Maedi-Visna Virus

Maedi-Visna Virus (MVV)

Maedi-Visna Virus is a slow-progressing lentivirus affecting sheep, closely related to Caprine Arthritis Encephalitis Virus (CAEV) in goats. MVV causes progressive respiratory and neurological disease, reduced productivity, and flock-level economic losses.

Transmission occurs via:

• Colostrum and milk
• Respiratory secretions in close-contact housing
• Shared equipment or poor hygiene during lambing

Clinical presentations include:

• Maedi (dyspnea) – chronic progressive respiratory disease in adult sheep
• Visna (neurological form) – rare; presents as hind limb weakness and wasting
• Mastitis – "hard udder" with low milk yield
• Poor body condition despite good nutrition

qPCR testing provides:

• Highly sensitive detection of MVV proviral DNA in whole blood (EDTA) or milk
• Ideal for identifying asymptomatic carriers and early infection
• A faster and more reliable alternative to serology, particularly in young or recently exposed animals

This test is valuable for:

• Flock accreditation programs and MVV eradication schemes
• Pre-purchase or pre-introduction screening
• Supporting biosecurity and breeding decisions in commercial and pedigree flocks

Early diagnosis enables strategic culling, improved productivity, and long-term flock health.