Hemagglutinating encephalomyelitis

Hemagglutinating encephalomyelitis disease only affects pigs less than 4 weeks old and is characterized by vomiting and wasting.

Alternative names: Haemagglutinating encephalomyelitis, Vomiting and Wasting Disease, VWD, HEV

It is caused by coronavirus porcine hemagglutinating encephalomyelitis virus (PHEV), which is widespread in the pig population in North America and Europe, but its clinical disease is rare. This is because most sows that have been infected are immune and pass on immunity to their piglets through the colostrum, which protects them during their vulnerable period.

Although the virus can infect susceptible pigs of any age, it only causes clinical disease in piglets that are younger than 4 weeks old. The strains vary in virulence, leading to two different syndromes- either the vomiting and wasting disease or encephalomyelitis. Both begin around day 4, with a very sudden onset and affect entire litters.

Sows, nursery and fattening

• Not seen.

Nursing piglets

• Piglets pile up.
• Vomiting.
• Constipation.
• The piglets lose their ability to suck or swallow. They are thirsty and stand with their head over the water, but are unable to drink.
• Wasting, emaciation, and death.
• Seizures.
• Tremors.
• Arched backs.
• Blindness.

• Failure of sow to pass on sufficient immunity to the piglets in colostrum.

• Pathognomonic presentation. Blood tests can be done.

• There is no treatment. The disease does not occur again in the same herd.