

(64 citation statements)

References 22 publications

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“…All animals included in the experiment underwent a two-week quarantine protocol to ensure no previous exposure to MG. In brief, animals were monitored for two weeks for visible eye lesions, and were tested for MG-specific antibodies (as per Hawley et al 2011) on day 14 post-capture to account for time for development of antibodies in case exposure to MG in the wild occurred on the day of capture. Only individuals that were seronegative, never showed clinical signs, and were never housed with a cagemate that showed clinical signs were used in this experiment.…”

Section: Methodsmentioning

confidence: 99%

“…Although it is extremely challenging to quantify MG exposure levels in natural populations, these lines of evidence suggest that free-living house finches are likely exposed to variable amounts of MG while feeding, with some individuals likely experiencing repeated exposure to relatively low doses of MG. However, to date, experimental exposures of house finches to MG have used relatively high infectious doses (≥10 4 color changing units[=CCU]/ml) and/or single time-point exposures (Dhondt et al 2007b; Bouwman and Hawley 2010; Bonneaud et al 2011; Hawley et al 2011; Bonneaud et al 2012; Adelman et al 2013a), which are unlikely to be fully representative of the range of variation in MG exposure in the wild.…”

Section: Introductionmentioning

confidence: 99%

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Host Responses to Pathogen Priming in a Natural Songbird Host

Leon

Hawley²

2017

EcoHealth

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Hosts in free-living populations can experience substantial variation in the frequency and dose of pathogen exposure, which can alter disease progression and protection from future exposures. In the house finch-Mycoplasma gallisepticum (MG) system, the pathogen is primarily transmitted via bird feeders, and some birds may be exposed to frequent low doses of MG while foraging. Here we experimentally determined how low-dose, repeated exposures of house finches to MG influence host responses and protection from secondary high-dose challenge. MG-naive house finches were given priming exposures that varied in dose and total number. After quantifying host responses to priming exposures, all birds were given a secondary high-dose challenge to assess immunological protection. Dose, but not the number of exposures, significantly predicted both infection and disease severity following priming exposure. Furthermore, individuals given higher priming doses showed stronger protection upon secondary, high-dose challenge. However, even single low-dose exposures to MG, a proxy for what some birds likely experience in the wild while feeding, provided significant protection against a high dose challenge. Our results suggest that bird feeders, which serve as sources of infection in the wild, may in some cases act as “immunizers”, with important consequences for disease dynamics.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Host Responses to Pathogen Priming in a Natural Songbird Host

Leon

Hawley²

2017

EcoHealth

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“…Capture was conducted with mist nets or cage traps in Virginia under permits from the Virginia Department of Game and Inland Finches were held in groups during quarantine, during which they were monitored for clinical signs of M. gallisepticum and at the end of which they were tested for prior M. gallisepticum exposure via enzymelinked immunosorbent assay (ELISA) (30,31) and quantitative PCR (qPCR) (32) as done previously. Animals with signs of disease or seropositivity were excluded from the experiment.…”

Section: Methodsmentioning

confidence: 99%

Attenuated Phenotype of a Recent House Finch-Associated Mycoplasma gallisepticum Isolate in Domestic Poultry

