Systematic Veterinary Bacteriology and Mycology

PATHOGENICITY

Symptoms

Corynebacterium ovis

• Caseous lymphadenitis in sheep is characterized by skin wounds, enlarged lymph glands and abscesses distributed throughout the body.
• But the disease can be a mild infection and it is unnoticed until postmortem is done.
• Ulcerative lymphangitis in horses are similar to glanders.
• Initially there is a pain and swelling of the hind limbs and enlargement of lymphatic vessels.
• Ulcers develop, discharging purulent material. In severe cases it spreads to abdomen, forelegs and neck, leading to death.

Corynebacterium renale

• In pyelonephritis, characteristically frequent passage of turbid or blood stained urine by animals, which are pregnant or recently calved.
• Restlessness and kicking at the abdomen may indicate renal pain. The urine contains red blood cells, pus cells and albumin.
• Ulcerative balanoposthitis (Pizzle rot), particularly common in Merino sheep and Angora goats, is characterized by ulceration around the preputial orifice, with a brownish crust developing over the lesion

Rhodococcus equi

• In suppurative bronchopneumonia, the foals develop cough, fever and increased respiratory rate.
• In severe cases purulent discharge from nose just before death.

Lesions

Corynebacterium ovis

• In caseous lymphadenitis the superficial lymphnode contains a mass of greenish yellow caseation in concentric layers, which have an onion ring appearnce in, cross section (hence, named it as Corynebacterium pseudotuberculosis). In advanced cases, similar lesions are seen in lungs, kidney, liver and spleen.

Corynebacterium renale

• The kidneys are enlarged, necrosis and suppuration in the medulla. Wedge shaped suppurative foci in the cortex.
• The kidney pelvis contains blood and pus
• The bladder contains blood and pus with petechial haemorrhages and ulceration of the tract.

Rhodococcus equi

• Characterized by pyogranulamatous lesions with abscesses in the lung, associated lymphnodes and pus in the bronchi.