The D.C. Monument Full of Zika Mosquitoes
The newest monument in Washington, D.C., is not a soaring stone obelisk or a bigger-than-life statue but a thigh-high cement birdbath.
Once two tiered, now one, the birdbath is no less apt a symbol of unconscionable inaction in the Capitol three blocks away.
On each of the previous four years, the birdbath has produced living specimens of Aedes aegypti mosquitoes, best known for carrying the Zika virus.
And, even as the Senate proceeds to the Fourth of July recess without passing a bill funding Zika research, a scientific team is poised to test whether the birdbath and its immediate vicinity have produced a fifth generation of the bugs.
“People need to have the Congress have a tour and look at the birdbath,” says David Severson, an eminent researcher at the University of Notre Dame specializing in the molecular genetics of disease transmission by mosquitoes.
So far, none of the Capitol Hill mosquitoes have been tested for Zika, and there is no reason to believe they are carrying it, but there is a chance—however slight—that one of them will happen to bite an infected human. That mosquito could then bite someone else and pass on the virus.
“It’s a slim possibility, but is possible,” Severson says.
Such slim possibilities—along with “transovarial transmission,” in which a small percentage of females infect their eggs—have spread Zika bite by bite since it was first discovered in 1947 in the Ugandan forest from which it gets its name.
“They just like people,” Severson says of Aedes aegypti.
And the presence of these mosquitoes as far north as Capitol Hill was itself such a slim possibility as to astonish the scientist who first found one there nearly five years ago.
The scientist, 34-year-old Andy Lima, is a mosquito biologist as well as a musician and rapper who goes by the name MC Bugg-Z. He offered to take a look when a music buddy complained to him in October 2011 about getting bitten in a garden apartment in Capitol Hill.
Lima visited the apartment and, sure enough, spotted a mosquito. He swatted it with a cupped hand, so as to stun but not squash it.
“In a way only a mosquito biologist does,” he recalls.
On examining the unsquashed thorax of this lone female, Lima was surprised to behold the lyre shape that is the distinctive marking of Aedes aegypti, a primary vector of dengue as well as Zika. The species is not known to live in such an untropical clime.
“I said, ‘Wow, that’s very interesting,” Lima remembers. “I kind of didn’t believe it.”
Lima surveyed the area around the building where his friend lived and found Aedes aegypti larvae in various places, notably including the birdbath. He reasoned that Aedes aegypti probably arrived at Capitol Hill in a shipping container or some other chance conveyance from its native habitat. He assumed that these mosquitoes would not survive the winter.
“I didn’t expect that they would be able to overwinter at all,” he says. “It’s not known to happen this far north.”
But the following September, he decided to check, again dipping a metal cup into the birdbath and other likely places.
“I thought there’s no way this thing is here again, but let me take a look,” he recalls.
Lima again found her larvae. He wondered if perhaps the area had been reinfested.
He came to figure otherwise when he found the larvae again the next year and the next, each and every time in the birdbath.
Lima reared some of the larvae into adults, then froze and dried them. He killed other larvae with hot water and preserved them in ethyl alcohol. He sent the specimens from the various years to Severson’s lab at Notre Dame for genetic analysis.
DNA comparison showed that the infestation was a single, continuous population that must have found some way to survive the winter cold, most likely by seeking refuge underground. The findings were reported in a paper published in the November 2015 issue of The American Journal of Tropical Medicine and Hygiene.
“Evidence for an Overwintering Population of Aedes aegypti in Capitol Hill Neighborhood, Washington, DC,” the title announced.
The paper included an aerial map showing the various places larvae had been collected. There was a “TC” for a trash can as well as a “PS” for potted plant saucers. And there was a “BB” for birdbath.
“BB breeding site, where larvae were detected all four collection years,” the paper noted.
