Sometime this spring or summer, you’ll surely feel that annoyingly familiar sensation. You’ll probably swat, maybe curse.
If it’s particularly small, striped in white and black, it could be the Aedes aegypti or Aedes albopictus variety with the potential to carry the Zika virus.
You’ll almost certainly be fine.
After all, mosquitoes actually infected with Zika have yet to buzz the continental U.S.
The idea that they’d show up in Kansas City without showing up first in Tampa, Houston or Little Rock — if they ever arrive there — runs more to the theoretical than the plausible.
(One scenario: Traveler goes to Brazil, is bitten by a mosquito with the virus, returns to Westport, gets bitten by another mosquito that bites someone else and transfers Zika. Indeed, five travelers in Kansas and Missouri have returned with the virus. Another scenario: Infected mosquitoes hitch a ride on a truck that motors up Interstate 35 or a boat that steams up the Missouri River and they somehow survive to bite the locals.)
The Pan American Health Organization reported in late April that scientists captured Aedes albopictus mosquitos bearing the virus in Mexico — signaling the movement further north in the Americas. That marked the first time in the Western Hemisphere that researchers found the disease in that breed. Previously, it had been found only in the A. aegypti.
The virus landing here would be so awful — horrific birth defects when a pregnant woman is infected — that physicians, biologists and bureaucrats have begun to ready the region for battle.
Among those on the lookout is Christopher Rogers. He’s setting traps.
“We’ve got to figure out where the suckers are,” he said.
Rogers is an invertebrate zoologist for the Kansas Biological Survey at the University of Kansas. For years he has been tracking other mosquito species, particularly those in the Culex genus, that can carry West Nile virus. About 60 people in Missouri and Kansas contracted that mosquito-borne disease (it’s usually mild but can sometimes be fatal) last year.
His traps, about the size of two paint cans, tempt the winged menaces with infrared lights and carbon dioxide from dry ice. A fan sucks them in. Rogers collects them, freezes them, counts and categorizes them under a microscope. Then he sends those with the potential to harbor West Nile to a lab for viral testing.
Next month, pending grant money from Washington, he and a graduate assistant will retool that work to look for A. aegypti, known to harbor Zika elsewhere, and A. albopictus, another possible carrier.
The traps will be similar. But instead of dry ice, he’ll bait them with pheromones. Instead of concentrating around Wichita, he’ll move 10 traps around Kansas daily to see where their numbers are greatest.
“I want to know where these things are, because I don’t want people to get Zika virus,” he said.
Pinpointing their concentrations would prove to be valuable intelligence if Zika ever shows up. Then public health officials would know where to deploy an attack — pressuring residents to eliminate standing water and dousing areas with larvicide that eats up mosquito guts before they hatch.
They would pose an especially pesky insurgency. The A. aegypti breed most often in the tiniest of spaces, gravitating to tree holes and other small collections of water in shady nooks.
The discovery of Zika in A. albopictus could
Those catch basins at the bottom of your flower pots? They’re ideal for the A. aegypti because they’re stagnant and fed with organic material leaking from the soil. Same for the tarp covering your firewood, where creases collect water, twigs and leaves. The A. aegypti need no more room than a bottle cap to thrive.
It’s unclear how A. albopictus mosquitoes carrying the virus might change the dynamics of any spread of the disease. Unlike the A. aegypti, they are less prone to flit from one animal to the next. Instead, they find a host to bite on and feed until they’ve got their fill. That could mean they’d be less likely to carry disease from one place to the next.
That means they could be harder to conquer than other species that congregate more along streams and gullies, breeding grounds more easily spotted and treated with tablets of larvicide. The tablets carry bacteria that mosquito larvae eat only to find it destroys their insides.
“This kind of mosquito can be particularly hard to get at,” said Joe Conlon, medical entomologist and technical adviser to the American Mosquito Control Association. “It’s logistically intense.”
By some reckoning, the mosquito is the deadliest animal on the planet. Its bites kill about a million people a year by transmitting disease, mostly malaria in Africa, Asia and South America.
They can also carry dengue, encephalitis, yellow fever, chikungunya, West Nile and myriad other microscopic horrors.
Yet only half of all mosquito species bite humans. Of those that do, only the females suck your blood, and they do so only when they have eggs to lay.
A mosquito plunges its proboscis into your skin and then excretes its saliva to stop your blood from clotting. That’s where a virus carried by the pest enters your bloodstream.
