The World Health Organization (WHO) has confirmed that there is no evidence that efficient transmission of the highly pathogenic avian influenza virus has emerged from a family cluster of cases in Indonesia.
Analysis now has indicated that the virus itself has not undergone the genetic mutation that might mark its development of a capability for efficient and sustained human transmission, the Antara news agency reported Friday, quoting a statement from the international body.
Seven members of the same family in a village in Karo district, North Sumatra, were exposed to the disease and six died in late April and early May.
Disease experts from WHO and the U.S. Centers for Disease Control and Prevention joined Indonesian health officials in examining the cases to determine how these various people were exposed and what those findings may reveal about potential mutation of the H5N1 virus.
This influenza strain, which has caused the deaths of more than 200,000 birds, is thought to have the potential to set off a human influenza pandemic if the virus develops the capability to pass efficiently from human to human.
In trying to find out whether that happened in North Sumatra, health experts put 54 close contacts of the infected family under quarantine. They are being monitored for disease, and receiving an anti-viral drug that has shown some effectiveness in combating H5N1.
"Despite multiple opportunities for the virus to spread to other family members, health care workers or into the general community, it has not, on present evidence, done so," according to the WHO statement.
The H5N1 virus has caused 127 deaths in 224 cases since it was detected in humans in late 2003. In all but a handful of cases, humans have become infected through direct contact with ailing birds, their feces or blood.
Indonesia has detected 48 cases of H5N1, 31 of those appearing since January, and ending in 36 fatalities.