Avian flu research unravels why and how swine flu outbreak came about
April 30th, 2009 - 2:05 pm ICT by IANS ( 1 comment )New York, April 30 (IANS) A lethal avian flu virus can cause human flu pandemic more easily than previously thought, according to a new study.
University of Maryland (U-M) researchers have explored the mechanisms of how combined avian-human viruses are transmitted and how virus outbreaks like that of the current swine flu came about.
Daniel Perez, associate professor, U-M, showed that after an avian and human-like virus combine, the virus requires relatively few mutations to spread rapidly between mammals by respiratory droplets.
“This is similar to the method by which the current swine influenza strain likely formed,” said Perez,
“The virus formed when avian, swine, and human-like viruses combined in a pig to make a new virus. After mutating to be able to spread by respiratory droplets and infect humans, it is now spreading between humans by sneezing and coughing.”
Generally, avian flu viruses infect birds, and human viruses infect humans. Because their immune systems “remember” what the viruses look like from previous exposures, humans and birds tend to have some level of immunity to their respective viruses.
Though avian flu viruses do sometimes infect humans and cause severe illness, these viruses do not transmit easily from human to human so the spread is rare.
A problem arises when an intermediary species that can host both avian and human-like viruses, such as a pig, is infected with both types of virus, said an U-M release.
In cases like these, the viruses can combine in the host to make hybrid avian-human viruses. These viruses can infect humans but escape the immune response because their surface proteins are foreign to the immune system. While these viruses can cause serious illness, they are generally not passed easily between humans.
However, Perez has shown that this type of virus can fairly easily mutate to spread quickly and potentially cause a human pandemic.
The study was published in the Proceedings of the National Academy of Sciences.
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Tags: avian flu, avian flu virus, daniel perez, flu, flu outbreak, flu pandemic, human viruses, immune response, immune systems, immunity, influenza, influenza strain, mammals, mutations, new virus, respiratory droplets, surface proteins, swine flu, swine influenza, virus outbreaks
April 30th, 2009 at 2:23 pm
Funny how the FAO is denying swine origins of the pandemic H1N1 strain:
http://english.chosun.com/site/data/html_dir/2009/04/30/2009043000765.html
Swine Flu Source Apparently Not Pigs, Says FAO
The UN Food and Agriculture Organization (FAO) is responding to the swine flu outbreak by sending out emergency assessment teams and monitoring whether any evidence appears that the disease is actually affecting pigs and not just humans. Joseph Domenech, the FAO’s chief veterinary officer spoke to VOA about what actions the agency is taking. “The FAO is doing, as a technical agency… alerting all the countries and governments through people in the field through very active rumor tracking of anything which could happen in pigs,” he said. “One is to confirm that pigs are not the origin of the human crisis. And second, to be ready to detect and respond if there is an infection of pigs from this new virus coming from humans.” An FAO assessment team is heading for Mexico, along with experts from the World Health Organization and the U.S. Centers for Disease Control. “We have mobilized funds to assist our country members to strengthen their surveillance system in pig production,” Domenech said. Clarifying the apparent lack of evidence of pig involvement, he added “Today, all the processes we are working on are based on the fact that the crisis is human to human without intervention of pigs. It’s a pure contagious human to human (transmission) and there is no declaration, there is no rumor, there is no identification of flu in pigs. Of course, this has also to be carefully investigated more than it was before… We hope that it will be confirmed.” Domenech has taken the lead for the FAO in efforts to track the spread and control avian flu. Asked to compare avian flu and swine flu, he said, “It’s totally different in the sense that the avian flu was and still is an avian problem of the poultry sector with millions of dead and killed animals.” The big fear has been a mutant strain of bird flu causing a human pandemic. That has not happened. As for swine flu, he said, “In this case it’s totally the contrary. It’s human and pigs are, for the moment, not involved.” The FAO will step up efforts to support member countries in carefully monitoring the pig population. “Obviously, if pigs become infected this could be a problem for pig program and for humans because it will contribute to the epidemiological cycle,” he says.
I’d assess that the FAO is more concerned with the welfare of animals than people.
http://www.thaindian.com/newsportal/sci-tech/avian-flu-research-unravels-why-and-how-swine-flu-outbreak-came-about_100186427.html
Avian flu research unravels why and how swine flu outbreak came about
(IANS) A lethal avian flu virus can cause human flu pandemic more easily than previously thought, according to a new study. University of Maryland (U-M) researchers have explored the mechanisms of how combined avian-human viruses are transmitted and how virus outbreaks like that of the current swine flu came about. Daniel Perez, associate professor, U-M, showed that after an avian and human-like virus combine, the virus requires relatively few mutations to spread rapidly between mammals by respiratory droplets. “This is similar to the method by which the current swine influenza strain likely formed,” said Perez. “The virus formed when avian, swine, and human-like viruses combined in a pig to make a new virus. After mutating to be able to spread by respiratory droplets and infect humans, it is now spreading between humans by sneezing and coughing.” Generally, avian flu viruses infect birds, and human viruses infect humans. Because their immune systems “remember” what the viruses look like from previous exposures, humans and birds tend to have some level of immunity to their respective viruses. Though avian flu viruses do sometimes infect humans and cause severe illness, these viruses do not transmit easily from human to human so the spread is rare. A problem arises when an intermediary species that can host both avian and human-like viruses, such as a pig, is infected with both types of virus, said an U-M release. In cases like these, the viruses can combine in the host to make hybrid avian-human viruses. These viruses can infect humans but escape the immune response because their surface proteins are foreign to the immune system. While these viruses can cause serious illness, they are generally not passed easily between humans. However, Perez has shown that this type of virus can fairly easily mutate to spread quickly and potentially cause a human pandemic. The study was published in the Proceedings of the National Academy of Sciences.