The use of bovine tuberculin in intradermal tests
Some farmers mistakenly think they can administer bovine tuberculin to cattle themselves.
Following the introduction of stringent veterinary requirements imposed by the South
African veterinary authorities on the importation of livestock from Namibia, a widespread
misconception exists regarding the administration of bovine tuberculin to cattle.
A number of farmers are under the impression cattle must be injected with bovine tuberculin as part of these requirements, and also that they can administer this themselves - which is not the case.
The above-mentioned regulations require, among others, the testing of cattle to be exported to ensure these animals are free from bovine tuberculosis. To that end the so-called “intradermal TB test” has to be performed on the individual animals. In short, this test consists of the following steps:
1. Shaving a small area of the skin on the left side of the neck of the animal;
2. Measuring the thickness of the skin at that site with calipers;
3. Injecting 0,1 ml of a reagent, bovine tuberculin, into the skin with a special syringe at that site;
4. Remeasuring the skin thickness after 72 hours at the injection site; and
5. Comparing the two skin thickness readings to determine a positive or negative reaction.
This test has to be performed by an official of the Directorate of Veterinary Services of the Ministry of Agriculture, Water and Forestry.
The farmer or animal owner who needs to have his cattle tested for TB prior to export, will have to purchase the bovine tuberculin and supply it to the veterinary official for the test.
Bovine tuberculin is a thermosensitive biological product and maintenance of the cold chain is critical during transport and storage of this product.
Summary
Bovine tuberculin is not a vaccine which has to be administered to cattle destined for export to South Africa. It is a biological reagent used to perform a screening test on cattle to detect bovine tuberculosis.
KASSIE ASB
What is tuberculosis?
Tuberculosis (TB) is a chronic infection that can affect nearly all vertebrate animals. Tuberculosis in cattle or bovine tuberculosis is caused by Mycobacterium bovis, human tuberculosis by Mycobacterium tuberculosis, and tuberculosis in birds by Mycobacterium avium.
Humans are, however, also as susceptible to M. bovis as they are to M. tuberculosis.
The disease, which usually has a very chronic course, is characterised by the formation of typical tubercles, or caseous necrosis of tissue and progressive wasting away. Tubercles are small, rounded translucent nodules of a grayish colour.
Bovine tuberculosis as a zoonosis is of enormous importance due to the danger it poses to humans. Currently 15 244 people in Namibia are suffering from tuberculosis, which is an infection rate of 722 per 100 000 people.
Of these 8 186, or 59%, are HIV positive.
There is also a worrying increase in highly resistant XDR-tuberculosis cases.
Good news is that 75 – 85% of cases can be treated successfully.
Namibia has the second highest human TB-infection rate in the world. TB is regarded as an indicator of poverty.
TB in humans in Namibia is exclusively as a result of M. tuberculosis infection, transmitted between humans. Bovine tuberculosis is not important as a zoonosis in Namibia.
Bovine tuberculosis is scheduled a notifiable disease, controlled by the state veterinarian, and involves annual testing of dairy cows used for commercial milk production.
Due to the long, chronic course of the disease, tuberculosis can remain inapparent in an infected herd and will then present variable symptoms, depending on the organ system affected.
The disease primarily affects the lungs but can also cause mastitis and can produce tuberculous lesions in many other organs.
Animals in advanced stages of TB are usually emaciated with a rough hair coat and may have enlarged lymph nodes.
The disease can be diagnosed by a post-mortem examination and laboratory tests, or it can be detected in the live animal with a skin test.
Positive animals are branded with a “T”-brand and slaughtered in specified abattoirs.
Poultry, pigs, sheep, goats, horses and certain game species, like buffalo, are also susceptible to TB and can cause a threat to human health.
Humans are mainly infected by drinking raw, unpasteurised, infected milk, as well as direct or indirect contact with infected animals, through droplet inhalation, or while working with animals - especially in intensive farming operations, like dairies.
Apart from the respiratory system, many other human organ systems can be affected.
Humans suffering from starvation, malnutrition or immune-suppressive diseases like HIV/Aids, and humans living in crowded, unhygienic, poor housing conditions, are particularly at risk of contracting TB.
Prevention
and control
• Vaccination of babies.
• Pasteurisation of milk.
• Annual testing of dairy cattle with intradermal tuberculin tests and elimination of positive animals.
• Regular testing of
dairy workers.
• Proper human nutrition and strict hygiene.
• Elimination of poverty.
• Control or elimination of immune-suppressive diseases like HIV/Aids.
