HILARY KOPROWSKI 
infected with drug-susceptible bacilli; however, if the patient’s 
infection should become reactivated in 1955, a child exposed to 
him at that time might become infected with drug-resistant 
organisms. As happens in most cases, the primary lesions of the 
Adult Reactivation 
_> R 
ON 1953 


1955 



1955 i 
=> Latent 
\ hrs 

Fig. 1. ‘‘The natural history of tuberculosis: the writer’s concept of a likely 
reason for the delay in the occurrence of resistant tubercle bacilli in untreated 
patients as a great clinical problem.” (Reprinted with the permission of Dr. 
William Stead from American Review of Respiratory Diseases, 1962, 86, 420.) 
child will heal spontaneously; however, reactivation may occur 
any time from ten to twenty years later, so that drug-resistant 
bacilli would first be isolated in this family in the period 
1966-1976. Families with a similar history are numerous 
throughout the world, and future attempts to control tuber- 
culosis have a bleak outlook if drug treatment alone remains the 
common denominator, particularly when the initial case has 
transmitted the infection to contacts. 
It should be mentioned in passing that a factor associated 
with drug resistance of some species of bacteria such as Salmonella 
200 
