Report in the paper yesterday, September 6, 2009: 2000 of the 17,753 college students at Washington State University in Pullman, WA have influenza, and they stopped testing because they were all coming back H1N1.
It is hitting the 20-50 year old population instead of the usual elderly and very young pattern. Influenza mutates every year as it travels around the world and in fact, mutates continuously. Usually it hits Washington State in January or February, so this is very early. Luckily even though it is making people sick, it does not seem to have a high complication or kill rate.
Influenza is a virus. It is transmitted by fairly close contact so hand washing, covering one's mouth when coughing and staying home if you are sick, helps reduce transmission and exposure. Symptoms are fevers of 102 to 104, muscle aches, cough and some nasal drainage. The newspaper says not to return to work or school until one's fever is down: for influenza I would say wait until one's temperature stays under 99 for 24 hours and check your pulse.
The pulse is very important in tracking influenza and you can do this at home. Influenza is a weird virus in that it causes tissue swelling in the lungs. Pneumonia fills part of the lungs with fluid, bronchitis ditto and asthma means that the involuntary muscles around the bronchi in the lungs are tight, shrinking the air spaces. Influenza is unique. With the tissue swelling, asthma inhalers don't help, antibiotics don't help because it's a virus and cough medicines aren't very effective either. What does this have to do with the pulse?
The heart takes up the slack. If the lung tissue is swollen so that the available air space is smaller, it is harder to breathe. With less oxygen available, the heart beats faster in order to oxygenate the whole body and brain. Even if you take tylenol or aspirin or ibuprofen to bring the fever down, your pulse may still be fast. Lie down and use a watch with a second hand. Count the number of heartbeats in 60 seconds, feeling your pulse at your wrist, in your neck or with your hand on your chest. That number is your pulse. Does it feel like it is fast? Normal is 60-100 for an adult. I had complicated influenza in 2003 and my resting pulse was no longer 70; it was 100. When I walked across the room, it jumped to 125. This is called tachycardia and is a fast heart rate and is very tiring. I had to rest halfway up one flight of stairs. It took two months for my lungs to recover and my pulse to drop to normal. Most people will not have trouble for that long.
The pulse is the key. If you walk around your house and your pulse is over 100: 110, 120, 130; you are NOT ready to return to school or work. Rest, rest, rest. The fever may be gone but the lung swelling has not resolved and you need to wait. If you push yourself, not only will you be exhausted, but you are at high risk for a secondary infection, meaning bacterial pneumonia, colds, and collapse. My medical training did NOT cover this well, so if you need a note from your doctor, take this article to them and have your pulse documented before and after you walk.
This explains why pregnant women have been hit hard by influenza: they are already circulating 1/4-1/3 extra blood volume and to add lung injury and a fast heart rate to that is rather a load. Influenza is hard on people with asthma or lung disease or emphysema or heart disease. Get your shot, wash your hands, stay home if you are sick or if you have an acutely sick family member: you may catch it and shed the most virus, that is, be contagious, right BEFORE you have symptoms.