*Article contributed by Agra ProVision.
African veterinary authorities on the importation of livestock from Namibia, a widespread
misconception exists regarding the administration of bovine tuberculin to cattle.
A number of farmers are under the impression cattle must be injected with bovine tuberculin as part of these requirements, and also that they can administer this themselves - which is not the case.
The above-mentioned regulations require, among others, the testing of cattle to be exported to ensure these animals are free from bovine tuberculosis. To that end the so-called “intradermal TB test” has to be performed on the individual animals. In short, this test consists of the following steps:
1. Shaving a small area of the skin on the left side of the neck of the animal;
2. Measuring the thickness of the skin at that site with calipers;
3. Injecting 0,1 ml of a reagent, bovine tuberculin, into the skin with a special syringe at that site;
4. Remeasuring the skin thickness after 72 hours at the injection site; and
5. Comparing the two skin thickness readings to determine a positive or negative reaction.
This test has to be performed by an official of the Directorate of Veterinary Services of the Ministry of Agriculture, Water and Forestry.
The farmer or animal owner who needs to have his cattle tested for TB prior to export, will have to purchase the bovine tuberculin and supply it to the veterinary official for the test.
Bovine tuberculin is a thermosensitive biological product and maintenance of the cold chain is critical during transport and storage of this product.
Summary
Bovine tuberculin is not a vaccine which has to be administered to cattle destined for export to South Africa. It is a biological reagent used to perform a screening test on cattle to detect bovine tuberculosis.
KASSIE ASB
What is tuberculosis?
Tuberculosis (TB) is a chronic infection that can affect nearly all vertebrate animals. Tuberculosis in cattle or bovine tuberculosis is caused by Mycobacterium bovis, human tuberculosis by Mycobacterium tuberculosis, and tuberculosis in birds by Mycobacterium avium.
Humans are, however, also as susceptible to M. bovis as they are to M. tuberculosis.
The disease, which usually has a very chronic course, is characterised by the formation of typical tubercles, or caseous necrosis of tissue and progressive wasting away. Tubercles are small, rounded translucent nodules of a grayish colour.
Bovine tuberculosis as a zoonosis is of enormous importance due to the danger it poses to humans. Currently 15 244 people in Namibia are suffering from tuberculosis, which is an infection rate of 722 per 100 000 people.
Of these 8 186, or 59%, are HIV positive.
There is also a worrying increase in highly resistant XDR-tuberculosis cases.
Good news is that 75 – 85% of cases can be treated successfully.
Namibia has the second highest human TB-infection rate in the world. TB is regarded as an indicator of poverty.
TB in humans in Namibia is exclusively as a result of M. tuberculosis infection, transmitted between humans. Bovine tuberculosis is not important as a zoonosis in Namibia.
Bovine tuberculosis is scheduled a notifiable disease, controlled by the state veterinarian, and involves annual testing of dairy cows used for commercial milk production.
Due to the long, chronic course of the disease, tuberculosis can remain inapparent in an infected herd and will then present variable symptoms, depending on the organ system affected.
The disease primarily affects the lungs but can also cause mastitis and can produce tuberculous lesions in many other organs.
Animals in advanced stages of TB are usually emaciated with a rough hair coat and may have enlarged lymph nodes.
The disease can be diagnosed by a post-mortem examination and laboratory tests, or it can be detected in the live animal with a skin test.
Positive animals are branded with a “T”-brand and slaughtered in specified abattoirs.
Poultry, pigs, sheep, goats, horses and certain game species, like buffalo, are also susceptible to TB and can cause a threat to human health.
Humans are mainly infected by drinking raw, unpasteurised, infected milk, as well as direct or indirect contact with infected animals, through droplet inhalation, or while working with animals - especially in intensive farming operations, like dairies.
Apart from the respiratory system, many other human organ systems can be affected.
Humans suffering from starvation, malnutrition or immune-suppressive diseases like HIV/Aids, and humans living in crowded, unhygienic, poor housing conditions, are particularly at risk of contracting TB.
Prevention
and control
• Vaccination of babies.
• Pasteurisation of milk.
• Annual testing of dairy cattle with intradermal tuberculin tests and elimination of positive animals.
• Regular testing of
dairy workers.
• Proper human nutrition and strict hygiene.
• Elimination of poverty.
• Control or elimination of immune-suppressive diseases like HIV/Aids.
*Article contributed by Agra ProVision.
Kommentaar
Republikein
Geen kommentaar is op hierdie artikel gelaat nie