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Actinobacillosis (Wooden tongue) Disease

Actinobacillosis (Wooden tongue) Disease also known as timber tongue and Big head disease.

It is a chronic and infectious disease of cattle and sheep featured by inflammation of soft tissues of the head, neck, oro-pharyngeal lymph nodes, oesophageal groove and nasal cavity.

Etiology

Actinobacillosis is caused by Actinobacillus lignieresi. It is a small, rod shaped, motile, gram negative, aerobic organism and appears as single or in short chain. The organism is susceptible to ordinary environment and disinfectants. The organism may live for year in lyophilized culture. Blood and serum is required for growth of the organism.

Epidemiology

Prevalence of infection

The disease is world wide in distribution.
Its occurrence is sporadic and prevalent in India.

Predisposing factors

Eruption of permanent teeth in young animals favors the organism to penetrate sub-epithelial tissues. Other diseases causing vesicular and erosive stomatitis predispose animals for Actinobacillosis.

Source of infection

Infection is spread through discharges from infected animals. Grazing on infected pastures.

Transmission

TransmissionFeeding of animals with contaminated feeds.
Through injury and abrasion made by sharp objects permit the entry of organisms through oral mucosa.
External parasites help the development of cutaneous actinobacillosis.

Host Affected

Cattle, buffalo and sheep are found susceptible.
Horses, pigs and human beings are also affected by the natural infection.
Intra-peritoneal injection of guinea pigs with suspected materials demonstrates “Strauss reaction” and death.
Young animals of 2-5 years of age are found more affected.

Pathogenesis

The organism is a normal inhabitant of digestive and respiratory tract, nevertheless, they gain into nasal and buccal mucosa and into dependent lymph nodes following trauma or injury of them.
Unlike Actinomyces spp., this organism has affinity to soft tissues of head and neck and occasionally invade into bony tissues.
In localized infection, inflammatory and granulomatous tissue changes occurs followed by necrosis and suppuration with discharge of pus to the exterior and spread into adjacent lymphnodes.
Infection of tongue interfere in prehension and mastication.
Theoretically, inflammatory changes occur at an earlier stages and deformity of the tongue occur at an later stages.

Clinical Findings

Cattle

Affected tongue appears like wood and hence the disease has got the name wooden or timber tongue.
Inflammation of tongue followed by ulceration.
Ulceration of tongue leads to drooling of saliva, difficulty in mastication. Animals unable to eat in spite of a good appetite and loose body weight.
Enlarged abscess in inter and sub-mandibular lymphnodes open and discharge pus .
Affection of retropharyngeal region interfere with breathing and causes loud snoring.
Abscess in posterior margin of soft palate produces dyspnoea.
Discharge of nodules from subcutaneous tissues and mediastinal lymphnodes.
Swelling in mediastinal lymph ndoes imparts a pressure on esophageal groove and produce tympany.
Affected lymph nodes are normally evinces pain.
The organism also produce infection in liver, rumen, reticulum, peritoneum and lungs. In testis produces granulomatous lesion.

Sheep

Tongue is usually not affected in this species.
Lesion seen in cutaneous portion of lower jaw, face and extending into sternum.
Affected lymphnodes have yellowish greenish pus discharging from the openings. Bilateral nasal discharges noticed.
Affected sheep die due to starvation.
Chronic form Accumulation of fibrous tissue affects prehension and mastication.
Death in sheep is due to in-anition may occur.

Necropsy Findings

The tongue becomes hard by proliferation of fibrous tissues.
Lesions of soft tissue appeared as thick walled abscesses filled with thick tenacious pus.
Firm, pale nodules containing in the center with minute yellow “sulfur granules”.

Diagnosis

Based on clinical signs and lesions.
Identification of gram negative coccobacilli in stained pus.
Examination of rosettes formation in granules (less than one mm in diameter).
Press cheesy mass on a glass drop slide with 10% KOH solution and observe rosette mass under microscope with out staining.

Treatment

X-Ray radiation for 10 consecutive weeks along with antibiotics and Sodium Iodide is beneficial.
Lugol’s Iodine injected into the lesion may be useful.
Oral feeding of cattle with Iodine 10 gm/1000 lb bw daily for 2-4 weeks until iodism signs appears (anorexia, salivation and depression).
Administration of Sodium Iodide @70 mg/kg bw (10-20% ) solution in slow i/v and repeated after 7-10 days.
Administration of streptomycin sulphate @5 g/day i/m for 3-5 days.

Prevention

There is no vaccination available as it is a self limiting disease and administration of antibiotic itself sufficient.

Control

Actinobacillosis is also affecting human beings and hence due care in handling of diseased animals and processing of infected tissue samples in laboratory is very important.