Meningoencephalitic Listeriosis in Iranian Sheep and Goats

Background: Meningoencephalitic listeriosis is a significant disease affecting goats and sheep, with potential implications for public health. This study aimed to investigate and report the occurrence, clinical manifestation, laboratory findings, and further understanding of neurolisteriosis in the goat and sheep populations in Tehran, Qazvin, and Kurdistan provinces of Iran. Methods: From 2018 to 2021, a program was implemented to monitor multiple flocks for meningoencephalitic listeriosis. Clinical manifestations of animals that showed suspected neurological signs of listeriosis (19 animals) were recorded, and necropsies were performed. Sampling of the brain tissue of infected animals was done. The specimens underwent a 'cold-enrichment' procedure, and subsequent culture and biochemical tests were conducted to confirm the presence of Listeria monocytogenes. Results: According to the clinical and bacteriological findings, 19 animals were diagnosed with neurolisteriosis. The affected animals exhibited various signs of the disease, including head deviation, head tilt, head pressing, mouthfuls, walking in circles, drooping of the ear, and unilateral hypalgesia. L. monocytogenes was isolated from brain samples of 11 animals. Conclusion: The study revealed potential indications of meningoencephalitic listeriosis in certain breeds of goats and sheep. Recognizing these typical signs can contribute to early detection, diagnosis, and proper management of listeriosis cases, improving welfare and health outcomes for affected animals. The results underscore the importance of strengthened disease surveillance, prevention, and control strategies.