By Liz Greenbank
A couple of winters ago, I got sick. I had a pounding headache and a sore throat. My back ached, I had chills and I felt as though aliens had invaded my body and turned me into a zombie.
In a way, that’s exactly what happened. I had influenza.
Influenza has more severe effects than the common cold, lasts longer and people who catch it are more likely to develop complications like pneumonia.
It was difficult to treat until 1999, when Relenza, the first specific anti-influenza drug, came onto the market – the result of research by CSIRO scientists in the 1980s.
To infect someone successfully, the influenza virus needs a guaranteed way of getting into the cell, and a guaranteed way of getting out again.
Influenza does this using two proteins carried on the virus surface. The haemagglutinin protein acts like an entry key, binding the virus to the cell it is infecting. The neuraminidase protein detaches the virus from the cell, allowing newly made virus to exit the infected cell and infect surrounding cells.
CSIRO scientists researched the neuraminidase and compared the structures of this protein taken from two influenza strains isolated 10 years apart. They realised that part of the protein – the neuraminidase active site – was preserved in both strains.
From this, they knew that blocking the active site would be an effective way of stopping the spread of influenza infection.
Together with colleagues from the Victorian College of Pharmacy, they developed an effective neuraminidase inhibitor – a drug which binds to and blocks the neuraminidase active site.
Relenza can’t prevent you catching influenza, but it is highly effective in stopping the spread of the virus in the body. So taking Relenza within 36 hours of catching the flu dramatically reduces your symptoms. All identified influenza strains are susceptible to Relenza, a fact that’s worth remembering as we head into the 2012 flu season.