It’s helpful to note why Americans aren’t shivering away in large numbers with malaria or vomiting with yellow fever. For starters, those diseases don’t dwell much in North American mosquitoes. And we don’t have the same nonstop exposure to mosquitoes as people in developing countries. We have screens on our windows. Most of us have air conditioning. Because we have running water, we don’t store pails in our kitchens where the insect can breed.
“We’re colder and drier than the places where these things show up,” said Ingrid Garrison, the Kansas public health veterinarian. “We don’t have as many places where it’s easy for mosquitoes to breed. We have trash service.”
For reasons like that, public health officials say it’s much too early to launch a Midwest mosquito war sure to be expensive and laborious.
“We’re dealing in probabilities now,” said Peter Lyskowski, the director of the Missouri Department of Health and Senior Services. “And the Zika virus hasn’t been transmitted in the continental United States yet.”
Instead, Lyskowski and other officials focus primarily on travelers heading to South America or the Caribbean. That’s where Zika has been detected and blamed for microcephaly — the birth defect that leaves children with abnormally small heads and, quite often, mental disabilities.
Pregnant women are warned particularly about the dangers of traveling to regions where Zika has hit. So are those thinking about conceiving, along with their partners. The virus can remain in a man’s semen for six months after an infection he was never aware of. Most people who get Zika show no symptoms.
At the Kansas City Health Department, epidemiology and communicable disease specialist Lisa Hubbert has been fielding 15 phone calls or more a week from worried, sometimes panicked, travelers.
“We try to get them to change their plans. Can they go another time or go somewhere else?” she said.
If they’re returning from a trip to Zika territory, she counsels them to delay pregnancy and check with their doctors for testing.
So far, Kansas has found one person who tested positive for the virus after returning to the southwest part of the state. In Missouri, 154 tests have found four returning travelers with the virus. The most recent one, announced Friday, came with a pregnant woman returning from Nicaragua. For privacy reasons, health officials won’t identify where they live in the state.
The U.S. territory of Puerto Rico has seen hundreds of thousands of Zika infections, potentially affecting hundreds of babies.
“Everything we look at with this virus seems to be a bit scarier than we initially thought,” Anne Schuchat, a deputy director at the U.S. Centers for Disease Control and Prevention, testified in Washington recently. The Obama administration wants $1.9 billion for Zika prevention efforts — everything from public education campaigns to laboratory testing to Rogers’ mosquito traps in Kansas.
“We absolutely hope we don’t see widespread local transmission in the continental U.S.,” Schuchat said, “(but) we need the states to be ready for that.”
Bracing for bites
Local officials say they monitor weekly, even daily, bulletins from the CDC and other agencies about Zika.
In the Kansas City area, there are no plans yet to fog ditches with insecticide or kick in heavy codes enforcement forcing residents to pick up the buckets and other things in their yards that might breed mosquitoes. But it could come.
“(Zika is) not occurring right here, right now,” said Nancy Tausz, director of the Johnson County Health Services Division. “But we need to plan.”
The World Health Organization says the best protection against Zika is “protection against mosquito bites.” That means wearing long pants and long-sleeved shirts in the summer and using insect repellants with DEET.
It also means keeping mosquito populations down. That’s harder.
“It is expensive work to do,” said Rick Miller, a Kansas State University agricultural extension agent in Johnson County. “It’s impractical work to do on a year-in, year-out basis.”
Mosquitoes can be beaten. The Panama Canal wasn’t built until they were. There’s talk in Florida of releasing genetically modified mosquitoes to disrupt breeding patterns, or of setting loose another species that hunts the A. aegypti. Of course, that more southern, soggy terrain is much closer to the threat.
The CDC’s maps show much of the southern and eastern parts of the United States as home to the right, or wrong, kind of mosquito. They include the Kansas City area.
Some work is underway. Kansas City residents recently received an insert with their water bills urging them to “dry up the mosquitoes” by emptying anything outside that holds water, changing birdbath water every three days, getting rid of tires stored outside and flushing gutters.
Meanwhile, the city has taken some actions to fight the biters. As supervisor of rat control in Kansas City, Michael Swoyer also battles mosquitoes. He recently put a larvicide tablet in a Northland pool that’s no longer in use and has worked with parks officials to treat their ponds.
In the end, though, he said fighting the tiny beasts demands people tend their own yards and the many places water can pool.
“It’s about people taking responsibility,” he said. “We have to look out for each other and for ourselves.”