Monitoring influenza A virus in wild migratory birds and waterfowl in Libya using RT-qPCR

Avian influenza viruses (AIVs) pose a global threat to avian and human health, with wild migratory birds being recognized as major natural reservoirs and vectors of viral dissemination. Libya, with its diverse wetlands and geographic positioning along key migratory routes, serves as a critical stopover for numerous bird species, presenting a potential hotspot for AIV transmission.

This study aimed to detect the presence of type A influenza virus in wild migratory birds in eastern Libya using reverse transcription real-time polymerase chain reaction (RT-qPCR) and evaluate the role of AIV in the ecology and surveillance of the region.

From June to October 2024, 72 nasopharyngeal, cloacal, and fresh fecal swabs were collected from various species of wild migratory birds across key wetlands and lakes in eastern Libya. The morphological identification and characterization of the bird were performed. Detection of the matrix gene of AIV was conducted using the SVIP-MPv2 assay for the detection of type A influenza virus with primers and probe for H5 subtype detection adapted from validated protocols.

Among the 72 tested samples, one cloacal swab collected from a Eurasian teal (Anas crecca) tested positive for type A influenza virus, whereas the remaining 71 samples were negative. The positive case highlights the silent circulation of AIV among asymptomatic wild birds in the region. Clinical examinations during sampling confirmed no visible signs of illness, such as respiratory distress, lethargy, or neurological symptoms in the positive teal, consistent with typical LPAI reservoir behavior in waterfowl. However, follow-up RT-qPCR testing for the H5 subtype was negative, indicating a non-H5 influenza A strain.

The detection of AIV in a migratory bird in Libya highlights the importance of continued surveillance in wild avian populations, especially in ecologically sensitive areas along migratory pathways. Early detection through molecular diagnostics is essential for informing public health strategies and mitigating the transmission risk to domestic poultry populations. Future efforts should prioritize the continued monitoring of AIV, with particular emphasis on the detection of H7 and H9 subtypes, using a larger sample size to enhance surveillance efforts.