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Published Date: 2012-10-19 17:40:48
Subject: PRO/AH/EDR> Novel coronavirus - Saudi Arabia (12): RFI
Archive Number: 20121019.1353615

NOVEL CORONAVIRUS - SAUDI ARABIA (12): REQUEST FOR INFORMATION
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Date: Thu 18 Oct 2012
Source: Calgary Herald, The Canadian Press [edited]
http://www.calgaryherald.com/health/Study+coronavirus+suggests+comes+from+animals+possibly+bats/7405549/story.html

Study of new coronavirus suggests it comes from animals, possibly bats
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"It's hard to say anything definitive, but humans do not come in contact with bats a whole lot. And so the chance that 2 humans get into contact with bats is even less likely, with the same species of bats carrying the same virus," said Fouchier, a senior scientist at Erasmus Medical Centre in Rotterdam, the Netherlands.

The novel coronavirus found in the Middle East earlier this year probably came to humans from bats, though whether it travelled through another species before infecting people is unclear, a new report suggests.

The scientists who 1st identified the new virus -- which comes from the same family [the family _Coromaviridae}_] as the SARS virus -- reported Wednesday [17 Oct 2012] on the case that brought the virus to light, the fatal infection of a 60-year-old man from Saudi Arabia. In their report, published in the New England Journal of Medicine, they predict pipistrellus bats may be the source of the virus. Senior author Ron Fouchier, the virologist whose laboratory 1st spotted that this was a never-before-seen coronavirus, said bats and coronaviruses have co-evolved over millenniums. Because of that fact, one can generally predict which bat is host to which coronavirus, Fouchier said in an interview. Study of the virus cannot reveal if there was an animal go-between, though it is a possibility, he said.

To date only 2 infections with the new virus have been spotted. The 1st, the man from Saudi Arabia, occurred in June [2012]. The 2nd was in a man from Qatar, who 1st sought medical assistance in early September [2012]. The Qatari man was sent by air ambulance to London, where he is still in hospital.

While Fouchier mentioned the possibility of spread from person to person, at this point the suspicion is that the men were probably infected by animals. Both are reported to have had contact with some animals, including sheep and camels in the case of the man from Qatar. Public health authorities have been investigating whether friends and family of the cases or health-care workers who came in contact with them developed symptoms, but so far it appears that the virus has not spread from those 2 cases.

In fact, in the journal report the authors reveal that the microbiologist in Saudi Arabia who was trying to puzzle out the source of the man's infection has developed a test that can detect antibodies to the virus in blood samples. Dr. Ali Mohamed Zaki, of Dr. Soliman Fakeeh Hospital in Jeddah, tested 2400 blood samples from people who came to the hospital for treatment from 2010 to 2012. None of them contained antibodies to the virus. Zaki is one of the authors of the New England Journal paper. His data support the idea that this may be an animal virus that is occasionally spilling over into people, not a human virus that just hasn't been spotted before, Fouchier said.

Whether there have been or will be more cases of the virus is a question without an answer at this point -- though Fouchier suggested chances are good there will be. "Personally I do think that we are going to find a few more cases. Because these 2 cases were 3 months apart and I do not think that our diagnostic capacity is such that we would detect 2 out of 2 cases in the world," he said. "I'm guessing that we are going to find a few more cases and I hope it's going to be just a few." Still, at this point the risk the new virus poses doesn't appear to be broadly based, an editorial in the journal suggests.

Dr. Larry Anderson, an infectious diseases expert at Emory-Children's Centre in Atlanta, [Georgia], said at present the risk that exists is likely within the local community or the region. Until the source of the virus is discovered it will be hard to assess what that means geographically. "What we have right now . . . is a virus that doesn't appear to transmit person to person. So it's not a broader global risk," said Anderson, who during the SARS outbreak in 2003 was with the U.S. Centers for Disease Control, leading their laboratory efforts in the response to the outbreak. "Now, it may still be a risk locally, depending on the types of exposure that lead to infection -- which we don't really know about. The fact that they've only had a couple of cases would argue that it's not a frequent introduction. It may just periodically introduce."

