Thanks to malaria elimination efforts in United States in the 1940s, most people in the U.S. today have never had any direct contact with the disease, and most doctors have never seen a case. That success means it's easy to have a relaxed attitude about protecting ourselves.

Vaccines and antibiotics have made many infectious diseases a thing of the past; we've come to expect that public health and modern science can conquer all microbes. But nature is a formidable adversary.

I loved clinical practice, but in public health, you can impact more than one person at a time. The whole society is your patient.

Over and over, nature shows that it's a really tough adversary. That's why it's important that we invest in laboratories, disease detectives, research, mosquito control, the public health system around the world to find, stop, track, prevent health threats.

Health is correlated with quality of life. If you get regular physical activity, have social connections, control your cholesterol, keep your blood pressure at a normal level, don't smoke - these things can make an enormous difference not only in how long you live, but how much you enjoy your life in those years.

The way we work in public health is, we make the best recommendations and decisions based on the best available data.

Our progress against malaria is impressive. But vigilance remains a critical ingredient to protect the health of all people.

The bottom line is, if you're pregnant, don't travel to an area where Zika is spreading.

The first case of Ebola diagnosed in the United States has caused some to call on the United States to ban travel for anyone from the countries in West Africa facing the worst of the Ebola epidemic. That response is understandable. It's only human to want to protect ourselves and our families.

The United States has made remarkable progress in reducing both teen pregnancy and racial and ethnic differences, but the reality is, too many American teens are still having babies.

Pregnant women who are in places where Zika is spreading should do everything they can to avoid mosquito bites. And we, as a society, need to do everything we can to control Zika. That means learning more about it; that means controlling mosquitoes more effectively. That means achieving a vaccine.