Bovine Tuberculosis Mycobacterium bovis (Bovine Tuberculosis) (or cattleTuberculosis) was first discovered by Columella (Louis Junius ModeratusColumella) which was born in Cadiz, Spain and resided in Northern Italy when hediscovered the bovine Tuberculosis in the year 14 A D.
In 1882 Robert Kochdiscovered that the connection between human and animal Tuberculosis actuallywere established. When Koch realized that children were becoming infected fromcontaminated cow’s milk most nations brought out legal instruments designed toremove chronically infected animals and take a look at the public health aspectof the problem. The Disease Mycobacterium bovis is the bacterium that causesbovine Tuberculosis. It manifests itself in livestock (especially in cattle andhogs) and it has also affected wild life such as White Tailed Deer, Bear,Coyotes, Raccoons, and Bobcat in the northeastern part of the Lower Peninsula ofMichigan.
From 1995 to 1999 17,721 deer from six counties (Alpena, Montmorency,Oscoda, Alcona, Presque Ile, and Otsego) in Michigan were taken and examined andto date only 228 deer, 1 bear, 5 coyotes, 2 raccoons, and 1 bobcat have testedpositive for bovine Tuberculosis. In the same area there was also 3 herds ofcattle infected with the disease. This disease is also known all over thecountry and the world from Australia to New Zealand to the United Kingdom. Themost likely way to spread the disease in the wild is the bobcat, coyotes,raccoons, and bear eating the lungs and lymph nodes of infected animals.
Thereare three main types of bovine Tuberculosis: human (MycobacteriumTuberculosis)which can affect humans and can be transmitted to dogs, cats,cattle, hogs, goats, sheep, and most any other mammal on earth, bovine(Mycobacterium bovis) which affects animals and can be transmitted to humans(but it is very rare that this may happen), avian (Mycobacterium avian complex)which primarily effect only birds but in some cases there has been some cases inwhich cattle and hogs have been infected with the avian Tuberculosis. Thetwo-mammalian types are more closely related to each other then the avian type. The disease’s presence in humans has been reduced as a result in theeradication program, advances in sanitation and hygiene, the discovery ofeffective drugs, and pasteurization of milk. There is another minor type ofbovine Tuberculosis, which is as microti (Mycobacterium Microti) which affectsrodents. Mycobacterium Tuberculosis is the most host specific of the three majortypes of Tuberculosis, rarely being transmitted to other birds (Mycobacteriumavian), or mammals (Mycobacterium bovis). Bovine Tuberculosis is the mostinfectious type of Tuberculosis it infects most warm-blooded animals to includehumans.
Condition Bovine Tuberculosis can only live for only a few weeks outside of the host’s body because it can not handle the exposure of the heat,direct sunlight, or extremely dry conditions. Bovine Tuberculosis will survivelonger under cool to cold, moist, and dark conditions. The only place theMycobacterium will grow (outside of the host) is on a culture plate, where thebacteria will multiply at a very slow rate of about every 20 hours or so. Astime goes on, bovine Tuberculosis is a disease that take many months or may takemany years to develop or may lie dormant in the host’s body for a lifetime. Ifthe disease does not become dormant, in wildlife and in livestock it will leavemultiple tan or yellow lumps on the rib cage or yellow lesions on the lungsabout the size of a pea.
Transmission Bovine Tuberculosis is a chronic, highlycontagious and infectious disease caused by several bacteria of theMycobacterium family (tubercles) which it first affects the respiratory systemand the lymph nodes and may be found in any organ or body cavity. There areseveral different ways for animals to contract the disease; one is airborneexposure from coughing and sneezing, (which is the most frequent way to contractthe disease) which the risk is much higher in enclosed areas, such as barns. Another way to be infected is the consumption of contaminated food, water, ormilk, from infected animals rubbing on a post or wire and another animal rubsagainst the same area, also using infected cattle trailers or transportvehicles, and avoid interaction and contact with other herds. EradicationProgram The most effective way to handle the problem of bovine Tuberculosis inhumans is to eradicate it in livestock.
The eradication program began in 1917,the cooperative state-federal Tuberculosis eradication program, which wasadministered by the U. S. Department of Agriculture (USDA) Animal and PlantHealth Inspection Service (APHIS). All cattle herds were tested, and all of thecattle that tested positive for bovine Tuberculosis were sent to theslaughterhouse.
