A bird flu strain called H7N9 has been dominating headlines lately, and with good reason. The strain, which has never been known to infect people before, has suddenly begun popping up in eastern China, where it has now killed eight people. So far, there have been 24 confirmed cases but the tally is steadily rising by the day.
But yesterday, another bird flu strain was quietly in the news: H5N1, which — until H7N9 came along — was the most notorious of the bird flu strains.
This story came out of eastern Bangladesh, where a two-year-old baby died of H5N1 — making him the country's first known fatality from bird flu.
H5N1 made its world debut in 1996 when a poultry outbreak in Hong Kong wound up killing six people. The region's entire chicken population was slaughtered but that didn't stop the virus from spreading amongst birds — and infecting people in other parts of the world. Today, human cases have been recorded everywhere from Vietnam and Cambodia to Nigeria, Turkey, Egypt and, now, Bangladesh, which has seen six cases since 2008, five from the last two years. In a decade, 622 people have been infected with H5N1 and 371 have died — a fatality rate of about 60 per cent.
For infectious disease experts now watching H7N9, that other bird flu is likely haunting their thoughts. Even if H7N9 doesn't become easily transmissible between humans (the nightmare scenario), it may very well follow in H5N1's footsteps and continue spreading in bird populations — thus turning H7N1 into a global terror, always lurking and threatening to pop up. Or, even worse, mutate into a more dangerous form.
But there is one key difference between H7N9 and H5N1 that makes the former even more concerning — unlike H5N1, which decimates entire chicken flocks, H7N9 doesn't seem to make birds sick, meaning it can spread undetected. If H7N9 does start flying around the world, we will have a hard time noticing — that is, until people in other corners of the world start getting sick.
Jennifer Yang is the Star’s global health reporter. She previously worked as a general assignment reporter and won a NNA in 2011 for her explanatory piece on the Chilean mining disaster. Follow her on Twitter: @jyangstar