Serological evidence of egg drop syndrome 1976 in backyard poultry flocks in Southwestern Nigeria

Abstract

In Nigeria, egg drop syndrome 1976 (EDS’76), unlike other poultry diseases, has been given little attention as a cause of economic losses due to decreased egg production, particularly in backyard poultry flocks. This study aimed to investigate the presence of EDS’76 virus in backyard poultry flocks in Oyo and Osun states, Southwestern Nigeria. Blood samples were collected in 24 farms from 218 apparently healthy, unvaccinated birds which comprised 30 Japanese quails, 75 turkeys, 30 ducks, 57 indigenous chickens and 26 guinea fowls. Indirect ELISA was used to detect anti-EDS’76 virus antibodies in sera from the birds, and poultry owners were interviewed on their purposes with regard to bird raising. Overall, 139 (63.8%) sera were positive for EDS’76 with 26.7% (8/30), 90.7% (68/75), 33.3% (10/30), 89.5% (51/57) and 7.7% (2/26) from Japanese quails, turkeys, ducks, indigenous chickens and guinea fowls, respectively. Some of the farmers practiced placing eggs from guinea fowls under brooding indigenous hens for natural incubation, or sold eggs from turkeys and ducks to commercial hatcheries. Our findings suggest that these bird species serve as reservoirs of EDS’76 virus with the probable involvement of backyard poultry in its transmission, particularly to commercial poultry and other birds in Southwestern Nigeria. Thus, backyard poultry should be included in anti-EDS’76 vaccination schedules in the country.