help.txt

You've managed to infiltrate the human body's defenses and get your virus particle into the bloodstream! Now you must infect cells and use them to make more copies of your virus before the immune system wipes you out.

After a particle infects a cell, the virus will use the cell's machinery to start making copies of itself. Once the cell is full of new virus particles, press the SPACEBAR or click the MOUSE to kill the cell, causing virus particles to burst through the cell wall towards other cells in the direction the arrow is pointing. You can pick which cell to burst using the LEFT and RIGHT arrow keys.

Aim carefully though, because the immune system has sent out macrophages to absorb your particles. If a particle hits a macrophage, it will signal a B-cell, which will start producing antibodies. If an antibody attaches to an infected cell, a T-cell will attack it. If you don't burst the cell in time, the T-cell will kill it, destroying all the particles inside!

Luckily, your virus can mutate and temporarily escape the immune system. Every time the virus replicates, there are errors when copying the virus's genetic material. These errors may cause mutations in the virus. Each time you infect a cell, the virus becomes more and more likely to mutate. Once you mutate, the immune system will not be able to attack you until a macrophage absorbs a virus particle from the new strain.

How long will your virus be able to survive?