A group of scientists has determined that highly contagious H5N1 bird flu virus has infected pigs in Indonesia. The scientists believe that some variants of the virus may infect humans.
The researchers, who are mainly from the Institute of Medical Science of the University of Tokyo, collected specimens from pigs from 2005 to 2009 in various parts of Indonesia.
Of 702 nasal membrane specimens, 52, or 7.4 percent, contained H5N1 avian flu virus. Virus from one of the pigs has acquired the ability to infect the human throat and other body parts.
The researchers believe that the influenza virus reassortment incorporated genes of the avian and human-type viruses within a pig.
Human can contract H5N1 bird flu, although it is rare, but 60 percent of those whose infection was confirmed died.
Professor Yoshihiro Kawaoka of the research group says pigs do not show signs of influenza-like symptoms often, making it difficult to detect.
He says that may lead to a spread of the H5N1 type of virus in many locations.
He says monitoring should be strengthened to guard against the emergence of a new type of influenza.