10 August 2012

CDC and WHO are really busy! 
For a reason...

It’s not just the containment of the Ebola Virus in Uganda the health authorities are dealing with, even though containment is being carried out. Now they have to deal with Swine Influenza which has struck a few U.S. states already. In one count, there have a been a bit over 100 cases, where the young kids and young adults are of the majority of those afflicted. These individuals have been in one way or another handling or having contact with sick swine. A few cases have been documented in individuals attending a fair or people working in the swine industry, such as farmers, and also veterinarians. There have been a limited number of person-to-person transmissions. Health officials point out that this flu is not a foodborne illness.  Instead, it spreads like any other flu: someone sneezes or coughs, spreading the virus to other mammals (humans included) and onto surfaces.

 - This is a new Variant strain of Swine Influenza possibly as a result of an individual harboring concomitant strains. According to the CDC, human infections with H1N1v, H3N2v and H1N2v viruses have been detected in the United States. The “v” at the end of the strain name stands for “variant.” So, what to do for now is for swine handlers and others exposed to sick pigs is to practice strict precautions such as:

  1. -Wash your hands with soap and water before and after touching pigs.
  2. -Don't drink or eat near pigs, and don't take food into animal areas.
  3. -Avoiding contact with animals such as pigs may be the best protection if you are among those likely to suffer severe symptoms if you get the flu: people with lung disease or diabetes, for instance.

  - H3N2 flu viruses are common among pigs. H3N2 viruses are a subgroup of influenza A viruses, and they are known to adapt in humans. This new version has picked up a gene from the H1N1 virus that became a pandemic a couple of years ago. This variant infection can occur if the person or animal has had a concomitant  exposure to both viruses. The H1N1 serves as a “matrix gene” from which the H3N2 picks up a novel gene.

 - This variant of swine flu was detected in 2010, according to an authority at the U.S. Department of Agriculture. The human cases started to show up in mid-2011. The regular seasonal flu vaccine contains a strain of the A-flu virus group, but it will not prevent you from getting sick if you come into contact with the new flu strain.

 - The CDC posted this info on Dec. 23, 2011, on their Morbidity and Mortality Weekly Report. (http://www.cdc.gov/mmwr).

 - From August 17 to December 23, 2011, CDC received reports of 12 human infections with influenza A (H3N2)v viruses that have the matrix (M) gene from the influenza A (H1N1)pdm09 virus (formerly called swine-origin influenza A [H3N2] and pandemic influenza A [H1N1] 2009 viruses, respectively. The 12 cases occurred in five states (Indiana, Iowa, Maine, Pennsylvania, and West Virginia), and 11 were in children. Six of the 12 patients had no identified recent exposure to swine. Three of the 12 patients were hospitalized, and all have recovered fully.

 - A case in an adult male in Indiana with occupational exposure to swine was among the 12, and two children in West Virginia who regularly attended the same day care accounted for the latest cases. This report describes those cases and swine influenza virus (SIV) surveillance being conducted by the U.S. Department of Agriculture (USDA). Cases of Swine Influenza are not that common. However these new cases bring into question not only our understanding of this new virus, but also the new modes of transmission we are still beginning to witness.

 - According to the CDC authorities, Guidance materials for persons who work with swine have been published by OSHA. In addition, the National Pork Board, **CDC, and the National Association of State Public Health Veterinarians have published guidance for persons exposed to swine in public settings. Clinicians should consider variant influenza virus infection in the differential diagnosis of patients with febrile respiratory illness who have been near swine whether at work or at an agricultural event, such as a fair or exhibit.

 - To date, serologic studies in children have not demonstrated a previous immunity to this virus which started appearing in the 1990s. Young adults may not be prepared for this either. The hemagglutinin genes of these viruses are related to human influenza A (H3N2). Certain persons, including young children, pregnant women, persons with chronic health conditions such as asthma, diabetes, or heart and lung disease, and persons aged ≥65 years, are likely to be at greater risk for serious influenza-related complications from variant influenza viruses such as influenza A (H3N2)v.

 - The current Seasonal Influenza vaccines are not likely to provide protection from this variant strain. Guidance documents related to A(H3N2)v viruses are available online from CDC at http://www.cdc.gov/flu/swineflu/influenza-variant-viruses.htm.

 - To protect yourself, the CDC has also put out a detailed  fact sheet on their site: you can check it out at http://www.cdc.gov/flu/swineflu/h3n2v-factsheet.htm

 - An updated official health advisory issued on Aug. 3, 20212 can be viewed here on the Health Alert Network:  http://www.bt.cdc.gov/HAN/han00325.asp
A total of 145 cases of infection with influenza A (H3N2v) variant virus have been confirmed by CDC since outbreaks began in July 2012, the agency reported today (Aug.9, 2012) during a telebriefing. The total includes 113 cases in Indiana, 30 cases in Ohio, and 1 case each in Hawaii and Illinois.There have been no reported deaths from this outbreak. Nevertheless, the CDC has posted the precautionary measures on their site. The usual influenza vaccine offers no protection. At this point, no evidence exists for sustained human-to-human spread of H3N2v in the community, and CDC does not consider it to be a pandemic situation. Preliminary steps have been taken to develop a vaccine for the new H3N2 swine flu strain, a CDC official said

    This colorized negative stained transmission electron micrograph (TEM)       depicted some of the ultrastructural morphology of the A/CA/4/09 swine flu virus.
Author: Photo Credit: C. S. Goldsmith and A. Balish, CDC

Swine Flu in Asia

 - There have been reports of the swine influenza in Vietnam in February of this year. Vietnam has released sequences from swine trH3N2, and Hong Kong has recently released sequences from swine cases which have Asian H3 and N2 on isolates with H1N1pdm09 internal genes. The H3 sequences in Hong Kong and China (Guangxi) are similar to those reported in Vietnam, and are easily distinguished from US cases. In the US, all H3N2v cases were identified after the start of the 2009 pandemic.

