Blackleg, black quarter, quarter evil, or quarter ill (Latin : gangraena emphysematosa) is an infectious bacterial disease most commonly caused by Clostridium chauvoei , a Gram-positive bacterial species. It is seen in livestock all over the world, usually affecting cattle, sheep, and goats. It has been seen occasionally in farmed bison and deer. [1] The acute nature of the disease makes successful treatment difficult, and the efficacy of the commonly used vaccine is disputed. [2]
Most losses due to blackleg occur when the cattle are between the ages of six months and two years, although it can occur when they are as young as two months. Typically, cattle that have a high feed intake and are well-conditioned tend to be the most susceptible to blackleg. Furthermore, many blackleg cases occur during the hot and humid summer months or after a sudden cold period, but cases can occur at any time during the year. [3]
Blackleg is caused by infection with Clostridium bacteria. The most common causative agent is C. chauvoei, but the disease can also be caused by C. septicum, C. sordelli, and C. novyi. [4] [5] C. chauvoei is Gram-positive, rod-shaped, anaerobic, and motile, and can produce environmentally persistent spores when conditions are not ideal for growth. These spores can remain in the soil for years in an inactive state, and return to their infectious form when consumed by grazing livestock. Contaminated pasture is a predominant source of these organisms, which are also found naturally in the intestines of animals. [6] Cases can occur over many years in areas where soil or manure is contaminated with the bacteria, and it is exceedingly difficult to remove the spores from the environment.
C. chauvoei can produce a large amount of gas as a metabolic byproduct when growing and reproducing, hence the alternate name gas gangrene, present in humans. [7] This gas builds up in infected tissue, usually large muscles, and causes the tissue to make a crackling or popping sound when pressed. Large gas-filled blisters can also form, which can be extremely painful as they build up in the tissues.[ citation needed ]
When infection begins, the animal may develop a fever, and the affected limb can feel hot to the touch. The limb usually swells significantly, and the animal can develop lameness on the affected leg. Crepitation (the sensation of air under the skin) can be noticed in many infections, as the area seems to crackle under pressure. [8]
Once clinical signs develop, the animal may only live a short while, sometimes as few as 12 hours. Occasionally, cattle succumb to the disease without showing any symptoms, and only a necropsy reveals the cause. During a necropsy, a diagnosis is usually made very quickly, as the affected muscle is usually mottled with black patches, which are dead tissue, killed by the toxins the bacteria release when they infect live tissue. If viewed under a microscope, small rod-like bacteria can be seen to confirm the diagnosis.[ citation needed ]
The use of a seven-way clostridial vaccination is the most common and cost effective preventative measure taken against blackleg, [5] but its efficacy is disputed. [2] Burning the upper layer of soil to eradicate left-over spores is the best way to stop the spread of blackleg from diseased cattle. Diseased cattle should be isolated. Treatment is generally unrewarding due to the rapid progression of the disease, but penicillin is the drug of choice for treatment. Treatment is only effective in the early stages and as a control measure.[ citation needed ]
Botulism is a rare and potentially fatal illness caused by botulinum toxin, which is produced by the bacterium Clostridium botulinum. The disease begins with weakness, blurred vision, feeling tired, and trouble speaking. This may then be followed by weakness of the arms, chest muscles, and legs. Vomiting, swelling of the abdomen, and diarrhea may also occur. The disease does not usually affect consciousness or cause a fever.
Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the gangrene is caused by an infectious agent, it may present with a fever or sepsis.
Necrotizing fasciitis (NF), also known as flesh-eating disease, is a bacterial infection that results in the death of parts of the body's soft tissue. It is a severe disease of sudden onset that spreads rapidly. Symptoms usually include red or purple skin in the affected area, severe pain, fever, and vomiting. The most commonly affected areas are the limbs and perineum.
Clostridium is a genus of anaerobic, Gram-positive bacteria. Species of Clostridium inhabit soils and the intestinal tracts of animals, including humans. This genus includes several significant human pathogens, including the causative agents of botulism and tetanus. It also formerly included an important cause of diarrhea, Clostridioides difficile, which was reclassified into the Clostridioides genus in 2016.
Clostridium perfringens is a Gram-positive, bacillus (rod-shaped), anaerobic, spore-forming pathogenic bacterium of the genus Clostridium. C. perfringens is ever-present in nature and can be found as a normal component of decaying vegetation, marine sediment, the intestinal tract of humans and other vertebrates, insects, and soil. It has the shortest reported generation time of any organism at 6.3 minutes in thioglycolate medium.
The Clostridia are a highly polyphyletic class of Bacillota, including Clostridium and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are obligate anaerobes and oxygen is toxic to them. Species of the class Clostridia are often but not always Gram-positive and have the ability to form spores. Studies show they are not a monophyletic group, and their relationships are not entirely certain. Currently, most are placed in a single order called Clostridiales, but this is not a natural group and is likely to be redefined in the future.
Gas gangrene is a bacterial infection that produces tissue gas in gangrene. This deadly form of gangrene usually is caused by Clostridium perfringens bacteria. About 1,000 cases of gas gangrene are reported yearly in the United States.
