The equine influenza is a very contagious viral disease which only affects equids. This virus generates an acute infection of epithelium of the higher respiratory tracts and lungs. It is generally without complications, but infections bacteria can sometimes cause more serious complications.
The donkeys are particularly sensitive to this virus, and show clinical signs more severe then that of the horse.

Contamination

The virus is very easily transmitted between equids by air, for several kilometers by the wind. The virus can also be transmitted by various objects like feeding troughs, halters...

After inhalation, the influenza virus develops very quickly in the cells of the respiratory tract, thus causing the death of the infected cells. It follows from there a reduction of the animals immune defence system, thus facilitating the multiplication of many bacteria. The disease can also develop towards disease of bacterial origins like strangles.

Symptoms

The incubation period is short (1 to 3 days), and the first symptoms appear suddenly:
• high fever for 1 to 5 days
• dry coughing fit's which can persist several weeks
• nasal discharge
• lost of appetite
• lymphopaenia

The donkey can have a very high fever for 2 to 3 days after the first symptoms of the illness, and sometimes longer in duration. Then, the cough becomes loose, and nasal discharge becomes thicker, white or yellowish. Generally, the symptoms disappear in about fifteen days without after-effects.

Bacterial complications can appear: bronchitis, pharyngitis, pleurisy, infection of the gutturals pockets and myocarditis (inflammation of the cardiac muscle). It can result in death for the older animals or very young foals.

Prevention - Treatment

The equine influenza is very contagious so the sick donkey will have to be isolated for at least two weeks. It will stay in a ventilated stable without dust at least for a month (1 day of fever = 1 week of rest) in order to find its full respiratory capacity. To begin training to soon could result in bacterial complications and chronic respiratory obstructive diseases.

A vaccination is available, 2 doses of vaccine are initially given 4 to 6 weeks apart followed by boosters at 6 monthly intervals and at least every year.

Vaccination is often incomplete and vaccinated donkeys can as a result contract the virus. But the vaccinated animals will avoid the major clinical signs of the disease, and will be able to work after a shorter convalescence.