Zika Wake-Up Call


The spread of the mosquito-transmitted Zika virus should be yet another wake-up call for public officials around the world. As a relatively new threat, Zika has captured headlines in a world where many insect-transmitted diseases continue to wreak havoc on public health. Unfortunately, the ability to control all such vector-borne diseases is hindered by more than our limited scientific understanding. Disease control is limited by the lack of political will to use all tools in our arsenal, including politically incorrect pesticides.

Zika has long been known to cause mild infections and rashes, but health officials are now investigating the possibility that it can cause birth defects when mothers are infected during pregnancy. The disease appeared in Brazil last spring and during 2015, the nation experienced a dramatic increase of babies born with neurodevelopmental problems associated with unusually small heads, a defect called microcephaly. Researchers are investigating whether the two phenomenon are connected. They are also investigating the possibility that Zika caused an increase of Guillain–Barré syndrome, an autoimmune disease.

Regardless of what they find, we already know that mosquito borne diseases cause a wide range of health effects that include neurological problems as well as immediately deadly infections.  The impact in impoverished nations is devastating with diseases like Malaria and Dengue taking millions of lives every year.

Even here in the United States, many people suffer from vector-borne diseases, which West Nile virus, Lyme disease, Babesiosis, and many others.  And there is real concern about things like Dengue taking a hold in the United States.

Around the world entomologists, medical doctors, and other vector control experts dedicate their lives to controlling dangerous vector populations. As I have documented elsewhere, too often their hands are tied because of foolish government regulations and alarmist politics related to pesticides and other vector control methods.

In fact, anti-pesticide activists have advanced bans and regulations on all sorts of products that have public health uses. In the United States, many products have been removed from the market simply because of fool-hearted regulations. For example, see my paper on the West Nile virus for more information, as well as the pesticide information on my website at SafeChemicalPolicy.org and information on RachelWasWrong.org.

The most obvious example is their push to completely eliminate the pesticide DDT in developing nations. There many people lack basic amenities that we take for granted in developed nations—such as windows with screens—that limit our exposure to mosquitos. In that case, DDT can be applied in and around the homes to repel dangerous disease-carrying mosquitos, greatly reducing transmission. 

There are other technologies that are under development, including the introduction of genetically modified mosquitos. But in the meantime, officials need to access tried-and-true technologies—regardless of whether or not environmental activists agree. A recent article in the New York Times, highlights the importance of allowing officials to employ such tools, including DDT. It notes:

So for now, experts say, the best modes of prevention are to intensify use of the older methods of mosquito control and to lower the risk of being bitten using repellents and by wearing long sleeves.

Women are being advised to not get pregnant and to avoid infested areas if pregnant, since the virus is strongly suspected of causing babies to be born with abnormally small heads and damaged brains.

One old method that is not getting serious attention would be to use DDT, a powerful pesticide that is banned in many countries because of the ecological damage documented in the 1962 book “Silent Spring.” Still, it is being mentioned a bit, and some experts defend its use for disease control.

“That concern about DDT has to be reconsidered in the public health context,” said Dr. Lyle R. Petersen, director of the division of vector-borne diseases at the Centers for Disease Control and Prevention. He said the damage to fish and wildlife stemmed from widespread outdoor use of DDT in agriculture, not the use of small amounts on walls inside homes to kill mosquitoes.

Other experts say the old methods can work if applied diligently.

 “We’ve had great success using old methods for the last 50, 60 years,” said Dr. Peter J. Hotez, dean of the National School of Tropical Medicine at the Baylor College of Medicine. “We just need to be very aggressive and exercise political will.”

So far, the first confirmed transmission of Zika in the United States (some incidences among U.S citizens occurred while on travel) resulted from sexual transmission from another infected person rather than from a mosquito here. In any case, Americans should remember that mosquitos and other vectors, such as ticks, transmit a variety of  diseases. Things we can do include limiting breeding grounds (such as cleaning out dirty bird baths) and allowing local vector control to address these risks using a host of methods.  Don’t panic if they need to spray pesticides either.

There is little reason to fear the use of chemicals in these battles. As I document in my paper and elsewhere, the risks of those are far less than that of the vectors. 

In addition, the chemical repellant DEET offers some of the best protection while working outdoors in the yard or recreating at the beach or barbeque. This is particularly important when it comes to mosquito species that are active feeders during daylight when people are most active outside. That is true of the Aedes aegypti mosquito, which carries Zika. So don’t be afraid to use DEET to protect yourself, particularly if you are pregnant! Mosquitos and other vectors pose far greater risk to unborn babies than proper use of a chemical like DEET ever could.  


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