field investigation of mycoplasma gallisepticum infections in house finches (carpodacus mexicanus) from maryland and georgia.a field study investigating the occurrence of mycoplasma gallisepticum (mg) in house finches (carpodacus mexicanus) was conducted in maryland and georgia. eighty-eight finches were captured and examined grossly and microscopically for mg-related conjunctivitis. serum samples were obtained for serum plate agglutination (spa) and hemagglutination inhibition (hi) testing. swabs from conjunctiva, sinus, and choanal cleft were inoculated into two mycoplasma broth media for culture and polymerase chai ...19968790883
mycoplasma gallisepticum isolated from house finches (carpodacus mexicanus) with epornitic of conjunctivitis in free-flying house finches (carpodacus mexicanus) occurred in several mid-atlantic and eastern states of the usa in 1994. clinical signs and gross lesions ranged from mild to severe unilateral or bilateral conjunctival swelling with serous to mucopurulent drainage and nasal exudate. microscopic lesions consisted of chronic lymphoplasmacytic conjunctivitis, rhinitis, and sinusitis. notably slow-growing mycoplasmas were isolated from conjunctival and/or infraorbita ...19968790904
mycoplasmal conjunctivitis in wild songbirds: the spread of a new contagious disease in a mobile host population.a new mycoplasmal conjunctivitis was first reported in wild house finches (carpodacus mexicanus) in early 1994. the causative agent was identified as mycoplasma gallisepticum (mg), a nonzoonotic pathogen of poultry that had not been associated with disease in wild songbirds. since the initial observations of affected house finches in the mid-atlantic region, the disease has become widespread and has been reported throughout the eastern united states and canada. by late 1995, mycoplasmal conjunct ...19979126448
mycoplasmal conjunctivitis in a european starling.bilateral conjunctivitis and episcleritis were identified in an adult european starling (sturnus vulgaris). a novel mycoplasma species, mycoplasma sturni, was isolated in pure culture from the conjunctiva of both eyes. the clinical presentation was similar to that of conjunctivitis in house finches (carpodacus mexicanus) caused by mycoplasma gallisepticum. however, the histologic lesions were distinct, by the presence of ulceration and by the absence of epithelial hyperplasia and lymphoplasmacyt ...19979131571
molecular epidemiologic investigations of mycoplasma gallisepticum conjunctivitis in songbirds by random amplified polymorphic dna ongoing outbreak of conjunctivitis in free-ranging house finches (carpodacus mexicanus) began in 1994 in the eastern united states. bacterial organisms identified as mycoplasma gallisepticum (mg) were isolated from lesions of infected birds. mg was also isolated from a blue jay (cyanocitta cristata) that contracted conjunctivitis after being housed in a cage previously occupied by house finches with conjunctivitis, and from free-ranging american goldfinches (carduelis tristis) in north caroli ...19979284386
epidemic mycoplasmal conjunctivitis in house finches from eastern north the winter of 1993-94, house finches (carpodacus mexicanus) with severe conjunctivitis (later shown to be caused by mycoplasma gallisepticum) were first observed in sub-urban washington d.c. (usa) and adjacent states. using a large network of volunteer observers in eastern north america, we were able to track the monthly prevalence of the disease between november 1994 and march 1997. using the information on 24,864 monthly data forms, we describe the very rapid spread of the conjunctivitis ep ...19989577773
risk factors associated with mycoplasmal conjunctivitis in house finches.observations from a citizen-based survey were used to identify potential risk factors associated with mycoplasmal conjunctivitis (mycoplasma gallisepticum) in eastern house finches (carpodacus mexicanus). between november 1994 and october 1996, 778 volunteers provided 7,224 monthly observations at residential bird feeding sites across an eight state region in the eastern usa. information collected by questionnaires included health status of house finches and four sympatric passerine species, typ ...19989577774
natural mycoplasma gallisepticum infection in a captive flock of house finches.naturally-occurring mycoplasmal conjunctivitis is described among 104 wild-caught, and initially seronegative, house finches (carpodacus mexicanus) maintained in captivity for 12 wk during november 1995 through january 1996. finches housed in three pens were monitored for clinical signs, and > or = 10 birds were euthanatized for necropsy and mycoplasma testing every 2 wk. within 2 to 4 wk following initial detection of lesions, > 50% of the birds in each of three pens developed a debilitating di ...19989577775
mycoplasma sturni from blue jays and northern mockingbirds with conjunctivitis in florida.northern mockingbirds (mimus polyglottos) and blue jays (cyanocitta cristata) in a florida (usa) wildlife care facility developed clinical signs and gross lesions suggestive of the ongoing outbreak of mycoplasma gallisepticum (mg) conjunctivitis in house finches (carpodacus mexicanus) and american goldfinches (carduelis tristis). mycoplasmal organisms were cultured from conjunctival/corneal swabs of birds with sinusitis, conjunctivitis, and/or epiphora. all of the isolates tested were identified ...19989577796
potential for transmission of the finch strain of mycoplasma gallisepticum between house finches and chickens.although mycoplasma gallisepticum (mg) is established in house finch (carpodacus mexicanus) populations in at least 33 states, the potential risk of mg introduction to domestic poultry by infected finches currently is unknown. the objectives of this study were to determine if chickens could be infected with the finch strain of mg via direct, across-wire, and proximity (across-room) contact with naturally infected house finches and to determine if house finches could be infected through direct co ...19989645326
field investigation of mycoplasma gallisepticum infections in house finch (carpodacus mexicanus) eggs and nestlings.we conducted a field study to investigate the occurrence of mycoplasma gallisepticum (mg) in eggs and nestlings from nests of house finches (carpodacus mexicanus). forty-three nests were located between the months of april and august 1998 and were followed with one to three sampling efforts. vitelline membrane of fresh eggs, whole embryos, or swabs from the choanal cleft or conjunctiva of nestlings were inoculated into mycoplasma broth for mg isolation and polymerase chain reaction (pcr) testing ...199910494429
