INFECTION AND IxXFKCTIOUS AGENTS 31 



hactericmia. If multiplication occurs in the blood stream, it is 

 called septicemia unless multiple abscesses develop, when the term 

 pyemia is used. 



Acute and Chronic Infections. — Infections are often classified 

 according to the duration of the disease. Those that disappear 

 within a few days or at most a few weeks are called acute infections, 

 while those that persist are either subacute, or cJironic infections. 



Focal Infections. — Chronic infections causing pus pockets 

 around the roots of the teeth and inflammatory processes in the 

 tonsils, sinuses, prostate gland, cervix of the uterus, or elsewhere 

 are called focal infections. The detection and eradication of such 

 foci of infection is regarded by most ph^'sicians as good medical 

 practice. A critical apprai-sal of their importance in systemic dis- 

 ease is given by Reimann and Havens (1940). They seem to feel 

 that an overemphasis has been placed upon the importance of focal 

 infections in systemic disease and tliat surgical interference is fre- 

 quently detrimental to the patient. 



Beneficent Infections. — There are a few infections in man 

 which, w'hen viewed in one way, may be regarded as beneficent 

 although not without danger in themselves. For example, consider 

 a patient suffering from syphilis, which is caused by Treponema 

 pallidum. He may have extensive infection of the tissues, includ- 

 ing the brain, and develop spastic paralysis and insanity. This 

 condition resists the ordinary treatment of syphilis, but if the 

 patient should become infected with the malarial parasite, a 

 clinical cure is passible. After his symptoms of syphilis have dis- 

 appeared, he still has malaria, which can be treated and usually 

 cured with quinine. 



Specific Microbic Association. — Until recently it has been 

 thought that each infectious disease was caused hy a single specific 

 infectious agent. Now it appears that swine influenza may be an 

 exception to this concept. Shope (1931) and Lewis and Shope 

 (1931) seem to have shown that this disease is due to simultaneous 

 infection with two agents, one filtrable and a second that belongs 

 to the hemophilic group of bacteria. This would seem to be an 

 example of an infectious disease caused by specific microbic asso- 

 ciation wiiere both microorganisms may be regarded as primary 

 agents. Zinsser and Bayne- Jones (1939) seem to regard these as 

 examples of primary (virus) and secondary (hemophilic bacteria) 

 infections. 



