View Full Version : Environmental tamiflu contamination

06-29-2009, 06:32 PM

Facilitating the Arrival of Antiviral Resistant Influenza

Tamiflu is a widely prescribed medication against influenza. Unfortunately, this drug is not degraded in the environment (water) after it is metabolized (processed) in the body.

This is a problem, because the natural host of influenza A (the most common influenza variant) are dabbling ducks (ducks which typically feed on the surface rather than diving for food). This means that the natural host of influenza A may be exposed to low quntities of the most important drug against the virus, which may lead to the development of drug resistance.

Jerker Fick (Umeň University, Sweden) and coworkers have tested for this possiblity in river water samples from Japan. Tamiflu metabolites were found in the water, which may enable the influenza A virus to acquire resistance to the drug.

Analysis of Japanese river water.

The scientists chose to carry out their study in Japan because Japanese citizens consume more Tamiflu medication, on a per-capita basis, than any other country. Almost 40% of Japanese citizens infected with influenza during the 2004/2005 influenza season are thought to have been prescribed the drug.

Additionally, the regions they studied (Kyoto and Osaka) are highly, densely populated. If the drug is out there in the water (the Yodo River system), it should be most readily detectable in these locations.

The scientists collected river water before and during the 2007/2008 influenza season from three rivers (six total sites) in the Yodo River system. These sites are located before, in, or after river passage through the major metropolitan areas.

They then quantified the amount of Tamiflu metabolite in the water samples by chromatographic purification and electrospray ionization mass spectroscopy. This spectroscopy technique is widely utilized to facilitate the fragmentation of a molecule, and subsequent determination of the identity of the molecule based on the size of these fragments and their transport profile through the spectrometer.

Tamiflu metabolites in Japanese river water.

The scientists found Tamiflu metabolites in river water, during but not before the influenza season. Some of the water samples possessed so much of the drug that the amount in the water approached that required for 50% inhibition of the virus.

The highest amounts were found near large sewage treatment plants and downstream of major population centers. All of these results are strong evidence that the scientists' detection of Tamiflu metabolites in the water is not artifactual.


Dabbling ducks will be drinking this drug-laden water. This may enable influenza viruses in their intestines to acquire drug resistance.

Scientists do not know for sure which influenza strain will be at the forefront of yearly outbreaks, especially not during an unexpected severe pandemic. If a drug-resistant strain were to unexpectedly appear, as a consequence of ducks drinking drug-laden water, early mitigation of the viral outbreak may not be possible, which may lead to severe and deadly global health consequences.

The acquisition of drug resistance is a common problem in the fight against bacteria and viruses. The most effective solution may be to prescribe drugs primarily to patients most at risk (young, elderly, and immune-compromised individuals), and those with severe symptoms. :eek:

06-30-2009, 06:22 AM
This is a very interesting article. I posted a cross reference to it in the flu clinic too. Thank you Torange!

Auburn Boy
07-02-2009, 11:44 PM
This was news years agao when tami was raised as an issue in fighting H5N1.

Nothing concrete has come of how temiflu resistance would occurr due to the matabolized tami being in wastewater..,