Tuberculosis of Animals

                                         Tuberculosis of Animals

It is progressive disease in which emaciation of body occurs. It can affect almost all species but sheep and horses are resistant to this infection.

Etiology:

This disease is caused by genus mycobacterium

M. bovis causes disease in cattle buffalo

M. tuberculosis causes in human

M. avium causes in birds

Predisposing Factor:

Main factor is close contact in closed area. If large numbers of animals are confined in small areas, there will be more chances of infection.

Debilitating Factor:

Factors which cause emaciation are poor feeding, poor housing, and lack of ventilation.

Sources of Disease:

Exhaled air

Secretion of infected animals i.e. sputum, urine, semen, uterine discharges, and milk

Discharges from open peripheral lymph nodes

Re-ingestion of sputum and excreted in feaces

Wild animals e.g. deer are the reservoir

Mode of Transmission:

Through inhalation and ingestion.

During grazing, animal may ingest sputum of infected animal.

Under natural conditions animal having T.B drinks water from the pond of stagnant water and goes away. That water remains contaminated for 80 days. Then other animals drink from that water and get infection. In running water there is no such problem.

Drinking infected milk; it is more common in calves.

Contaminated feed

Contaminated semen, saliva and sputum 

Clinical Signs:

Progressive emaciation

Weakness

Anorexia

Fluctuating temperature

Initially cough is low (once or twice a day) but with time loudness increases. Cough is more in morning and cold weather. 

Nasal discharge

Difficult breathing

Digestive tract involves rarely but if involved there is diarrhea and indigestion

Swelling of L.N.

Lower jaw becomes immoveable

In case of reproductive tract involvement abortion may occur

Sever decrease in milk production

Sometimes greenish pus in milk

Diagnosis:

Single Intradermal Tuberculin Test:

Tuberculin is purified protein derivative of Mycobacterium bovis. It is more potent and specific. 0.1 ml of tuberculin is injected to each animal of herd in cervical fold of skin in centre of neck or anal and caudal region. If animal is positive for T.B then there will be diffused swelling at injection site after 48 hours.

Short Thermal Test:

Inject 4 ml of tuberculin subcutaneously in neck of animal having temperature 102.5 oF. Check temperature after 2, 4, 6, and 8 hours. If increase in temperature after 2 hours of injection then animal is positive. After 2 hours temperature may reach upto 104.5 oF and it remains upto 6 hours.

Comparative Tuberculin Test:

Inject avian tuberculin at upper side of neck and inject bovine tuberculin 12 cm apart at lower side of first injection at neck. Where is more swelling after 4 - 48 hours that is positive.

Avian tuberculin is used because it is antigenically similar to Jhone’s Disease. The Johne’s organism i.e. Mycobacterium paratuberculosis is present intracellularly and does not give good response to antibiotics.

Treatment:

No specific treatment available because very much expensive and time consuming. So people prefer to slaughter. There are chances of reoccurrence of this disease as the organism is intracellular. Huge quantity of antibiotics are required and for long term.