et al. 2017

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Mycoplasma gallisepticum, known primarily as a respiratory pathogen of domestic poultry, has emerged since 1994 as a significant pathogen of the house finch (Haemorhous mexicanus) causing severe conjunctivitis and mortality. House finch-associated M. gallisepticum (HFMG) spread rapidly and increased in virulence for the finch host in the eastern United States. In the current study, we assessed virulence in domestic poultry with two temporally distant, and yet geographically consistent, HFMG isolates which differ in virulence for house finches-Virginia 1994 (VA1994), the index isolate of the epidemic, and Virginia 2013 (VA2013), a recent isolate of increased house finch virulence. Here we report a significant difference between VA1994 and VA2013 in their levels of virulence for chickens; notably, this difference correlated inversely to the difference in their levels of virulence for house finches. VA1994, while moderately virulent in house finches, displayed significant virulence in the chicken respiratory tract. VA2013, while highly virulent in the house finch, was significantly attenuated in chickens relative to VA1994, displaying lesssevere pathological lesions in, and reduced bacterial recovery from, the respiratory tract. Overall, these data indicate that a recent isolate of HFMG is greatly attenuated in the chicken host relative to the index isolate, notably demonstrating a virulence phenotype in chickens inversely related to that in the finch host.KEYWORDS Mycoplasma gallisepticum, chicken, house finch, pathology, virulence M ycoplasma gallisepticum is a bacterial pathogen associated with acute and chronic respiratory disease in domestic poultry. Previously, M. gallisepticum was thought to be relatively host specific and pathogenic only for gallinaceous birds (1). The emergence of M. gallisepticum infection in a wild North American songbird host-the house finch (Haemorhous mexicanus)-was first reported in 1994 in Virginia and Maryland and was associated with severe and chronic lymphoplasmacytic conjunctivitis, sinusitis, and rhinitis, contrasting with the respiratory form of M. gallisepticum disease primarily observed in poultry (2-4). The epidemic quickly spread throughout the eastern, or introduced, house finch range across the mid-Atlantic and the eastern states, and it eventually spread to the native house finch range in the western United States (2,(5)(6)(7)(8). House finch-associated M. gallisepticum (HFMG) has been associated with dramatic declines in house finch populations, likely as a result of affecting the host's ability to forage or to avoid predation (3,(9)(10)(11). This well-documented spread of HFMG has enabled dynamic modeling of various aspects of the epidemic as an example of the spread of an emergent pathogen (12, 13).

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“…At 16.00 on the day before sampling, feeder ports were wiped for 10 s with Vircon S disinfectant (DuPont Disinfectants, Sudbury, Suffolk, UK) to remove MG. After 24 h, feeders were sampled for MG by rotating a sterile, TPB-dipped cotton swab inside the port for 10 s, then processing as above. The amount of MG in all samples was determined by quantitative PCR using published methods [12,13]. Conjunctival lesions were scored on a scale of 0-3 per eye (see electronic supplementary material).…”

Section: Methodsmentioning

confidence: 99%

Deposition of pathogenic Mycoplasma gallisepticum onto bird feeders: host pathology is more important than temperature-driven increases in food intake

et al. 2013

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Although ambient temperature has diverse effects on disease dynamics, few studies have examined how temperature alters pathogen transmission by changing host physiology or behaviour. Here, we test whether reducing ambient temperature alters host foraging, pathology and the potential for fomite transmission of the bacterial pathogen Mycoplasma gallisepticum (MG), which causes seasonal outbreaks of severe conjunctivitis in house finches (Haemorhous mexicanus). We housed finches at temperatures within or below the thermoneutral zone to manipulate food intake by altering energetic requirements of thermoregulation. We predicted that pathogen deposition on bird feeders would increase with temperature-driven increases in food intake and with conjunctival pathology. As expected, housing birds below the thermoneutral zone increased food consumption. Despite this difference, pathogen deposition on feeders did not vary across temperature treatments. However, pathogen deposition increased with conjunctival pathology, independently of temperature and pathogen load, suggesting that MG could enhance its transmission by increasing virulence. Our results suggest that in this system, host physiological responses are more important for transmission potential than temperaturedependent alterations in feeding. Understanding such behavioural and physiological contributions to disease transmission is critical to linking individual responses to climate with population-level disease dynamics.

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Experimental infection of domestic canaries (Serinus canaria domestica) withMycoplasma gallisepticum: a new model system for a wildlife disease

Cited by 61 publications

References 22 publications

Host Responses to Pathogen Priming in a Natural Songbird Host

Host Responses to Pathogen Priming in a Natural Songbird Host

Attenuated Phenotype of a Recent House Finch-Associated Mycoplasma gallisepticum Isolate in Domestic Poultry

Deposition of pathogenic Mycoplasma gallisepticum onto bird feeders: host pathology is more important than temperature-driven increases in food intake

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