Mouse Studies Pits H5N1 Bird Flu Virus Up Against Tamiflu Antiviral Drug
Scientists who conducted an experiment using mice confirm that the antiviral medication generic tamiflu currently being used to combat and control seasonal influenza is also capable of thwarting the deadly H5N1 avian influenza virus. Bird flu, as it is known, has spread from the avian population to humans causing copious fatalities amongst the people of southeast Asia, including Vietnam, Thailand and Cambodia beginning in about 2004. The research experiment was the initial study done on Oseltamivir to judge its effectiveness against the relentless H5N1 influenza variety spreading about Vietnam. They discovered that oseltamivir, also known as tamiflu, significantly augmented the survival rate of the mice in the experiment.
The experiment was paid for and sponsored by the National Institute of Allergy and Infectious Disease [NIAID], which is affiliated with the National Institute of Health [NIH]. Health officials are concerned that the bird flu virus might produce the capability to transmit more easily from human to human and become far more deadly taking millions of lives via a flu pandemic. The point is to learn whether antiviral medications have the strength and endurance to treat and act as a prophylaxis for the avian virus since an early phase outbreak would mean few if anyone would be vaccinated. Once a vaccine becomes viable, months would be needed to produce, deliver and administer it.
Scientists who carried out the study administered one of three daily dosage amounts to the H5N1 contagious mice. The maximum amount was adjusted to the weight of the mice and was the equivalent of the expected dose for humans infected with the illness. The protocol for generic tamiflu is to take it for a course of five days, the also tested an eight day course in 50 percent of the mice. the H5N1 virus continued to spread if the medication was ceased after five days. Generic tamiflu reduces the action of the virus in the mice, inhibiting its ability to spread into uninfected cells by stopping the neuraminidase enzyme, the surface protein which enables the virus to move from infected cells to others.
There were 8-0 mice total infected with the H5N1 virus and twenty of those received a placebo drug, thirty were given tamiflu at one of those three dosage levels for a five day span, while thirty got the dose of one of three levels for an eight day period. None of the placebo group of mice lived. Just five of ten mice who were administered the top level five day dose of tamiflu survived. Oseltamivir did aid in suppressing the flu virus in the infected rodents, the virus continued to thrive if the tamiflu was discontinued after day five.
Those mice that were administered the tamiflu over eight days did do better at surviving. One of the ten mice given a low dose survived as did six of ten in the mid level range of dosage and eight out of ten that were administered the highest dosage amount survived. The eight day course of oseltamivir gave added time for the virus to decrease its levels and there was a lesser chance of the avian virus from bouncing back after the tamiflu medication dosing was closed.
On top of testing for the effective response from the tamiflu versus H5N1 flu virus in these rodents, researchers also evaluated the vigorous nature of the current avian virus from Vietnam to a 1997 strain of the same virus that caused the deaths of half a dozen individuals in Hong Kong. Scientists discovered that The recent H5N1 influenza avian virus now working its way around Vietnam is far more virulent than its previous 1997 counterpart. They are suggesting that a longer phase of tamiflu antiviral medication will likely be necessary to defeat the ferociousness of the antigenic version of the H5N1 bird flu virus.
They believe that H5N1 is going through a quickening redevelopment phase that is tenacious. Experts were taken back by the persistence of this strain of bird flu. This initial study will be useful when future research is conducted by offering up a basis for measurement towards treatment and prevention of the avian virus utilizing oseltamivir – tamiflu antiviral medication.
After a spinal tap procedure on a young Vietnamese victim of influenza H5N1 performed in England physicians found traces of H5N1 in the boy’s spinal fluid which indicates this flu virus has the capability to transmit to the brain. More science is required to determine whether higher doses of tamiflu over a longer course can thwart H5N1 from entering the lungs and establishing a grip so it can then spread to the brain. Animal study models using avian flu virus to closely mimic the illness in a person are planned.
The NIAID is a section of the National Institute of Health connected with the United States Department of Health and Human Services and the NIAID is supportive of basic and practical research in order to diagnose, treat and prevent infectious communicable diseases like influenza, among others.