What the rise of Zika (and other viruses) might tell us about our planet byJohn Ross, MD, FIDSA, Contributing Editor for Harvard health publication.

Zika virus, a pathogen that was almost unknown a few months ago, is now rampant in Central and South America and the Caribbean. In Brazil, it has already infected about 1.5 million people and caused nearly 4,000 cases of microcephaly, a severe birth defect. It is almost certain to spread to every country in the Americas, except Canada and Chile, which lack the Aedesmosquitoes that spread Zika.

Zika is not the only virus that has come from the tropics to menace the United States. Dengue, an unpleasant and potentially fatal viral infection, has broken out in Texas, Florida and Hawaii in the past 10 years. Chikungunya, a virus that can cause prolonged joint pain and ruin your vacation, has caused recent outbreaks in Florida, Puerto Rico and the U.S. Virgin Islands. All three of these viruses are spread by Aedes mosquitoes.

Globalization for mosquitoes: Have Zika, will travel

Globalization, the explosion of international trade and travel, is one factor in the spread of Zika, dengue, and chikungunya. Viruses may travel the globe via infected humans, or via mosquitoes that are riding in freight containers. One mosquito species that transmits Zika and other viruses, Aedes albopictus (also known by the more formidable name of the Asian tiger mosquito), probably arrived in the U.S. in the 1980s in shipments of old tires from Asia. (Aedes aegypti, another virus-spreading mosquito, probably arrived in the United States from Africa in colonial times.) Read more here.