Until recently it was thought that only H1, H2, or H3 strains were capable of causing disease in humans. "What has changed are the recent fatal cases of H5N1 flu in Asia showing that H5 virus is capable of causing severe disease in humans, and the recent spread of H5N1 virus over very wide areas that increases the probability that mutant viruses capable of spreading in humans might arise," Strauss wrote.
"Further," he continued, "the recent determination of the complete sequence of the 1918 flu showing how a bird flu can mutate to spread in humans has told us that some of the mutations required to adapt to humans have already occurred in the H5N1 strain currently spreading in birds."
Dr. Robert G. Webster discovered in 1957 that the Asian flu virus was the strain of virus that had been carried by certain birds years before. That was four decades ago, when few people thought much of his conclusions.
More recently, Huang, wife of Cal Tech President Dr. David Baltimore, wrote in a November 2004 letter to Merck Vaccines President Dr. Adel Mahmoud, that "particularly with the increasing regularity of the avian H5 and H7 strains crossing into humans and pigs, I feel I have the responsibility to support Rob Webster."
"Nature is giving us ample warnings with these crossovers; the first was given in 1997," she cautioned. "It is time to act and to take the multiple avian influenza threats seriously."
Webster, a microbiologist originally from New Zealand, is currently at St. Jude's Children's Research Hospital in Memphis. If people weren't listening before, they are listening now.
"The virus can infect people," Moriarty said, "but at this point, transmission to people requires close contact with birds for a prolonged time period. The real danger comes when the virus in an infected person either mutates and/or combines with a human virus into a form that can easily be transmitted from person to person."
According to the Centers for Disease Control (CDC), birds become infected by contact with contaminated saliva, nasal secretions and feces from other birds.
But, "how the H5N1 virus is spreading is still unknown," Strauss said. "Migratory birds may be responsible in whole or in part. But some believe this is it being spread by the movement of infected domestic fowl."
SARS and avian flu
SARS may have served as a major warning sign in 1997, but SARS and avian flu differ in several significant ways.
First, "SARS virus and influenza belong to different virus families," Strauss explained. "SARS is a coronavirus and is in the same family as human coronavirus that causes about 25 percent of common colds. It has a very large RNA genome, about 30,000 nucleotides, in one piece that is a messenger RNA. The many strains of influenza comprise a different family. The genome is in eight pieces of RNA that sum to about 14,000 nucleotides of anti-messenger sense RNA. Perhaps this is more than you want to know about the details of these viruses but the fact that one virus has messenger sense RNA, called plus sense, and the other anti-messenger sense, called minus sense, means that the details of their replication inside cells differ in many fundamental ways. Further, the reservoir of SARS virus is bats, whereas that of flu is birds."
Article comments
1 - Bennett
Great Post! Thanks so much for the clearly presented information.
Purple Tigress, you are the best!
2 - Dr. Kurt
Now, we wait for a Libertarian to post a reply decrying socialized medicine, big government, and the need for lowered vaccine regulations; then, a Neocon will advocate massive subsidies to multinational pharmaceutical companies, so long as poor Americans pay the brunt of the price...
If we aren't worried, we aren't paying attention! Thanks for the info.
3 - Nancy
As I've mentioned on previous articles' posts, IF it happens, just because it's a "pandemic" doesn't mean necessarily it's going to be deadly. The MSM are hyping it for all it's worth because it sells; the various health orgs are hyping it for all it's worth because it's a chance for them to get funding from nervous governments, & the governments are hyping it because that way they can claim they tried to do something to prevent the problem when & if it DOES go down, so they can get re-elected.
If it DOES explode into a pandemic, chances are it will happen so quickly, there's nothing anyone can do about it - including the government, WHO, the CDC, or anyone else including the pope. Got news for ya: if there's a vaccine (& I'm willing to bet a considerable amount there already is) you & I ain't gonna be among those who get it; that will be reserved for the rich, influential (i.e. congress & their dirty friends), & famous.
Therefore, there's no point in agonizing, fixating, or hyperventilating over it, or allowing the media/government or anyone else to stampede the public with it. Just wash your hands. A lot.
4 - Purple Tigress
Pandemic only means an epidemic over a wide geographic area and affecting a large portion of the population.
Any influenza epidemic has the possibility of death of certain high-risk groups. However, even if the mortality rate is relatively low, if you or yours belongs to the unlucky percentage, you won't feel it was something that should have been ignored.
