Between 1838 and 1845, John Croghan, the owner of Mammoth Cave in Kentucky from 1839 onwards, brought a number of people with tuberculosis into the cave in the hope of curing the disease with the constant temperature and purity of the cave air; each died within a year. Hermann Brehmer opened the first TB sanatorium in 1859 in Görbersdorf (now Sokołowsko) in Silesia. In 1865 Jean Antoine Villemin demonstrated that tuberculosis could be transmitted, via inoculation, from humans to animals and among animals. (Villemins findings were confirmed in 1867 and 1868 by John Burdon-Sanderson.) Robert Koch identified and described the bacillus causing tuberculosis, M. tuberculosis, on 24 March 1882. He received the Nobel Prize in Physiology or Medicine in 1905 for this discovery. Koch did not believe the cattle and human tuberculosis diseases were similar, which delayed the recognition of infected milk as a source of infection. During the first half of the 1900s the risk of transmission from this source was dramatically reduced after the application of the pasteurization process. Koch announced a glycerine extract of the tubercle bacilli as a "remedy" for tuberculosis in 1890, calling it "tuberculin". Although it was not effective, it was later successfully adapted as a screening test for the presence of pre-symptomatic tuberculosis. World Tuberculosis Day is marked on 24 March each year, the anniversary of Kochs original scientific announcement. Albert Calmette and Camille Guérin achieved the first genuine success in immunization against tuberculosis in 1906, using attenuated bovine-strain tuberculosis. It was called bacille Calmette–Guérin (BCG).
Its heritability (
  
    
      
        
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  ) is as high as 89%. Both familial clustering and isolated valve defects have been documented. Recent studies suggest that BAV is an autosomal dominant condition with incomplete penetrance. Other congenital heart defects are associated with bicuspid aortic valve at various frequencies, including coarctation of the aorta.Bicuspid aortic valve abnormality is also the most observed cardiac defect in Turner syndrome. == References ==