# What approach could be used for modelling virus infections?

I'm a physics graduate who ended up doing infosec so most of the statistics I ever learned is useful for thermodynamics. I'm currently trying to think of a model for working out how many of a population of computers are infected with viruses, though I assume the maths works out the same way for real-world diseases so references in or answers relevant to that field would be welcome too.

Here's what I've come up with so far:

• assume I know the total population of computers, N.
• I know the fraction D of computers that have virus-detection software (i.e. the amount of the population that is being screened)
• I know the fraction I of computers that have detection software that has reported an infection
• I don't know, but can find out or estimate, the probability of Type I and II errors in the detection software.
• I don't (yet) care about the time evolution of the population.

So where do I go from here? Would you model infection as a binomial distribution with probability like (I given D), or as a Poisson? Or is the distribution different?