The names in the headlines can seem like a Who’s Who of infectious diseases: Zika. Dengue. Chikungunya.
Many of them affect people far away — the length of a continent, the width of an ocean.
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But with modern travel and transport shrinking those distances, Dr. Ali Khan said it’s important not to be complacent about our risk from such diseases, even in the United States.
Khan, dean of the College of Public Health at the University of Nebraska Medical Center, said his purpose in delivering such reminders is not to scare people but to educate them about the importance of vigilance and of maintaining the kind of robust public health infrastructure that can conduct the surveillance and response needed to keep threats at bay.
As a former disease detective and director of the Centers for Disease Control and Prevention’s Office of Public Health Preparedness and Response, Khan has seen — and tracked — a number of such vector-borne diseases, those transmitted by the bite of an infected insect.
He wrote about them and many other biological threats, from influenza to anthrax, as well as his encounters with them during his 23-year CDC career, in “The Next Pandemic: On the Front Lines Against Humankind’s Gravest Dangers,” which was published last year.
Thursday, Khan will appear as a featured expert in “Mosquito,” a new Discovery Channel documentary that focuses on the insect that some consider the deadliest in the world, responsible for hundreds of thousands of deaths each year. Not only do mosquitoes carry the three diseases mentioned above, they also transmit yellow fever and malaria.
Yellow fever and malaria both originated elsewhere in the world and found their way to the United States. Both played a role in the nation’s history. Understanding the role mosquitoes played in yellow fever and malaria transmission allowed the United States to build the Panama Canal at the turn of the 20th century. The CDC’s origins are closely linked to malaria control activities in the U.S. South.
The elimination in the United States of both yellow fever and malaria is a sign of our progress against vector-borne diseases, Khan said, but we still face risks from more recently arrived maladies.
Indeed, an insect-borne disease that shows up and finds local carriers may be around for the long haul. West Nile, another mosquito-borne disease, is one example. It came on the scene in the United States in the 1990s. Now it has spread across the country, including Nebraska and Iowa, and has a significant impact each year.
“The story of vector-borne disease is really the story of emerging infectious diseases, which is (that) a disease anywhere is a disease everywhere,” he said.
Dengue, another example, has found a little home in Florida, where it causes some cases each year. Zika also arrived in Florida and Brown County, Texas, last year and was being transmitted locally. Khan said he expects that some cases will continue to occur in Florida.
He does not expect local transmission to be a problem in Nebraska, however. The No. 1 carrier of the Zika virus, a mosquito called Aedes aegypti, has not been found in the state. A second but much less efficient carrier, Aedes albopictus, or the Asian tiger mosquito, has been found only in Richardson County in southeast Nebraska.
Indeed, little has been heard of Zika in recent months. The CDC in early June lifted the recommendation it made last year advising pregnant women not to travel to the Miami-Dade County area. However, the agency noted that sporadic cases were still possible and recommended that people living in or traveling to the area continue to protect themselves from mosquito-borne illnesses, including Zika.
Khan said the outbreak delivered a reminder about the importance of paying attention to strategies to manage mosquitoes and other vectors. Last year, he said, there were delays in getting funding for the CDC to respond to the crisis.
Keeping track of vector-borne diseases also means monitoring changes in the environment, including climate change.
“The big concern being that things will move where they aren’t,” Khan said. “That matters because, A, you have a new risk area that you didn’t know you had and, B, you need to make sure clinicians are aware.”
Currently, he said, a number of innovative approaches are being investigated to address vector-borne diseases. A British biotech company has genetically engineered male mosquitoes to keep them from producing viable offspring. Another method involves infecting male mosquitoes with a bacteria that does a similar job.
Khan’s focus, meantime, has shifted to a broader view of health. He’s laid out a challenge to help make Nebraska the healthiest state in the union by 2020. The state now ranks No. 12, according to the United Health Foundation’s America’s Health Rankings 2016. Not only does the state have the talent to get there, it also has a relatively small population and a bent toward collaboration, he said.
“It’s a great time in public health,” he said, “to really think about ‘How do we approach health and how do we fund health and not fund health care?’ ”
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