Actinomycosis:

Syn: Lumpy Jaw

• It is chronic infectious disease, primarily of cattle and secondarily to pig, horse and man.
• It is characterized by rarefying osteomyelitis of bone of skull in cattle.
• In pig, it is characterized by a tumor like enlargement of the mammary gland and in horse, involvement of the bursa of the ligamentum nuchae.

Fig: Actinomycosis in a cow, with typical enlargement of the mandible.

Etiology:

• Actinomyces bovis
• It is ascribed as fungus like bacteria.
• It is gram +ve, non-capsulated, branching filamentous bacterium

Epidemiology:

• Disease is worldwide in distribution.
• The incidence in cattle is higher where they are fed with straw and ensilage.
• It is common inhabitant of mouth and infection occurs through wound in the buccal mucosa.
• It remains sporadically in the affected herd.
• Cattle of 2-5 years old are more susceptible to disease.
• It is most commonly observed in weaned calves, young bull and heifers.

Transmission:

• Infection usually occurs through wound, abrasion or injury
• Through dental alveoli at time of eruption

Pathogenesis:

Clinical Findings:

1. Cattle and buffaloes:

• Lesion appear initially as a hard, painless, circumscribed protuberance usually at the level of central molar teeth of the mandible or maxilla.
• In some cattle, large granulomatous mass appear on the surface of the jaw followed by development of sinus tracts.
• Discharge from the tracts are thick, mucoid, yellowish, purulent exudates.
• Exudates contain granules with clubbing. Granules are white to yellow in color and termed as sulphur granules.
• Impairment of digestion due to extensive involvement of mandible and maxilla
• Loose teeth or missing teeth may be found.
• Foul breath from the mouth known as halitosis.

Fig: Lumpy jaw, suppurative lesion, cow

2. Horses:

• Fistulous withers and poll evil.
• Bursa between nucheal ligament & the primarily through thoracic spine as well as the bursa between nucheal ligament and atlas-axis are affected

3. Pig:

• On rare occasion, pigs may suffer from extensive granulomatous lesion of the skin more particularly over the udder.
• Emaciation

4. Dog:

• Chronic pyogranulomatous lesion appears on the skin of submandibular, abdomen and thoracic region.

PM Findings:

• There is rarefaction of bones with wide spread destruction of them.
• There is presence of pus containing granules referred as sulphur granules.
• There is thread like bacteria in the exudate.
• In cattle, lumpy jaw is common manifestation.
• Cavities are formed in the affected bones filled with specific granules containing nodules.
• Softening and liquefaction occur and pus gradually affects the cortex and rarefies it.
• Miliary nodules may be seen in the udder and lungs.

Diagnosis:

• Based on clinical findings
• Based on PM lesion
• Microscopic examination of stained pus for presence of sulphur granules.
• Histopathological examination of tissue section will show cellular change.
• X-ray examination: lesion reveals radiolucent areas of the osteomyelitis in centre surrounded by periosteal new bone and fibrous tissue.

Differential Diagnosis:

1. Actinobacillosis:

• Characteristic lesion in tongue
• Isolation of specific agent

Treatment:

• Flushing with Lugol’s Iodine or Povidine Iodine and then packed with Iodine soaked gauze.
• Potassium iodide (KI) @10 gm, PO for 2-4 weeks
• Sodium iodide (NaI) @ 70mg/kg, b.wt. IV, repeated after a week
• Antibiotics like streptomycin combined with iodide and surgical drainage may yield good response.
• Tetracycline @1m/10 kg b. wt or chloramphenicol @10ml, IM, OD for 3-5 days

Control Measures:

• There is no vaccine against this disease.
• Isolation of infected animals and their treatment are to be rendered.
• Removal of contaminated materials and disposal of animals with discharging foci may be made.
• Avoid feeding coarse steamy feeds and feed with sharp awns.