Tyzzer's disease is an acute epizootic bacterial disease found in rodents, rabbits, dogs, cats, birds, pandas, deer, foals, cattle, and other mammals including gerbils and spinifex hopping-mice. It is caused by the spore-forming bacterium Clostridium piliforme, formerly known as Bacillus piliformis. It is an infectious disease characterized by necrotic lesions on the liver, is usually fatal, and is present worldwide. Animals with the disease become infected through oral ingestion of the bacterial spores and usually die within a matter of days. Animals most commonly affected include young, stressed animals in laboratory environments, such as immature rodents and rabbits. Most commonly affected wild animals include muskrats (Ondatra zibethicus) and occasionally cottontail rabbits (Sylvilagus spp.). Even today, much remains unknown about Tyzzer's disease, including how and why it occurs.
Collagenases are enzymes that break the peptide bonds in collagen. They assist in destroying extracellular structures in the pathogenesis of bacteria such as Clostridium. They are considered a virulence factor, facilitating the spread of gas gangrene. They normally target the connective tissue in muscle cells and other body organs.
Clostridium septicum is a gram positive, spore forming, obligate anaerobic bacterium.
A clostridial vaccine is a vaccine for sheep and cattle that protects against diseases caused by toxins produced by an infection with one or more Clostridium bacteria. Clostridial vaccines are often administered to pregnant ewes a few weeks before they are due to give birth, in order to give passive immunity to their lambs. Clostridial bacteria multiply rapidly in infected sheep, and produce large amounts of toxin which can cause the sheep to die within hours.
Abomasitis is a relatively rare ruminant disease characterized by inflammation of abomasum usually caused by larval development in young calves, lambs, and goat kids. It occurs with gastroenteritis, but can also be a side effect of other diseases. However, it is seldom diagnosed as a separate condition.
Clostridium novyi (oedematiens) a Gram-positive, endospore- forming, obligate anaerobic bacteria of the class Clostridia. It is ubiquitous, being found in the soil and faeces. It is pathogenic, causing a wide variety of diseases in humans and animals.
Hathewaya histolytica is a species of bacteria found in feces and the soil. It is a motile, gram-positive, aerotolerant anaerobe. H. histolytica is pathogenic in many species, including guinea pigs, mice, and rabbits, and humans. H. histolytica has been shown to cause gas gangrene, often in association with other bacteria species.
Clostridium innocuum is an anaerobic, non-motile, gram-positive bacterium that reproduces by sporulation. While there are over 130 species of Clostridium, C. innocuum is the third most commonly isolated. Although it is not normally considered an aggressive human pathogen, it has been isolated in some disease processes. C. innocuum and other Clostridium line the oropharynx and gastrointestinal tract, and are considered normal gut flora.
Clostridium cadaveris is an enteric, gas-forming, motile, strictly anaerobic gram-positive bacterium of the genus Clostridium. First described by Klein in 1899, it was noted to be the most prominent bacteria during human decomposition; historically it was described as "putrefying flora".
Clostridium chauvoei is an anaerobic, motile, Gram-positive bacterium. It is a soil-borne pathogen that can cause blackleg in cattle and sheep. It is named after Auguste Chauveau, a French bacteriologist and veterinarian.
Anaerobic infections are caused by anaerobic bacteria. Obligately anaerobic bacteria do not grow on solid media in room air ; facultatively anaerobic bacteria can grow in the presence or absence of air. Microaerophilic bacteria do not grow at all aerobically or grow poorly, but grow better under 10% carbon dioxide or anaerobically. Anaerobic bacteria can be divided into strict anaerobes that can not grow in the presence of more than 0.5% oxygen and moderate anaerobic bacteria that are able of growing between 2 and 8% oxygen. Anaerobic bacteria usually do not possess catalase, but some can generate superoxide dismutase which protects them from oxygen.
Clostridium tertium is an anaerobic, motile, gram-positive bacterium. Although it can be considered an uncommon pathogen in humans, there has been substantial evidence of septic episodes in human beings. C. tertium is easily decolorized in Gram-stained smears and can be mistaken for a Gram-negative organism. However, C.tertium does not grow on selective media for Gram-negative organisms.
Vaccinations for cattle involves the process of applying subcutaneous injections of biological microorganisms in a weakened state to help the immune system develop protection by providing active acquirement of immunity to a particular disease. Cattle are bovine livestock and are thus very susceptible to diseases. Vaccinations for cattle are widely used in the livestock industries of the Australian agriculture sector by farmers to prevent harmful and deadly diseases from infecting their livestock, avoiding any economical or biological harm. Farmed livestock industries account for 45% of the gross value of Australian agricultural output, beef cattle being the largest farmed livestock nationally with around 26.2 million head of cattle nationwide. The beef industry within Australia generates a gross value of approximately $8 billion AUD in beef exports and a total gross value of $11.4 billion in farm production (2017–18). Thus, vaccinations play a vital role in protecting, sustaining and growing the beef cattle industry in the Australian agriculture sector.
