By March, when the government sounded the alarm to WHO, cases had already spread from the forest area to the capital of Conakry.
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今年五月，几内亚的疫情中心强劲蔓延到了塞拉利昂，今年六月疫情真正在利比里亚出现。
In May, the focus of the outbreak in Guinea expanded strongly to Sierra Leone and in June it really took hold in Liberia.
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自今年七月以后，所有三个国家的病例数量都出现急剧上升。
From July onward, there were sharp increases in case numbers in all three countries.
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预测
Projections
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虽然西非现行流行规模空前，但病毒感染临床病程和传播力与以往发生的埃博拉疫情相比较为类似。
Although the current epidemic in west Africa is unprecedented in scale, the clinical course of infection and the transmissibility of the virus are similar to those in previous Ebola outbreaks.
“We infer that the present epidemic is exceptionally large, not primarily because of biologic characteristics of the virus, but in part because of the attributes of the affected populations, the condition of the health systems, and because control efforts have been insufficient to halt the spread of infection,” says Dye.
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这一地区存在可加剧快速控制病毒难度的复杂局面。
There are challenges in this region that exacerbate the struggles to contain the virus quickly.
Most importantly the health systems in all three countries were shattered after years of conflict and there was a significant shortage of health workers, leaving the system weaker than in other countries with Ebola outbreaks.
In addition, certain characteristics of the population may have led to the rapid spread of the disease, for example, the populations of Guinea, Liberia, and Sierra Leone are highly interconnected, with extensive cross-border traffic at the epicentre and relatively easy connections by road between rural towns and villages and the densely populated capital cities.
“The large intermixing population has facilitated the spread of infection, but a large outbreak was not inevitable,” says Professor Christl Donnelly, Professor of Statistical Epidemiology, Imperial College, and the MRC Centre for Outbreak Analysis and Modelling.