Six months after the World Health Organization (WHO) has been informed of the Ebola outbreak in West Africa , experts have published a new study warning that the situation is growing rapidly worse and the Ebola virus can even "become endemic in the human population of West Africa, a perspective that has never been previously considered. "
the US Centers for Disease Control and Prevention (CDC) Atlanta, meanwhile, released a new model for the spread of the deadly virus. the worst case scenario estimated that up to 1.4 million people could be infected by the end of January. If the control efforts are strengthened fairly dramatically and prove surprisingly successful, however, the epidemic could be nearly complete at that time. "Delay is extremely costly in terms lives and efforts, "said CDC Director Tom Frieden told a news conference today.
the Ebola epidemic, which probably began in Guinea in December last year has sickened at least 5,843 people, according to the latest figures from the WHO, more than twice all known previous outbreaks combined and killed 2803. epidemiologists expect the actual numbers are two or three times, however, because only a fraction of cases is reported. And spread of the disease continues to accelerate.
The new study by experts and WHO scientists at Imperial College London, published today The New England Journal of Medicine , is "excellent" because it fills important gaps, says Preben Aavitsland, a Norwegian epidemiologist. "For example, the study gives an average of 6.4 days of stay in hospital," he says. It is important to know because it means that approximately as many beds are needed because it has there new Ebola cases every week. This also means that tens of thousands of beds will be needed by the end of November, said Aavitsland. "It is quite difficult to know where the beds and people for their personal will . "
the authors also found that the so-called virus levels in each country, representing the average number of reproductive individuals each infected person infects turn. it varies from 1.38 Sierra Leone to Liberia 1.51 to 1.81 in Guinea. This means that cases are almost doubling every 2 weeks in Guinea, every 3 weeks in Liberia, and every month in Sierra Leone, said Christl Donnelly, an epidemiologist at Imperial College London and one of the authors of the study. "the great thing is that we still see exponential growth and that must be stopped."
There are a month into his alleged Ebola Response Roadmap, WHO wrote that the number of cases "could exceed 20,000 during this emergency." In the new model, it projects that number to be reached by November 2, if the epidemic continues to grow unchecked.
there's more bad news. Although WHO said earlier that about half of patients die from Ebola, the paper estimates that the case fatality rate is actually just above 70%. "I think that can be fed through more aggressive therapy well below 50%," says Aavitsland. Offering a better chance of survival is important to convince patients to seek treatment instead of staying at home, he said, where they can infect other people. "for now, all these processing units have to offer is a lonely death."
in a perspective published with the article, Jeremy Farrar, Director of the Wellcome Trust, and Peter Piot, director of the London School of Hygiene & Tropical Medicine, warns that hitting the effects will kill many more people. "West Africa see a lot more suffering and more deaths during childbirth and from malaria, tuberculosis, HIV-AIDS, enteric and respiratory diseases, diabetes, cancer, cardiovascular disease and mental health during and after the Ebola epidemic, "they write . "Indeed, there is a real danger of a complete breakdown in civil society, as desperate naturally lose faith communities in established systems."
the model published by CDC today looks further, and its projections are even more sobering. If the virus continues to spread at its current rate, Liberia and Sierra Leone alone reported about 550,000 cases of Ebola January 20, the authors write. But if the official figures to date represent 40% of the actual load, which many believe could be the case, it would mean a total of 1.4 million cases of Ebola in both countries on 20 January. "I hope we do not see anything like these projections," Donnelly said. "But I think it is a realistic projection of what would happen if we did we organized."
Projecting what happening in Guinea is impossible because of the wild fluctuations in the number of cases, Frieden said. "You see three separate cases waves increased in amplitude" which probably reflect the reimportation of the two countries, he said at the press conference.
CDC also released the model as an Excel worksheet "so that planners in the countries and international organizations can model what might happen under different circumstances," said Frieden. He also said he does not believe that the most dire predictions are coming. "The model shows, and I do not think it has been shown by other modeling tools there, that the surge can now break the back of the epidemic," he said. Specifically, the epidemic begins to slow, and eventually peter out, though about 70% of patients in health care facilities or Ebola treatment units, or, if they are full are cared for in a so that they do not transmit the virus to others.
Although this may seem somewhat reassuring, it is unclear how this can be achieved, because doctors do not even know about 60% of all cases of Ebola in the region. "I do not see the huge influx in aid is needed to achieve this goal," says Jonas Schmidt-Chanasit, a virologist at the Bernhard Nocht Institute for Tropical Medicine in Hamburg, Germany. In part, Schmidt said Chanasit it is a matter of speed. The United States, for example, promised 17 field hospitals will be able to accommodate 100 patients each, but it is expected to take 50 to 100 days for those to be fully functional. in that time, the need will be much larger already
the CDC model shows the need for speed clearly :. for every additional 30 days it takes to get 70% of patients in treatment, the researchers estimate that the number of daily cases occurring at the peak of the epidemic will triple. Provide home care kits to protect people who care for family members themselves can help prevent the least some infections, said Schmidt-Chanasit. "It is certainly a good idea, but it will not by itself curb this epidemic." The key Aavitsland said, is still a massive increase in beds and staff. "It seems very difficult to stop now, but I think we all just to believe it is possible."
There is at least a glimmer of hope in the new data, Donnelly said. "Reproduction rate, at least in Sierra Leone and Liberia, was higher at the beginning of the epidemic. This may be a first sign that some efforts have an impact," she said. Christian Althaus, an epidemiologist at the University of Bern, warns that this may just be an artifact, though. As hospitals filled, the proportion of cases are not reported may have increased, creating the illusion of some improvement. "I wish it were true," said Althaus. "But I doubt it."
* Ebola files: Given the current Ebola outbreak unprecedented in terms of the number of people killed and the rapid geographic spread, Science and science Translational Medicine made a collection of research articles and news on the viral disease available for researchers and the general public.
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