Spreaders vs Super-spreaders

[Gemineye]

If none of Duncan's contacts contract Ebola, it might raise the issue of "spreaders" vs. "super-spreaders". This distinction, I believe, was first made during the SARS outbreak when 5 such super-spreaders were identified (see link below). Super-spreaders are able to infect many more people, presumably because they shed more virus than "ordinary" spreaders. I don't know if any super-spreaders have been identified in this Ebola outbreak but it does have public health ramifications.

If Duncan turns out to be a spreader, which is more likely, it might give people a false sense of security. The public might conclude that Ebola is not that infectious. But the next infected person might be a super-spreader and likely to cause much more panic. Also, health providers may get a little lax if all they see (at first) are spreaders.

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5218a1.htm

 

[Gemineye]

Re: Spreaders vs Super-spreaders

Actually, super spreaders have been found in Ebola outbreaks.

Khan AS, Tshioko FK, Heymann DL, et al. The reemergence of Ebola hemorrhagic fever, Democratic Republic of the Congo, 1995. J Infect Dis 1999;179(Suppl 1):S76--S86

 

[AlaskaDenise]

Re: Spreaders vs Super-spreaders

The use of the term "super-spreader" in the Kikwit, DRC epidemic is problematic. In some cases there is not a biological reason (like co-infection) for anyone to have a higher viral shedding rate - instead they simply had more contacts. In Kikwit, the ebola was misdiagnosed first as dysentery, entered a maternity hospital (where there were cesareans on infected women), and when it was misdiagnosed as a intestinal perforation, the surgical team all got sick, the anetheist spreading it to the most because of his job. Considerable time passed before the HCW started using proper protective practices - which was what brought the epidemic to a halt.

The Reemergence of Ebola Hemorrhagic Fever, Democratic Republic of the Congo, 1995

.....The concept of a ?super-spreader? or ?high-frequency transmitter? is novel for this viral hemorrhagic fever, and the mechanism for this high-frequency transmission is unknown. The large number of cases may simply have been a matter of a larger number of contacts of these case-patients or some inherent differences in the virus-host relationship. These differences could include a more virulent virus strain or high levels of viral shedding; unfortunately, no samples are available from these case-patients......

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