Virus may have crossed species barrier [ SARS ]

From Saturday's Globe and Mail ^ | March 29, 2003 | By ANDRÉ PICARD

[Lessismore]

The deadly respiratory ailment SARS may have spread to humans from cattle, just like mad-cow disease.

Scientists say the infectious agent they have identified as the likely cause of severe acute respiratory syndrome is a previously unknown coronavirus, one that some researchers say looks remarkably like bovine coronavirus. In cattle, the common disease is known as "shipping fever."

Coronaviruses — which take their name from the prominent "crown" of spikes clearly visible by electron microscopy — occur in cattle, pigs, mice and humans.

The new pathogen may have crossed the species barrier and mutated.

"It's hard to be definitive at this point, but it can be hypothesized that it crossed the species barrier," Frank Plummer, scientific director at the National Microbiology Laboratory in Winnipeg, said in an interview yesterday.

He said he had examined the new coronavirus, which does not yet have a name, under an electron microscope and "it somewhat resembles several animal viruses. It's somewhere between a mouse corona, a bird corona and cow corona."

Dr. Plummer said that many new diseases have jumped from animals to humans in recent years, including HIV-AIDS, bovine spongiform encephalopathy [commonly known as mad-cow disease and in humans, Creutzfeldt-Jakob disease] and Ebola virus, often with deadly consequences. "As we change the way we interact with our environment, these things are going to occur, new diseases are going to emerge," he said.

While much of the attention of the scientific world has focused on the new coronavirus, Dr. Plummer said it is necessary to keep an open mind. In many of the samples analyzed, researchers have also found metapneumovirus, which comes from a family of viruses that usually cause respiratory ailments in children.

"At this point, we don't know if there are two separate epidemics, or if these two viruses somehow work together to cause SARS. There are still pieces of the puzzle missing."

Worldwide, there have been 1,485 SARS cases, including 54 deaths. In Canada, there have been 29 confirmed cases, including three deaths.

World Health Organization officials now say that the first known case of SARS occurred on Nov. 16, 2002, in Foshan, China. The city is located in Guangdong province, an agricultural area where there are large cattle farms. Guangdong is also a major supplier of food to Hong Kong, which has been hit hardest by SARS.

The Canadian outbreak, however, has its origins in a chance encounter in the elevator of the Metropole Hotel in Hong Kong on Feb. 21 of this year. There, a Toronto woman and a Vancouver man crossed paths with a professor from Guangdong who was infected with SARS.

Researchers now believe that professor was a "super-spreader," a modern-day Typhoid Mary who spread the disease readily to others. It is well-established that some people shed viruses much more readily than others, making them particularly infectious.

But viruses often lose their potency as they are passed on to others, and that may explain why the disease may be becoming less infectious and less deadly with each passing day.

After months of denial, China has acknowledged that the unusual pneumonia epidemic that started there last November was indeed SARS. It has just opened its doors to WHO investigators and it has agreed to start releasing daily statistics, like every other affected country.

Like a common cold, SARS is spread by droplets, and appears to be spread only by face-to-face contact. Virtually all the cases in Canada are among family members of those originally infected and health-care workers who treated them.

Containment measures, including quarantine of those affected and those who may have come in contact with SARS in Toronto, have been put into place to stop the spread of the disease.

[MarMema]

wow, I have treated a case here of shipping fever myself, in the past. Not just for cattle....

[TightSqueeze]

The new pathogen may have crossed the species barrier and mutated.

More likely a bio-weapons FUBAR from an escaped genetically engineered pathogen.

[Mamzelle]

re: researchers have also found metapneumovirus)))

What about that collection of kids in Michigan and Va who died weeks back? Is this the pathogen?

[thescourged1]

My thoughts exactly.

[Lil'freeper]

the disease may be becoming less infectious and less deadly with each passing day.

Now, there's a sentence you don't see too often in SARS articles.

[AAABEST]

ping

[Ahban]

Another reason that making animals with human genes, and transplanting organs from animals into humans, is not a good idea.

[RWG]

Exactly. Growing a pathogen in human culture could accelerate the 'crossing.'

[equus]

Good point. God knows what will happen in the future.

[aristeides]

World Health Organization officials now say that the first known case of SARS occurred on Nov. 16, 2002, in Foshan, China. The city is located in Guangdong province, an agricultural area where there are large cattle farms. Guangdong is also a major supplier of food to Hong Kong, which has been hit hardest by SARS.

I wonder if anybody on the faculty of Foshan University was researching shipping fever.

[aristeides]

A number of the medical and veterinary faculty members at Foshan University are members of the Communist Party. I suspect any researcher working on bioweapons would belong to the Communist Party.

[per loin]

The Canadian outbreak, however, has its origins in a chance encounter in the elevator of the Metropole Hotel in Hong Kong on Feb. 21 of this year. There, a Toronto woman and a Vancouver man crossed paths with a professor from Guangdong who was infected with SARS.

Hmmm...I wish they would mention where this professor taught. He is also described as a doctor who was treating patients with the disease.

[EternalHope]

But viruses often lose their potency as they are passed on to others, and that may explain why the disease may be becoming less infectious and less deadly with each passing day.

Yes, some viruses do exhibit this behavior.

So far, SARS has not.

[An American In Dairyland]

"More likely a bio-weapons FUBAR from an escaped genetically engineered pathogen."

Many thought that the 1918 Flu was caused by something in the mustard gas used in World War I. It wasn't. The flu was later connected to pigs...swine flu of some type. It is unclear as to whether humans got the flu from pigs or whether humans passed the flu to pigs.

It is more likely that SARS comes from cows or pigs than from Iraqi's. Most flu's originate in Asia as did SARS. Many in that region of the world do not live sanitary lives. As someone jokingly said, they sleep with their pigs and chickens.

While birds cannot pass viruses directly to humans, they can pass viruses to pigs and pigs can spread viruses to humans.

[An American In Dairyland]

"the disease may be becoming less infectious and less deadly with each passing day.

Now, there's a sentence you don't see too often in SARS articles."

But that is just common sense. All flu's eventually go away. Else we'd still be dying of the 1918 flu. The only way for flu's to go away is by becoming less infectuous with passing time.

[firebrand]

SARS ping

[An American In Dairyland]

"Another reason that making animals with human genes, and transplanting organs from animals into humans, is not a good idea."

Unfortunately that doesn't matter. Pig DNA is very close to human DNA by nature. That is why pigs are used for replacement heart material, growing human ears, etc.

People and pigs have been passing viruses back and forth for at least the last 90 years and probably much longer.

[An American In Dairyland]

"Exactly. Growing a pathogen in human culture could accelerate the 'crossing'."

I'm just guessing but I think it would be less likely to happen under lab conditions. Reason being labs would have good cause to want to screen out as much contamination as possible before doing any 'crossing.'

[HetLoo]

So I want to know, if it is a coronavirus, is it one of those that mutates like FIP in cats? And are the people falling ill under high stress? I'm not familiar with "shipping fever", but, if it too is a coronavirus then the name would imply it follows true to form mutating in stressed animals...