A coronavirus is shown in this colorized transmission electron micrograph. British authorities announced Tuesday that another person has died from infection with the new coronavirus as European scientists revealed the new virus easily infects the cells of the airways of the human lung. THE CANADIAN PRESS/HO-US National Institute for Allergy and Infectious Diseases-RML Beth Fischer
TORONTO - The current cluster of novel coronavirus cases in Britain may have included another infection, a World Health Organization official says.
To date, three members of an extended family have tested positive for the new virus, which is a cousin of the SARS coronavirus. One of the three died earlier this week.
But officials investigating how the virus moved from one member of the family to the next suspect another relative may have contracted the virus and may even have spread it to the third confirmed case in the cluster. This fourth family member had a respiratory illness but was not tested until after she recovered, at which point the test came back negative.
Dr. Anthony Mounts, the WHO's point person for the new coronavirus outbreak, says the U.K. cluster adds slightly to the WHO's concern over the virus, but in the main serves to confirm some things the organization has already strongly suspected.
Those are: In some circumstances, person-to-person spread can occur, though so far, it appears those chains of infection has been short. And while the first few cases spotted all involved severe illness, some infections can produce mild symptoms only.
The WHO revised its new coronavirus case definition this week to remind doctors not to automatically rule out people with mild symptoms when they look for possible cases. And Mounts says the organization's recommendations on how to do surveillance for cases will also be updated.
Mild infections are a mixed blessing. Obviously everyone would hope the virus didn't always cause severe disease. But people suffering only mild infections may be more likely to spread the virus, if the virus transmits easily.
That's because people sick enough to be in hospital ICUs mainly encounter health-care workers protected by masks, but people with mild respiratory infections generally go about their daily life. And mild infections are much harder to spot, especially when they occur during cold and flu season.
The third confirmed case in this cluster had only mild symptoms and has since recovered. "The fact that she had such a mild illness really does raise our concerns about what we might be missing," Mounts admits.
Others share the WHO's concern. In fact, several of the researchers who were key players in the response to the 2002-2003 SARS epidemic admit the patterns they are seeing bring back memories.
"It is certainly beginning to look concerning, given the obvious fact that there can be onward transmission," says Malik Peiris, chair of the department of microbiology at the University of Hong Kong.
"It is somewhat reminiscent of the emergence of SARS in 2002."
Ron Fouchier, a virologist at Erasmus Medical Centre in Rotterdam, the Netherlands, also sees those similarities.
And Fouchier is concerned about how many infections may be going unnoticed, untested or unreported. He notes that several of the 12 confirmed cases were diagnosed in European hospitals.
In addition to the current family cluster in Britain, one case from Qatar was diagnosed in Britain in September and a second from Qatar was diagnosed in Germany in October. Both men got sick in Qatar but left the country for treatment — a practice which is not uncommon for wealthy residents of Middle Eastern countries.
"The fact that we are finding these cases in Europe and not anywhere else, that has to raise suspicion," Fouchier says. "What we're seeing in Europe is just the tip of the iceberg and we really have no clue how big the iceberg is."
Saudi Arabia has reported five cases, the most recent in late November. Qatar has had the two confirmed cases. And Jordan has reported two cases, but the confirmations came months after the two individuals died.
Samples taken during an unexplained respiratory outbreak at a Jordanian hospital last April were tested for the virus late last year. At the time of the outbreak, the existence of the virus was not yet known.
Fouchier feels not enough is being done to find cases or to track down the source of the virus.
The virus's genetic sequence indicates it likely comes from bats, but it still isn't clear how people are becoming infected. "We know that humans don't come into contact with bats a whole lot," Fouchier says.
He and other experts suspect there may be some intermediate host — a domestic animal, perhaps — that is being infected and is passing on the virus to people.
Mounts says the WHO is trying to get countries to look harder for the virus. "We're concerned and really watching it very closely and trying to push people to do more investigation."
He also says the organization is putting together networks of experts to help it with the coronavirus situation — an approach the WHO used with much success during the SARS outbreak.
A laboratory network and a network of expert epidemiologists — sometimes called disease detectives — are being set up. As well, a group of clinical experts who have advised the WHO over the past decade on possible treatments for H5N1 — bird flu — and during the 2009 H1N1 pandemic is being reactivated to help with this situation, Mounts says.