pathogenic effects on domestic poultry of a mycoplasma gallisepticum strain isolated from a wild house finch.mycoplasma gallisepticum (mg) has been isolated from wild house finches. the pathogenic effects of mg finch strain (k4058) and mg r-strain were compared after exposure of chickens and turkeys. gross and histologic lesions, reisolation of the organism, serology, and clinical disease were evaluated. milder histologic and gross lesions, in addition to lower serologic titers, occurred in birds inoculated with the finch strain. mortality, concurrent with clinical and gross respiratory signs and lesio ...199910611979
density-dependent decline of host abundance resulting from a new infectious disease.although many new diseases have emerged within the past 2 decades [cohen, m. l. (1998) brit. med. bull. 54, 523-532], attributing low numbers of animal hosts to the existence of even a new pathogen is problematic. this is because very rarely does one have data on host abundance before and after the epizootic as well as detailed descriptions of pathogen prevalence [dobson, a. p. & hudson, p. j. (1985) in ecology of infectious diseases in natural populations, eds. grenfell, b. t. & dobson, a. p. ( ...200010792031
mycoplasmal conjunctivitis in songbirds from new york.a field study was conducted to determine the prevalence of conjunctivitis and mycoplasma gallisepticum (mg) infections in house finches (carpodacus mexicanus) and other songbirds common to bird feeders in tompkins county (new york, usa). eight hundred two individuals of 23 species and nine families of birds were captured and given physical examinations during the 14 mo study beginning in february 1998. clinical conjunctivitis (eyelid or conjunctival swelling, erythema, and discharge) was observe ...200010813607
host range and dynamics of mycoplasmal conjunctivitis among birds in north epidemic of conjunctivitis among house finches (carpodacus mexicanus) caused by mycoplasma gallisepticum (mg) bacterial infections was first described in 1994. the disease exhibits high primary host specificity, but has been isolated from a limited number of secondary avian hosts at various times and locations. we used records from the house finch disease survey, a continent-wide, volunteer monitoring project, to document the host range of conjunctivitis in birds at feeding stations and to in ...200111272507
characterization of the mycoplasmal conjunctivitis epizootic in a house finch population in the southeastern epidemiological study of the prevalence of mycoplasmal conjunctivitis in the house finch (carpodacus mexicanus) was conducted in auburn (alabama, usa) between march 1998 and february 1999. clinical disease was observed in 4% of the 1,214 finches trapped and examined. this rate is comparable to the average annual prevalence observed in this population since 1996, although the prevalence of clinical disease observed in the peak months of september through november was lower than in previous yea ...200111272508
diagnosis and treatment of conjunctivitis in house finches associated with mycoplasmosis in ongoing outbreak of mycoplasma gallisepticum-associated conjunctivitis in house finches (carpodacus mexicanus) that began in 1994 in the eastern united states has been spreading westward. house finches presenting with the clinical signs of m. gallisepticum-associated conjunctivitis were first seen at the wildlife rehabilitation center of minnesota (minnesota, usa) in july of 1996, and 42 cases were admitted from 26 december 1996 to 10 august 1997. a nested pcr was designed for sensitive and s ...200111310874
characterization of mycoplasma gallisepticum infection in captive house finches (carpodacus mexicanus) in 1998.since 1995, the epidemic of mycoplasmal conjunctivitis in eastern house finches has affected the auburn, al, house finch population. to better characterize the current status of this host-parasite interaction, we established a captive flock of 38 seronegative, healthy finches in fall 1998. after a minimum quarantine period of 4 wk, two mycoplasma gallisepticum (mg)-infected house finches were introduced into this flock. over a 12-wk period, the flock was captured every 2 wk and each bird was obs ...200111332501
mycoplasma gallisepticum in house finches (carpodacus mexicanus) and other wild birds associated with poultry production facilities.since 1994, an epidemic of conjunctivitis caused by mycoplasma gallisepticum (mg) has spread throughout the eastern population of house finches (carpodacus mexicanus). the adaptation of mg to a free-flying avian species presents potential problems for the control of mycoplasmosis in commercial poultry. to evaluate risks associated with this emerging problem, a field survey was conducted to assess prevalence of mg infection in house finches and other passerine birds associated with poultry farms. ...200111417811
mycoplasmosis in evening and pine grosbeaks with conjunctivitis in outbreak of conjunctivitis affected evening grosbeaks (coccothraustes vespertinus) and pine grosbeaks (pinicola enucleator) in quebec (canada) during the winter 1998-99. one to 30% of the individuals from these two species were sick at 13 feeding stations. sick birds were thin and had unilateral or bilateral catarrhal and lymphoplasmacytic conjunctivitis and rhinitis, and mucopurulent infra-orbital sinusitis. mycoplasmal organisms were isolated in cultures in an affected evening grosbeak and ...200111763749
susceptibility of a naïve population of house finches to mycoplasma gallisepticum.since 1994 an epidemic of mycoplasmal conjunctivitis has spread throughout the eastern house finch (carpodacus mexicanus) population leading to a significant decline in this population. the infection has not yet been reported from house finch populations west of the great plains. we hypothesized that the western population, like the eastern population, is susceptible to infection, and we tested this hypothesis by experimentally infecting house finches from missoula, montana (usa) with the house ...200212038126
