There is no evidence that this contact has resulted in persistent viral infection. People drinking milk from infected does can develop antibodies to the CAE virus. The goat may or may not be antibody positive for CAE at the time of blood testing because of the delay between exposure to the virus and the development of antibodies. The virus usually enters a clean property in an infected goat. Venereal spread in semen and in utero spread to kids are less likely but can occur. Transfer sometimes occurs by blood on gear such as vaccination needles, tattooing equipment, dehorners or foot/hair shears, or through exposure to open wounds.
The virus can also be spread by respiratory secretions, saliva and tears when goats are kept in close quarters. Adult goats can also become infected by exposure to infected milk droplets during milking. The main spread of the virus between goats is through the ingestion of infected milk by kids or adults. Well managed infected goats may never express clinical signs. The majority of CAE infected goats do not show any outward clinical signs, although viral mastitis may be present in does.Ĭlinical signs can arise in a previously sub-clinical goat if the goat is exposed to stressful situations such as poor nutrition and overcrowding. Kids less than 6 months of age are more likely to show neurological disease. Neurological disease due to inflammation in the brain and its covering (meningitis/encephalitis) or inflammation in the spinal cord, resulting in progressive paralysis. Pneumonia following inflammation in the lung tissue, and ‘Hard udder’ (indurative mastitis) can occur.Īrthritis in any joints, most notably the carpal joints (big knee), due to inflammation of the tendon sheaths and joint lining (synoviae), Viral mastitis, with an increase of white blood cells in the milk and a decreased resistance against mastitis. The clinical signs that can occur in an infected goat are mainly due to the body's reaction against the virus infected cells. The disease occurs when the monocytes carrying the latent virus mature and multiply as macrophages in different body 'target' organs – mammary gland, lungs, tendons sheaths, joints and nervous tissue. Caprine retrovirus is an OIE listed disease. It also causes significant production losses through mastitis, ill-thrift, arthritis, pneumonia, ascending paralysis and arthritis, pneumonia, ascending paralysis and encephalitis in kids. Control programs have been conducted in many countries but CAE is still causing problems in dairy goat populations world-wide, including within NSW.ĬAE is a concern in terms of market access and animal welfare.
The virus occurs mainly in improved dairy goat breeds and is spread primarily via infected colostrum and milk. Symptoms can vary markedly between animals with most well managed goats showing no obvious clinical signs. Caprine arthritis encephalitis (CAE), commonly known as 'big knee', is caused by a lentivirus or 'slow' virus associated with nervous disorder (encephalomyelitis) in kids and slowly-developing disease syndromes in older goats.
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