Feb. 22, 2005 — The CDC is “amazingly concerned” over the “exceptionally ominous” risk of feathered creature flu, CDC officials say.
It’s not a modern worry. Public health officials have been worried for a long time that a particularly awful form of feathered creature flu — H5N1 influenza A virus — will learn how to spread effortlessly from human to human. That hasn’t happened yet.
In case it did, the affect on world health would predominate the SARS flare-up, says CDC medical disease transmission expert Tim Uyeki, MD.
“SARS isn’t that contagious, although there were super-spreading events,” Uyeki tells WebMD. “Most individuals with SARS did not transmit the illness to numerous social contacts. In contrast, human flu virus is exceptionally contagious. With a pandemic H5N1 influenza virus there would be no pre-existing insusceptibility — most individuals would be exceptionally helpless — so there would be proficient transmission to social contacts. … In case it begun where an contaminated person may get to Bangkok or Ho Chi Minh City and get on a plane, the spread may well be exceptionally quick.” Are you stressed around bird flu? Take our survey.
How likely is it this truly will happen? Uyeki is quick to note that no one really knows. All kinds of relevant data are lost. But the small that’s known is beautiful scary.
So far, the World Wellbeing Organization (WHO) knows of 55 human infections with the H5N1 feathered creature flu virus — 37 in Vietnam, 17 in Thailand, and one in Cambodia. It killed 42 of these people. It’s likely that there have been numerous more cases than this, many of them likely lethal. Most people probably get milder cases, but that’s far from clear. As it were individuals with serious malady show up in clinics.
Concurring to the CDC, the detailed indications of avian influenza in humans have extended from the commonplace flu-like indications of fever, cough, sore throat, and muscle hurts to eye infections, pneumonia, intense respiratory distress, viral pneumonia, and other severe and life-threatening complications.
“Of the 11 cases since the conclusion of December 2004, 10 were fatal. That is exceptionally disturbing,” Uyeki says. “It is quite likely that there are more extreme and fatal cases that have happened and typically an think little of of affect among people. The surveillance has not been done for milder sickness or asymptomatic disease. We are essentially picking up cases of severe infection, among which a tall proportion is fatal.”
The endless lion’s share of these human contaminations came straightforwardly from chickens or ducks. There’s been one case of conceivable human-to-human transmission (the tragic case of a youthful mother who caught it after holding her passing on child overnight). There may have been others, but there’s been no progressing fowl flu spread among people.
“The good news is these viruses have not yet acquired the ability to transmit from person to person in a sustained way. The key word is supported,” Uyeki says. “There have been a number of instances of limited person-to-person transmission. This highlights the potential for a widespread within the future.”
The longer winged creature flu infections continue to spread among poultry, the more noteworthy the risk. The first time H5N1 raised its head — in Hong Kong, in 1997 — the butcher of all the city’s millions of chickens and a enormous cleanup of live poultry markets disposed of the virus. But presently the virus appears to have taken root in Southeast Asia — not only among residential chickens and ducks but in wild feathered creatures, as well.
“The longer these infections continue to circulate among poultry, it raises the potential for a [human] H5N1 pandemic, because of the capability of these infections to advance,” Uyeki says.
And the direction of this evolution isn’t reassuring, notes medical analyst Henry L. Niman, PhD, founder and president of Recombinomics, Inc.
“It’s clear that the [H5N1] infection is advancing and getting a broad host range,” Niman tells WebMD.
“We do know that these H5N1 viruses have been documented to transmit to a number of distinctive creature species. That incorporates tigers and leopards and domestic cats,” Uyeki says. “H5N1 is also affirmed to infect pigs in China; there have been a restricted number of cases reported in pigs. The point is that these viruses are greatly concerning. They have transmitted to a number of creature species and have killed people.”
A later report within the New England Journal of Pharmaceutical shows that human infection with H5N1 fowl flu is more complicated than previously thought. The infection contaminated the brain and gut of two Vietnamese children who passed on with severe seizures and — forebodingly — serious the runs.
“The confinement of infection from a rectal example is a major source of concern, since it highlights a potential course of human-to-human transmission, particularly in combination with swarmed living conditions and the runs,” Jenno D. de Jong, MD, and colleagues wrote.
The leader of this think about, Jeremy Farrar, MD, PhD, is clearly worried.
“The extraordinary concern is there is an incredibly virulent avian flu that shows the capacity to hop to humans,” Farrar told WebMD in a December 2004 interview. “And when it gets to people, it is clearly a really awful disease with a high mortality rate.”
In a recent assessment of the danger postured by a bird flu pandemic, the World Health Organization noted that typically the primary time in history people have had any warning that a executioner flu could be on the way.
“A pandemic may be imminent,” composes WHO director-general Lee Jong-wook, MD. “This time, the world has an opportunity to guard itself against a infection with pandemic potential before it strikes.”
CDC and WHO researchers as of now have recognized viruses from which they can make a bird flu vaccine. Candidate immunizations are planned for testing at the National Institutes of Health. And Uyeki says that Vietnam is testing its possess vaccine in animal studies.
It’s not yet clear whether these test vaccines are safe or whether they will inspire immune responses that protect against H5N1 flu infections in people. Should an H5N1 immunization be safe and compelling, there’s still the issue of creating sufficient immunization for U.S. and world request. And, of course, vaccine makers will need to keep up with the infamous ability of flu viruses to alter their genetic makeup.
The fowl flu is, unfortunately, resistant to one kind of flu drug. It’s touchy to Tamiflu — but supplies are short.
“Indeed in a scenario where we have a few of months to plan for a pandemic, the reply is no, there are not sufficient antiviral drugs accessible for treatment or [prevention of infection] during a widespread circumstance — indeed within the U.S., let alone the rest of the world,” Uyeki says. “Other governments besides the U.S. are attempting to stockpile it. Right now there is an insufficient supply. … What are needed are not only more availability and more production, but we require other sorts of antivirals as well.”