A new strain of bird flu, H7N9, has been detected in Shanghai in recent weeks. While a number of people who have come into contact with the virus have died, it can be only be hoped the outbreak can be constrained.
Birds, of course, are not the sole sources of influenza viruses, and strains can take their origins from pigs, horses, seals, bats, and, as goes without saying, humans.
This Information Is Beautiful visualisation, (full size) that tracks the sources of recent, and well known, flu strains, also sets out the links between various strains, and who they may affect.
The often cited 1918 Spanish Flu pandemic was by no means the first of such widespread infections, influenza outbreaks of its kind have been with us for centuries. What has changed though is their primary method of origin and transmission, and many of the pandemics of the last 500 years can be traced to horses, rather than birds or pigs.
But even the 1889 pandemic wasn’t the first large-scale deadly flu epidemic. Ziegler cites an article by David Morens and colleagues, showing that flu pandemics have a recorded history that now spans 500 years. Although recent pandemics (including the 1918 flu and the 2009 H1N1 pandemic) have come from poultry and swine, for centuries the most common route to human infection was through horses, which is now much rarer. Why don’t we see much equine flu in humans any more? My guess is the rise of the automobile: Few people live around horses today, so transmission is rarer.
As flu season approaches in this part of the world (aided by what feels like about two weeks of almost non-stop rain in Sydney), news of progress of a universal vaccine against influenza is especially welcome:
Current immunizations create antibodies that target a specific piece of a molecule on the surface of the virus that researchers call its “head.” That piece of the hemaglutinin protein evolves very quickly, which is why you have to get a different flu shot each year as new types of flu develop. The next-generation vaccine causes antibodies to go after a piece of the hemaglutinin that changes less often and that is present in many influenza strains. Researchers are calling them “headless HA” vaccines, and they could be the key to a universal flu shot.
Asprin – used in far stronger doses than today – rather than helping in the treatment of some sufferers of the 1918 – or Spanish flu – pandemic, may have aggravated their condition and inadvertently brought about their deaths.
Dr. Karen M. Starko, author of one of the earliest papers connecting aspirin use with Reye’s syndrome, has published an article suggesting that overdoses of the relatively new “wonder drug” could have been deadly. What raised Dr. Starko’s suspicions is that high doses of aspirin, amounts considered unsafe today, were commonly used to treat the illness, and the symptoms of aspirin overdose may have been difficult to distinguish from those of the flu, especially among those who died soon after they became ill.