A/H1N1 flu virus first infects humans months before outbreak: university study

Report
from Xinhua
Published on 12 Jun 2009 View Original
HONG KONG, Jun 12, 2009 (Xinhua via COMTEX) -- A study conducted by University of Hong Kong (HKU) Li Ka Shing Faculty of Medicine showed that the initial transmission of A/H1N1 flu virus to humans may take place in early 2009, months before the outbreak was detected.

In a press release on Friday, the HKU said their study used evolutionary analysis to estimate the timescale of the origins and the early development of the swine-origin influenza A/H1N1 virus ( S-OIV) epidemic. The results show that the S-OIV virus resulted from the mixing of genes from two viruses that had been circulating in swine for at least 10 years.

They also found that the initial transmission to humans very likely occurred in January 2009, several months before the outbreak in Mexico was first detected in March 2009.

An international collaboration between researchers that the State Key Laboratory of Emerging Infectious Diseases (SKLEID), The HKU Li Ka Shing Faculty of Medicine, University of Edinburgh, University of Arizona and University of Oxford has investigated the origin and evolution of this newly emerged virus using data from long-term influenza surveillance conducted in Hong Kong .

The results highlight the need for systematic surveillance of influenza in swine, and provide evidence that new genetic elements in swine can result in the emergence of viruses with pandemic potential in humans.

"Despite widespread influenza surveillance in humans, the lack of systematic swine surveillance allowed for the undetected persistence and evolution of this potentially pandemic strain for many years," said the research team in the press.

This collaboration has resulted in a publication "Origins and evolutionary genomics of the 2009 swine-origin H1N1 influenza A epidemic" in the prestigious scientific journal Nature.