Multi-state analysis of the impacts of avian pox on a population of Serins (Serinus serinus): the importance of estimating recapture rates

Multi–state analysis of the impacts of avian pox on a population of Serins (Serinus serinus): the importance of estimating recapture rates.— Disease is one of the evolutionary forces shaping populations. Recent studies have shown that epidemics like avian pox, malaria, or mycoplasmosis have affected passerine population dynamics, being responsible for the decline of some populations or disproportionately killing males and larger individuals and thus selecting for specific morphotypes. However, few studies have estimated the effects of an epidemic by following individual birds using the capture–recapture approach. Because avian pox can be diagnosed by direct examination of the birds, we are here able to analyze, using multistate models, the development and consequences of an avian pox epidemic affecting in 1996, a population of Serins (Serinus serinus) in northeastern Spain. The epidemics lasted from June to the end of November of 1996, with a maximum apparent prevalence rate > 30% in October. However, recapture rate of sick birds was very high (0.81, range 0.37–0.93) compared to that of healthy birds (0.21, range 0.02– 0.32), which highly inflated apparent prevalence rate. This was additionally supported by the low predicted transition from the state of being uninfected to the state of being infected (0.03, SE 0.03). Once infected, Serin avian pox was very virulent with (15–day) survival rate of infected birds being of only 0.46 (SE 0.17) compared to that of healthy ones (0.87, SE 0.03). Probability of recovery from disease, provided that the bird survived the first two weeks, however, was very high (0.65, SE 0.25). The use of these estimates together with a simple model, allowed us to predict an asymptotic increase to prevalence of about 4% by the end of the outbreak period, followed by a sharp decline, with the only remaining infestations being infected birds that had not yet recovered. This is in contrast to the apparent prevalence of pox and stresses the need to estimate recapture rates when estimating population dynamics parameters.

[1]  G. McFadden,et al.  Poxviruses and immune evasion. , 2003, Annual review of immunology.

[2]  R. Woodroffe.  Managing disease threats to wild mammals , 1999 .

[3]  Development and application of a mark-recapture model incorporating predicted sex and transitory behaviour , 1999 .

[4]  R. May.  Parasitic infections as regulators of animal populations. , 1983, American scientist.

[5]  G. Hess.  Disease in Metapopulation Models: Implications for Conservation , 1996 .

[6]  G. Hill,et al.  Sex, size, and plumage redness predict house finch survival in an epidemic , 1998, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[7]  A. Dhondt,et al.  DYNAMICS OF CONJUNCTIVITIS AND MYCOPLASMA GALLISEPTICUM INFECTIONS IN HOUSE FINCHES , 2001 .

[8]  C. Atkinson,et al.  Interactions of climate change with biological invasions and land use in the Hawaiian Islands: Modeling the fate of endemic birds using a geographic information system , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[9]  David R. Anderson,et al.  Model selection and multimodel inference : a practical information-theoretic approach , 2003 .

[10]  Peter J. Hudson,et al.  The ecology of wildlife diseases , 2002 .

[11]  Matthias Leu,et al.  High Parasite Load in House Finches (Carpodacus mexicanus) is Correlated with Reduced Expression of a Sexually Selected Trait , 1997, The American Naturalist.

[12]  J. Gog,et al.  Disease in endangered metapopulations: the importance of alternative hosts , 2002, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[13]  M. Friend,et al.  Field guide to wildlife diseases. Volume 1. General field procedures and diseases of migratory birds , 1987 .

[14]  S. I. Rothstein,et al.  RECENT INCREASE IN MALE HOUSE FINCH PLUMAGE VARIATION AND ITS POSSIBLE RELATIONSHIP TO AVIAN POX DISEASE , 1999 .

[15]  James D. Nichols,et al.  Analysis and Management of Animal Populations: Modeling, Estimation and Decision Making , 2002 .

[16]  E. Kaleta,et al.  Pathology of Avian Pox in Wild Red‐Legged Partridges (Alectoris rufa) in Spain , 2002, Annals of the New York Academy of Sciences.

[17]  C. van Riper,et al.  EPIZOOTIOLOGY AND EFFECT OF AVIAN POX ON HAWAIIAN FOREST BIRDS , 2002 .

[18]  W. Hochachka,et al.  Density-dependent decline of host abundance resulting from a new infectious disease. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[19]  Evan G. Cooch,et al.  Mycoplasma gallisepticum infection dynamics in a house finch population: seasonal variation in survival, encounter and transmission rate , 2004 .

[20]  F. E. Kellogg,et al.  AN EPORNITIC OF AVIAN POX IN WILD BOBWHITE QUAIL 1 , 1980, Journal of wildlife diseases.

[21]  M. Scott.  The Impact of Infection and Disease on Animal Populations: Implications for Conservation Biology , 1988 .

[22]  C. Ralph,et al.  Demography and Movements of Apapane and IIWI in Hawaii , 1995 .

[23]  J. Clobert,et al.  The statistical analysis of survival in animal populations. , 1993, Trends in ecology & evolution.

[24]  D. Stallknecht,et al.  Mycoplasmal conjunctivitis in wild songbirds: the spread of a new contagious disease in a mobile host population. , 1997, Emerging infectious diseases.

[25]  J. Senar,et al.  Trapping methods can bias age ratio in samples of passerine populations , 1997 .

[26]  I. Newton,et al.  Population Limitation in Birds , 1998 .

[27]  N. Ling.  The Mathematical Theory of Infectious Diseases and its applications , 1978 .

[28]  R. Villafuerte,et al.  Descriptive study of an avian pox outbreak in wild red-legged partridges (Alectoris rufa) in Spain , 2004, Epidemiology and Infection.

[29]  A. Dhondt,et al.  EPIDEMIC MYCOPLASMAL CONJUNCTIVITIS IN HOUSE FINCHES FROM EASTERN NORTH AMERICA , 1998, Journal of wildlife diseases.

[30]  K. Burnham,et al.  Program MARK: survival estimation from populations of marked animals , 1999 .

[31]  G. Hill,et al.  EFFECTS OF COCCIDIAL AND MYCOPLASMAL INFECTIONS ON CAROTENOID-BASED PLUMAGE PIGMENTATION IN MALE HOUSE FINCHES , 2000 .

[32]  A. J. Hall.  Infectious diseases of humans: R. M. Anderson & R. M. May. Oxford etc.: Oxford University Press, 1991. viii + 757 pp. Price £50. ISBN 0-19-854599-1 , 1992 .