characterization of a naturally occurring infection of a mycoplasma gallisepticum house finch-like strain in turkey outbreak of mycoplasma gallisepticum (mg) in commercial turkeys involving very mild clinical signs was difficult to confirm by routine methods. in the first part of this study (trial a), we conducted a bioassay to increase the likelihood of detecting mg. susceptible turkeys were inoculated with sinus exudates from four different affected commercial turkey flocks. turkeys were evaluated for clinical signs, as well as by serology and culture of tracheal swabs, at 21 and 42 days postchallenge. a ...200314562878
molecular variability of house finch mycoplasma gallisepticum isolates as revealed by sequencing and restriction fragment length polymorphism analysis of the pvpa gene.mycoplasma gallisepticum, a major pathogen of chickens and turkeys, has caused significant declines in house finch (carpodacus mexicanus) populations in the eastern united states since it was first observed in this species in 1994. there is evidence that m. gallisepticum infection is now endemic among eastern house finches, although disease prevalence has declined, suggesting an evolving host-parasite relationship. studies based on randomly amplified polymorphic dna (rapd) have documented the pr ...200314562892
health survey of house finches (carpodacus mexicanus) from wisconsin.we conducted a health survey of house finches (carpodacus mexicanus) without evidence of mycoplasma gallisepticum infection in order to establish baseline population health measures and estimate prevalence of potential pathogens likely to influence host susceptibility to mycoplasmosis. seasonal changes in several physiologic parameters were observed. weights were greater in winter compared with the breeding season (p < 0.01), fat scores were greater in winter than during fall migration (p < 0.01 ...200415077801
safety and efficacy of the avirulent mycoplasma gallisepticum strain k5054 as a live vaccine in poultry.a mycoplasma gallisepticum (mg) isolate from an atypically mild outbreak in turkey breeders was found to be similar to house finch isolates by dna analyses. a preliminary study in turkeys showed that this isolate (k5054) caused very mild lesions and protected turkeys against subsequent challenge with a virulent mg strain. in this study, k5054 was further evaluated as a potential vaccine strain in commercial layer-type chickens and turkeys. the safety of k5054 was evaluated by aerosol challenge f ...200415077802
experimental infection of house finches with mycoplasma gallisepticum.mycoplasma gallisepticum (mg) has caused an endemic upper respiratory and ocular infection in the eastern house finch (carpodacus mexicanus) after the epidemic first described in 1994. the disease has been studied by a number of investigators at a population level and reports describe experimental infection in group-housed mg-free house finches. because detailed observation and evaluation of individual birds in group-housed passerines is problematic, we studied individually housed house finches ...200415137491
the effect of mycoplasmosis on carotenoid plumage coloration in male house finches.parasites are widely assumed to cause reduced expression of ornamental plumage coloration, but few experimental studies have tested this hypothesis. we captured young male house finches carpodacus mexicanus in alabama before fall molt and randomly divided them into two groups. one group was infected with the bacterial pathogen mycoplasma gallicepticum (mg) and the other group was maintained free of mg infection. all birds were maintained through molt on a diet of seeds with tangerine juice added ...200415143143
carotenoid-based plumage coloration predicts resistance to a novel parasite in the house finch.the hamilton-zuk hypothesis proposes that the bright colours displayed by many species of birds serve as signals of individual resistance to parasites. despite the popularity of this hypothesis, only one previous study has tested whether plumage coloration predicts how individuals respond to a disease challenge. we inoculated 24 male house finches (carpodacus mexicanus) of variable plumage hue with a novel bacterial pathogen, mycoplasma gallicepticum (mg). we found no relationship between plumag ...200515558224
seasonality and wildlife disease: how seasonal birth, aggregation and variation in immunity affect the dynamics of mycoplasma gallisepticum in house finches.we examine the role of host seasonal breeding, host seasonal social aggregation and partial immunity in affecting wildlife disease dynamics, focusing on the dynamics of house finch conjunctivitis (mycoplasma gallisepticum (mg) in carpodacus mexicanus). this case study of an unmanaged emerging infectious disease provides useful insight into the important role of seasonal factors in driving ongoing disease dynamics. seasonal breeding can force recurrent epidemics through the input of fresh suscept ...200415615682
dynamics of a novel pathogen in an avian host: mycoplasmal conjunctivitis in house early 1994, a novel strain of mycoplasma gallisepticum (mg)--a poultry pathogen with a world-wide distribution--emerged in wild house finches and within 3 years had reached epidemic proportions across their eastern north american range. the ensuing epizootic resulted in a rapid decline of the host population coupled with considerable seasonal fluctuations in prevalence. to understand the dynamics of this disease system, a multi-disciplinary team composed of biologists, veterinarians, microbio ...200515777638
stress responses and disease in three wintering house finch (carpodacus mexicanus) populations along a latitudinal laboratory studies, stress hormones have been shown to impair immune functions, and increase susceptibility to diseases. however, the interactions between stress hormones and disease have rarely been studied in free-ranging populations. in this study, we measured concentrations of the avian stress hormone corticosterone across four winter months (december-march) over two years in three eastern north american house finch populations (carpodacus mexicanus) along a latitudinal gradient. because ...200515922346
susceptibility of wild songbirds to the house finch strain of mycoplasma gallisepticum.conjunctivitis in house finches (carpodacus mexicanus), caused by mycoplasma gallisepticum (mg), was first reported in 1994 and, since this time, has become endemic in house finch populations throughout eastern north america. although the house finch is most commonly associated with mg-related conjunctivitis, mg has been reported from other wild bird species, and conjunctivitis (not confirmed as mg related) has been reported in over 30 species. to help define the host range of the house finch st ...200516107666
