APPENDIX O 
of this type of disease (fi;oin the anus of an infected patient to the 
mouth of a prospective victim) can be effectively disrupted by esta- 
blished practices of common-sense hygiene. Only the respiratory route 
of transmission of infectious agents is difficult to control in countries 
like the U.S., and the ability to travel this route is not within the 
arsenal of pathogenic strains of coli . Thus, unfortunate as diarrheal 
diseases and urinary tract infections may be for the individual involved, 
these conditions are definitely not candidates for life-threatening 
global epidemics. coli (as well as many other normally inocuous bac- 
teria) may also cause serious infections of organs and blood in newborns 
and in adults whose defense mechanisms against infections have been 
seriously impaired by other underlying diseases (e. g. leukemia). For 
obvious reasons, none of these conditions can give rise to widespread 
epidemics among the general population. 
In order for coli to cause a worldwide epidemic of fatal infection 
it would have to acquire most or all of the following traits, each of which 
is likely to be complex in itself and therefore to require the presence 
of several genes for its expression. (i) It must be able to spread via the 
respiratory route of infection which, in turn, means that it must be able 
to infect the adult (i.e. other than newborn) human lung, and must survive 
in droplets of sputum which dry out in the air and which are exposed to 
lethal ultraviolet radiation from the sun. (ii) It must be able to ac- 
tively penetrate through skin or the epithelial linings which cover the 
body's tissue, (iii) It must be able to resist engulfment or other\>;ise 
avoid being killed by the phagocytic cells of the body, (iv) It must 
resist the effects of antibodies and other antibacterial substances in 
the body fluids, (v) it must be capable of producing powerful iron che- 
lators in order to compete with the body for this metal and (vi) it must 
be resistant to the action of all clinically useful antibiotic drugs. 
Certainly, it will take more than the introduction of one or a few genes 
into _E. coll to give it all the properties needed to turn it into a 
global menace, especially when an "enfeebled" EK-2 or EK-3 strain is 
used. 
As a final thought it is pertinent here to point out that modem 
medicine has been able to conquer all those highly pathogenic bacteria 
which were the ancient scourges of mankind. The once-dreaded worldwide 
epidemics of highly fatal plaque or cholera are no more, the large 
numbers of deaths from tuberculosis or pneumococcal pneumonia have 
disappeared from the statistics. Infections are still a major cause 
of disease and death in this country but the nature of the causative 
agents has shifted from "super-pathogens" to bacteria of relatively low 
virulence (including^, coll ) , which often are highly resistant to 
most clinically useful antibiotics and which cause serious infections 
in patients whose body defenses against bacteria have been impaired by 
other underlying diseases (5). It is apparent therefore that, if some 
terrorist were indeed able to deliberately create a new bacterial patho- 
gen of the same caliber as, say, the plague bacillus, this would be the 
very kind of infectious agent which modem medicine is best equipped to 
handle. 
Appendix O — 4 
