Zika: Bite-Me-Not! Edition

To understand the extent of Brazil’s public health fail in the face of Zika, one the most frightening disease outbreaks in recent memory, consider this: Screens do not come standard in the dorms of the Olympic Village. One of the most effective ways to keep mosquitoes that can carry the virus (along with dengue and chikungunya) away from athletes is considered an “extra.” If teams want screens in their rooms, they are going to have to pony up and pay for them.

In effect, this is a health tax that unfairly burdens teams from poorer countries and lends an Orwellian twist to the Olympic ideal of a level playing field: Those that can pay really are more equal than others.

“…The screens, one measure Brazilians are using to help ward off the mosquito that is the primary transmitter of Zika, will be installed in communal areas “where required” but only affixed to lodging if national delegations decide to pay for it, said Philip Wilkinson, a spokesman for the Rio 2016 organizing committee.

The committee did not say how much the screens would cost or what type they would use. Low-end screens attached to windows with Velcro can cost as little as $15 while more rigid and durable screens can cost more than $100…”

— Rio Olympics to charge teams for mosquito screens to prevent Zika virus, The Guardian (2.26.16)

One can only hope that this stunningly tone deaf decision will soon be reversed. It is too late, though, for a beleaguered tourism industry, bringing to light yet another concern for travelers visiting the ever-expanding Zika-dengue-chikungunya zone: Make sure your accommodations come with screens. Maybe pack a bed net, just in case…

WORSE AND WORSER

Zika was always bound to be trouble: a primate virus transmitted by a mosquito species whose victim of choice is us. Spark meet kindling. Still, no one could have imagined just how much trouble Zika would prove to be. The magnitude of the still unfolding disaster is staggering:

• Evidence linking the virus to cases of microcephaly in babies continues to build. Researchers suspect that even healthy-looking infants born to Zika-infected mothers may be at an increased risk for developing mental illness later in life.
• Evidence linking Zika to Guillain-Barré Syndrome (GBS), an auto-immune-triggered paralysis in adults, is also mounting. Although only a tiny percentage of those infected with Zika go on to develop GBS, no one knows what the risk factors are. Until science can tease apart cause and effect, there is a chilling roulette-style randomness to the devastation and no one is safe.
• Sexual transmission is likely not quite as rare as recently thought. The pervasiveness of mosquito transmission in South America may have masked it. Does sexual transmission present a greater risk for microcephaly in babies? Could a pregnant woman be repeatedly infected through sex? What are the implications for the immune response? No one knows. No one has had the time to study it. But we do now know that Zika can survive in semen for nearly two months, long after any symptoms of the illness—if there were any—have cleared. Disturbing questions seem only to lead to even more disturbing questions.
• A single Zika-infected female mosquito can spread the disease to multiple human hosts: It can take as many as five sips, potentially from different victims, to gather enough blood for the mosquito to nurture her offspring. The process also works in reverse, too: An infected human can transmit the virus to a mosquito, who then goes on to share it with more humans. It is also possible that mama mosquito may “vertically” transmit the virus to her babies, who would be born armed and dangerous.
• Aedes aegypti, mosquito-species enemy-number-one, has evolved to breed in dirty water and breeds faster as the mercury climbs. Overwintering populations have been found as far north as Washington DC. Soon, researchers will tell us whether or not Zika can be effectively transmitted by Culex mosquitoes. If the trend of bad news continues and answer is yes, that would mean that the virus could become endemic almost anywhere.
• Insecticide fogging only kills about half of an adult mosquito population in a given area (the rest crawl in crannies to wait out the assault). Pesticide resistance is on the rise, so the percentage killed will likely go down.

No screens? Really, Rio Olympic organizing committee?

