The avian flu has not yet become pandemic, but the first requirement for its spreading--human-to-human infections--has been confirmed by software designed by the Fred Hutchinson Cancer Research Center (Seattle).
The avian flu, known officially as H5N1, must mutate before it can be passed among humans and thus be capable of spreading worldwide via airplane travelers. New software, called TranStat--the first program capable of real-time analysis of such infectious-disease outbreaks--has concluded that the dreaded human-to-human mutation occurred in 2006 in Indonesia.
Using a statistical analysis methodology, TranStat evaluated an outbreak among a small number of people within an extended family in northern Sumatra and found that only one of the eight infected got the disease from birds. The disease then mutated and infected the other family members. The parameters considered by TranStat included the number of infected cases, the number of people exposed and the incubation period, concluding that seven of the humans contracted the disease from each other. All but one of the flu victims has since died, and more than 50 surviving friends and relatives remain under quarantine to contain the outbreak. TranStat rated the risk of infection by the mutated strain to be 29 percent, which is similar to other common flu viruses.
The study will be published next month in the Centers for Disease Control and Prevention journal called "Emerging Infectious Diseases." The study was funded by the National Institute of General Medical Sciences' MIDAS network and the National Institute of Allergy and Infectious Diseases. MIDAS (Models of Infectious Disease Agent Study) will make the data available for other researchers to study after the publication, and TranStat will also be made available free online.