Out for Blood

Photo: Plamen Petkov

1. An Epic Summer

They are coming. There is no doubt that they are coming. What we don’t know is when they will come and how many there will be.

The last outstanding question is: Are we prepared? From a public-health standpoint, that is, and from the standpoint of dealing with seriously annoying things. Because mosquitoes are both a major health hazard and about the most irritating creatures known to man. Even ticks are easier to get along with, which is saying a lot, given that they are bloodsuckers, too.

Biologists call mosquitoes commensals, from the Latin indicating that we share the same table. The table is our lives, in the summer. The meal is our blood.

Most winters thin the mosquito population. When weather is warmer, mosquitoes tend to thrive. This winter, as is well known, there was no winter.

2. The Sewer Skeeter

Many mosquitoes are already here, of course, waiting down the street or somewhere back in that abandoned lot where construction has stopped, in your park’s puddles or the suburban woods, anywhere there is some water, any amount really, ranging from the rainwater in a soda cap or a garbage-can lid to the gallons filling a backyard swimming pool. And they are also in the sewers. A lot of them. Those are the ones that the city seems to worry about most: the sewer skeeters.

Between the metal grate you see on street corners and the pipe below that carries water from the grate into the sewer system is a peculiar structure called a catch basin—a chamber designed to catch debris before it clogs our pipes. At the bottom, each catch basin can hold a few feet of water, perfect for mosquito eggs to float in, with air warm enough to keep female mosquitoes alive throughout the winter. These creatures not only don’t mind water that is not exactly pure like a mountain stream; they prefer it.

The catch basin is one of those things we think help separate us from natural ecosystems, when in fact it only expands them. If God, say, were to ask humans to create a system with which to breed mosquitoes, a sewer system relying on catch basins to filter debris might be it. God did not ask us to do that, but we did it anyway. We also went and created an entire landscape filled with cracks and crevices and ditches and underground chambers with hardly any mosquito predators in them. The subway is an especially great place to be a mosquito: In 1998, entomologists in England announced a new species living in the London Underground, which they named Culex pipiens molestus. Unlike the outdoor version, these mosquitoes cannot hibernate and die in the cold. But in the tube they don’t need to hibernate, or encounter the cold, so their underground life cycle can continue uninterrupted. An apartment building on West 84th Street got infested with these skeeters a few years ago, leaving those who live there with welts, and the bugs won’t leave, since they’re protected from the winter by the building walls.

One female mosquito generally produces about 200 eggs, sometimes connected in rafts as wide as a match head and as long as the fingernail on a pinkie. The new female mosquitoes will themselves soon be laying about 200 eggs. They can lay a batch of eggs as often as every three or four days, in the right conditions, which means a single female mosquito in May could multiply into many thousands come August. (Some will die, naturally, but if the world were a math problem, that mosquito would be millions upon millions by September.) And if an early spring means that a particular catch basin starts the season holding twenty mosquitoes instead of just one—well, that’s a big difference. Especially in terms of what the mosquitoes might be carrying, as far as disease goes.

3. The Scourge in Context

In the fifties, when we sprayed DDT from trucks and covered marshes with oil in hopes of killing larvae, clouds of mosquitoes were so thick on the Jersey shore “you couldn’t tell Tom from Dick,” one mosquito-control worker told Popular Science. In 1984, after a mild winter and a wet spring, the New York mosquito population quadrupled, and residents in the Rockaways were shutting themselves indoors to avoid the bugs.

How biblical will it be this time around? “Everybody’s talking about how bad it could be,” says Jim Skinner, owner of A&C Pest Management. “You know when you have a cold winter, regardless of the species, you get a good kill. And so without a winter, it should be a really good year for insects. And mammals, too. We’ve seen an uptick in mice already.”

Two species of skeeter—the common, lightercolored Culex pipiens, also known as the northern house mosquito, and the darker, fierce newcomer, the Aedes albopictus, or Asian tiger.Photo: Plamen Petkov

There is a line across the country above which winter nighttime temperatures average below freezing. That line crosses our area in the general vicinity of Staten Island, or just below it. (Climate warming has it shifting toward the Bronx someday.) Mosquitoes notice that line; if they are above it, some of those camping out till summer do not last. There are caveats to the rule—rains can help or hinder a particular species of mosquito, for instance, and some find shelter in places like sewers, where the ravages of winter are lessened—but we can say that if mosquitoes could read, they would be inclined to like the news about global warming. We can also say that after any extreme weather event, such as last winter’s lack of severe cold or our warm early spring, mosquito-control people get anxious.

