Friday, March 11, 2016

Zika Updates

Things have happened so quickly on the Zika virus front over the past three months, I thought a short update might be in order.  You may recall a post I wrote in December warning about a need to brace ourselves for what might possibly be a big year for the new Zika phenomenon.  As my wife might say, "Well, at least you were right this once."  A quick peak at Google Trends surely bears this out.  The following graph shows the relative number of times people on the Internet used the search term "Zika" in recent years:

Much of the excitement about Zika virus, of course, has centered around the possibility, insisted on by many Brazilian public health officials, that there is a connection between Zika infection and a condition in newbornes called microcephaly.  Since the initial reports, there has been some pretty wild speculation about whether Zika really is the cause of the condition.  One was a blog posted on Reddit, a "social networking newsite" that bills itself as "the front page of the Internet".  The post speculated that the real reason there had been no previous connection between microcephaly and Zika was that the microcephaly in Brazil was actually linked to experiments with genetically modified mosquitoes in some parts of the country where microcephaly was rampant. Many people have since discredited the logic behind this conspiracy theory.  But expect this idea to float around the Internet for a long time anyway--that's what conspiracy theories do.

Another theory posted online claimed that the real reason for microcephaly increases in Brazil is a pest control insecticide being used in the drinking water of Zika outbreak zones.  The insecticide was pyriproxifen, which we in the pest control industry use under the trade names Nylar® and Archer® flea and roach sprays. The anti-GMO group blaming pyriproxyfen claims that the association between microcephaly and areas where pyriproxyfen is used "is not a coincidence." Like the genetically modified mosquito claim, this group also asserted that so far, there have been no cases of microcephaly reported in other countries affected by Zika. While microcephaly does not (yet) seem to be as prevalent in some Zika areas, like Colombia, this claim is not strictly true. Higher rates of central nervous system malformations were also found in French Polynesia following the Zika outbreak there in 2014.  In addition, there is no scientific evidence of any connection between pyriproxyfen and brain abnormalities, and officials in Brazil point out that some areas that do not use pyriproxyfen to treat mosquitoes still have seen increases in microcephaly.  Pyriproxyfen, by the way, is an insect growth regulator that is one of the lowest toxicity treatments (LD50 greater than 5000 mg/Kg) available for fleas, cockroaches and other pests. The EPA does not consider it an endocrine disruptor, and it is not considered a carcinogen.

On the scientific side, last week an article was posted in the New England Journal of Medicine (a much more reliable source than social networking news sites) that provides some of the strongest evidence yet for a link between Zika and microcephaly.  Fetuses from 42 women with evidence of Zika infection during gestation were examined.  Preliminary analysis of ultrasound examination of these fetuses showed 29% (!) occurrence of microcephaly in infected women compared to 0% in 17 non Zika infected women.  The authors concluded that "despite mild clinical symptoms, ZIKV infection during pregnancy appears to be associated with grave outcomes, including fetal death, placental insufficiency, fetal growth restriction, and [central nervous system] CNS injury."

If research continues to show similar associations between Zika infection and microcephaly the stakes are surely raised this summer with thousands of expected travelers coming back into the U.S. from Zika zones, including the Olympic venues in Brazil.  All the more reason for all of us to be aware of travel safety recommendations by the CDC.

For our part, Texas A&M is also ramping up its educational efforts this summer with launch of a new website to collect information pertaining to ways to prevent Zika.  The bottom line of all the current news, however, is that there is currently no way to prevent getting the disease from an infected mosquito other than by avoiding mosquito bites.  And pest control is an important part of that equation.  So take the time to learn more about the Aedes mosquitoes that carry Zika, and consider how you might respond to the concerns that are sure to be around this summer.

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