What do people think about outbreaks v. sporadic infection and the boom in incidence in the early eigthies. It seemed there was some pathogen that was quite contagious causing outbreaks every year or so since the thirties or whenever. It would hit 100 or 200 hospital staff for example and then be gone like Keyser Soze. Then in around 1983 the numbers really headed north quickly and it seems like most of the infections aren't clusters, they're sporadic. Ie it is not as contagious at any one point in time, but it spreads further and infects many, many more people. At the same time outbreaks seemed to go up too: Lake Tahoe, Lyndonville, Miami, North Carolina (?), Rhode Island (?), several more listed on p.328 osler's web. In Osler's Web, Walter Gunn said CDC was getting at least 10 reports of outbreaks from doctors a year in the late 80s and early nineties and CDC only pretended to investigate even two of them. And perhaps some outbreaks were not noticed as such as the disease became common. Do you think that a cluster strain of a pathogen somehow got more virulent to cause more clusters, or a co-factor was introduced that facilitated this? And do you think a new strain emerged that caused sporadic cases and resulted in the boom in incidence? or was there always a sporadic strain and some cofactor made facilitated it's virulence?