Scientists have found the strongest evidence yet that a virus is to blame for a mysterious illness that can quickly paralyze children.
The very rare condition, called acute flaccid myelitis or AFM, is similar to the polio disease. The first reports of the disease came from the American state of California in 2012. Since then, the U.S. has experienced an increasingly bigger outbreak every other year, from late summer into autumn.
Doctors have long believed that certain viruses known as enteroviruses caused AFM. But they did not have enough evidence to prove it.
So researchers tried something new. They checked patients' spinal fluid for signs the immune system had fought an invading virus. Children who got sick had antibodies that target enteroviruses.
Dr. Michael Wilson is with the University of California, San Francisco. He helped lead the research. He said the evidence did not prove their idea. But it was a powerful sign enteroviruses cause AFM.
His team reported the findings in the publication Nature Medicine.
Study co-writer Dr. Riley Bove is with the same university as Wilson. Bove's son developed AFM at age four. He noted, "If you don't have a cause, you can't have a vaccine." Bove added that Wilson developed "a good enough microscope, in a sense, to find things they suspected were there."
About 590 cases of the illness have been confirmed in the U.S. since 2014. Cases increased that year, in 2016 and in 2018. Only a few were reported in the years in between. So far, there have been 22 cases this year.
1.be to blame 是……的原因
Not you but he was to blame for it.
2.be similar to 与……相似
You can only attract someone similar to yourself.
有一种罕见的疾病叫急性无力脊髓炎（AFM），这种疾病与天花类似 。首批与该疾病有关的报道是2012年在美国加州出现的 。自那之后，美国每隔几年就会爆发几次规模越来越大的疾病浪潮，一般都是从晚夏到秋天 。
长期以来，医生们一直认为是肠道病毒引发了AFM 。但他们没有充分的证据可以证明这一点 。
于是，科学家尝试了新方法 。他们检测了病人的脊髓液，寻找免疫系统对抗入侵病毒的迹象 。生病的儿童有针对肠道病毒的抗体 。
迈克尔医生来自于旧金山的加州大学 。他助力牵头了这项研究 。他表示，所发现的证据并未证实他们的想法 。但这是有一个有力的迹象，可以表明是肠道病毒引发了AFM 。
该研究的合著者莱利医生跟迈克尔来自同一所大学 。莱利的儿子在4岁的时候染上了AFM 。莱利表示，“如果不知道病因，就没法研制疫苗 。”莱利补充说，迈克尔研发了一种“强大的显微镜，从某种程度来说，该显微镜可以印证他们的怀疑 。”
自2014年以来，美国已有590起AFM病例 。病例数量在2016年和2018有所上涨 。在中间的年份只有几个病例出现 。今年目前为止有22个病例 。