Caprine arthritis encephalitis (CAE) is a multisystemic inflammatory disease of goats, caused by caprine arthritis encephalitis virus (CAEV). CAEV affects the lungs, the central nervous system (CNS), joints and mammary glands of goats.
CAEV is an enveloped, single-stranded RNA virus in the Lentivirus genus of the Retrovirus family. CAE is closely related to Visna/Maedi Virus(VMV) which affects sheep, and collectively they are both referred to as small ruminant lentiviruses (SRLV)s. Lesions induced by SRLVs are characterized by mononuclear infiltration in target organs and persistent inflammation.
There are five known clinical forms of CAE that are seen in goats:
- Arthritis: the most common form
- Subclinical infection
- Chronic, progressive, interstitial pneumonia: the respiratory form
- Progressive weight loss
- Mastitis : the udder form
- Leukoencephalomyelitis: the neurological form
Clinical signs associated with the arthritis form of CAE varies depending on the severity of the infection. Early signs of arthritis may be subtle or obvious in its presentation, depending on the pain tolerance of the goat. Goats may have difficulty rising, a stiff gait, deceased ambulation, weight loss, and an abnormal posture after rising, and/or swelling of one or multiple joints. The next most commonly involved joints are the tarsal, stifle, and fetlock joints.
Transmission
CAEV can be transmitted vertically, from dam to kid via ingestion of virus-contaminated colostrum and milk, and horizontally, by direct or close contact with infected animals. Sexual transmission is a possible but unlikely factor in the spread of CAEV infection. Atrogenic transfer of CAEV is also a consideration in horizontal transmission.
Incubation period
It may take several months to years for goats to develop clinical signs of infection with CAEV.
