Black Leg in Cattle | Treatment, and Vaccine | Can Humans get blackleg?

Cause of Blackleg in Cattle and Sheep:

Table of Contents

The causative agent of blackleg is a Clostridium bacterium (Clostridium chauvoei ). Pathogens of Clostridium bacteria can be grouped on the basis of the site of action of their potent exotoxins. Out of other pathogenic clostridial bacteria, Clostridium chauvoei is a histotoxic clostridium.

Some Characteristics of Clostridial Bacteria:

Large, Gram +ve, fermentative, catalase, and oxidase negative
Straight or slightly curved rods
Require enriched media for growth
Motile with peritrichous flagella
Spore forming
Strict anaerobes but some are aerotolerant

How Black Leg is Transmitted Between Cattle and Sheep?

C. chauvoei is a bacteria that lives in the intestines of animals. Spores can live for years in the soil and are thought to be a cause of infection. After intake of contaminated feed, the first entry point is through the alimentary mucosae. The excrement of diseased animals or the decomposition of animal carcasses contaminates soil and grassland. The organisms are most likely ingested, pass through the GI tract’s wall, and after getting access to the bloodstream, are deposited in muscle and other tissues (spleen, liver, and alimentary tract), where they can lie dormant eternally. Spores grow in anaerobic environments and produce toxins such as Alpha (necrotizing), Beta (Deoxyribonuclease), Gamma (Hyaluronidase), and Delta (Hyaluronidase) (Hemolysin).

Can Humans Get Black Leg?

No, It is Not a Zoonotic Disease

Clinical Signs of Black Leg in Cattle and Sheep:

The onset is usually abrupt, and a few cattle may be discovered dead with no warning symptoms. Acute, severe lameness is prevalent. There is a fever at first, but by the time clinical indications become apparent, the body temperature may be normal or subnormal.
Edematous and crepitant swellings appear in the hip, shoulder, chest, back, neck, or other parts of the body. The swelling is modest, heated, and painful at first. The swelling enlarges as the disease advances, there is crepitation on palpation, and the skin becomes chilly and insensitive as the blood supply to the affected areas decreases.
Prostration and tremors are two common symptoms. Within 12–48 hours, death occurs.
Gaseous swelling beneath the skin, primarily in the hindquarters and shoulders.
One of the legs is stiff or limping.
Gaseous swelling can occur anywhere on the body, including the neck, chest, and flanks.
Swellings are hot, unpleasant, and confined at first, but as time passes, they get larger, colder, and painless.
The skin over the swellings becomes dry, and black in color, and crepitation is noted when palpated.

Important Postmortem Features:

Lesions are restricted to the myocardium and the diaphragm.

How to Diagnose Black Quarter in Animals and Sheep:

It is a well-renowned saying that ” forget the treatment, diagnosis is everything. ” Diagnosis of every disease revolves around 3 things

1- History

2- Clinical signs

3- Lab test for isolation of the causative agent

Age, season, and swelling in a specific location are used to make a diagnosis. Make a smear, stain it with gram stain, and look for clostridium. Blackleg is a swiftly deadly, febrile disease that affects well-fed young cattle, especially beef breeds, and is characterized by crepitant swellings of the massive muscles. The damaged muscles are dark red to black, dry and spongy, with a sweetish odor and tiny bubbles but no edema. Serum creatinine phosphokinase and serum aspartate aminotransferase levels are frequently elevated.

Treatment of Black Leg in Cattle:

Within 24-48 hours, treatment must be administered. For specialized treatment, provide oxytetracycline 10 mg/kg body weight intravenously for several days (without xylocaine or lignocaine). Give multivitamins as a supportive treatment. In the event of an outbreak, all susceptible cattle should be vaccinated and given penicillin (10,000 IU/kg, IM) prophylactically to prevent new infections for up to 14 days. Cattle should be removed from pastures that have been contaminated.

Prevention of Quarter ill in Animals:

The best way to prevent this is by a vaccine.

A vaccine prepared by Veterinary Research Institute (VRI) is available. (Alum precipitated)

Black Quarter

March/April

5 ml s/c for 275 kg

Conclusion:

Blackleg is a disease that attacks well-fed beef cattle quickly and kills them. Edematous and crepitant swellings in the hip, shoulder, chest, back, and neck are specific indicators. The disease can be prevented with a vaccine.

References:

Merck Veterinary Manual, Black Leg in Animals, Available here

Blackleg (disease). (2022, August 16). In Wikipedia. Available here

The Cattle Site, Black Leg in Cattle, Available here

Blokhin, A. A., Toropova, N. N., Burova, O. A., Iashin, I. V., & Zakharova, O. I. (2022). Blackleg in Cattle in the Irkutsk Region. Frontiers in Veterinary Science, 9. Available here