Egg drop syndrome (EDS 76) in Algeria: Epidemiological investigation, serological evidence, and assessment of field veterinarians' awareness.

Egg Drop Syndrome-76 (EDS-76) is an economically significant viral disease of laying hens, characterized by sudden declines in egg production and eggshell quality deterioration, often without overt clinical signs. Despite its global importance, data on EDS-76 in Algeria remain scarce. This study provides the first nationwide assessment of EDS-76 in Algerian layer flocks, combining a veterinary survey and serological investigation. A structured questionnaire was administered to 91 veterinarians across Eastern, Central, and Western Algeria to document egg production drops, associated clinical signs, and preventive measures. Serological analyses using ELISA were performed on 15 selected farms, with two blood samples collected from each bird at a 21-day interval. Survey results revealed widespread occurrence of production drops, predominantly moderate (20-40%), with abnormal eggs observed in 95.6% of cases. Knowledge and vaccination coverage against EDS were limited (46.2% and 25.3%, respectively). Serological testing indicated heterogeneous exposure: 8 out of 15 farms were seropositive, yet only one farm showed seroconversion. Seropositivity was observed in 8 out of 15 farms, indicating exposure to EDSV. However, only one farm showed seroconversion, suggesting limited evidence of recent infection. These findings highlight the circulation of EDSV in Algerian layer flocks, although no causal relationship between EDSV and egg production drops can be definitively established. Geographical region, flock strain, and vaccination status showed no statistically significant association. These findings underscore the need for heightened awareness, targeted surveillance, and appropriate preventive measures to mitigate EDS-76 impact in Algerian poultry production. Given the absence of molecular data and controlled epidemiological studies in Algeria, initial investigations based on serological and field observations are essential to establish baseline evidence of EDSV circulation.