characterization of experimental mycoplasma gallisepticum infection in captive house finch flocks.the use of controlled, horizontal-transmission experiments provides detailed information on the spread of disease within fixed social groups, which informs our understanding of disease dynamics both in an empirical and theoretical context. for that reason, we characterized in 2002, horizontal transmission of mycoplasma gallisepticum (mg) in two flocks of 11 wild-caught house finches housed in outdoor aviaries over a 6-mo period. all birds were initially free of mg by a polymerase chain reaction ...200616617979
a cdna macroarray approach to parasite-induced gene expression changes in a songbird host: genetic response of house finches to experimental infection by mycoplasma 1994, the bacterial parasite mycoplasma gallisepticum expanded its host range and swept through populations of a novel host--eastern us populations of the house finch (carpodacus mexicanus). this epizootic caused a dramatic decline in finch population numbers, has been shown to have caused strong selection on house finch morphology, and presumably caused evolutionary change at the molecular level as finches evolved enhanced resistance. as a first step toward identifying finch genes that respo ...200616626453
genotypic analyses of mycoplasma gallisepticum isolates from songbirds by random amplification of polymorphic dna and amplified-fragment length polymorphism.mycoplasma gallisepticum (mg) conjunctivitis emerged in 1994 as a disease of free-ranging house finches (carpodacus mexicanus) in north america and has also been isolated from other songbirds with conjunctivitis. random amplification of polymorphic dna (rapd) of house finch and other songbird isolates has suggested that a single 'strain' initiated this outbreak. to explore the possibility of genomic variability among house finch isolates of mg and to evaluate the utility of a second technique fo ...200616870869
further western spread of mycoplasma gallisepticum infection of house finches.mycoplasma gallisepticum, an important pathogen of poultry, especially chickens and turkeys, emerged in 1994 as the cause of conjunctivitis in house finches (carpodacus mexicanus) in their eastern range of north america. the resulting epidemic of m. gallisepticum conjunctivitis severely decreased house finch abundance and the continuing endemic disease in the eastern range has been associated with repeating seasonal peaks of conjunctivitis and limitation of host populations. mycoplasma gallisept ...200616870870
evolutionary genetics of carpodacus mexicanus, a recently colonized host of a bacterial pathogen, mycoplasma gallisepticum.we present molecular data documenting how introduction to the eastern united states and an epizootic involving a bacterial pathogen has affected the genetic diversity of house finches, a cardueline songbird. population bottlenecks during introduction can cause loss of genetic variation and may negatively affect a population's ability to adapt to novel stressors such as disease. although a genome-wide survey using amplified fragment length polymorphism (aflp) markers suggests little loss of genet ...200717103248
genetic diversity predicts pathogen resistance and cell-mediated immunocompetence in house finches.evidence is accumulating that genetic variation within individual hosts can influence their susceptibility to pathogens. however, there have been few opportunities to experimentally test this relationship, particularly within outbred populations of non-domestic vertebrates. we performed a standardized pathogen challenge in house finches (carpodacus mexicanus) to test whether multilocus heterozygosity across 12 microsatellite loci predicts resistance to a recently emerged strain of the bacterial ...200517148199
spatial spread of an emerging infectious disease: conjunctivitis in house this paper we quantify the rate of spread of the newly emerged pathogen mycoplasma gallisepticum of the house finch, carpodacus mexicanus, in its introduced range. we compare and contrast the rapid, yet decelerating, rate of spread of the pathogen with the slower, yet accelerating rate of spread of the introduced host. comparing the rate of spread of this pathogen to pathogens in terrestrial mammalian hosts, we see that elevation and factors relating to host abundance restrict disease spread, ...200617249229
state-specific detection probabilities and disease prevalence.investigations of disease dynamics in wild animal populations often use estimated prevalence or incidence as a measure of true disease frequency. such indices, almost always based solely on raw counts of infected and uninfected individuals, are often used as the basis for analysis of temporal and spatial dynamics of diseases. generally, such studies do not account for potential differences in observer detection probabilities of host individuals stratified by biotic and/or abiotic factors. we dem ...200717479842
experimental evidence for transmission of mycoplasma gallisepticum in house finches by fomites.ever since mycoplasma gallisepticum emerged among house finches in north america, it has been suggested that bird aggregations at feeders are an important cause of the epidemic of mycoplasmal conjunctivitis because diseased birds could deposit droplets of pathogen onto the feeders and thereby promote indirect transmission by fomites. in this paper we bring the first experimental evidence that such transmission (bird-to-feeder-to-bird) does actually take place. house finches infected via this rou ...200717497332
contrasting natural experiments confirm competition between house finches and house sparrows.after house finches were introduced from the western to the eastern united states and rapidly increased in numbers, house sparrows declined, leading to suggestions that the decline was caused by interspecific competition. however, other potential causes were not excluded. the rapid decline in house finches following the emergence of a new disease (mycoplasmal conjunctivitis) caused by a novel strain of mycoplasma gallisepticum (mg) in 1994 has provided a natural experiment and an opportunity to ...200717536703
