Abscess - Corynebacterium pseudotuberculosis
By Dr Mackie Hobson BSc(Agric),BVSc

1. Diseases

The abscesses are also called ‘caseous lymphadenitis’ or ‘cheesy gland’. It was previously known as Corynebacterium ovis.

The chronic and debilitating nature of the disease will lead to poor hair production and poor reproduction.

How long can the bacteria survive?

The bacteria can survive for 8 weeks in wood, straw, and faeces and for up to 8 months in soil. Survival is improved in moist conditions and lower environmental temperatures.

How does the bacteria enter the body?

The bacteria enters through skin break or mucous membranes, but it cannot penetrate through intact skin. The organism can survive if taken in by phagocytic cells and spreads in the body through the lymphatic system to lymph nodes where it creates abscesses.

How long does it take to form an abscess?

The incubation period is 2 to 6 months.

What does the abscess look like?

The abscess contains thick yellow-green viscous pus.

Where do the abscesses occur?

• Superficial form: lymph nodes (parotid, submandibular, pre-scapular, and subiliac). Foot abscess ‘Sweerklou’
• Visceral form is presented by abscessing of different internal organs ( internal lymph nodes, liver, lungs, uterus,kidney and spleen. Other less common sites include the scrotum, mammary gland, the central nervous system, and joints.

What clinical signs does it cause in the Angora goat?

• Internal abscesses can be subclinical but are commonly associated with weight loss, poor doers.
• External abscesses are characterized by slowly enlarging encapsulated masses in or near a peripheral lymph node. The abscess matures and ruptures through a fistula, draining infective purulent into the environment

What is the difference between the sheep and goats abscess?

• The superficial form is more frequent among goats as opposed to the visceral form among sheep.
• Lymph node abscesses of the head and neck are more frequent in goats, while in sheep, abscesses are found in the subiliac and pre-scapular lymph nodes
• In the case of sheep, it appears like an onion (laminar) when cut. This is caused by the development of layers of fibrous tissue. In goats it is a thick caseous material.

Prevention and control

1. Lance and flushing the abscess. See how to lance and flush an abscess https://www.angoras.co.za/article/lancing-an-abscess
2. Drainage of the abscess need to be carried out to avoids environmental contamination, with proper disinfection of the surgical material during the procedure.
3. Antibiotic therapy is another treatment option that is not very effective, despite the fact that C. pseudotuberculosis is sensitive to nearly all antibiotics tested in vitro. The intracellular location of C. pseudotuberculosis, together with the formation of biofilm in natural infections making antimicrobials inefficient
4. The main way to introduce infection is through infected animals which results in cases in 2-3 years.The infected animals contaminate the soil, water, pastures, feed and facilities with pus from draining abscesses, nasal secretions and faeces. BIOSECURITY is important.
5. Vaccination leads to a gradual decline in the occurrence of abscesses but does not lead to full protection. (Glanvac and OBP Corynebacterium vaccines are available). The limitations of the vaccines is important to know.

Zoonosis (humans can become infected)

It is important to provide PPE when working with animals with draining abscesses or lancing and an abscess.

References:
Recent perspectives on caseous lymphadenitis caused by Corynebacterium pseudotuberculosis in goats–A review Md.
Aftabuzzaman, Yong-il Cho