Thus, health-department personnel are now tromping out to check discreetly placed mosquito traps. And helicopter pilots are being booked to spray the city’s marshes, and even certain parks, with larvicide, which kills the mosquito before it flies. This year’s war on mosquitoes has officially begun.

4. Maybe “Scourge” Is Too Strong a Word

On the other hand, most mosquito experts know better than to predict. Nobody counts total mosquito populations; there’s sampling and numbers from those tracking West Nile, but mostly, you consider a particular mosquito’s lifestyle (river, beach, sewer, tidal floodwaters, or fresh floodwaters), watch the weather, and guess. “The forecast is difficult to really nail down,” says Roger Nasci, of the arboviral-diseases branch of the Centers for Disease Control. Scott Crans, a mosquito expert at Rutgers University’s Center for Vector Biology, agrees: “It’s not an easy explanation.”

Weather is everything for mosquitoes, but the environmental variables are complex, and different mosquitoes hatch under different conditions. A sewer-based mosquito likes a long hot summer with not too much rain, since rain washes away its eggs. A mosquito that lays its eggs in a floodplain, on the other hand, needs rain—the eggs won’t hatch until water reaches the eggs, parked in the mud of the vernal pond or drainage basin. And this year, there is an argument to be made that, despite the temperature, the weather could be working for us: This winter was relatively dry, thus depleting habitat for those who like to lay eggs in wetland ponds, and the spring came early, meaning many mosquitoes emerged from their eggs early, making them vulnerable to a spring freeze. Depending on the species of mosquito, cold can equal death.

5. The Enemy

Looking closely at the mosquitoes biting you, you’ll see a lot of different kinds out there: about 150 species in North America and close to 60 in the New York area (3,000 in the world). At any given moment, dozens of species dart and hover over the city, wings beating at an estimated 250 to 600 beats per second, like airplanes about to take off from JFK, La Guardia, and Newark. Those that fly at night are guided by stars; by day, polarized light from the sun.

The Culex pipiens is the star, in terms of visibility and West Nile–spreading potential, but despite its star status, it is a boring-looking mosquito. Its alias: the common house mosquito. Its look: brown and gray with relatively unmarked gray legs and a compact antenna. It prefers murky water and likes to drop its egg floats in catch basins; it is the gray rat of mosquitoes. A pipiens prefers a blood meal from a bird and so will come out primarily in the evening, when birds roost in the trees, their breath creating invisible columns of carbon dioxide that the pipiens follow to their meal. If there is no bird in the vicinity, they will find a human. “It’s like steak or a hot dog—if you take the steak away, people will take the hot dog,” says Dickson Despommier, professor emeritus of public health at Columbia and co-host of the podcasts “This Week in Virology” and “This Week in Parasitism.” “For the Culex pipiens, we are the hot dog.”

Of the Aedes vexans it has been said, “They will chew on a rock if they get a chance. They will even go after hubcaps.”

The Aedes solicitan is a salt floodwater mosquito that can travel for miles—an F-14-like creature that could audition for the next installment of Transformers. Striped legs, with a band of white scales around the center of its proboscis. It seems to curl as it stings—a yoga move. This is the mosquito that Dutch settlers in the Meadowlands said was as big as a sparrow.

The Aedes albopictus is the new mosquito on the block—an especially efficient disease carrier also known as the Asian tiger. It likely came to New York from Houston, it is believed, in a shipment of old tires. It is known as a “hard biter.”

6. The Life of a Mosquito, In General

I am a mosquito. I am born as an egg that hatches into a larva. (Mosquito people call larvae “wrigglers.”) Then I become a ­comma-shaped pupa, then I hatch, then my exoskeleton hardens, then I fly. If I am a male mosquito, I eat nectar. I am attracted to individual females by the sound of their wings—a nice wing sound makes me crazy for mosquito sex. But humans do not interest me, no matter what. I can get no nectar from humans, and I am not interested in blood. I live for one week, get laid, and die.

If I am a female mosquito, I eat nectar and take blood for my eggs. I can live longer—months. No matter what kind of mosquito I am, I lay my eggs in water. I might prefer clean freshwater, or saltwater, or brackish water, or water that is polluted, containing more bacteria, frankly. Where I lay my eggs is a matter of species preference and personal preference. I might end up in water the size of the pond in Central Park, or the top of a Snapple cap on 23rd Street. But any water will do. And then I feed. As an average mosquito, in an average human blood heist, I take away about three times my own body weight in blood.

7. Hunters

“They’re hunters,” says Leslie Vosshall, the Robin Chemers Neustein Professor at the Rockefeller University of New York, an expert on the science of smell and someone who is not afraid to put her arm into a chamber of mosquitoes and get bitten a lot. “And they’ve adapted to be very sensitive to the smell of their prey, be it birds or humans.”