But both Fouchier and Anderson admitted that this could be the early steps in a more complicated dance between this virus and humans. It is now known that before SARS adapted to be able to spread reasonably efficiently from person to person the virus had a stuttering start, probably jumping from its animal source to people a number of times before taking off. Fouchier said it's possible this virus is also on a path to adapting to people. But because it has been spotted at this early stage, it could be easier to control, he said. "(But) it's critical that we find out where it comes from." Fouchier said samples from suspected cases are still coming into his laboratory. In fact, he was waiting Wednesday [17 Oct 2012] for samples from Lebanon. Given the fact that it's currently the start of the season for respiratory illnesses in the Middle East, his lab may find a lot of influenza in the samples, he admitted.

Interestingly, the report notes that the Saudi man who died also had a mix of bacterial infections over the course of his illness. _Acinetobacter_ and _Staphylococcus aureus_ were isolated from his airways, as was _Klebsiella pneumoniae_, which can cause serious respiratory illness. Could a bacterial co-infection explain the severity of the man's illness? Fouchier said it is possible, but the bacteria were susceptible to antibiotics and the man was treated aggressively with anti-bacterial drugs. "We certainly cannot exclude that these bacteria have played a role in the disease, but what is really unusual that you find this coronavirus in the lower airways," he said. "So it is quite likely that this lower airway coronavirus is a key in this disease. But it's absolutely true that bacterial co-infections or super-infections can explain this clinical picture quite well as well."

[Byline: Helen Brancswell]

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[Coronaviruses infect a wide range of mammals (including humans) and birds. They exhibit a marked tropism for epithelial cells of the respiratory and enteric tracts. In addition to such infections, other diseases caused by coronaviruses include hepatitis, neurologic disease, infectious peritonitis, nephritis, pancreatitis, runting, and adenitis. Severe acute respiratory syndrome (SARS) emerged in 2002 to 2003 in southern China. The origin of the etiological agent, the SARS coronavirus (SARS-CoV), remains elusive. Various species of bats are natural hosts of coronaviruses both unrelated OR closely related to the coronavirus virus responsible for the SARS outbreak. It is likely that the 2 patients in the Middle East were infected by one of the many species of coronavirus naturally present in bats. The severity of the disease may have been a fortuitous consequence of co-infection with a pre-existing bacterial pathogen. Further analysis of the taxonomy and diversity of bat coronaviruses may clarify this situation. - Mod.CP]

[The full text of Zaki AM, van Boheemen S, Bestebroer TM, Osterhaus AD, Fouchier RA. Isolation of a Novel Coronavirus from a Man with Pneumonia in Saudi Arabia. N Engl J Med. 2012 Oct 17 can be found at http://www.nejm.org/doi/full/10.1056/NEJMoa1211721?query=featured_home#t=articleTop. The authors give a very thorough description of the clinical course of the 1st case in addition to detailed discussions on the virologic studies and findings. The authors draw comparisons of the clinical course of this patient with that described as the clinical course seen with SARS -- an ARDS (acute respiratory distress syndrome) accompanied by a multisystem organ failure including renal failure. Of note, the authors mentioned that while none of the medical personnel working with the patient were found to have the implicated coronavirus, at the time of publication of this article, serologic studies had not been performed on these close contacts. An important comment made in the above newswire is that "this could be the early steps in a more complicated dance between this virus and humans." These 2 confirmed cases may well be the early cases in the evolution of human disease. This moderator hopes that a diagnosis of "ARDS" now automatically leads to respiratory isolation and precautions in the clinical setting so that nosocomial outbreaks of novel respiratory agents will be prevented.

At present there are ongoing serosurveys being implemented to attempt to determine the possible background prevalence of antibodies to this novel coronavirus. We eagerly await the results of these studies.

In an earlier post on this novel coronavirus, Dr. Irene Lai mentioned a report on an outbreak of an as yet undiagnosed severe respiratory disease among health care workers in Jordan. The outbreak involved 11 cases including 7 nurses and 1 physician from an ICU (intensive care unit) in a hospital. There was one death associated with this outbreak. ProMED-mail had requested more information from knowledgeable sources on that outbreak. If that outbreak still remains "undiagnosed," it would be interesting to know results of serology for the novel coronavirus among the affected individuals. - Mod.MPP

A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/r/1HAJ.]

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