[quote=Leos Klien]
There's no way on on gods green earth that you could maintain 30 million military personnel and 1.1 billion civilians, think about it, today's largest military is china with ONLY 2 million personnel in it.You'd have a civil war on your hands instantly.The average wage for a soldier is about £14,700 per year (including tax) times that by 30 million and your total military upkeep comes out at 429,000,000,000 per year, instantly bankrupting your nation.Even if you half those wages you've still bankrupted your nation.So no, 30 million isn't going to do it.
[/quote]

This is really a poorly thought out response. Here is why.

Currently, military sizes are low because we are living in a relatively peaceful period in history. There hasn't been a war between two major world powers since the Second World War; the only thing nearing an exception are the proxy wars. The twin facts of nuclear weaponry and a global economy reliant on open borders has made large scale militaries unnecessary.

To get a more appropriate look at how many soldiers have been fielded in the past, we see larger numbers. The peak strength of the soviet union during WW2 was 12 million. That was in 1945, and in a nation with a population of roughly 200 million people. China has enough people to field. The problem becomes economic and structural.

So how do you field that many men? Its not difficult. Governments, unlike people, do not have the same pressure to pay their bills. The concept of a nation adding military costs, even expensive ones, to their public debt isn't too strange. It has happened before. In reality, it is a major part of what makes up many national debts. 

But there are other ways of doing it. In some drastic cases, pay is witheld (this typically causes rebellion). Or soldiers could be forced into the military (also a potential cause for rebellion). However, there are ways a person could finance a military. A popular ancient method was to give out land or titles. This played a part in the Roman expansion into Gaul and Iberia - these places weren't worth much, but they had good farming land that an aspiring politician could parcel out to soldiers to gain their love and affection. Feudal military classes figure into this too. This wouldn't work the same way in this Chinese military since 30mil is a lot of people, but it could mean that a soldier is guarenteed a place to live and a stipend of food. If the economy is bad enough, that might be all it takes. 

You could also go the Starship Troopers route and have military participation be a requirement for citizenship, or at least access to certain rights. This would especially work if a majority of the military functions as a reserve that is able to hold a job. 

Another tried-and-true ancient method would be looting. If this world is particularly damaged by this disease and whatever other set of events caused things to change so rapidly, There would probably be no international protection against something otherwise considered barbaric. One could see using this as a way to subsidized the Starship Troopers method. You feed your family with a job when you are on reserve, and when on duty you loot shit and use that. If China institutes slavery for the conquered or raided, this would help even further.

The final thing to add to this is that there could be more of an incentive to this military than warfare. If you use excess troops to do things that bring economic benefits, like building infrastructure or even bringing in resources, this military could pay for itself.

The important thing to do is not pigeon hole things based on overly elementary understandings. Shit is complicated, yo.