- Diseases, Disorders & Conditions
The Swine Flu Incubation Period
A Brief History Of The Swine Flu
The swine flu is a relatively new virus that has become a pandemic around the world. It is the predominant influenza virus in most countries and is being attributed to 99% of all positive influenza cases. The flu is moderately severe and can cause death in healthy and sick people alike. The determining factor is unknown, but vitamin d deficiency, genetics, and viral load have all been postulated as causes of death in otherwise healthy people.
This flu was discovered in mid April, but it was spreading in Mexico and the Western US at least as early as March. The US detected the virus first in California and by the time they realized it was a highly communicable and potentially deadly disease, the swine flu was already on its way to becoming a full-fledged pandemic.
There are several strains of the virus circulating, but the major mutations appear to be the Tamiflu resistance which is becoming increasingly common and the PB2 mutation found in the Netherlands that allows the virus to replicate more effectively in colder temperatures and will therefore allow it to deliver a higher viral load.
The Incubation Period Of Swine Flu
The incubation period of swine flu is 1-7 days, although most people start getting sick somewhere between 1-4 days, with the median time being about 2 days. You can generally consider yourself safe if you make it 4 days without showing symptoms and 7 days almost guarantees that you don't have the virus, that is unless you're asymptomatic, which is possible.
While the incubation period is important, you'll also want to make note of when people are contagious and for how long, especially if you're around high risk people or are one yourself. Studies have shown that people can shed the virus up to 16 days after resolution of symptoms, specifically fever, and that they are also contagious up to a day before symptoms even appear! If you've been infected with swine flu, you should isolate yourself or at least avoid contact with people in high risk groups for at least a week after symptoms subside. A few extra days of movement are not worth a life.
Rapid Deaths From Swine Flu
The flu has caused an increasing number of rapid deaths from onset of symptoms. While this isn't directly related to the incubation period, I believe it is worth mention because it might signal an increase in virulence or a mutation relating to a higher viral load - people seem to be dying from the virus itself moreso than bacterial co-infection, which was previously the case.
The median time from onset of symptoms to death is 10 days, but recent data has shown multiple people, generally children, dying in as little as 24 hours after showing symptoms. They literally get sick with a cough and die in the hospital the next day. It is not uncommon to see deaths within 24 to 72 hours. It is therefore advised that you get Tamiflu as quickly as possible and closely monitor the health of your loved ones if they are sick.
Here are some symptoms that indicate severe illness, from the CDC:
- Difficulty breathing or chest pain
- Severe or persistent vomiting
PB2 Mutation and Tamiflu Resistance
A PB2 mutation, specifically E627K has been discovered in two unrelated patients in the Netherlands. The samples are dated from July, so that means that the mutation is probably wide spread if it is fit to become a dominant strain.
The significance of the PB2 mutation is that it can increase viral load due to more virus being present in the upper respiratory tract, like the nose and throat. This is because the E627K mutation allows the virus to more effectively replicate in colder temperatures, like those in your nose. The current flu is most effective at temperatures around 100°F. This makes it more effective in the lungs, where it is hard to spread the virus because few people actually project particles from that deep when they cough. The increase in viral load from this mutation can lead to increased virulence and quicker deaths - specifically from the virus, not bacterial co-infection.
Another mutation worth mentioning is Tamiflu resistance. It doesn't seem like this mutation has caught on yet, but it will have dramatic effects if it does. Tamiflu is responsible for saving a number of lives and Hong Kong actually believes that a double dose of Tamiflu in critically ill patients will save their lives. If the virus becomes resistant or immune to Tamiflu, then this line of defense is lost. Make sure to keep an eye out for this mutation, especially in your community!
Prepare For Swine Flu
This is a comprehensive guide on how to survive any pandemic, including the swine and bird flu. You'll want to have this information if the flu comes to your community.