Visna Maedi Virus (VMV) is a highly contagious and chronic viral disease that primarily affects sheep and goats, causing a variety of serious health problems. It is caused by a lentivirus belonging to the Retroviridae family, similar to the Human Immunodeficiency Virus (HIV). VMV primarily targets the lungs, central nervous system, and joints of infected animals.
The disease is characterized by a combination of two sister syndromes: Visna, affecting the nervous system, and Maedi, primarily infecting the lungs. Infected animals gradually develop clinical signs, including weight loss, respiratory distress, arthritis, mastitis, and neurological disorders. VMV is transmitted through the inhalation of respiratory secretions, ingestion of colostrum or milk from infected animals, and direct contact with infected birth fluids.
While VMV is highly contagious, it has a slow progression with a long incubation period that can range from several months to years. This makes the disease difficult to detect and control, leading to economic losses in affected flocks due to reduced productivity, increased mortality, and reduced market value of infected animals.
Prevention and control strategies involve implementing strict biosecurity measures, culling infected animals, and separating healthy livestock from infected ones. Vaccination is also available as a preventive measure to reduce the risk of VMV transmission within flocks. Prompt and accurate diagnosis through serological tests is crucial for early detection and management of the disease.
Overall, Visna Maedi Virus poses a significant threat to the livestock industry, and effective control measures are necessary to limit its spread and minimize its impact on affected sheep and goats.
