Risk Factors Associated With Mycoplasmal Conjunctivitis in House Finches

Abstract

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, types and number of bird feeders maintained, neighborhood housing locale and altitude of the observation site. Bivariate analyses revealed that house finches were 14 to 72 times as likely to be observed with conjunctivitis than the sympatric species studied. Year of the study, season, and the presence of platform, hopper, and tube type feeders were significantly associated with conjunctivitis in house finches. Multivariate analysis using a logistic regression model suggests that increased risk of conjunctivitis in house finches was associated with the second year of the study (the third year of the outbreak), the cooler non-breeding periods from September through March, and the presence of tube style feeders. In addition, the presence of raised platform type feeders may have been protective against conjunctivitis in house finches. Prevention of spread of this disease may include modifying bird feeding activities based on season and type of feeder.

Experimental evidence for transmission of Mycoplasma gallisepticum in house finches by fomites

“…Existing evidence is circumstantial: Hartup et al (1998) reported that the odds of observing a wild house finch with conjunctivitis were higher at sites with tube feeders than at sites without them (i.e. with platform feeders or food on the ground).…”

Density-dependent decline of host abundance resulting from a new infectious disease

“…The disease was caused by a previously undescribed strain (14) of M. gallisepticum, a pathogen of poultry with a worldwide distribution that was first described in North America in 1936 and that had not previously been considered a pathogen of wild passerines (15). This pathogen apparently also infects American goldfinch (Carduelis tristis), purple finch (Carpodacus purpureus), and house sparrow (Passer domesticus) (16), although at far lower rates than house finches. House finches naturally infected with M. gallisepticum and held in captivity with ad libitum food developed conjunctivitis within 2-4 weeks, lost weight rapidly, and many (17) or all (18) died.…”

Use of polymerase chain reactions to detectMycoplasma gallisepticum,Mycoplasma imitans,Mycoplasma iowae,Mycoplasma meleagridisandMycoplasma synoviaein birds of prey

“…gallisepticum has been isolated from a variety of different avian species, including galliformes (Benčina et al, 2003), anseriformes (Ibrahim et al, 2000), psittaciformes (Bozeman et al, 1984), columbiformes (Benčina et al, 1987), passeriformes Hartup et al, 1998;Mikaelian et al, 2001) and birds of prey (Poveda et al, 1990a,b;Morishita et al, 1997). M. iowae, usually found in turkeys, has been isolated from a range of free-flying birds (Amin, 1977), geese (Lin et al, 1995), a yellow napped amazon (Amazona ochrocephala auropalliata) (Bozeman et al, 1984) and even an apple seed (Grau et al, 1991).…”