The cells that transmit scent to the mosquito’s brain have the same shape and structure as those in the human nose, but are shoved into antennae and are more sensitive to odors. And they do have preferences: In some cases, “one individual will attract 90 percent of the mosquitoes and another only 20 percent,” says Vosshall, though we don’t yet understand why. “They are sensitive to human skin odor in ways that are unimaginable to humans, so we can just expose them to a one-by-one-inch square of human skin in the lab and run some air over it, and the mosquitoes will just go wild.”

What happens to a mosquito in this state of aromatic frenzy? It unsheathes its beaklike proboscis, preparing to penetrate the skin of its victim. The proboscis contains six separate tubes and stylets. It begins a complicated process of fluid dynamics such that chemicals are injected, fluids withdrawn. Put another way, it sucks and spits. Among the stuff injected is an anti-coagulant saliva, to ease the extraction, and a painkiller that gives the mosquito time. In that time, the bug inserts and withdraws its proboscis repeatedly, searching in the flashy darkness for a capillary, which, when found, is probed, as if the mosquito were conduting a ­teeny-tiny angiogram.

8. The Rats of the Air

Mosquitoes aren’t just irritating—they’re not just about stinging and itching and buzzing in your ear. (The theory about the buzzing, by the way, is that they fly toward the ceiling of a room, tracking the carbon dioxide, then dive down to sting, passing an ear.) They are one of the deadliest creatures in the world, killing over 1 million people a year via disease. They carry at least five forms of encephalitis—Eastern equine, Western equine, Japanese, La Crosse, and St. Louis. They also carry dengue fever, yellow fever, Rift Valley fever, malaria, and West Nile virus.

Mosquitoes spreading yellow fever took out one ninth of the population of New York in 1702. In 1793, when Philadelphia was the U.S. capital, 5,000 people out of a population of 45,000 died. Yellow fever struck the United States repeatedly in the eighteenth and nineteenth centuries. Memphis suffered terribly in 1878, with as many as 150,000 deaths. “A lot of people think of mosquito-borne illness as something from another country,” says Joseph Conlon, a former naval entomologist, now technical adviser to the American Mosquito Control Association. “But we had about 128,000 malaria cases annually up until 1935.”

9. The Mosquito Moment

West Nile Virus entered the U.S. in 1999, landing first in Queens. It was brought by Culex pipiens. Between August 12 and August 23, 1999, six people were admitted to Flushing Hospital with similar symptoms—high fever, altered mental state, and a headache. In three weeks, three of the elderly patients died.

West Nile is an odd virus. It may not infect you, and you may have picked up an immunity after a decade of living around it—maybe getting infected by a pipiens, perhaps thinking you had the flu. Eighty percent of people infected will feel fine; close to 20 percent may have flu symptoms. But one out of every 150 people will suffer from tremors, convulsions, muscle weakness, vision loss, numbness, and paralysis. They may end up in a coma, and the neurological effects can be permanent. In other words, West Nile can kill you.

Initially, officials thought it was just St. Louis encephalitis. Meanwhile, birds were dying everywhere, especially crows. Before 2000, New York City had a crow problem. West Nile took care of the crow problem.

At first, no one noticed. Local exterminators, protesting a law being considered to ban a poison, had unloaded a bunch of the poison in local parks. Birds ate it, and died. Investigators were inundated with dead birds as a result, and didn’t notice West Nile, which, according to Despommier’s theory, probably came to New York with a tourist bitten at an Israeli goose farm—the geese raised to produce foie gras.

10. After West Nile

The West Nile Virus completely changed how the city worries about, plans for, and fights against mosquitoes. Before 1999, the city was not so worried about pipiens per se—they’d order spraying in parks and marshes and at beaches, targeting adult-mosquito populations. Mosquito experts call this “adulticiding,” and consider it far less effective than attacking larval populations, when the toxin needs to be much less toxic. At one point during the initial West Nile breakout, the Giuliani administration had helicopters spraying highways and neighborhoods with malathion, an organophosphate pesticide, related to nerve gas, which kills mosquitoes by disrupting the action of their nerve cells. Mosquito-control workers said the spray made them ill. Critics said the pesticide helped kill off the lobster population in Long Island Sound—lobsters being sort of like giant mosquitoes, if you think about it. At one point, Giuliani put fish in the sewer-treatment plants, to eat the larvae.

