Colvan has decided to help increase the population and military by recruiting and helping the natives of the new area. They have also given the natives of the area the same rights and new technology. This will boost the relationship between them and help them with population problems. Also, a side note, most of the natives have a resistance to the virus because they mostly eat fish. They have also had the virus for hundreds of years. It is probably one of the reasons why it wasn't on the map before. (All the explorers ( not the ones from colvan early ones) died from the virus)
This is expected to increase the population by 2.5 million at a minimum.