mycoplasma gallisepticum infection in house finches (carpodacus mexicanus) affects mosquito blood feeding patterns.disease-induced lethargy can diminish host capacity to repel or kill biting mosquitoes. we exposed house finches (carpodacus mexicanus) to mosquitoes (culex pipiens pipiens), repeated the experiment after inoculating finches with mycoplasma gallisepticum, and then repeated the experiment with the same birds after curing their infections. we videotaped avian behaviors before and during mosquito exposure, identifying hosts through blood meal dna fingerprinting. results revealed heterogeneity in mo ...200717827365
detection and quantification of mycoplasma gallisepticum genome load in conjunctival samples of experimentally infected house finches (carpodacus mexicanus) using real-time polymerase chain reaction.a taqman-based real-time, quantitative polymerase chain reaction (qpcr) assay utilizing the mgc2 gene was developed to detect mycoplasma gallisepticum in conjunctival swabs of experimentally infected house finches. the assay was demonstrated to be quantitative by the standard curve method with reproducible results within runs and between runs. the detection limit of the mgc2 assay was examined using two standards. the test had a detection limit of less than 14 copies per reaction when tested wit ...200818622854
the potential impact of disease on the migratory structure of a partially migratory passerine population.since its introduction into eastern north america in the 1940s, the eastern population of house finches (carpodacus mexicanus) has become partially migratory, unlike its nonmigratory source population in southern california (able and belthoff in proc. r. soc. lond. 265 (1410), 2063-2071, 1998; belthoff and gauthreaux in condor 93, 374-382, 1991). the infectious disease mycoplasmal conjunctivitis (pathogen mycoplasma gallisepticum or "mg"), which has been monitored in the house finch population s ...200818716845
comparative infectiousness of three passerine bird species after experimental inoculation with mycoplasma gallisepticum.mycoplasma gallisepticum has been isolated from various species of free-living birds, and we therefore tested the hypothesis that bird species other than the main host, the house finch (carpodacus mexicanus), could play a role in the epidemiology of the infection. we compared the disease course in the house finch, american goldfinch (carduelis tristis) and house sparrow (passer domesticus) after inoculation into the conjunctival sac with m. gallisepticum, and also the degree to which the three s ...200819023761
production of house finch (carpodacus mexicanus) iga specific anti-sera and its application in immunohistochemistry and in elisa for detection of mycoplasma gallisepticum-specific iga.the iga antibody response plays a vital role in mucosal immunity because it functions to neutralize pathogens at the mucosal surface and thus impedes attachment to underlying tissues. although the importance of iga in the mucosal immunity of galliform birds has been established, studies examining iga-based immunity in passerine birds are lacking, perhaps due in part to the absence of reagents that can detect passerine iga. a 469 base pair region of the house finch (carpodacus mexicanus) iga heav ...200919581004
spatial variation in an avian host community: implications for disease dynamics.because many pathogens can infect multiple host species within a community, disease dynamics in a focal host species can be affected by the composition of the host community. we examine the extent to which spatial variation in species' abundances in an avian host community may contribute to geographically varying prevalence of a recently emerged wildlife pathogen. mycoplasma gallisepticum is a pathogen novel to songbirds that has caused substantial mortality in house finches (carpodacus mexicanu ...201020130959
sickness behaviour acting as an evolutionary trap? male house finches preferentially feed near diseased behaviour towards infectious conspecifics is a crucial yet overlooked component of pathogen dynamics. selection is expected to favour individuals who can recognize and avoid infected conspecifics in order to reduce their own risk of infection. however, evidence is scarce and limited to species employing chemical cues. here, we experimentally examine whether healthy captive house finches (carpodacus mexicanus) preferentially forage near a same-sex, healthy conspecific versus one infected wit ...201020164082
common garden experiment reveals pathogen isolate but no host genetic diversity effect on the dynamics of an emerging wildlife genetic diversity can mediate pathogen resistance within and among populations. here we test whether the lower prevalence of mycoplasmal conjunctivitis in native north american house finch populations results from greater resistance to the causative agent, mycoplasma gallisepticum (mg), than introduced, recently-bottlenecked populations that lack genetic diversity. in a common garden experiment, we challenged wild-caught western (native) and eastern (introduced) north american finches with ...201020561136
mycoplasma sturni from a california house finch with conjunctivitis did not cause disease in experimentally infected house finches.mycoplasma gallisepticum conjunctivitis emerged in 1994 as a disease of free-ranging house finches (carpodacus mexicanus) in north america and has also been isolated from other songbirds with conjunctivitis. a key feature for the successful study of natural and experimental disease has been the apparent, very-high correlation between characteristic eye lesions and m. gallisepticum. mycoplasma sturni was originally isolated from an adult european starling (sturnus vulgaris) with bilateral conjunc ...201020688712
experimental infection of domestic canaries (serinus canaria domestica) with mycoplasma gallisepticum: a new model system for a wildlife disease.the ethical and logistical challenges inherent in experimental infections of wild-caught animals present a key limitation to the study of wildlife diseases. here we characterize a potentially useful domestic model for a wildlife disease that has been of particular interest in recent decades; that is, infection of north american house finches (carpodacus mexicanus) with mycoplasma gallisepticum, more commonly known as a worldwide poultry pathogen. seven domestic canaries (serinus canaria domestic ...201121711192
