Epidemiological and serological study of the low pathogenic avian influenza disease H9N2 in broiler flocks in Algeria

The aim of our epidemiological and serological study is to monitor and control the serological status of a number of broiler farms, i.e. to control the quality of vaccination and to detect whether there is any circulation of the wild virus of the Low Pathogenic Avian Influenza Disease Pathogenic H9N2 Avian Influenza (LPAI) virus, as well as assessing the risk factors associated with this pathology. Our results show that: Broiler flocks showed 60% of seroprevalence. The scores show the effect of risk factors, when vaccination was not applied, farms were significantly more seropositive by 68% (OR = 1.68, p = 0.02) than vaccinated farms. In addition, farms with poor hygiene were 58% more seropositive (OR = 1.58, p = 0.03) than those with good hygiene. Finally, farms with a mortality rate of more than 30% were 48% more likely to be seropositive (OR = 1.48, p = 0.04) compared with those with a mortality rate of less than 30%. However, there was no significant effect of season, climate, strain, density or age on disease occurrence. Good control of risk factors and serological monitoring must be carried out to guarantee good protection of the flock and reduce the impact of pathologies on poultry farms.