After the animals were slaughtered the premises were cleaned anddisinfected after the animals were removed. As a result of the eradicationprogram, the rate of infected cattle were reduced by approximately 5% tocurrently less than 0. 02%. The human Tuberculosis also was reducedsignificantly. The recent surge of human Tuberculosis is due M. Tuberculosis.
Today, there is a very low rate of bovine Tuberculosis cases in humans. State orFederal meat inspectors check the glands and organs of cattle and hogs and insome cases wildlife for signs of bovine Tuberculosis. If these inspectors findany lesions or other signs of bovine Tuberculosis, tissue samples are taken andsent to APHIS, National Veterinarian Services Laboratories in Aimes, IA, forconfirmation. If the laboratory confirms that the lesions are a result of bovineTuberculosis, an attempt to track down the livestock from where it originallycame from and to find the herd that the infected cattle were affiliated with,then a Tuberculin PPD (Purified Protein Derivative) (Bovine) test will beadministered to all of the herd.
If the herd is infected with bovineTuberculosis the rest of the herd will be taken to the slaughterhouse to bedestroyed. If the whole herd can not be eliminated it is held under quarantineand tested repeatedly until all evidence of infection is eliminated. Veterinarians also try to find out the date that the herd was probably infected. Then they try to trace all cattle that moved into or out of the affected herdand try to find out where the infection probably started and where it might havegone and where it might be going. Testing A skin test is the most reliable wayto identify bovine Tuberculosis in cattle.
If cattle have been infected orexposed to bovine Tuberculosis a reaction will occur at the test site on theskin. (So far to date there is no effective vaccine or medications for treatmentfor wild animals). If a reaction does occur an additional test is required toidentify which type of Tuberculosis that the animal is infected with. Once thetype is identified you would use a sterile liquid containing protein derivativesfrom a heat killed Mycobacterium bovis (Strain AN 5), which is grown on asynthetic medium.
If the test resulted in the bovine Tuberculosis you would usethe Tuberculin PPD (Purified Protein Derivative) (Bovine). Retesting Retestingmay only be done at least 60 days after the last injection of Tuberculin PPD wasadministered. This applies to either the intradermal caudal fold test or acomparative test was completed. Dosage and Administration Use the singleintradermal test (skin test). Give a single intradermal 0.
1-ml injection ofTuberculin PPD (bovine) (The vaccine should be stored between 2 and 8 degreesCelsius, but do not freeze and keep it out of the light). The caudal fold(stomach or abdominal area) is where the Injection will be administered. Cleanthe area thoroughly with Betadine or an iodine solution where the injection willtake place, for sterilization, prior to injection. Government actions In orderto protect the human population, the Government has introduced the followingactions: (1) Heat treatment of milk (Pasteurization). (2) Inspection ofcarcasses at slaughterhouses.
(3) Reduce the population of infected animals. Summary It is highly unlikely (less then 1%) the humans will contract bovineTuberculosis from animals, but there is always the possibility of transmissionof the disease. If you do come in contact with an animal that has bovineTuberculosis you will need to get in contact your state or federal inspectors tohave the animal eradicated. Bibliography”Cattle: Tuberculin PPD (Bovine)”, available at: www. csl.
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au/vet_div_cattle/c_t_bonv. htm visited 14 Oct 99 “Animal DiseaseControl Programs”, available at: www. state. oh. us/agr/animal/animal2c. htmvisited 14 Oct 99 Wayne Cunningham, 13 Aug 98, “Colorado Department ofAgriculture”, available at: www.
state. co. us/animals/livestock%20disease/tb. htmvisited 20 Oct 99 “Bovine Tuberculosis”, 20 May 99, available atwww. irlgov.
ie/daff/9851. htm visited 20 Oct 99 “Tuberculosis in cattle andhumans-detailed information”, available at: www. maff. gov.
uk/animalh/tb/public/sheeta2. htmvisited 22 Oct 99 J. Flerke, Aug 98, “Bovine Tuberculosis in Michigan”,available at: www. dnr. state.
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“Merck VeterinarianManual” 1998