OFFENSE AS DEFENSE

As experts square off on the best way(s) to whack-a-bug (nuclear radiation, genetic engineering, infection or chemical attack), the best defense is a good offense:

• Eliminate standing water so mosquitoes can’t breed (a nearly impossible and almost pointless task with mosquitoes that can breed in a capful of water).
• Wear long sleeved clothing and pants (uncomfortable on hot muggy days), preferably infused with permethrin (expensive and treated clothes must be washed separately).
• Install screens and/or air-conditioning (expensive) to minimize the risk indoors.
• Spritz on insect repellent, especially when outdoors.

Insect repellent—sales of which will no doubt break records this summer—is an iffy proposition. For years, the “go to” answer has been DEET (N,N-diethyl-m-toluamide), a compound developed by the US army in 1944 to help soldiers who were fighting in the mosquito-filled jungles of the Pacific during WWII. It took over a half century before researchers began to figure out how it worked. It turns out that it isn’t the smell that bothers the bugs, but rather that their sense of smell has been hobbled. Unfortunately, it is a condition to which some bugs can adapt. For others, sadly including Aedes aegypti, DEET’s effectiveness is limited. It also stains clothing and can cause skin irritation.

Picaridin (aka, Icaridin), also ranks high on the World Health Organization’s list of repellents, but its effectiveness can vary among different mosquito species.

That leaves a raft of natural repellents such as oils derived from citronella, eucalyptus, lemongrass and geranium; and, according to researchers at New Mexico State University, a perfume called, of all things, Bombshell. Effectiveness varies and can be reduced simply by sweating.

In general, none of the repellents are recommended for use on young children, leaving the most vulnerable more vulnerable.

DAZED, CONFUSED, VAMOOSED!

There could be a better way to shoo away mosquitoes.

Rockefeller University’s Leslie Vosshall, whose pioneering work on the mechanics of mosquito olfaction were instrumental in unraveling the mystery of DEET, has been looking at ways to confuse mosquitoes by selectively deactivating sensors so they can’t find us. Although the science is different, it could be called the Febreze approach: a “nose blind” mosquito would be oblivious to the all the tasty aromas that mark a human. The work, supported by Grand Challenges funding from the Bill and Melinda Gates Foundation, has been slow-going. Mosquitoes use a variety of ways to zero in on victims, so if they can’t smell us, they simply switch gears.

At Vanderbilt University, a team lead by Laurence Zweibel, also supported by Grand Challenges funding, has taken the opposite tack: They came up with compound that turns on all of mosquito’s smell receptors at once, blinding it by overloading its sensory circuits. VUAA1 (Vanderbilt University Allosteric Agonist 1) doesn’t just work on mosquitoes, but on all insects. “It’s like getting on an elevator with someone who’s put on way too much perfume, explains Zweibel. The mosquitoes “very aggressively move away.”

Zweibel’s team is now working on VUAA4 to create a wristband repellent device. “We’re going to try to get these compounds into plastic. We want to make something that people don’t even know they’re using,” he explains. The device, which could be powered by a battery, a solar cell or perhaps even movement, would release VUAA4 chemicals into the air to generate a literal no fly (or mosquito or tick or flea or louse) zone bubble of protection.

he good and the bad news is that VUAA’s affect all insects. While it offers a brilliant all-in-one solution to keep a variety of biting, sipping and generally annoying insect pests at bay, the potential for collateral damage is significant if used in in large scale applications such as agriculture or lawn-care.

VUAA’s do not kill insects, but a treated field would present a daunting barrier to migrating insects such as butterflies, or force bees to waste precious energy flying further than they might otherwise have to to find flowers to pollinate. A treated field would also keep out beneficial insects such as ladybugs, with ramifications up and down the food chain: Silent Spring redux.

Still, a personal anti-insect cloaking device has its charms.

FINGERPRINTS

“Over and over again, Nature deals us wildcards….The mosquito kills more people than any other animal on earth”

— Dr. Tom Frieden, Director, CDC | CNN interview

It it disturbing when the head of the one the most important public health agencies in the world so cleanly misses the point. Nature didn’t “deal us” a Zika wildcard. Nature doesn’t deal wildcards. And mosquitoes don’t kill people. Pathogens do.

