The long search for the MERS virus' natural reservoir may have finally come to an end.
Although the bat had always been suspected to be the reservoir, only a couple of weeks ago the Saudi government announced that it thought camels were actually the culprit. That came following a case of a camel herder who became infected while tending retired racing camels.
These latest news however, have pinpointed an infected bat with a close geographical connection with the Arabian region that suffers the outbreak.
The bat tested for MERS confirmed an important clue: the virus' genome trace was found in an Egyptian tomb bat in the Arabian peninsula. Another species could also provide a virological bridge between the bat and humans, however.
Another case that points to the bat as the source, is the evidence of MERS in a South African bat. The virus in the South African bat had a very close genomic resemblance to the one that has caused the outbreak.
One of the scientist that has been involved in this latest research is Ian Lipkin, a Columbia University virologist who is among a handful of scientists that have been allowed access to animal samples from Saudi Arabia. The Arabian health authorities have come under strong criticism for their handling of the outbreak, namely the stubborn stance of restricting almost all access to both human and animal samples during and after the outbreak.
One of the things that Lipkin did, was to travel to 'patient's zero's' area, a man who died in June of 2012: the town of Bisha. There he collected samples from various tissues of bats that lived in an abandoned date palm only a few miles from where the deceased patient resided.
It was after the samples were studied that the DNA sequencing confirmed that the fecal pellet of the Egyptian tomb bat (Taphozous perforatus) contained an identical ribosomal sequence as that of the MERS coronavirus that has infected 97 people, mostly in the Arabian peninsula.
However, the sequence obtained from the samples was incomplete, meaning that the bat could have a virus that is very closely related to that of the MERS that has caused the outbreak, but not the exact one.
Another issue also intervened during transport to Columbia University, as uninformed customs officer forced the samples to sit at room temperatures for 2 days, before they were released to Lipkin. That alone, could have damaged the sequences.
However, the finding points to a very close identification of the Mers virus, if not the one, since the sequence is incomplete, but it nevertheless confirms the bat as the reservoir of the MERS and like coronaviruses in the Arabian peninsula and neighboring regions.
The finding was published when the discovery of the South African bat was made more recently, which gave Lipkin and his team greater confidence that they had made the right conclusion.
However, Likpin does not think that the outbreak is derived from a direct bat to human transmission. A direct link, in fact has not been established. That is when the retired racing camels could be playing a role, since a couple of the beasts were found to have MERS antibodies in their blood samples. However, that is too simplistic an idea, since most of the people stricken with the disease had no contact whatsoever with camels or camel herders.
Lipkin suggests that more animals be tested to see which one could be the Mers virological bridge. He is flying back to Saudi Arabia for further studies next month.
Source : Science / 8.22.13
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