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Bacterial Disease - Black Quarter

Synonyms

Symptomatic Anthrax, Quarter ill.

Host affected

It is an acute ,infectious, and fatal disease of cattle, sheep and goats. Affected animals develop skeletal muscle damage, severe gangrenous, necrotizing, emphysematous myositis and a fatal systemic toxaemia. Cattle, 6 months to 2 years and well-nourished are mostly affected.

Etiology

Black Quarter (BQ) is caused by Clostridium chauvoei. It is a gram positive, spore forming, rod shaped bacteria measuring 0.6µ in dia and 3-8µ in length. It is a toxin producing anaerobic bacterium.

Epidemiology

Disease is endemic in both developed and developing countries. In India, the disease occurs sporadically, however, in some region, the disease is endemic.

Predisposing factors:

Occasional outbreak: Damage to tissues caused by administration of formalised vaccines, accidental injury of muscle and injury made by chemical agents. Cattle: Digging of soil spreads the infection. Alternate hot and dry seasons followed by heavy rainfall favors the dispersion of spores for long distance. Turning up of soil expose the spores to the top surface.

Sources of infection

Organism present in decomposed carcass of black leg affected animals and persists in soil for long period.

Sheep: Infection mostly spreads via wound developing during shearing, docking and navel infection etc., hence, it is called as traumatic BQ.

Inhabitation: Organism exists as normal inhabitant in spleen, liver and alimentary tract of healthy animals.

Transmission

It is transmitted by ingestion, inhalation of spores and absorption of toxins through wound. Wound contamination by spores especially in sheep and goats is possible.

Pathogenesis

Black quarter is a soil borne infection.

Spores ingested would be taken via alimentary mucosa and then distributed to tissues and skeletal muscles via the circulation.

Injured muscles favors spores germination in the wound that provides anaerobic condition.

Mostly, the organism affects muscles of loin, shoulder and gluteal muscle.

In addition, muscles of diaphargm may be affected.

If animals consume the preformed toxins while grazing, ingested toxins is directly absorbed and spread along the systemic circulation which leads to fatal toxaemia.

Some spores are directly phagocytosed by the immune cells, the remaining assumes latency in the muscle, followed by transformation as vegetative form once the muscle is injured.

Injured muscle: The oxidation reduction potential (creates anaerobiosis) and reduced hydrogen ion concentration (pH) provides a condusive atmosphere for germination of spores and causes true black leg following the release of exotoxin.

C.septicum is a potent exotoxin producer as compared to C.chauvoei because virulent form of C.chauvoei only able to produce exotoxin. These exotoxin is responsible for the development of edema and pulmonary congestion.

C.chauvoei produce neuraminidase at optimum pH 4.5 and at 40° C. At low pH neuraminidase promotes anaerobiosis, muscle damage and leads to gas accumulation.

At optimum pH and temperature neuraminidase desialate haemoglobin free RBC membrane of cattle, sheep, goats, and horses at a significant level. High neuraminidase activity is found in edema fluid.

Cleaving of sialic acid from blood vessels by neuraminidase causes vascular permeability and inflammation of muscles.

During pyrexia, the removal of sialic acid is at the peak.

Toxins develops hyperplasia and congestion in spleen, haemorrhages and degenerative foci in liver and kidney.

Toxins causes damage to leucocytes, platelets which leads to leucopenia and thrombocytopenia.

Toxins released by the organism produces a severe necrotizing myositis in skeletal muscles and a systemic toxaemia followed by death.

In cattle and sheep during atypical outbreak, sudden death follows attributable to clostridial cardiac myositis.

Clinical Signs

Cattle

Peracute form

Affected animals show sudden death.

Acute form

Incubation period is 2 to 5 days.

Disease follows a rapid and fatal course of infection following ingestion of preformed toxins.

Fever (41°C) not common, marked depression, anorexia and ruminal tympany.

Prominent swelling on the upper part of the affected limbs leads to marked lameness.

Swelling of throat, tongue and protrusion of the tongue.

Edema, emphysema, crepitation of affected heavy muscles on thigh with muscle stiffness.

Discolored, gangrenous to black, dry and cracked skin.

Increased pulse rate 100 to 120 per minute.

Death follows in 12 to 36 hours of infection.

Cattle with cardiac myositis are found dead.

A thin sanguineous fluid containing bubbles of gas from affected sites.

Sheep

No palpable crepitation swelling as in cattle.

Stiff gait, disinclined to move, severe lameness either unilateral or bilateral.

Painful walking, discoloration of skin with no necrosis and gangrene.

Extensive local lesion in vulva and vagina occurs through skin wounds.

Head swelling leads to haemoptysis, high fever, anorexia, depression and quick death.

Short course of the disease, dyspnoea and recumbancy in 3 to 4 days occurs.

Horses

Pectoral edema, stiff gait and incoordination is recorded.

Diagnosis:

Based on clinical signs and necropsy findings.

Isolation of organism by culture of heart blood, peritoneal fluid, muscles and liver is important for both Cl.chauvoei and Cl.septicum.

Muscle bundle separation by gas.

Tube agglutination test, counter immuno electrophoresis, double immuno diffusion test used to detect humoral antibody, Immunofluorescence, Fluorescent antibody test to detect antigen.

Biological inoculation

Filtrate containing spores obtained from infected animals heated at 60°C for 30 minutes and injected one ml into glutial muscle of guinea pig leads to death in 48hrs.

Differential diagnosis

Malignant edema.

Anthrax.

Lightening stroke.

Bacillary haemoglobinuria

Treatment

Penicillin 10,000 IU/kg IM is a drug of choice for 5-6days, (Large dose of 40,000IU/kg bw) can be given following administration of Crystalline Penicillin via IV.

Oxytetracycline in high doses i.e. 5-10 mg/Kg body weight IM or IV.

Tease the swelling and drain off.

B.Q. antiserum in large doses, if available.

Injection of antihistamines can be given.

It can also be sprayed directly on affected tissues

Prevention:

It is by vaccination

The vaccine is prepared from highly antigenic strain of C. chauvoei by anaculture method, inactivated by formalin and precipitated by addition of alum. It is used for active immunization of cattle, buffaloes, sheep and goats against black quarter. Cattle and buffaloes 3 ml, s/c, sheep and goats 1-2 ml, s/c. Immunity last for 6 months.

Control

Isolation of affected cattle.

Constant surveillance and early treatment is necessary.

Destruction of carcasses by burning or deep burial to limit soil contamination is essential.

The organism can be destroyed by 3% formalin in 15 minutes is advisable.


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