Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mouse studies of oseltamivir show promise against H5N1 influenza virus

19.07.2005


Experiments in mice show that an antiviral drug currently used against annual influenza strains also can suppress the deadly influenza virus that has spread from birds to humans, killing dozens of people in Vietnam, Cambodia and Thailand since early 2004. This study, the first published report conducted on oseltamivir against the H5N1 influenza strain circulating in Vietnam, found that the drug, sold commercially as Tamiflu, dramatically boosted the survival rate of infected mice.



The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), funded this research at St. Jude Children’s Research Hospital in Memphis, TN. Results of the study are now available online in the Journal of Infectious Diseases.

Public health experts fear that the avian flu virus could develop the ability to spread easily from person to person and kill millions in a deadly flu pandemic. "We need to know whether antiviral drugs can prevent and treat avian flu, because in the early stages of a global outbreak, most people would be unvaccinated," says NIAID Director Anthony S. Fauci, M.D. "If a pandemic occurs, it will take months to manufacture and distribute a vaccine to all who need it."


In its study, the St. Jude research team gave one of three possible daily dosage levels of oseltamivir or a placebo to mice infected with H5N1 influenza virus. The highest dosage level, adjusted for weight, was equivalent to the dose currently recommended for humans sick with the flu. Although the recommended human dose of oseltamivir is taken for five days, the researchers also tested an extended eight-day course in half of the mice. Oseltamivir decreases the ability of influenza virus to spread from infected cells to uninfected cells by inhibiting neuraminidase, which is an influenza protein required for the virus to exit infected cells.

Of 80 mice infected with H5N1 virus, 20 received a placebo, 30 were given oseltamivir at one of three dosage levels for five days, and 30 received the drug at one of three dosage levels for eight days. None of the mice receiving a placebo survived. Only five of 10 mice given the highest daily dose of oseltamivir for five days survived. Although oseltamivir suppressed the virus in the mice, the virus continued to grow if the drug was stopped after five days.

Mice given the drug for eight days fared better. Survivors included one of 10 mice given the lowest daily dose, six of 10 given the middle-range daily dose, and eight of 10 given the highest daily dose. The eight-day dose of oseltamivir allowed more time for virus levels to fall and less chance for avian flu to rebound after the drug was stopped.

In addition to testing the efficacy of oseltamivir against H5N1 virus in mice, the St. Jude researchers compared the virulence of the new Vietnam virus with a 1997 variant of H5N1 that killed six people in Hong Kong. Researchers found that the 2004 H5N1 virus, currently circulating in Vietnam, is much more virulent than its 1997 predecessor. A longer course of antiviral treatment may be required to conquer the aggressiveness of the new antigenic variant of H5N1 virus, the researchers suggest.

"The H5N1 avian flu viruses are in a process of rapid evolution. We were surprised at the tenacity of this new variant," says St. Jude researcher Elena A. Govorkova, Ph.D. "Our results provide baseline information that will be needed for further studies on preventing and treating avian flu with antiviral drugs." Co-authors include Hui-Ling Yen, M.S., and renowned flu researchers Robert G. Webster, Ph.D., also of St. Jude, and Arnold S. Monto, M.D., of the University of Michigan.

British researchers reported finding H5N1 flu virus in the spinal fluid of a young boy who died of influenza in Vietnam earlier this year, an indication that H5N1 is able to infect the human brain. The St. Jude researchers say that further study is needed to see if using higher doses of oseltamivir for a longer period of time can prevent the H5N1 virus in the lungs from gaining a foothold and then spreading to the brain. The researchers are planning additional studies in small animal models in which avian flu infection closely resembles the disease in humans.

Linda Joy | EurekAlert!
Further information:
http://www.niaid.nih.gov

More articles from Life Sciences:

nachricht Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory

nachricht How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>