In report 3 it was indicated that many modern infectious and invasive diseases of man did not obtain global distribution. The causes of their limited distribution over territories of the world were diverse. Thus, certain naturally focal diseases could not be encountered on these or those territories only because they had not migrated there.
Trans. of Zhurnal Mikrobiologii, Epidemiologii i Immunobiologii (USSR), v41 n2 p73-80 1964. See also AD638579.