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 Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute

nachricht Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>