Caprine arthritis encephalitis

Overview

Cause

Caprine arthritis encephalitis virus in the lentivirus group

Description

Caprine arthritis encephalitis (also known as caprine retrovirus or CRV) occurs only in goats causing arthritis, encephalitis or pneumonia.

Where the disease occurs

Caprine arthritis encephalitis ( CAE) has been reported from Australia, the United States, Canada, Europe and New Zealand. It is present in Queensland, mainly in dairy goats in eastern parts of the State.

The disease in animals

Under natural conditions, most goats are infected when young, carry the virus for life and develop the disease months or years later. The signs of disease vary according to the age of the animal.

Encephalitis affects young kids 2-4 months old but older animals can be affected. There is a sudden occurrence of a short, stilted gait. This progresses to an ascending unilateral or bilateral posterior paralysis. Affected kids retain their alertness and appetite during this period. Eventually, hyperaesthesia develops with convulsions and death. The course of the disease can vary from two weeks to two months. Kids affected in this way should be humanely destroyed.

Arthritis occurs in mature goats, around 1-2 years old, but can be seen as early as four months. The onset may be sudden or slow. The animal becomes depressed, loses weight and the coat becomes rough. Lameness, incoordination and progressive paralysis occur as a result of the development of enlarged painful joints.

A progressive pneumonia is seen in some infected goats, mainly adults. They show respiratory distress, loss of weight and slow deterioration.

How the disease spreads

The main method of spread is from doe to kid through colostrum or milk. The virus does not cross the placenta and kids born to infected does, in the main, do not have the disease. There is a small risk of spread during the birth process if the kid is contaminated with blood due to vaginal tears. However, one drink of infected milk will cause disease.

Some spread of infection occurs by contact between adult goats especially in intensively managed situations, such as dairy goat herds. The disease is less common in meat, fibre and feral goats under extensive grazing conditions.

People may also contribute to the spread of infection by having contaminated hands, clothing and footwear.

Diagnosis

Diagnosis is normally by the testing of blood samples.

Control of the disease in animals

The disease can be controlled by blood testing and removal of infected animals. Kids should be removed at birth from infected does, kept in isolation and reared on bovine colostrum and milk, milk substitutes or milk from known CAE free does. Goats should only be introduced from CAE free herds or blood tested before joining the herd. There is no successful treatment for infected animals.

Caprine arthritis encephalitis accreditation scheme

A voluntary CAE accreditation scheme is administered by Biosecurity Queensland.

Responsibility for meeting the conditions of the scheme rests with the owner of the flock and an approved private veterinary practitioner. Owners are required to meet all veterinary and laboratory costs and to pay an accreditation fee to Biosecurity Queensland.

Flock owners must abide with the rules of the scheme with regard to flock management and biosecurity, testing requirements and purchase of stock. Two negative blood tests of all goats over six months of age are required for accreditation. Re-accreditation is required annually or biennially, depending on the time the flock has been accredited. If infection is detected in the flock, accreditation is withdrawn until all reactors are removed and the flock tested back to accreditation standards.

For more information, please contact Biosecurity Queensland.

Can people get the disease

No.

Further information

Last updated 08 January 2014