Pathogenicity and immunogenicity of three Mycoplasma gallisepticum isolates in house finches (Carpodacus mexicanus).Mycoplasma gallisepticum (MG) has become a common cause of conjunctivitis in free-living house finches (Carpodacus mexicanus) since its emergence in the early 1990s. To date, temporal and spatial genotypic variation in MG has been documented, but phenotypic variation in pathogenicity and immunogenicity has not been examined. House finches were inoculated with MG isolates Virginia (VA)1994, California (CA)2006, or North Carolina (NC)2006, which were cultured from free-living house finches with co ...201121885217
apparent effect of chronic plasmodium infections on disease severity caused by experimental infections with mycoplasma gallisepticum in house epidemic caused by a successful host jump of the bacterial pathogen mycoplasma gallisepticum from poultry to house finches in the 1990s has by now spread across most of north america. m. gallisepticum causes severe conjunctivitis in house finches. we experimentally show that m. gallisepticum transmission to birds with or without chronic plasmodium infection does not differ. however, once infected with m. gallisepticum house finches chronically infected with plasmodium develop more severe clin ...201728348959
eye of the finch: characterization of the ocular microbiome of house finches in relation to mycoplasmal conjunctivitis.vertebrate ocular microbiomes are poorly characterized and virtually unexplored in wildlife species. pathogen defense is considered a key function of microbiomes, but determining microbiome stability during disease is critical for understanding the role of resident microbial communities in infectious disease dynamics. here, we characterize the ocular bacterial microbiome of house finches (haemorhous mexicanus), prior to and during experimental infection with an inflammatory ocular disease, mycop ...201727871125
changes in corticosterone concentrations and behavior during mycoplasma gallisepticum infection in house finches (haemorhous mexicanus).glucocorticoid stress hormones are important for energy mobilization as well as regulation of the immune system, and thus these hormones are particularly likely to both influence and respond to pathogen infection in vertebrates. in this study, we examined how the glucocorticoid stress response in house finches (haemorhous mexicanus) interacts with experimental infection of the naturally-occurring bacterial pathogen, mycoplasma gallisepticum (mg). we also investigated whether infection-induced co ...201627288634
house finch (haemorhous mexicanus) conjunctivitis, and mycoplasma spp. isolated from north american wild birds, 1994-2015.sampling wild birds for mycoplasma culture has been key to the study of house finch (haemorhous mexicanus) conjunctivitis, yielding isolates of mycoplasma gallisepticum spanning the temporal and geographic ranges of disease from emergence to endemicity. faced with the challenges and costs of sample collection over time and from remote locations for submission to our laboratory for mycoplasma culture, protocols evolved to achieve a practical optimum. herein we report making m. gallisepticum isola ...201627285414
feeder use predicts both acquisition and transmission of a contagious pathogen in a north american songbird.individual heterogeneity can influence the dynamics of infectious diseases in wildlife and humans alike. thus, recent work has sought to identify behavioural characteristics that contribute disproportionately to individual variation in pathogen acquisition (super-receiving) or transmission (super-spreading). however, it remains unknown whether the same behaviours enhance both acquisition and transmission, a scenario likely to result in explosive epidemics. here, we examined this possibility in a ...201526378215
response of black-capped chickadees to house finch mycoplasma gallisepticum.tests for the presence of pathogen dna or antibodies are routinely used to survey for current or past infections. in diseases that emerge following a host jump estimates of infection rate might be under- or overestimated. we here examine whether observed rates of infection are biased for a non-focal host species in a model system. the bacterium mycoplasma gallisepticum is a widespread pathogen in house finches (haemorhous mexicanus), a fringillid finch, but an unknown proportion of individuals o ...201525880849
immune responses of wild birds to emerging infectious diseases.over the past several decades, outbreaks of emerging infectious diseases (eids) in wild birds have attracted worldwide media attention, either because of their extreme virulence or because of alarming spillovers into agricultural animals or humans. the pathogens involved have been found to infect a variety of bird hosts ranging from relatively few species (e.g. trichomonas gallinae) to hundreds of species (e.g. west nile virus). here we review and contrast the immune responses that wild birds ar ...201525847450
evolution of pathogen virulence across space during an epidemic.we explore pathogen virulence evolution during the spatial expansion of an infectious disease epidemic in the presence of a novel host movement trade-off, using a simple, spatially explicit mathematical model. this work is motivated by empirical observations of the mycoplasma gallisepticum invasion into north american house finch (haemorhous mexicanus) populations; however, our results likely have important applications to other emerging infectious diseases in mobile hosts. we assume that infect ...201525674688
house finch responses to mycoplasma gallisepticum infection do not vary with experimentally increased aggression.aggression can alter infectious disease dynamics through two, non-exclusive mechanisms: 1) increasing direct contact among hosts and 2) altering hosts' physiological response to pathogens. here we examined the latter mechanism in a social songbird by manipulating intraspecific aggression in the absence of direct physical contact. we asked whether the extent of aggression an individual experiences alters glucocorticoid levels, androgen levels, and individual responses to infection in an ecologica ...201525387693
