“Another Climate Change Warning” is by Jonathan Patz, Keynote speaker at the CCCDC Forum on May 7, 2016.
A view through a microscope shows the Aedes aegypti mosquito, which transmits the virus Zika, at a laboratory at the National Institute of Health in Bogota, Colombia. Credit: EPA
By Jonathan Patz
Zika. Once an anonymous word rarely discussed in public circles, it is rapidly becoming the Ebola of 2016.
On April 11, the White House and the Centers for Disease Control and Prevention acknowledged the virus is far more serious than original estimates. The administration committed nearly $2 billion to combat the virus. On April 13, The New England Journal of Medicine Special Report concluded there is a causal relationship between prenatal Zika virus infection and microcephaly and other serious brain anomalies.
Yes, the public definitely needs to know more about Zika and people need to take precautions to prevent exposing themselves to this threat.
Why Zika erupted this year remains an open question. But 2015 was the hottest year in recent history, according to the National Oceanic and Atmospheric Administration, and 2015 also marked an historic strong and long El Niño event that especially affected Latin America. Unprecedented hot and dry weather conditions occurred just prior to Zika’s rapid emergence in much of the region.
Zika is just one of many mosquito-borne diseases highly sensitive to weather conditions. Others include West Nile virus, dengue fever, malaria, encephalitis and many more. The surprise of Zika may serve as yet another warning flag for more public health threats linked to climate extremes that are already intensifying due to global climate change.
Mosquito-borne diseases are especially influenced by climate factors. One example is West Nile virus, which was discovered in the United States for the first time in 1999. That year, New York experienced an extremely wet spring followed by record July heat, creating ideal conditions for the particular urban mosquito that carries that virus.
One of the commonalities between the spread of West Nile virus and Zika is international travel. The other commonality is shifting climate conditions. Whether from extreme heat, extreme cold, drought or flooding, any climate shift can alter the balance of vector-borne diseases. To date, all Zika illnesses in the continental United States have been travel-related. But Zika’s mosquito vector, Aedes aegypti, already resides in the southern U.S., and local disease transmission is expected as summer temperatures arrive.
As the administration tackles the Zika epidemic, it’s important to step back a moment and look at the big picture. On April 13, I co-authored a letter with Howard Frumkin that appears in The Wall Street Journal, reminding us that we must not miss the forest by looking at one tree. Many pundits are zeroing in on single aspects of climate change, trying to score political points in the midst of great pain and suffering. There’s no place for selective, gratuitous contrarianism in assessing the science of climate change. Any fair reading of the growing body of evidence — summarized in a federal report — makes clear that climate change is a pressing, urgent health concern of the highest priority.
First, we must invest in prevention, increasing the resilience of those exposed to climate change-related impacts. These include risks from heat waves, cold snaps, extremes in the water cycle (more floods and drought) and sea level rise. Impoverished communities are the most vulnerable.
Second, we must implement public health policies that address the driving factors causing climate change (e.g. unsustainable energy, transportation, and food systems). Solutions to climate change are also public health prescriptions: clean sources of energy, such as ever-cheaper wind and solar; active transportation, such as walking, cycling, mass transit and urban green spaces.
If we fail to address these issues at a macro level, we will always be trying to catch up after the latest outbreak. Let’s work together for a healthier tomorrow.
Jonathan Patz, M.D., M.P.H., is director of the Global Health Institute at the University of Wisconsin-Madison.