Today, on CNN, it was said that some experts argued several epidemic consequences of global warming. One of them is tropical diseases are moving north. For example, malaria cases were reported in New Jersey.
I found this claim is a little far-fetch. According to scientists, the temperature change due to global warming is about (1.33 ± 0.32 °F) during the last 100 years. The difference between the average temperature of New Jersey and that of a tropical region is probably much greater than that. To me, one possible reason why a single disease is moving north can be genetic mutation in the virus strand that increases cold-resistance. And more frequent air travel can probably explain the trend that multiple diseases have been moving north.
Before having more data, one cannot conclude global warming as the cause and ignore other possible threatening causes.