Glasser's Disease
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Description
Glasser's disease is caused by the bacteria Haemophilus parasuis. It is a systemic condition affecting young pigs characterised by polyserositis, arthritis and meningitis. It is rapidly fatal in the acute form, in some cases animals die before the development of lesions. In older pigs respiratory signs are most common usch as bronchitis, other symdromes may also occur.
Signalment
The disease usually affects weanlings 6-10 weeks old when maternal antibodies wane but it can affect pigs of any age, particularly naive pigs introduced into a herd or through exposure to a strain to which there is little immunity. The stress of mixing, weaning and adverse environmental conditions are predisposing factors.
The disease occurs worldwide, it is endemic in most herds but incidence of clinical disease in the UK is sporadic due to widespread acquired resistance. Increased prevelance hgas been associated with PRRS, Circovirus and Swine Influenza. Mortality is high when there is no immunity, for example outbreaks in specific pathogen-free herds.
Diagnosis
Clinical signs
- Pyrexia
- Dyspneoa with abdominal effort
- Anorexia
- Cough
- Swollen joints and arthritis
- CNS signs, Trembling and paddling
- Sudden death
Clinical signs develop rapidly, the disease is often fatal within 2-5 days. The skin becomes discoloured, turning red to blue before death. Expressed lesions vary between animals.
Survivors or those affected by the chronic form of the disease show less severe clinical signs of weight loss and depression, they become lame with arthritis, develop congestive heart failure, pericarditis or intestinal obstruction due to formation of adhesions. Pregnant sows may abort their fetuses.
Pathology
Septicaemia
Acute inflammation affecting pleura, peritoneum, mediastinum, pericardium, joints and meninges
Causes a polyserositis - pericarditis, peritonitis, pleurisy and meningitis
Also causes suppurative bronchopneumonia, pleuritis, polyarthritis (also H. suis)
Fever, general malaise, repsiratory and abdominal signs, lameness, paralysis or convulsions. Due to transport, environmental stresses, dietary and managemental factors Fibrinous pneumonia secondary to enzootic pneumonia or virus infection e.g. swine influenza
Treatment
Prevention
An inactivated vaccine is available for protection against Glasser's disease, two doses should be given by IM injection 2-3 weeks apart before 10 weeks of age.
Other preventative measures include good management practice, minimising stress, avouiding mixing of age groups and the appropriate vaccination and isolation of naive stock being introduced to the herd.
Prognosis
References
- Jackson, G.G. and Cockcroft, P.D. (2007) Handbook of Pig Medicine Saunders Elsevier
- Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial
- Taylor, D.J. (2006) Pig Diseases (Eighth edition) St Edmunsdbury Press ltd