Zika, like most disease outbreaks, has human fingerprints all over it. This is a man-mediated disaster, a cascade of bad luck and opportunity that was centuries in the making. Aedes aegypti mosquitoes, the main carrier of the virus, were brought to the New World first by explorers, conquistadors and slavers and later by tourists and traders via ship, train, plane and truck. For its part, Zika hitched a ride in a mosquito that hitched a ride. Or it may have come in the body of a traveler who provided a pathogen-laced feast to local mosquitoes. Or perhaps a traveler transmitted it by sex to someone local and a mosquito feasted on her, too.

Zika followed in the tracks of dengue and chickungunya outbreaks, thriving for months or longer hidden in their shadows until doctors began noticing a troubling upsurge in the number of Brazilian microcephaly cases. It flourished in the absence of proactive public health system. It exploited every weakness, from a lack of window screens and air-conditioning in poor, densely populated neighborhoods; to sketchy water and sanitation services; to mosquito resistance to pesticides. Along with its insect transport, Zika has reveled in the warmth of a climate changed by carbon pollution, increasing its numbers and expanding its range. Thanks to trade and travel, it has rapidly spread throughout South and Central America and the Caribbean.

Zika is not a Nature wildcard, but rather operates by the laws of Nature, having proven itself remarkably “fit” for survival.

The hallmark and the Catch-22 of a successful, proactive public health system is that it is hard to see its success: People stay healthy. By contrast, the spate of global disease emergencies — from SARS to MERS to Ebola to Zika — is evidence of a system in crisis caught in a no-win cycle of constant catch-up. Acknowledging the human component in these disasters is critical if there is any hope of ever getting ahead of and mitigating, if not avoiding, these kinds of crises.

Prevention is a hard sell. Asking Congress for nearly $2 billion in emergency funding, as President Obama recently did for Zika, is oddly easier. But as tallies for these repeated hits to the global economy add up, the case for developing better prevention strategies become stronger.

Putting a dollar figure on a global scourge is no simple matter, given the spotty reporting from countries with precarious health care. But Donald Shepard, a health economist at Brandeis University, ran the numbers and concluded that in 2013 dengue cost the global economy $8.9 billion…

… As devastating as Shepard’s findings are, they do not include the toll on tourism…

…The fallout from other scourges can offer some insight. Tourist arrivals in Hong Kong were down 68 percent two months after the World Health Organization issued a warning about the SARS epidemic in 2003, and 54 percent in South Korea two months after the 2015 alert about the MERS outbreak, according to Bloomberg Intelligence.

— The Economic Cost of Zika Virus, Bloomberg View (2.5.16)

The specter of thousands, possibly tens of thousands, of children born with severe birth defects or at increased risk of mental illness due to Zika is a tragedy beyond words. The cost of this outbreak is already measured in billions of dollars. Whether the bottom line is human suffering or an economic hit, we simply can’t afford to continue business-as-usual public health. The next disaster will be along shortly.

In the meantime, screen installers have a bright future. And if Dr. Zweibel were to put his VUAA4 anti-bug wristband on Kickstarter, I would back it in a heartbeat. It is easy to get lulled by the bright sunshine and birdsong as winter turns to spring, but it has become a more dangerous world out there. Pathogens are on the march.

— J.A. Ginsburg / @TrackerNews

RELATED:

• The Quest to Make a Better Mosquito Repellent by Ed Young, The Atlantic
• Mosquito Repellents That Best Protect Against Zika by Sue Byrne, Consumer Reports
• Citadel Protectants (website)
• Whack-a-Bug: Vectors, Victors and Vanquished in the Age of Zika by J. A. Ginsburg, Dot to Dot
• Zika: Of Virus, Vector, Victim, Drought, Deforestation, the World Cup, the Epigenome & Evolution by J. A. Ginsburg, Dot to Dot