Although Zika can be transmitted via sexual contact, its primary carrier is Aedes aegypti. Known as the Yellow Fever mosquito, this flying killer has rebounded from near eradication in the 1960s to being a dangerous scourge in Brazil, other South and Central American countries, Puerto Rico, Caribbean islands, Africa and Asia.

Found in Hawaii and some southern U.S. states and European nations, as well, they also carry other dangerous diseases. Yellow fever causes fevers, chills, nausea, muscle pains, and liver and kidney damage when these symptoms recur. A vaccine exists, but it still kills up to 30,000 people annually.

Equally painful and debilitating, dengue fever can recur for years; there is no vaccine, and it sickens nearly 100 million people a year, killing some 25,000. Chikungunya causes often severe fever, headaches, muscle and joint pain, rashes and other non-lethal problems.

All these diseases also infect blood supplies, making transfusions risky and requiring blood from safe locales that often lack sufficient supplies themselves.

The prospect that Summer Olympics fans and athletes could get infected and carry these diseases from Brazil back to their home countries has health officials worried. So does the likelihood that thousands of other travelers will also spread these diseases.

Rarely flying farther than 80 feet from where they hatch, Ae. aegypti love people and houses, bite during the day, and hatch from eggs laid in tires, cans, jars, flower pots, vases, holes in trees, and almost any other container holding water around homes, indoors and outdoors, in backyards and junkyards.

Fortunately, individual families can eliminate mosquitoes and keeping them away from people. They need to destroy mosquito-producing sites and use insecticides and larvicides.