tag:blogger.com,1999:blog-829514279103338525.post5415383798732840089..comments2022-03-08T09:04:18.685-05:00Comments on Musings on Infection: Ebola: Thoughts on a public health disasterDavid Hartleyhttp://www.blogger.com/profile/05719693130719057219noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-829514279103338525.post-39800901009229211582014-11-13T03:57:35.740-05:002014-11-13T03:57:35.740-05:00Thank You for sharing this blog. Its very good to ...Thank You for sharing this blog. Its very good to know the current status of Ebola Infection.<br /><a href="http://www.thetrentonline.com" rel="nofollow">Ebola Infection</a><br /> Trenthttps://www.blogger.com/profile/12856684427343613067noreply@blogger.comtag:blogger.com,1999:blog-829514279103338525.post-69652101356295171392014-08-14T18:45:19.488-04:002014-08-14T18:45:19.488-04:00Biologically, the reproductive ratio is the number...Biologically, the reproductive ratio is the number of cases caused by the first case of a disease when introduced into a completely susceptible population. If this quantity (known as "R0" in epidemiology) is greater than one, then the infection spreads; if it's less than one, then it doesn't. The greater R0 is above one, the more "explosive" epidemics tend to be. (Sometimes R0 is referred to as the "epidemic potential" for this reason.) R0 can depend upon many parameters; for many directly transmissible diseases, R0 is proportional to the adequate contact rate between individuals, but it also depends on other important quantities, including the period of infectiousness, the lifetime of individuals in the general population, and the disease-associated mortality rate. In the case of influenza and measles viruses, measles has a *much* higher R0 than that for influenza, and epidemics of measles in unvaccinated populations are notoriously explosive; see, e.g., the post http://musingsoninfection.blogspot.com/2014/04/measles-right-here-in-river-city.html and links therein for how problematic this disease is at present, even in the US. Ebola, thankfully, isn't aerosol infectious like measles is (see http://www.ncbi.nlm.nih.gov/pubmed/16916564 for a description of aerosol transmission in measles and similar infectious diseases). If it were, then the contact rate would be much higher and thus its R0 could be as well. (It should be noted that R0 isn't always as straight forward as described above as described in http://www.ncbi.nlm.nih.gov/pubmed/21860658, but it's often a helpful quantity to think about nonetheless.)David Hartleyhttps://www.blogger.com/profile/05719693130719057219noreply@blogger.comtag:blogger.com,1999:blog-829514279103338525.post-2405469778293888482014-08-11T10:51:10.343-04:002014-08-11T10:51:10.343-04:00Dave, what is the relationship between reproductiv...Dave, what is the relationship between reproductive ratios and transmission rates? Is that a one-to-one mapping? If you had asked me beforehand which was more likely to be "catchy," flu or measles, I'd've said flu every time. Mind you, I've had the flu, and no one I've known has had measles, so that probably colors my thinking on it - I'm guessing that's why we all get vaccinated against measles.-dplhttps://www.blogger.com/profile/12810477237664064686noreply@blogger.com