Virucidal effect of commercial disinfectants on fowl adenovirus serotype 1 strains causing chicken gizzard erosion in Japan

To find an efficient control method for gizzard erosion (GE) caused by fowl adenovirus serotype 1 (FAdV-1) infection in poultry farms, we examined the virucidal effects of commercial disinfectants. In laboratory tests, the virucidal effects of the disinfectants calcium hydroxide (CHO), glutaraldehyde (GLT), orthodichlorobenzene, cresol, and didecyldimethylammonium chloride against FAdV-1s were examined. Among them, CHO and GLT were extremely effective in all tested viruses, even at low concentrations, under the condition of 20 degrees C. However, virucidal effect under the condition of 4 degrees C at low concentrations of GLT was attenuated. Then, in a broiler farm where GE in chickens continuously occurred, we applied 2 combinations of disinfectants on the inside and outside of poultry houses every chicken-free period after shipping of chickens. The disinfection effect was then evaluated by gizzard rejection rate in the next flock. We detected GE in the flocks after disinfection with a combination of GLT and CHO at an ambient temperature of approximately 11 degrees C. Moreover, we detected GE in the flock after disinfecting with didecyldimethylammonium chloride and CHO, regardless of the environmental temperature. In contrast, we did not detect GE in the flock after disinfecting with GLT and CHO under the condition of ambient temperature of approximately 21 degrees C. These findings underline the importance of performing thorough disinfection with effective disinfectants during the chicken-free downtime to prevent the persistence of GE caused by FAdV-1 infection. It is necessary to use liquid disinfectants such as GLT and to pay close attention to ambient temperatures and the working concentration of disinfectants.