Occurrence of chicken infectious anemia virus in industrial and backyard tunisian broilers: Preliminary results

Chicken infectious anemia virus (CIAV) is an economically important and widely distributed immunosuppressive agent in chickens. This study performed an epidemiological investigation on CIAV circulation in 195 Tunisian broilers, belonging to 13 lots from five industrial farms and in one rural farm. Fifteen animals were detected positive by a VP1 nested PCR. The amplicons were molecularly characterised by complete genome sequencing. All positive samples obtained in this study were from the rural farm, whereas the industrial farms sampled were negative. Nucleotide and amino acid sequence analyses showed a high degree of similarity among the sequences obtained, suggesting the circulation of a single CIAV strain in the positive lot. Phylogenetic analysis based on the CIAV VP1 nucleotide sequence and/or the complete genome showed that the sequences obtained in this study clustered with CIAV strains previously detected in Tunisia, Italy and Egypt, belonging to genogroup II. Our results highlight the need for constant CIAV surveillance in backyard chicken production

Serological monitoring of vaccination against the major avian viral diseases in poultry breeding farms in Tunisia

A sero-epidemiological study was conducted in six broiler breeding companies and four broiler breeding laying hen companies, covering most of the poultry breeding farms in Tunisia. The objective was to evaluate the effectiveness of the immune response following the application of vaccination protocols established by the owners and carried out against the viruses of Newcastle disease (NDV), infectious bronchitis (IBV) and infectious bursal disease (IBD). During eight visits per farm, questionnaires were completed and 2000 samples were taken. The samples were submitted to indirect ELISA using CIVTEST AVINDV, -IBV, and -IBD kits. For each date and each disease, the mean specific antibody titers and the coefficient of variation were calculated. These indicators revealed that the chicks were in good health, the kinetics of post-vaccination antibodies generally satisfactory, and the overall immune response sufficiently uniform. However, the vaccination protocol recommended by the National Commission for Avian Diseases was not always applied. This either caused a temporary drop in antibody levels resulting in a high risk of infection, or necessitated interventions resulting in economic losses because of vaccine-related costs. This work shows the need for farmers to have a database for the establishment of an immunoprophylaxis program adapted to the epidemiological conditions of these farms