Since the beginning of this century and especially since the most recent advances in the battle against tuberculosis through effective chemotherapy, the age distribution of the disease has changed radically in those parts of the world where a concerted attack on tuberculosis has been possible. The first great change was accomplished through effective sanitation of the milk supply, which resulted in practically complete control of bovine tuberculous infection in a few coun- tries, notably the United States; the secondary manifestations of bovine infections, particularly tuberculous osteomyelitis, have since become comparatively rare.
This achievement in combination with the enlightened concept that the exposure to the human bacillus in home life is the main source of clinical pulmonary tuberculosis resulted in a decline of the mortality among children to very low values even before the era of chemotherapy. American statistics show a remarkable decrease from about 200 deaths in children per 100,000
BLOCH RG. Tuberculosis, a Disease of Old Age. AMA Arch Intern Med. 1958;101(6):1057-1064. doi:10.1001/archinte.1958.00260180047006