Lima figures on making this year’s collections sometime after the Fourth of July weekend. There is every reason to believe that the newest generation of Aedes aegypti on Capitol Hill has been stirring three blocks away—even as the House and Senate have failed to come up with funding for Zika research and control.
And that was not the only public threat that the Congress failed to address. House Democrats became so frustrated last week with the failure to pass even modest new gun control bills that they staged a sit-in.
House Republicans then sought to change the subject by pushing through legislation that included $1.1 billion for Zika but also several “poison pill” provisions they knew the Senate Democrats could not accept. These included offsetting cuts in Obamacare and Ebola preparedness as well as restrictions on how Planned Parenthood could utilize funding in terms of pregnancies, contraception, and possible sexual transmission of the virus.
The Senate Democrats responded as the Republicans knew they would. The Republicans then sought to make it appear that the Democrats were allowing petty politics to place the most vulnerable Americans at risk from Zika.
“So today Democrats have a choice: continue pushing thinly veiled partisan arguments and block the Zika control funding or join with us to advance a serious solution and send critical funding to the president’s desk right now,” Senate Majority Leader Mitch McConnell said on the floor. “We should pass it to protect those especially at risk—pregnant women and babies.”
Senate Minority Leader Harry Reid replied: “I don’t know what planet my friend the Republican leader is living on.”
Reid termed the bill “the most irresponsible legislation I have ever seen in my 34 years in Congress.”
“That says a lot,” he added. “I can’t think of anything that is close.”
He said the Republicans were the irresponsible ones for tying the Zika funding to “nothing more than a goodie bag for the fringes of the Republican Party.” He also cited the numbers from the Centers for Disease Control and Prevention: Two thousand nine hundred Americans have contracted Zika, up 700 just from last week. Eight pregnancies here resulted in severe birth defects because of the virus.
“And when we talk about severe birth defects, we mean it,” Reid said. “They have little shrunken heads and their skulls are caved in. Mosquitoes have caused problems forever, but never like this.”
What is known about Aedes aegypti mosquitoes is that they are equally willing to bite Democrats and Republicans. And they are so indiscriminate in their hunger for human blood that they will feed even on politicians such as come and go just a short buzz from their birdbath outpost on Capitol Hill.
But too much else about the mosquitoes and the disease they can spread will remain unknown without funding for research.
“There’s so little information out there,” Severson says.
Records show that Zika was first detected in humans in 1952 in Africa, followed by cases in Southwest Asia and the Pacific Islands, but totaling as few was 14 cases before 2007. The first case in Brazil was confirmed only in May 2015. Then something happened, and by February of this year, it had become what was described by the World Health Organization as “a public health emergency of international concern.” Severson says scientists still do not yet fully understand how a virus such as Zika suddenly becomes a mosquito-borne terror.
“It’s really tough,” he says of working with such limited knowledge.
He adds, “There are a lot more of these obscure viruses. It could happen with others.”
In the meantime, Congress will be breaking for the Fourth of July weekend, and Lima expects that he will soon once again check the birdbath and other spots on Capitol Hill.
“Five years running,” he says.
He is careful not even to suggest that the mosquito-control authorities in Washington, D.C., are doing anything less than all they can. He joins mosquito biologists everywhere in saying the best way to counter Zika at the moment is prevention. They recommend wearing long, loose, light-colored clothing; applying an approved repellent that has the active ingredient DEET; eliminating standing water around the home; and trying to stay indoors at the peak feeding times, dusk and dawn.
In his rap-biologist persona as MC Bugg-Z, Lima will soon be adding to the prevention effort by dropping a music video, “Zika 101.”
“Vector control...vector control...
Yo, don’t get sick with Zika from the bite of a mosquita
Prevention is easy, relax and I’ll teach ya
Empty water from containers and dress to protect
When you feed ’em you breed ’em
So wear approved repellant.”
Both sides of both the House and Senate would do well to heed the advice when they return to doing nothing just three blocks from Washington, D.C.’s newest monument, a birdbath for bird brains.