Blue eye disease

Signs and diagnosis

Blue eye disease typically begins in piglets that are between 2–21 days old; 90 percent of the pigs that become infected with the disease die. It usually begins with a sudden onset of fever, arched back, or depression. The disease then progresses with neurological symptoms including weakness, ataxia, muscle tremors, abnormal posture, and rigidity of the hind legs. Some other symptoms associated with this disease are conjunctivitis, blindness, nystagmus, constipation, and diarrhea. Younger pigs can show neurological and respiratory signs which can be quite severe. Mature pigs may show blueing of the pupils in their eyes and experience reproductive difficulties.

Adults of both sexes may become infertile and sows may suffer from abortions and stillbirths.

• Inappetence
• Corneal opacity – conjunctivitis
• Nervous signs – fits and convulsions
• Dog sitting position
• Fever
• Increased returns
• Increased weaning to mating intervals
• Stillbirths
• Mummified piglets
• High mortality in piglets
• Swollen testicles
• Loss of libido

Cause

Blue eye disease is caused by the porcine rubulavirus, which first emerged in 1980 throughout parts of Mexico, including La Piedad, Michoacan, Jalisco, and Guanajuato.

The virus is transmitted directly and indirectly by fomites and birds and can be found throughout the body, including neurons and most soft tissues.

Diagnosis

Blue eye disease outbreaks can happen throughout the year but are most common during spring and summer months of April to July. The mortality rate usually rises and falls and between a two- to nine-week time frame. After the epidemic subsides, no more cases occur unless new susceptible pigs are introduced into the farm. In severe outbreaks of the disease a presumptive diagnosis can be made. Serological testing via virus neutralization and haemagglutination inhibition testing can be performed to diagnose the disease. Virus isolation from tissue samples is also possible.

Necropsy findings can help confirm the diagnosis.

Epidemiology

Blue eye disease in swine has only been reported in Mexico.

It can affect not only pigs but also dogs, cats, rats, and rabbits.

Treatment and control

There is no treatment for the disease. Symptomatic treatment for the inflammatory and respiratory signs can be given, but severe cases may require euthanasia.

General biosecurity protocols including adequate quarantine, testing, and disinfection can help prevent the entry or spread of the disease into a herd.

References

References

1. "ICTV 9th Report (2011) ''Paramyxoviridae''".
2. Stephan, H.. (2 January 1988). "Encephalomyelitis, reproductive failure and corneal opacity (blue eye) in pigs, associated with a paramyxovirus infection". Veterinary Record.
3. "Taxonomy". International Committee on Taxonomy of Viruses.
4. Mendoza-Magaña, M. L.. (7 July 2008). "Pig Paramyxovirus of the Blue Eye Disease Binding to a 116 kDa Glycoprotein Expressed in Pig Neuronal Membranes". Journal of Veterinary Medicine, Series B.