The study also calls for a re-examination of past pandemics, which could ultimately push the death toll for the last century of drug prohibition to over 100 million. In addition, concerns were raised about the possible future consequences of President Obama's Afghan drug policy.
The surprising announcement was made by researchers at the University of Cambridge on Wednesday afternoon. It concludes a year-long international collaboration between research teams at seven universities, who came together to investigate the origins of the mysterious pandemic through a grant from the World Health Organisation.
Professor Montgomery Pennwell of the Cambridge University Department of Epidemiology, who led the collaboration, explained the discovery. Although the team did not at first consider a connection between swine flu and the Merida Initiative, he said, it is a well-known fact that narcotic withdrawal symptoms are similar to those of influenza infection. But scientists had always assumed that these similarities were limited to external signs such as fever, sneezing, cramps, fatigue, watering eyes, vomiting, and diarrhoea.
The breakthrough came when a research assistant decided to test recovering addicts for presence of the virus. "All the tests returned positive for influenza," Professor Pennwell said. "The stress of withdrawal was turning immunocompromised drug addicts into a breeding ground for the pathogen."
The team then gathered additional serological data, along with records of the local prices of illicit substances. Computer models confirmed the hypothesis that withdrawal sickness, brought on by prohibition, is what caused the evolution of the new strain.
Many reacted with scepticism to the announcement, which disregards decades of medical theory blaming birds and farm animals for pandemics. The research team, however, remained confident.
"We were just as surprised as you are," said Professor Pennwell. "But the evidence is unassailable. We thought that pigs were to blame, but it turned out to be law enforcement."
His team is now directing its attention to the two twentieth century H1N1 pandemics, which occurred in 1918 and 1977. The latter pandemic trailed a similar period of interdiction in Mexico, with the US Drug Enforcement Agency's (DEA) 1976 Operation Trizo.
The famous 1918 pandemic, misleadingly called the Spanish flu, originated in Kansas and killed 50-100 million people. It came on the heels of the Harrison Narcotics Tax Act, the first major drug legislation in the United States, which was enforced from 1917.
Sources within the British government, speaking on condition of anonymity, confirmed that health agencies were still scrambling to craft a suitable response to the findings. "Too many people are familiar with the devastating consequences of drug addiction. But if prohibition threatens public health, the only real alternative seems to be full legalisation," said one Tory MP. "The public health problem could also be solved by executing addicts, but that would be rather unethical," he added.
Concerning the likely future of the war in Afghanistan, in which the control of illicit spice production plays a central role, the MP called for a cautious approach. "Supplying 90% of the world's black-market opium, Afghanistan is a bigger player than Mexico. And Obama's Afghan drug policy is more effective than Bush's. If coalition forces are to continue on their present course, then we should prepare for a pandemic of much greater severity within the next few years."
A spokesperson for the US DEA declined to comment for this article, but a source close to the agency painted a grim picture. "Nobody is happy about this," he said. "They are particularly anxious to avoid having to pay some kind of compensation to families of victims."