Being fatalistic isn't the solution. We've had warnings since 1957 and then again we had a 1997 wake-up call. We were slow to move.
Doing nothing more than washing your hands won't help institute change and it won't help Americans be prepared now or in the future.
We have made considerable progress against small pox, cholera, typhus and polio. Perhaps if we as Americans were less concerned about sexual orientation and showed more concern for African nations, we could have acted more quickly against AIDS.
5 - Liberal
Wait - didn't we all die already from Legionnaire's disease? Or was it West Nile virus? Or Saars? Or Mad Cow disease? Or shark attacks? Or hypodermic needles on the beach? Or was it the comet Kahoutek? I can't remember what killed us all but something must have. They keep telling us that something is going to kill us all. Aren't we all dead by now?
6 - Purple Tigress
I believe I addressed the tendency for media to sensationalize diseases.
According to the CDC, Legionnaires' disease hospitalizes between 8,000 and 18,000 people every year. Death occurs in 5% to 30% of patients.
BSE (bovine spongiform encephalopathy) or Mad Cow disease has a low transmission rate from cows to humans and a low discovery rate. It has a high transmission rate between sheep and cows. This is a progressive disease, often not showing up until long after the contaminated source has been digested. The warning in the UK went unheeded for years. As of June 2005, 177 cases were reported worldwide with 156 in the UK. While the risk of BSE is low in the US, this year a cow was identified with BSE and related herd members have not all been accounted for. There might be more cases worldwide, however, identifying this disease requires an autopsy of the brain and this is not usually requested. There is a man in Texas who seems to be suffering from vCJD (variant Creutzfeldt-Jakob disease) which his family believes he got from eating goat/sheep in the Middle East.
West Niles disease is through mosquito bites. Mosquito have a limited life span and are confined to certain areas. About 80 percent of the people have no symptoms. However of the 16,000 reported cases there have been 650 deaths.
SARS spreads by person to person close contact. A total of 8,098 people have become sick since 2003 and 774 died. Only eight were in the US. All of these people had traveled to locations of the world with SARS.
Since 2003, 100 human cases of avian flu (H5N1) have been reported. These have all been a result of close contact with feces, saliva or other contaminated secretaions or with contaminated surfaces. Unlike SARS, the spread cannot be controlled by limiting the movement of humans. The transmission is easier than BSE.
As a result of the outcry against BSE, standards for beef cattle have changed almost worldwide. BTW, I should add that there is a bigger problem in the US with CWD, chronic wasting disease which seems to spontaneously occur in deer and there is a caution, but no controls over eating venison.
The first evidence of AIDS was in 1959, found in the plasma of a man from what is now called the Democratic Republic of Congo. For a time, it was looked on as a black African disease and used by racists to justify white superiority. In the US, it became known as a gay male disease in the 1980s even though HIV was found in tissue samples of an American teenager who died in St. Louis in 1969 (per wikipedia.org).
HIV is found in our nearest relatives--primates. The eating of so-called bush meat by Africans and by rich non-Africans can also have contributed to the spread of disease in humans as well as the ownership of exotic primates. If we had not been so prejudiced toward gay men, could we have controlled AIDS sooner? If Magic Johnson hadn't become HIV positive, would it have taken longer?
It required famous people and not so famous people passionately advocating change and the deaths of famous people to turn the public's attitude around IMHO.
If people actively pursue and advocate change, we can have safety and health measure in place before avian flu has the chance to become a pandemic.
7 - elle
Purple Tigress,
I highly enjoyed your response. Just fyi, though, you have written several inaccuracies about the current scientific perceptions of BSE that I want to set right just in case someone needs the info. There is in fact no evidence of transmission of scrapie from sheep to cows and for hundreds of years sheep have been succumbing to prion disease without evidence that humans have been at all affected (although, of course, the hard science is missing, so there may be a super low, nearly undetectable transmission rate). After thorough retrospective analysis, scientists point towards cannibalistic feed practices as the reason that the BSE epidemic arose in English cattle, comparable to the start of the kuru epidemic in New Guinea. Also, there are several indications that we may have our own strain of BSE in America that has been around for a while, and perhaps has been the cause of sCJD. For relevant reading material, please see Prusiner's article in Science, 1997 and the book Deadly Feasts by Rhodes (a fantastic book, btw).