In the week and a half since scientists announced they had found a fragment of virus in a bat that seemed to match the Middle East respiratory syndrome coronavirus (MERS-CoV), many have raised questions about whether the fragment really was from the same virus that is striking people in Saudi Arabia and elsewhere in the Middle East.
The discovery was reported by a team of US and Saudi scientists, who said that a fecal sample from one Egyptian tomb bat (Taphosouz perforatus) in Saudi Arabia yielded a 190-nucleotide fragment that was a 100% match for the MERS-CoV from the first human case in the country. The sample was collected 12 kilometers from the man's home.
But the doubters say that the piece of genome was so small that, even though the sequence was a match for the corresponding piece of MERS-CoV, it might represent only a related virus. The MERS-CoV genome consists of about 30,000 nucleotides.
Among other points, critics also observe that the fragment came from a fecal sample, not from blood or a throat swab, opening the possibility that the virus was in something the bat swallowed. Questions also have been raised about the assay the scientists used.
The meaning of the bat finding has been a hot topic because no one knows where the MERS-CoV exists in nature or how it makes its way into humans. The virus is known to be a close relative of other coronaviruses found in bats, but last week's report was the first finding that seemed to clearly point to bats as the source—or at least one source—of the pathogen.
The finding was the result of two sample-collection campaigns in Saudi Arabia by the scientists, last October and April of this year. The team was led by W. Ian Lipkin, MD, of Columbia University, a famed virus hunter, and it included Ziad Memish, MD, Saudi Arabia's deputy minister of public health and its lead spokesman on MERS.