# 2605
Doctors tell us that, on average, adults have roughly 3 `cold & flu-like' respiratory illnesses each year, and children have about 6. With nearly 7 billion people on this planet, that's probably somewhere between 20 and 30 billion respiratory infections each year.
Maybe more.
The vast majority of the time, these victims never see a doctor.
Of those that do seek medical help, most will be told they either have a `cold' or the `flu' based on clinical presentation.
Some doctors, particularly in developed countries, may perform a `rapid flu test' in the office, that tells them if the patient has an influenza `A' virus, but not the type.
Comparatively few samples are ever sent to a lab to be identified.
In fact, out of 20 Billion+ respiratory infections that likely occur each year on this planet, fewer than 1 in 10,000 are ever laboratory typed.
Last week, here in the US, 3,035 suspected flu specimens were tested in state and CDC labs around the country. Of those, only 103 tested positive for influenza.
The other 96.6% of the respiratory illnesses were caused by something other than influenza.
Here is the CDC's week 51 summary.
The surveillance networks here in the United States, in Europe, and in selected parts of Asia and the Pacific are very good at spotting gross trends, but obviously can't catch every atypical influenza that comes down the pike.
And so it is somewhat remarkable that, from time to time, we actually hear of cases like the one below; of a patient infected with a rare form of avian influenza.
How often it really happens, is unknown.
But today's report is the fifth recorded case of a human H9 infection.
And all of those have come from Hong Kong or its vicinity (where testing is, admittedly, more likely to occur than in many other regions of the world).
The Associated Press
Published: December 30, 2008
HONG KONG: A 2-month-old Hong Kong-born infant who lives in China has contracted a mild strain of bird flu, a health official said Tuesday.
The baby girl, who contracted the H9 strain of avian influenza, is currently isolated at a local hospital and is in stable condition, Thomas Tsang, controller of Hong Kong's Center for Health Protection, told a news conference.
The baby lives with her family in the southern Chinese city of Shenzhen but recently visited a hospital in Hong Kong after showing symptoms, Tsang said.
He said health officials in the southern Chinese Guangdong province are trying to determine how she caught the virus.
Tsang said Hong Kong has recorded four previous human cases of H9 infections. All patients have fully recovered.
The list of pathogens that can cause ILI's (`influenza-like Illnesses') includes adenoviruses, influenza viruses, human metapneumovirus, parainfluenza viruses, respiratory syncytial viruses, and rhinoviruses.
And those are just the viruses.
We can add bacterial causes, such as Legionella spp., Chlamydia pneumoniae, Mycoplasma pneumoniae, and Streptococcus pneumoniae as well.
And, it seems, we are discovering new culprits all the time.
Most of these, even the exotic ones like H9 avian influenza, produce only mild or moderate disease symptoms. In most cases, victims recover without incident.
That, and the fact that they probably occur more often than we know, should be of some comfort to the reader.
The concern here is that viruses, particularly single strand RNA viruses like the influenzas, mutate all the time. They pick up, and discard, genetic bits as they move from host to host, and they make errors in replication.
This happens countless trillions of times every day.
Most of the time, these changes go nowhere. They either have no effect on the virus, or they are evolutionary dead-ends, rendering it less capable of replication and transmission.
Every once in a great while, however, a virus hits the jackpot.
The right combination of genetic changes occurs to make it highly transmissible, and capable of causing significant morbidity and mortality.
And if that happens someplace where the virus has a chance to get a foothold (a susceptible population), it can spark an epidemic.
And sometimes . . . not often, but sometimes . . . epidemics can turn into pandemics.
And so we watch, and our ears perk up, when we hear of a case like today. Not because this is an earth shattering story, or that it should be cause for alarm. It really isn't.
But because it could be an early warning that something has changed with the H9 virus in China. That, perhaps, the incidence of it jumping to humans may be increasing.
And that is always worthy of our attention.
2008-12-31 20:56:10
