Molecular characterization of Newcastle disease virus (AOAV-1) obtained from Western region of Libya.

Background: Since its discovery in 1926, Newcastle disease (ND) is still emerging in many avian species worldwide causing severe economic losses due to high mortality. Aim: This article aims to discuss the challenge of virulent ND in poultry in Libya, focusing on recent outbreaks investigated in Alzintan, Alrayaina, Nalut, and Surman, cities located in the western region of Libya. Methods: Clinical signs and lesions were recorded. Tissues, as well as tracheal and cloacal swabs, were collected. RNA extraction was performed for confirmation using PCR and sequencing. Results: Mortality, in general, reached 50%-100% in vaccinated flocks with respiratory distress, diarrhea, swelling of the face, and nasal discharges. Necropsy revealed severe hemorrhages in the proventriculus, necrosis, and hemorrhages in the intestine and cecal tonsils. All tested samples were positive for avian orthoavulavirus 1 (AOAV-1) using rRT-PCR and genetic analysis. The sequences obtained are referable to AOAV-1, which is the same strain in all tested samples. The amino acid sequences deduced from the cleavage site of the Conclusion: ND remains a significant threat to the poultry industry in Libya. Therefore, there is an urgent need to conduct an epidemiological study with a representative number of samples from all regions of the country, alongside the implementation of an inactivated vaccine targeting genotype VII.