Caprine Arthritis Encephalitis

Caprine Arthritis Encephalitis is a serious disease that causes mastitis, ill-thrift, arthritis, pneumonia, and paralysis that moves up the body, and brain disease (encephalomyelitis). CAE is also considered an animal welfare issue. There is no cure for CAE. 

The disease is also known as ‘big knee’ and is caused by a lentivirus or ‘slow’ virus associated with encephalomyelitis in kids and slowly-developing disease syndromes in older goats. 

~ Spread of the Disease ~

The main spread of the virus between goats is through drinking infected milk either as a kid or as an adult. The virus does not cross the placenta and kids born to infected does; generally, do not always have the disease. However, there is a risk of spread during the birth process if the kid is contaminated with blood due to vaginal tears. 

Goats kept in close quarters can spread the virus through respiratory secretions, eg nasal discharge, and cough, saliva and tears. Transfer sometimes occurs by blood on gear such as vaccination needles, tattooing equipment, dehorners and foot/fibre shears, or through exposure to open wounds. People may also contribute to the spread of infection with contaminated hands, clothing, equipment and footwear.

A clean goat herd will most likely become infected by a CAE-positive goat coming on to the property. Symptoms can vary markedly between animals, with most well managed goats showing no obvious clinical signs. 

The signs of CAE are mainly due to the body’s reaction against the infected cells. Clinical signs include: 

• Hard udder (indurative mastitis) 

• Arthritis in any joints, most notably the carpal joints (big knee) 

• Pneumonia 

• Neurological symptoms leading to progressive paralysis. (Kids less than six months of age are more likely to show neurological disease) 

Clinical signs can appear in an infected goat if the goat is exposed to stressful situations such as poor nutrition and overcrowding, which means well managed infected goats may never show clinical signs. 

The best way to know if your herd has CAE is to have all animals over six months of age blood tested, this can be done by one of our veterinarians. Repeated blood testing during a 12-month period will detect the majority of infected goats (a very small number may take longer to detect). Testing should be performed on goats six months and older. Adult does should not be tested in the period from one month either side of kidding as inconsistent results could occur. No goat should be tested within one month of any vaccination. 

~ Preventing CAE ~

Insist on a fully completed and signed National Goat Health Statement from the seller. 

If you lend or agist your goats and intend for these animals to return to your property, make sure you assess the CAE risk of the property where they are going before sending them and remember people and objects such as grooming tools, feed bins, rugs and trailers can transfer CAE from one property and herd to another. 

Promote hygienic management of the kids to avoid contamination by CAE from birth until maturity. If practised, in conjunction with test and culling of serological positive goats, owners can reduce the level of infection on a property over time. Herd management can further reduce the exposure of susceptible goats to the virus.