IMO that is a partial explanation, but there are a few factors which I feel the article missed. As the article did note that parts of Africa and Asia (and likely portions of Central and South America as well, for the same reasons) have large pools of pathogens, largely due to a climate which suits them being warm/hot and humid/wet. What I feel the article missed is that as local or regional climates change from what has been previously observed, more and more areas are becoming 'environmentally friendly' either for pathogens themselves, and/or host vectors. The Zika virus I mentioned in an earlier post being a good example. A particular genus of mosquito can spread the virus to/between humans when they bite. Where the change in climate came into play is that this particular genus was more partial to warm weather environments but the regional climate had warmed enough so that some of the more southern coastal areas of the Northeastern US, like portions of the state of Connecticut in New England, and Mid-Atlantic states like New York, New Jersey, Delaware, Maryland and Virginia now had populations of this particular genus.