a son and his sick father in Monrovia
PHOTO :. IMAGES JOHN MOORE / GETTY
When a traveler Liberia came down with Ebola in Dallas on 24 September, it was a warning to the world: As the number cases in West Africa continues to increase, so does the risk of disease spread beyond Guinea, Sierra Leone and Liberia. The United States was the third country, after Nigeria and Senegal to catch a spark of fire more; it was followed by Spain, which reported the first case of Ebola contracted outside of Africa, October 6. The patient, a nurse, had taken care of a priest who became infected in Sierra Leone.
None of these cases has triggered a generalized epidemic, and most experts are convinced that rich nations can contain introduced cases. "My first reaction was: Well, it had to be somewhere better than Dallas Mumbai." Says Peter Sandman, risk communication consultant based in Brooklyn, New York, on the case of the United States. But developing countries may not be so lucky when Ebola arrives at their door. This could result in entirely new chapters in the spread of the disease.
On October 3, the World Health Organization (WHO) reported 7470 cases and 3431 deaths in the three affected countries. These figures suspected of gross underestimates, are rising exponentially, and the models show they could reach hundreds of thousands in a few months. But the models can not predict unpredictable things like viral mutations, changes in human behavior, the impact of new vaccines and drugs, or where and how the disease will then take root. So researchers are looking beyond the models and scenarios, to prepare for what might happen. Scientists are naturally reluctant to speculate, Sandman said, but "risk communication and crisis communication are what-if."
On the optimistic picture, an effective vaccine could finally check the rise in the classic control cases, something methods such as isolation and quarantine have failed to do. Without a vaccine, "I think the best we can hope for is that the spread slows down a bit," said Alessandro Vespignani, a physicist at Northeastern University in Boston who has modeled the spread of Ebola. "The increase in action public health will have a huge impact, but I think it got to the stage where we need a vaccine to stop this epidemic, "said Jeremy Farrar, an epidemiologist who heads the Wellcome Trust in London.
[vaccineA candidate is already in phase I safety tests, and another will soon; at a meeting at the WHO on 29 and 30 September, experts discussed ways to accelerate the development of vaccines and how to deal with the thorny ethical problems involved in testing a vaccine for efficiency in affected countries (http://scim.ag/Ebolavac). But these tests are not likely to start until January, and they can not give results until April.
Meanwhile, some scientists fear the virus could mutate. In an op-ed piece in The New York Times September 11, Michael Osterholm, director of the Center for Research on Infectious Diseases and politics at the University of Minnesota, Twin Cities, has argued that Ebola could change in such a way "that just breathing would put a risk of getting" it. He was widely criticized for fear mongering. "I do not know of a viral infection whose mode of transmission has changed in this way," says Farrar. WHO issued a statement on October 6, calling the idea "speculation, unsupported by any evidence." Osterholm retorts that "it may be a very remote possibility, but we must be ready even for that."
DATA: MONSTER LAB, Northeastern University
which is more plausible, some researchers say, is a change that makes it less deadly virus, but also more difficult to dispose. the Ebola virus hides most likely in bats and monkeys sometimes spill over into the human population, probably when infected animals are hunted and eaten. Historically, outbreaks have tended to burn in the face aggressive containment efforts and sheer deadliness of Ebola. in essence, humans are dead ends for the virus. This could change if it becomes less fatal. "There's an evolutionary advantage to reduce the virulence and host adaptation," says Farrar. "What happened with many other diseases."
If this happens with Ebola, the only way to get rid of it this time could be a massive effort similar vaccination to those used in eradication campaigns against smallpox and polio. "We will review the vaccination of hundreds of millions of people in Africa," said Farrar.
Even if the virus does not change, the magnitude of the epidemic will lead to new challenges. As the number of beds in treatment units is far, more and more patients will be supported at home, where they are a major risk for the other. This could accelerate the spread of the Ebola virus and make it more difficult to trace its epidemiology . home care kits, which include basic protective equipment such as gloves and bleach, was never widely used before to fight against Ebola, but they could become important in the fight against infection. they must be accompanied by an education campaign, however, and nobody is sure how much protection they offer.
As health care systems already crippled in affected countries in the loop pressure, people are also more likely to die in a larger number of other diseases such as malaria, or during childbirth. "We must begin to look beyond Ebola," says Farrar. The food shortages may occur if crops are missed or commerce is paralyzed. "The whole region could become a failed state," says Osterholm.
Meanwhile, the risk of spreading beyond the three countries develop, said North Vespignani, which listed the most risky countries in an article published in PLOS Currents: Outbreak in September (see table). The three countries where the virus has since landed in Senegal, Nigeria and the United States-were-in the top 16. His most recent calculations also set during an event occurring in the vicinity of Ghana on October 24 nearly 50%, even with an expected 80% reduction in travel. Mali and Ivory Coast are at high risk, too. If the virus gains a new foot addition, a major effort would be needed to avoid a second storm, Osterholm said, even if it means diverting West African resources.
Scientists debate the use of travel bans, which worried many American citizens has asked the Dallas case. WHO and the Centers for Disease Control and Prevention strongly advised against closing borders because it would be difficult to get people and materials in the affected countries. The prohibitions are also difficult to implement, Vespignani said, because many countries should agree; otherwise carry Ebola could just fly to a country that does not impose restrictions and move from there. Those who manage to circumvent a ban could then be more likely to lie about their history of contact if they become ill. Ultimately, Vespignani said, travel bans would likely increase the risk for everyone.
But Sandman said the idea should not be dismissed completely. "It's perfectly reasonable for people to seek the best way to reduce the number of sparks out of Africa and threatening to ignite elsewhere," he said. The world may need to buy time to test vaccine candidates, so it should seek practical ways to reduce the number of travelers carrying Ebola in other places, Sandman said. "These are discussions that we need."
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