In September, Sakuntala Premphasri, an 11-year-old Thai villager, and her mother, Pranee Thongchan, died from bird flu. Days later, the girl's aunt, Pranom Thongchan, also became ill.
Jon Hamilton, NPR
Pranom Thongchan and her daughter. Thongchan's niece, Sakuntala Premphasri, died Sept. 8 from bird flu. The girl's mother, Pranee, died of the virus Sept. 20. Thongchan also became ill but survived.
Thai researchers feared the worst: the virus had mutated and was now moving easily from person to person. As NPR's Jon Hamilton reports, that could be the first sign of a global pandemic.
Influenza A (H5N1) — better known as avian influenza or bird flu — occurs naturally among wild birds worldwide. The virus is very contagious among birds and can be deadly to them — especially to domesticated birds like chickens.
· Infection: The virus doesn't typically infect humans. But in 1997, the first instance of direct bird-to-human infection resulted in six deaths in Hong Kong. Since then, there have been other instances of bird flu infection among humans. So far, H5N1 hasn't been able to jump from human to human efficiently.
· Spread: Infected birds shed H5N1 in their saliva, nasal excretions and feces. Bird flu viruses spread among birds when the animals come into contact with contaminated excretions. Scientists believe most cases of human infection have resulted from contact with infected poultry or contaminated surfaces.
Source: Adapted from the CDC
Three times in the past century, bird influenzas have spread to people, causing millions of deaths. Public health experts say the next global flu pandemic will probably start with birds as well. The key event is a genetic change that allows the virus to spread as easily among humans as it does among birds.
Scientists are afraid that's about to happen again. The deadly bird flu currently circulating in Asia has already shown a knack for adapting to new species. It's also infected more than 30 people.
Thai researchers got lucky with the Thongchan household: Doctors treated Pranom with oseltamavir — the only antiviral drug known to work against bird flu — and she survived. No one else in her family or her village became infected.
Apparently, the bird virus that killed Sakuntala and her mother wasn't well adapted to people. But the next time, Thai doctors say they can't rely on luck.