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Eperythrozoonosis (Epe)

See also chapter 8.

(216) This is a disease caused by a bacterium called Eperythrozoonosis suis which attaches to the surface of red blood cells and sometimes destroys them. The pig then may become anaemic and the products left after the destruction of the cells may cause jaundice. Clinical disease is more commonly seen in the young growing pigs. However it can also cause reproductive problems in the breeding herd. A sow may carry Epe and yet remain quite healthy, however, it can cross the placenta and infect pigs in utero causing weak piglets at birth. The disease can be transmitted by direct inoculation, through pig lice, biting house flies, mange mites and perhaps more importantly the needles that are used to inject pigs. It is also thought that Epe may enter through the mouth to the stomach and intestine and be transferred into the body this way. This is one reason why the practice of feed-back using placenta is not advised.

Epe is present in most if not all herds but the mechanisms which allow it to become pathogenic and produce disease in some populations and not in others are unknown. The incidence of disease is low.

Clinical signs

Acute disease
Affected sows are inappetent with fever 40-42ºC (105-107ºF) when high numbers of organisms are present in the blood. This clinical picture is seen after farrowing and anaemia is a common symptom. Similar acute infections occur in sows at weaning time together with anoestrus.

Chronic disease
Sows become debilitated and pale with jaundice, poor conception, repeat matings and anoestrus. Signs of infertility that have been attributed to Epe include:

  • Delayed returns to oestrus.
  • Anaemia.
  • Jaundice.
  • Bleeding into tissues.
  • Abortion.
  • Reduced conception rates.
The carrier state
This is common and blood provides a constant source of transmission throughout the herd, particularly when females are vaccinated using common needles.

This is carried out by making a blood smear on a glass slide, staining it with a special stain (Wright's stain) and looking for the organism under the microscope. The presence of Epe in a smear need not necessarily imply disease and there is still controversy over the actual role of this bacterium and its capacity to cause disease.


  • Arsanilic acid at a level of 90 grams to the tonne has been used to provide a dose of approximately 250mg per day to each female.
  • If the herd is infected with mange it is important to adopt a control programme.
  • Oxytetracycline at a level of 400g to the tonne for four weeks is claimed to have some effect but generally the response to treatment is only moderate.
Management control and prevention
There are no known methods for preventing this disease other than reducing its movement around the herd by changing needles very frequently. It is possible that infection with PRRS initiates disease.
  • Take precautions when vaccinating large numbers of sows. Change needles every 2 to 3 sows and gilts.
  • Wipe the needle between each animal with cotton wool and surgical spirit.
  • Reduce fighting episodes.
  • Take precautions to keep vice at a minimum.
  • Do not carry out feed back using placenta or farrowing liquids.
  • Keep stress and immuno-suppression to a minimum.
  • Control mange and lice if they are present.
  • Control biting insects.

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