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Clostridial Diseases
Clostridia are group of anaerobic, spore-forming bacteria found in the soil/environment, which produce rapidly fatal disease by secretion of potent toxins.
Several diseases are caused by Clostridial infections:
Botulism is a lethal food poisoning in cattle caused by eating material that contains Clostridium botulinum toxins. Bacillary haemoglobulinuria is a rapidly fatal disease caused by C. oedematiens type D.
Blackleg infection is caused by Clostridium chauvoei and is almost always associated with wound infection in cattle.
Malignant oedema is caused by the infection of wounds with any of several bacilli of the genus Clostridium (C. oedematiens type A; C. chauvoei; C. perfringens; C. sordellii; C. septicum). Tetanus is caused by the toxin tetanospasmin released from the spore-forming bacillus Clostridium tetani.
Causes
Toxins or spores from Clostridum spp.
Effects
Depends on the type of Clostridium. See under every specific disease.
Diagnosis
- Botulism
Botulism is a lethal food poisoning in cattle caused by eating material that contains Clostridium botulinum toxins. Clinical disease may be seen in individual animals or as group outbreaks of disease.
The incubation period before clinical signs appear varies from a few hours to two weeks, making it difficult to identify the causative material eaten by affected animals. The most common manifestation of the disease in cattle is a subacute disease with restlessness, incoordination and difficulty to swallow developing into recumbency, paralysis and death within 1-7 days.
The bacteria and the disease occurrence are world-wide. Cases are likely to occur either due to ingestion of silage contaminated with soil or poorly fermented (allowing persistence of clostridial spores), or contact with animal carcasses or skeletons of dead animals containing the toxin. The use of poultry litter as fertiliser on cattle pastures has been identified as a risk factor, due to the poultry mixed with the litter.
Outbreaks of disease may have implications to human health as the fate of botulinum toxins in the food chain are not easily predicted, therefore, restrictions on sale of livestock and milk will be made for two weeks following the diagnosis of the last clinical case under Food Standards Agency guidelines.
Bacillary haemoglobulinuria
Bacillary haemoglobulinuria is a rapidly fatal disease caused by C. oedematiens type D. The disease is associated with liver damage primarily caused by liver fluke. The condition is fairly rare. Young stock or dry cows inspected less regularly are often found dead. In lactating cows, a sudden drop in milk yield associated with high fever is seen. Other clinical signs include ruminal stasis with or without apparent abdominal pain, rapid breathing, dark red urine, jaundice and death within a short time of the onset of clinical signs.
Spores of C. oedematiens type D can be found both in the soil and in the livers of normal cattle on farms where the disease occurs.
Blackleg
Blackleg infection is caused by Clostridium chauvoei and is almost always associated with wound infection in cattle. Most cases occur in young stock between 10 months and two years of age. Feet or legs and the tongue are often the predilection site. Within 48 hours there is a high fever and if limb muscles are involved the animal becomes stiff and unwilling to move. Skin discolouration, subcutaneous oedema and gas production may be present and perineal oedema is sometimes seen.
Infections of the head may produce marked oedema and even bleeding from the nose. Death usually follows a period of anorexia, profound depression and prostration.
The spores of C. chauvoei survive well in the soil.
Malignant oedema
Malignant oedema is caused by the infection of wounds with any of several bacilli of the genus Clostridium (C. oedematiens type A; C. chauvoei; C. perfringens; C. sordellii; C. septicum). The condition is fairly rare and sporadic, but outbreaks involving several animals may occur after an event that has caused bruising or wounds (e.g. penning for a short period).
Clinical signs appear rapidly after infection and at the site of infection a swelling will develop which will 'pit' on pressure. Gas may be detected, as the skin becomes darkened and tenser. A high fever is present and toxaemia develops. The animal dies within 1 - 2 days.
Tetanus
Tetanus is caused by the toxin tetanospasmin released from the spore-forming bacillus Clostridium tetani. The disease in cattle occurs most often after surgical intervention or difficult calving after spores gain entry to a wound. Germination of spores occurs only if the microenvironment is anaerobic. After germination of the spores within the wound the C. tetani bacilli proliferate and produce toxin.
The incubation period can be very variable from 3 days to several months but most cases occur usually after about 10 days. At first the animal appears slightly stiff, becomes unwilling to move and develops a fine muscle tremor. The temperature rise is variable (39 - 42° C). The general stiffness of the limbs, head, neck and tail (raised tailhead) increases after 12 - 24 hours. The animal shows hyperaesthesia and repeated spasms. Mastication becomes difficult due to tetany of the masseter muscle (lockjaw), food is chewed with difficulty, the animal drools saliva and bloat often occurs. There is retention of the urine and constipation.
The animal becomes recumbent, with the legs rigidly extended, opistotonos and the jaws become rigid. The animal usually dies due to respiratory failure 3 - 4 days after the onset of clinical signs. Milder cases, which develop more slowly, can recover over a period of weeks or even months.
Treatment & Control
It is up to the veterinarian to decide whether or not clinical cases infected with clostridia species should be treated or humanely destroyed.
Treatment of bacillary haemoglobinuria with penicillin can be attempted. Treatment of clinical blackleg has met with little success, but intravenous hyperimmune serum together with an injection of crystalline penicillin both intravenously and into the wound has been shown some success. Treatment of malignant oedema can also be attempted with antibiotics and local treatment of the wound with hydrogen peroxide or other oxidising disinfectants. The use of herbal and homoeopathic treatments of wound may also be attempted.
Treatment of botulism carries a poor prognosis and attempts at treatment depend of the severity of clinical signs at presentation. The use of intra-venous glucose saline and administration of ruminal fluid was reported as successful in treatment of less severe cases.
Treatment of tetanus cases is difficult and the response is usually poor. Full doses of antibiotics such as products containing penicillin can be administered to eliminate the bacilli.
Tetanus antitoxin should also be given. Success often depends on good nursing with forced feeding (via stomach tube) if necessary. If the infected wound can be found it should debrided and treated with hydrogen peroxide and herbal and/or homoeopathic treatment. Sedation and reduction of muscle tetani, to avoid asphyxia, can also be attempted.
Medication/Vaccination
Since Clostridia are ubiquitous in the environment, the most effective way of controlling clostridial diseases is by vaccination. If clostridial disease has been a problem on the farm, prevention should be included as part of the herd health plan. Use of vaccine can also help prevent disease in young stock by passive transfer of immunity via antibodies in colostrum from vaccinated dams.
Single vaccines are preferred to more complex multiple vaccines unless such cover is specifically required. Vaccine choice and use should be agreed with the nominated veterinary surgeon to ensure adequate disease protection. Only healthy animals should be vaccinated.
This information was taken from:
http://www.vetsweb.com/diseases/clostridial-diseases-d226.html
For more information see:
http://www.organic-vet.reading.ac.uk/sheepweb/disease/clostr/clostr.htm
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