 - Of course a match of the H3N2v in Vietnam with the US cases would support widespread human transmission and provide more evidence for an emerging pandemic.  A match of Asian H3 would signal more lineages / constellations of swine H3N2v cases which can jump to humans.

 - Recombinomics' first paper, "Swine Influenza A Evolution via Recombination - Genetic Drift Reservoir" is available at Nature Procedings (where it can be downloaded). Recombinomics will be submitting a number of papers on recombination, which will conclusively demonstrate the role of recombination in influenza evolution.  These papers will significantly impact the two basic tenets of influenza genetics, drift via "random mutation", and shift via reassortment. Recombinomic’s website is at http://www.recombinomics.com/publications.html

 - Also take a look at the FluBoard site (Flu Tracker Forum): http://fluboard.rhizalabs.com/forum/viewtopic.php?f=5&t=7950

                          Preparedness is better than worriedness.

A Bit of History and Development

 - Viruses have been reported since the beginning of the 19th century. Then they were just known to be bacterial killers. The British bacteriologist Ernest H. Hankin reported in 1896 that the waters of the Jumna and Ganges rivers in India killed Vibrio cholerae bacteria. The responsible agent passed bacteriological filters and was destroyed by boiling. Then, in 1898, the Russian microbiologist Nikolai Gamaleya reported the lysis of Bacillus anthracis bacteria by a transmissible ‘ferment’. It is probable that these scientists would have discovered bacterial viruses, if suitable techniques
had been available.

-  The present period of phage research started in 1965 after D. E. Bradley published a seminal, still cited paper on phage morphology (republished in 1967). Novel phages were thereafter isolated at a rate of a 100 per year. Studies on their properties and manner of transmission have been rigorously investigated. It should be noted though, that these organisms exist in our environment in an ecosystem that makes them part of the normal life of animals, plants, and includes marine life. History shows that the study of virus infections of plants has led the overall subject of virology in the development of several major concepts including that of the entity of viruses
themselves. We learn for example that, in order for a plant virus to infect its host systemically, it must be capable of hijacking the host’s cellular machinery
to replicate and  move from  the  initially infected cell.  Once inside a cell, the virus initiates transcription (DNA viruses) and translation and replication (DNA and RNA viruses) activities.

 - While there are many facets of virology studies, one particular aspect has been mentioned in this post. And that is, the molecular basis for variability and evolution in viruses, including the recognition  that  recombination  is  a  widespread  phenomenon among RNA viruses and that viruses can acquire host nucleotide sequences. Notable human diseases caused by RNA viruses include SARS, influenza, hepatitis C, West Nile fever and polio. Viruses with RNA as their genetic material but which include DNA intermediates in their replication cycle are called retroviruses, which include HIV-1 and HIV-2.
For an exhaustive listing of viruses, check out the MeSH site. 

 - There are now many examples of species-specific RNAvirus / host coevolution, indicating very slow rates of virus evolution. One example is Hantavirus (genus Bunyavirus) coevolution with its rodent host, that suggests a 20 million year association. Not all RNA virus populations show this dynamic of a continual change or even the diversity expected  from quasispecies.  Even  in  influenza  virus A, avian isolates from natural host (waterfowl) can be genetically stable. 

 - Influenza vaccine has been the source of a number of issues related to safety over the years. Mass immunization against swine-like influenza was carried out in 1976–77 using the A/New Jersey swine-influenza vaccine.  At first, it appeared that this vaccine generated an increased risk of acquiring vaccine-related Guillain–Barre syndrome (GBS). In contrast, the 1978–79 influenza vaccine was not associated with a statistically significant excess risk of GBS. Although the original Centers for Disease Control study of the relation between A/New Jersey/8/76 (swine flu) vaccine and GBS demonstrated a statistical association and suggested a causal relation between the two events, controversy has persisted. There was no increase in the risk of vaccine-associated GBS from 1992–93 to 1993–94. A number of events in recent years has provoked concern that certain vaccines might be unsafe. Most of these concerns have proved to be unfounded, and some remain unproven or incompletely understood. Nevertheless, the U.S. FDA regularly advise regarding any injectable medication for any unwanted or deleterious ingredient. Sometimes, the medication in and of itself is beneficial, but the preservatives or packaging may be at fault and warrant that the product be withdrawn from the market.

 - The design and manufacture of vaccines are of such high standards today that they have become extremely safe. But it will never be possible to say that everything is known about the subject and that vaccines are totally safe. Nor can the unpredictable human element in administration ever be totally excluded from the equation. 

 - The problem also lies however in media coverage that is hyperbolic and inaccurate, and instead of educating the public, they create panic. This is irresponsible on their part.

 -  New  technologies will  complement  existing  safety measures. However, communicating to vaccine recipients or their parents that the vaccine they are about to receive is neither totally effective nor totally safe makes health pro-
fessionals uncomfortable. They should explain to these worried parents and patients that the risk of potential harm with the vaccine is nothing compared to the actual disease. As time and experts continue to unravel the whole role of viruses in our lives, we can expect better protection, disease control, and treatment.
The incremental process involves finding a good vaccine candidate, reassessing and testing the virus, developing seed vaccines and ensuring their safety. The goal is to have a vaccine quickly available in case a pandemic occurs, as with H1N1 in 2009.

 - Stay safe. And have a nice day!

 - Fernando Yaakov Lalana, M.D.


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