Friday, October 10, 2014

How contagious is ebola? Not very, experts say

This story was updated Monday, Oct. 13
Several days ago, Thomas Eric Duncan died from ebola after arriving in Dallas from Liberia. He didn't appear to be ill during his journey or soon after he arrived. "Various news outlets are reporting that travelers arriving in the United States from West Africa would have their temperatures taken and be asked to answer questionnaires ascertaining any possible exposure," Kris Hickman writes for the Association of Health Care Journalists.

This story, among other ideas circling the news, has caused worry, but do people really have a reason to panic? Contagion potential is indicated by the reproduction number, which refers to the number of individuals to whom an infected person is likely to pass a disease. Epidemiologists have estimated that ebola's reproduction number is between 1.5 and 2. Measles, one of the most contagious diseases in the world, has a reproduction number of 18, and HIV has a reproduction number of 4.

The calculations are based on how long infected individuals are contagious and how much of the virus is needed to pass the diseases, among other factors, "but these data indicate that ebola is, in fact, controllable with appropriate and timely responses from the public health sector," Hickman writes.

Ebola is transmitted through contact with bodily fluids, but only when the patient is showing symptoms. The fatality rate is approximately 50 percent, particularly without proper treatment. "Reporters tapping into public health experts who can explain the concept of reproduction number should be able to show how containable the disease is and put it into proper perspective," Hickman writes.

While it is well-documented and understood how e-bola is spread, Peter Jahrling, chief scientist at the National Institute of Allergy and Infectious Diseases, is concerned that the disease has mutated to become more contagious, Julia Belluz reports for Vox.

Jahrling is worried that the "mutations of the virus that are circulating now look to be more contagious than the ones that have turned up in the past, " Belluz writes.  His Liberian team has found that the patients in Liberia have a much higher "viral load," which means that they have more virus in their blood - and that could make them more contagious. He told Bulluz that they were continuing to run test on their patients in Liberia, and they continued to show high "viral loads." When asked what this means, he said, "Right now, we just don't know."

The state Department for Public Health has prepared materials to" help hospitals, public-health agencies, health-care organizations and other coalitions in their preparedness for Ebola, Jack Brammer reports for the Lexington Herald-Leader. The materials are online at

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