Prevalence of antibodies against respiratory viruses (parainfluenza virus type 3, respiratory syncytial virus, reovirus and adenovirus) in relation to productivity in Syrian Awassi sheep

Awassi sheep sera from all the provinces of the Syrian Arab Republic were tested for RSV, PI3, REO and Adeno viruses (IIF and AGID tests). RSV was the most prevalent infection with 63.6% of samples seropositive, followed by REO, PI3 and Adenovirus with seroprevalences of 27.3%, 24% and 8.1% respectively. Animals were more frequently infected by RSV alone. Mixed infections were also identified but the occurrence was not high. The RSV and REO virus infections occurred more frequently when transhumant flocks travelled for long distances (P < 0.001). The prevalence of RSV, PI3, REO and Adenovirus infections was higher in animals sheltered in poor conditions compared to those in good shelter or with no shelter (P < 0.001; P < 0.001; n.s.; P < 0.05, respectively). RSV and PI3 infections were related to an adult mortality rate of 10 to 20% (P < 0.001); REO virus was also proportionally related to mortality from low to high rates (P < 0.05). Concerning mortality of lambs, only Adenovirus infection was related to losses (>20%) (P < 0.001). REO virus was related to low milk yield (P < 0.05).