Abstract Supplementary feeding of wild birds can facilitate transmission of avian pathogens, with some pathogens able to spread indirectly from feeder surfaces (‘fomites’). Although feeder cleaning is a recommended mitigation strategy, effects of feeder cleaning on pathogen spread are rarely tested empirically. Further, protocols for cleaning feeders can be onerous, making them difficult for people to implement at the frequency needed to be effective. We used two experiments to test how a simple cleaning technique, surface cleaning of tube feeders using commercial bleach wipes, affects transmission of a bacterial pathogen, Mycoplasma gallisepticum (MG) among house finches ( Haemorhous mexicanus ). In the first experiment ( Fomite‐only ), we transferred pathogen‐contaminated feeders into cages of initially healthy ‘receiver’ birds, with or without wipe cleaning of high‐use feeder surfaces prior to transfer. In the second experiment ( Infected cagemate ), MG‐inoculated ‘donor’ birds were co‐housed with initially healthy receivers, and the high‐use feeder surfaces shared by each pair were wipe‐cleaned every other day for half of the study pairs. We determined effects of cleaning on spread by measuring receiver pathogen loads and severity of conjunctivitis, the disease caused by MG in house finches. When MG exposure was restricted to feeder surfaces, wipe cleaning of high‐use surfaces prior to feeder transfer prevented receiver birds from becoming infected with MG via fomite transfer only. In contrast, birds that received MG‐contaminated feeders without cleaning of high‐use surfaces became infected at high rates, though all infections via the fomite‐only route were subclinical. When infected donor birds and susceptible receivers were continuously co‐housed, we found no effect of feeder cleaning on transmission rate or disease progression within receivers. Practical implications . Our findings show that wipe cleaning of contaminated feeder surfaces prior to isolated exposure events can prevent fomite‐based MG spread. However, cleaning of feeder surfaces in a lab setting is inadequate for reducing spread in the presence of continuous interactions between sick and healthy birds. This suggests that while surface cleaning has short‐term benefits, its utility will be limited whenever diseased birds visit bird feeders at high frequency and continuously reinoculate feeder surfaces between cleanings.
Meyers et al. (Wed,) studied this question.