At this point in your life you’ve probably been infected with the influenza virus so think back if you can on what was probably a pretty miserable experience and think of the symptoms that you had, all the symptoms that we feel when we’re sick with the flu are related to the course that the virus takes as it moves through our body, but first the virus has to get into our body and so let’s say that someone who’s infected with the flu sneezes or coughs near you and they spray a bunch of tiny droplets into the air, each of these droplets can contain millions of influenza viruses and if we breathe this in through the nose or the mouth, we can get infected this way. Another way we can get infected is let’s say some of these droplets settle on a surface like a table for instance, the flu virus can survive on a surface like this for two to eight hours and so if we’re unfortunate enough to touch a surface like this and then touch our mouth or our nose, we can get infected this way as well and this is why practicing good hand hygiene is so critical in preventing the spread of disease so don’t forget to wash your hands especially during flu season. Now in this case, unfortunately the virus is entered into our system and it’s moving its way through our body, it’s going to affect and infect cells along the way and cause cell damage and the damage that these cells experience is going to show up as the symptoms that we’re so familiar with so as the virus moves in through the nose, we might get some congestion, then the virus is going to make its way down into the throat giving us a sore throat and then it’ll get all the way into the lungs causing a cough in response to the damage that the virus causes the body.
The immune system is going to increase the temperature of the body in hopes that this will make viral replication more difficult and this is why we get fever and chills, now this battle that the body is fighting against the influenza virus consumes a lot of energy and so this is why we are so exhausted when all is said and done, we’re just in bed for days, it’s miserable, so a lot of things and viruses can cause these symptoms right like the common cold for instance can give us a runny nose so how do we know that it’s actually the influenza virus specifically that’s making us feel so sick, typically a person infected with an influenza virus will have a fever of over a hundred degrees along with either a sore throat or a cough, this combination of symptoms is what we call an influenza-like illness, we say influenza like illness because it’s not yet confirmed with a laboratory test, it’s just a combination of symptoms and we shortened this by saying ILI. During flu season between December and February, doctors who see an influenza like illness will usually attribute this to an infection with the influenza virus without getting a laboratory test, so next time your friend says I had the flu last week, I was completely congested, now you know you can say well did you have a fever with either a sore throat or a cough because that’s what you really need for the clinical diagnosis of an influenza like illness, now some doctors actually might want to confirm their diagnosis of influenza with a lab test and they do this by using something that looks kind of like a giant q-tip and they go straight to the source, so let’s think about the places that you’d most likely find an influenza virus and someone who’s sick, you’d go to the nose and you go to the throat right, because remember this is why we have nasal congestion in a sore throat because the virus is hanging out here so we call this a nasopharyngeal swab nazo for nose and pharyngeal for throat and we’re going to take this nasopharyngeal swab into the nose into the back of the throat to collect some of these cells and we’re going to send us to the lab to find out if in fact it’s an infection with influenza virus, there are other kinds of lab tests that can confirm the diagnosis of influenza infection but this is the most common and most likely what you’ll see in a clinical setting.