Last Updated: April 2008
What is African horse
sickness and what causes it?
African horse sickness is a serious,
often fatal disease of horses, mules,
and donkeys. The virus is spread by
infected insects (biting midges) and
causes fever and, heart and respiratory
animals. Death is common and can
occur suddenly. The disease primarily
occurs in Africa, but outbreaks have
been reported in Egypt, parts of the
Middle East, Spain, Portugal, Morocco,
Pakistan and India. African horse
sickness has not occurred in the
What animals get African
African horse sickness can affect
horses, donkeys, mules, zebras, camels
and dogs. Zebras and donkeys rarely
develop serious disease, but horses
and mules can become very sick and
How can my animal get
African horse sickness?
African horse sickness is spread
by biting midges
“punkies” or “no-see-ums”) (vector).
Mosquitoes and biting flies may also
be able to transfer the virus. Dogs
can become infected by eating (oral)
How does African horse
sickness affect my animal?
African horse sickness can cause
respiratory (lung) disease, cardiac
(heart) disease, or a cyclic fever. Death
rates can be as high as 95% for some
forms of the disease.
The pulmonary or respiratory form
occurs rapidly (within days). Signs
of disease include fever, difficulty
breathing, coughing, sweating, and
frothy discharge from the nostrils.
Death usually occurs within a few
hours after illness is seen.
The cardiac form of the disease
causes fever and swelling (edema)
around the eyes, lips, cheeks, tongue,
and neck. Death usually occurs due to
Some affected animals may have
both pulmonary and cardiac signs of
Some animals may only develop
a cyclic fever (high in the afternoon,
gone in the morning). These animals
may also have depression and a
decreased appetite. Animals with this
horsesickness fever form of African