Why Swine Flu is Deadly

The swine flu refers to a strain of novel influenza that comes from pigs. The origin of the virus is unknown, but it was first discovered in Mexico and the Southern United States in early April. The flu was widespread in Mexico by this time, but was just making its way into the US. With the virus currently killing hundreds of people a week, you might be concerned as to how this flu is deadly and if it'll become even more deadly.

The main way that swine flu kills its victims is through viral pneumonia. This means that the virus will burrow deep into your lungs and destroy the alveoli, decreasing your blood oxygen level and eventually killing you. The actual cause of death can vary from respiratory failure, brain failure, heart failure, or total organ dysfunction. All have the same root cause, however: viral pneumonia. The virus can cause so much fluid to build up in the lungs that they compress to heart or it can just lower the oxygen level to such an extent that the patient dies.

Bacterial co-infection is the next most common way that swine flu kills people. The most common pathogens that co-infect with swine flu are strep, bacterial pneumonia, and MRSA. All of these diseases are dangerous on their own, but their virulence is compounded several times when combined with swine flu. They are able to infect the lungs and cause damage on top of what the flu causes. There is also evidence that co-infection with seasonal influenza can cause similar effects and can increase mortality.

Will the flu mutate into a more deadly form?

Unfortunately, this may have already happened. Two unrelated sequences with PB2 mutation E627K were isolated from individuals in the Netherlands. The fact that they are unrelated could signal widespread mutation, at least in Europe. This might have something to do with the increase in deaths from the actual virus and the decrease in time until death. The PB2 mutation allows the virus to deliver a large viral load because more of the virus will be present in the opening of orifices, instead of deep down, like in the lungs. That is not to say that it removes the virus' ability to replicate in the lungs, it just means that it's more effective at replicating at colder temperatures, like your nose in the winter. A higher viral load at infection is postulated to be a risk factor and can increase the virulence of the disease. Be on the lookout for this mutation in your community.