diverse wild bird host range of mycoplasma gallisepticum in eastern north america.emerging infectious diseases often result from pathogens jumping to novel hosts. identifying possibilities and constraints on host transfer is therefore an important facet of research in disease ecology. host transfers can be studied for the bacterium mycoplasma gallisepticum, predominantly a pathogen of poultry until its 1994 appearance and subsequent epidemic spread in a wild songbird, the house finch haemorhous mexicanus and some other wild birds. we screened a broad range of potential host s ...201425061684
a house finch (haemorhous mexicanus) spleen transcriptome reveals intra- and interspecific patterns of gene expression, alternative splicing and genetic diversity in passerines.with its plumage color dimorphism and unique history in north america, including a recent population expansion and an epizootic of mycoplasma gallisepticum (mg), the house finch (haemorhous mexicanus) is a model species for studying sexual selection, plumage coloration and host-parasite interactions. as part of our ongoing efforts to make available genomic resources for this species, here we report a transcriptome assembly derived from genes expressed in spleen.201424758272
evidence of trade-offs shaping virulence evolution in an emerging wildlife the mid-1990s, the common poultry pathogen mycoplasma gallisepticum (mg) made a successful species jump to the eastern north american house finch haemorhous mexicanus (hm). subsequent strain diversification allows us to directly quantify, in an experimental setting, the transmission dynamics of three sequentially emergent geographic isolates of mg, which differ in the levels of pathogen load they induce. we find significant among-strain variation in rates of transmission as well as recovery. ...201424750277
infection with mycoplasma gallisepticum buffers the effects of acute stress on innate immunity in house finches.when wild animals become infected, they still must cope with the rigors of daily life, and, thus, they still can be exposed to acute stressors. the suite of physiological responses to acute stress includes modifying the innate immune system, but infections can also cause similar changes. we examined the effects of an acute stressor (capture stress) on leukocyte abundance and bacteria-killing ability (bka) in wild birds (house finches haemorhous mexicanus) with and without a naturally occurring i ...201424642543
ketocarotenoid circulation, but not retinal carotenoid accumulation, is linked to eye disease status in a wild songbird.pathogenic or parasitic infections pose numerous physiological challenges to organisms. carotenoid pigments have often been used as biomarkers of disease state and impact because they integrate multiple aspects of an individual's condition and nutritional and health state. some diseases are known to influence carotenoid uptake from food (e.g. coccidiosis) and carotenoid use (e.g. as antioxidants/immunostimulants in the body, or for sexually attractive coloration), but there is relatively little ...201324080319
deposition of pathogenic mycoplasma gallisepticum onto bird feeders: host pathology is more important than temperature-driven increases in food intake.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 wit ...201323966599
multiple host transfers, but only one successful lineage in a continent-spanning emergent pathogen.emergence of a new disease in a novel host is thought to be a rare outcome following frequent pathogen transfers between host species. however, few opportunities exist to examine whether disease emergence stems from a single successful pathogen transfer, and whether this successful lineage represents only one of several pathogen transfers between hosts. we examined the successful host transfer and subsequent evolution of the bacterial pathogen mycoplasma gallisepticum, an emergent pathogen of ho ...201323843387
prevalence of blood parasites in eastern versus western house finches: are eastern birds resistant to infection?the rapid spread of the bacterial disease, mycoplasma gallisepticum (mg), throughout the introduced range of house finches (carpodacus mexicanus) in eastern north america, compared to its slower spread through the native western range, has puzzled researchers and highlights the need to understand the relative differences in health state of finches from both populations. we conducted a light-microscope survey of hemoparasites in populations of finches from arizona (within the western range) and f ...201323807632
chronic mycoplasma conjunctivitis in house finches: host antibody response and m. gallisepticum vlha expression.previous studies have shown that house finch field isolates of mycoplasma gallisepticum (mg) vary in virulence and ability to induce an antibody response. after experimental inoculation, mg causes persistent, severe disease in a subset of individuals. in this study, we further characterized mg infection using five field isolates, with an emphasis on chronically diseased birds. after experimental inoculation of house finches, mg load was measured by quantitative pcr and anti-mg antibody responses ...201323764469
parallel patterns of increased virulence in a recently emerged wildlife pathogen.the evolution of higher virulence during disease emergence has been predicted by theoretical models, but empirical studies of short-term virulence evolution following pathogen emergence remain rare. here we examine patterns of short-term virulence evolution using archived isolates of the bacterium mycoplasma gallisepticum collected during sequential emergence events in two geographically distinct populations of the host, the north american house finch (haemorhous [formerly carpodacus] mexicanus) ...201323723736
house finch populations differ in early inflammatory signaling and pathogen tolerance at the peak of mycoplasma gallisepticum individuals and populations often vary in their responses to infection, with direct consequences for pathogen spread and evolution. while considerable work has focused on the mechanisms underlying differences in resistance-the ability to kill pathogens-we know little about the mechanisms underlying tolerance-the ability to minimize fitness losses per unit pathogen. here, we examine patterns and mechanisms of tolerance between two populations of house finches (haemorhous [formerly carpodacus ...201323594550
