Isolating only "likely non-survivors" can stop Ebola
October 31, 2014
Isolating the sickest Ebola patients within four days of symptom onset would eliminate the Ebola epidemic in Liberia, according to a newly published modeling study.
According to the study, isolating only “likely non-survivors” would be enough, because they are the most contagious group. The study is published Oct. 28 online in the journal Annals of Internal Medicine.
West Africa is suffering the largest and deadliest Ebola epidemic ever recorded. Liberia has been especially hard-hit with more than 3,500 infections and 2,000 deaths in the past three months. About 70 percent of Ebola patients die in West Africa, although experts attribute the high mortality rate partly to lack of modern medical care in the area.
In the study, Karen N. Peart of Yale University and colleagues developed a model known as random-transmission to see how disease progression and case fatality affect transmission, and the effects of patient isolation. They found that the risk for transmitting Ebola depends on the viral load, or amount of viruses, in an infected person, and the number of people with which he or she interacts.
Distinguishing between survivors and non-survivors is important, they said, because survivors tend to achieve peak viral load about four days after symptoms develop; then viral load declines. But in non-survivors, with more severe symptoms, viral load is 100 times higher than that of survivors throughout infection and doesn't decline after peak.
The survivors were found to have a 32 percent probability of infecting at least one other person. Non-survivors have more than twice the probability of infecting someone else-67 percent, the study found.
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