Black Quarter disease of cattle,causes,pathogenesis,clinical signs and symptoms, diagnosis, treatment and prevention.

Introduction 

Fig:A BQ suspected patient

Another names of black quarter disease are blackleg disease,quarter evil and quarter ill disease.The disease is most prevalent in the rainy season in Bangladesh,mainly from the age 4 months to 2.5 years of aged cattle.It is an infectious disease of cattle and rarely other ruminants. The large muscles of the pectoral and pelvic girdles are affected with other skeletal muscles and heart involved less frequently.

What is blackleg disease? 

It is an acute infectious,febrile and highly fatal disease of cattle and other ruminants caused by clostridium chauvoei and characterized by necrotic myositis.

Clostridium chauvoei  is an anaerobic,gram positive,spore forming rod shape organism found in the soil and less frequently in the GI tract of many animals.

Clinical signs and symptoms 

1.Animals of acute nature die suddenly.

2.There is a high fever(105-106 degree Fahrenheit).

3.Lameness

4.Swelling of the affected part and grows slowly.The affected area is hot and painful at first.

5.When the swollen muscles are pressed, there is a squeaking sound produced.

6.The affected area looks dark 

7.When the swollen area is incised or cut air and sour smelling pus or fluids come out.

8.In the last stage,the body temperature of the animal decrease.

9.Gradually the animal's distasteful,weakness and dies.

Pathogenesis

The soil-born blackleg organism enters the animal by the ingestion of contaminated feedstuffs.Following ingestion, the organism may live in the gastrointestinal tract, spleen, and liver without causing any problem.What causes the bacteria to proliferate is not entirely known but its most likely a result of muscle bruising associated with handling and shipping.There is also a recognized increased incidence in blackleg when calves are on a high plane of nutrition and are experiencing rapid growth rates.When conditions in the animal are right, the bacteria enter into a rapid proliferation phase, producing toxins that cause muscle death and, subsequently, the death of the animal.

Diagnosis

A.Based on history and clinical signs

Rainy season,6 months to 2.5 years of aged animals.

Clinical signs and symptoms given  above.

B.Based on pathological examination

i) Gross pathology  

2.Microscopic pathology 

Treatment 

Treatment is usually futile. In the face of an outbreak it is effective to vaccinate and administration procaine penicillin-G at the same time.The antibiotic will stop the proliferation of the bacteria ant it's associated toxin,allowing time for the vaccine or bacterin to stimulate protective immunity in the calf. 

Prevention of Blackleg disease

1.Black quarter vaccine (killed) should be given first at the age of 2/3 months then a booster dose is given  every six months interval.

2.Disinfection and strict hygienic management.

3.Proper disposal of carcass etc.