cis-regulatory sequence variation and association with mycoplasma load in natural populations of the house finch (carpodacus mexicanus).characterization of the genetic basis of fitness traits in natural populations is important for understanding how organisms adapt to the changing environment and to novel events, such as epizootics. however, candidate fitness-influencing loci, such as regulatory regions, are usually unavailable in nonmodel species. here, we analyze sequence data from targeted resequencing of the cis-regulatory regions of three candidate genes for disease resistance (cd74, hsp90α, and lcp1) in populations of the ...201323532859
can american goldfinches function as reservoirs for mycoplasma gallisepticum?we performed experiments to test if american goldfinches (spinus tristis) could be a competent reservoir for mycoplasma gallisepticum and play a role in the epidemic spread of mycoplasmal conjunctivitis among house finches (carpodacus mexicanus) in north america. we infected one of two individuals housed together in a cage and determined if transmission occurred to the second bird. probability of transmission between an american goldfinch and a house finch (in either direction) was similar to th ...201323307371
experimental evidence for distinct costs of pathogenesis and immunity against a natural pathogen in a wild bird.protective immunity is expected to evolve when the costs of mounting an immune response are less than those of harbouring pathogens. estimating the costs of immunity vs. pathogenesis in natural systems is challenging, however, because they are typically closely linked. here we attempt to disentangle the relative cost of each using experimental infections in a natural host-parasite system in which hosts (house finches, carpodacus mexicanus) differ in resistance to a bacterium (mycoplasma gallisep ...201222924889
within-host dynamics of mycoplasma infections: conjunctivitis in wild passerine birds.the host-pathogen interaction drives infectious disease dynamics at the individual, population and community levels. here i present and analyze a model of the vertebrate immune response to mycoplasma infections, and use it to identify which pathogen and host immune characteristics drive patterns of mycoplasma gallisepticum (mg) infections in the house finch (carpodacus mexicanus) and other passerine birds. i also address which host and pathogen characteristics most affect host infectiousness and ...201222726809
extensive variation in surface lipoprotein gene content and genomic changes associated with virulence during evolution of a novel north american house finch epizootic strain of mycoplasma gallisepticum.mycoplasma gallisepticum, a significant respiratory and reproductive pathogen of domestic poultry, has since 1994 been recognized as an emergent pathogen of the american house finch (carpodacus mexicanus). epizootic spread and pathognomonic characteristics of house finch-associated mycoplasma gallisepticum (hfmg) have been studied as a model of an emergent to endemic pathogen in a novel host. here we present comparative analysis of eight hfmg genomes, including one from an index isolate and seve ...201222628486
innate immunity and the evolution of resistance to an emerging infectious disease in a wild bird.innate immunity is expected to play a primary role in conferring resistance to novel infectious diseases, but few studies have attempted to examine its role in the evolution of resistance to emerging pathogens in wild vertebrate populations. here, we used experimental infections and cdna microarrays to examine whether changes in the innate and/or acquired immune responses likely accompanied the emergence of resistance in house finches (carpodacus mexicanus) in the eastern united states subject t ...201222512302
ultrafast evolution and loss of crisprs following a host shift in a novel wildlife pathogen, mycoplasma gallisepticum.measureable rates of genome evolution are well documented in human pathogens but are less well understood in bacterial pathogens in the wild, particularly during and after host switches. mycoplasma gallisepticum (mg) is a pathogenic bacterium that has evolved predominantly in poultry and recently jumped to wild house finches (carpodacus mexicanus), a common north american songbird. for the first time we characterize the genome and measure rates of genome evolution in house finch isolates of mg, ...201222346765
contrasting epidemic histories reveal pathogen-mediated balancing selection on class ii mhc diversity in a wild songbird.the extent to which pathogens maintain the extraordinary polymorphism at vertebrate major histocompatibility complex (mhc) genes via balancing selection has intrigued evolutionary biologists for over half a century, but direct tests remain challenging. here we examine whether a well-characterized epidemic of mycoplasmal conjunctivitis resulted in balancing selection on class ii mhc in a wild songbird host, the house finch (carpodacus mexicanus). first, we confirmed the potential for pathogen-med ...201222291920
attenuated phenotype of a recent house finch-associated mycoplasma gallisepticum isolate for domestic poultry.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, yet geographically consistent, hfmg isolates ...201728396323
development and validation of a house finch interleukin-1β (hfil-1β) elisa system.a unique clade of the bacterium mycoplasma gallisepticum (mg), which causes chronic respiratory disease in poultry, has resulted in annual epidemics of conjunctivitis in north american house finches since the 1990s. currently, few immunological tools have been validated for this songbird species. interleukin-1β (il-1β) is a prototypic multifunctional cytokine and can affect almost every cell type during mycoplasma infection. the overall goal of this study was to develop and validate a direct eli ...201728854912
host responses to pathogen priming in a natural songbird host.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 pr ...201728766063
snps across time and space: population genomic signatures of founder events and epizootics in the house finch (haemorhous mexicanus).identifying genomic signatures of natural selection can be challenging against a background of demographic changes such as bottlenecks and population expansions. here, we disentangle the effects of demography from selection in the house finch (haemorhous mexicanus) using samples collected before and after a pathogen-induced selection event. using ddradseq, we genotyped over 18,000 snps across the genome in native pre-epizootic western us birds, introduced birds from hawaii and the eastern united ...201628725414
Displaying items 1 - 85 of 85