After West Nile, the city began to do a better job thinking about mosquitoes, especially under the leadership of Waheed ­Bajwa, who is now the executive director of the Health Department’s Office of Vector Surveillance and Control. (A vector is the medical term for anything that spreads disease from one creature to another, like the fleas that carried plague from rats to people during the Black Death.) A citizen will hear from Bajwa if he keeps a birdbath full of water—remember, a pipiens needs just a thimbleful to ruin your day and the days of your neighbors. And a citizen can consult his department’s press releases and maps—they publish the results of the West Nile sampling surveys throughout the summer. Last year, the black-and-white maps of the city were devoid of red hot spots marking West Nile reports in the early summer, but slowly Staten Island went red, along with parts of Brooklyn, Queens, and the Bronx, and then the West Village—a surprise. (Turned out, because Washington Square Park was under construction, the mosquito larvae could not be treated.)

But the people out in the field dealing with the pipiens problem are not city workers but exterminators—in particular, the men and women at Kingsway Exterminating. Motto: “We kill with skill.” They are a family business, operated by Richard Kourbage, who responded to a call for bids from the city after the West Nile outbreaks.

11. Kourbage’s Army

Kourbage is getting ready. He sits in his office overlooking an intersection of catch basins on Flatbush Avenue, on the border of Marine Park and Flatlands. He arms his crews with tea-bag-like packets of crystals, which release a bacteria that is eaten by mosquito larvae, lodging lethally in their gut; in the U.S., it goes by the brand name VectoMax WSP.

“It’s always best to start early,” says Kourbage. “Mosquitoes can be overwhelming in a short time. We don’t want them to get a foothold.”

Kourbage has been in the business since 1962, working with rats, roaches, and now bedbugs. He was trained by Chuck Schumer’s grandfather and great-grandfather (the senator comes from a long line of exterminators). Kourbage and his men visit each catch basin in the city, over 200,000 of them. In crews of two dozen men, they visit each about four times. They use bikes to speed the trip—folding bikes that can fit in cars or be taken on subways.

At first, the men were mistaken for terrorists and reported to police. Now the police are aware of them. So they don’t repeat treatment of a single catch basin, they leave a colored dot on the basin when they’re finished; the history of the city’s war with pipiens is written on our curbs. “We’re not allowed to use red or orange,” says Kourbage. “We’re limited by the city to certain colors. Black we did once. Silver we’ve used.”

Catch-basin density is a neighborhood thing: seventeen of them, for instance, at the intersection of Hillside Avenue and 240th Street in Bellerose, Queens. “In Queens, you could go five blocks and get 100 catch basins,” says Saifee Mehta, Kourbage’s deputy in charge of the catch-basin fleet.

Kourbage got into the business accidentally; he was going to be a cop and took a temporary job. “You were solving problems on a day-to-day basis—on an hour-to-hour basis, actually.” But he takes great pride in what he does. “It has been a very great project for us and for the city and for the citizens of New York, basically, because nobody’s dying, and it’s basically ’cause of us.”

12. The Next West Nile

West Nile tells us that as the world gets smaller with air travel, and as the barriers between animal and human illnesses break down, we are going to be experiencing new illnesses, many from pathogens brought to us courtesy of vectors such as mosquitoes.

The next pathogen on the CDC radar is Chikengunya virus, which causes seriously debilitating joint pain—months-out-of-work debilitating—and is known to be transmitted by the Asian-tiger mosquito, among others. (As opposed to West Nile, a large percentage of those infected with the virus show symptoms.) The name comes from the East African Makonde language, from the word meaning “that which bends.” It was first isolated in Tanzania in 1953. It has caused epidemics in Africa and Asia and most recently Europe. It is most likely already here.

13. Skeeter Silence

What does the health department say about the upcoming summer? Nothing. Maybe they don’t want to panic people. Maybe they’re not that worried. They just won’t say.

14. Mosquito Hazmat

Does DEET work? Debatable, though under a microscope you can see the mosquitoes reacting to it, cleaning it from their feet and mouth parts, more or less as we would if we had it sprayed on our feet and mouth parts. Which is more or less what the experts are asking of us: “DEET, if you wear it properly, can be highly effective, and properly means you have to wear the higher formulations,” says Vosshall. “So you’ve got to go to the highest concentration that’s sold to consumers and be very diligent about spreading it in every part of the skin.”

Because they will get us. The chances are pretty good they won’t kill us. But they will get us. When we finally find time for a vacation, or just a beer on the stoop (watch for cops), or in the backyard, if you have one. They will unsheathe their proboscis and suck the hell out of us, depositing, at least, the irritants that will make you itch. If that’s all they deposit this summer, the mosquitoes will be merely a nuisance. All they do is bite.

Out for Blood