It seems a little-known fact that one of the world's leading authorities and engineers of mosquito abatement tactics is headquartered in St. Charles, Illinois. The City of Batavia, Illinois contracts with Clarke to help residents stave off the annual onslaught of mosquitoes.
To show how and why certain mosquito abatement methodologies work, Clarke researcher Julia Moore leans close to one of the mesh-covered mosquito cages in the lab and exhales a stream of air into the presence of about 50 adult mosquitoes. The insects lift into a frenzied swarm. “It’s the carbon dioxide in our breath,” she explains. “These mosquitoes would react even more if they're weren't already well-fed. Mosquitoes in the wild are flying around half-starved. So they get kind of aggressive.” And that explanation, she grins.
That little experiment explained why mosquitoes are such pests to human beings. The air that human beings and other mammals exhale creates a chemical trail that can be followed by female mosquitoes seeking a blood protein meal to coincide with their breeding cycles. It’s a relationship that has had a long time to evolve, yet rather rare in the insect world as a whole. According to the NCBI website,
"Blood-feeding as a behavioural adaptation is exceedingly rare in insects. Of the 1-10 million insect species on earth, only ~10,000 feed on the blood of live animals1. Among these, only about 100 species blood-feed preferentially on humans1. When biting insects evolve to prefer humans, they can spread diseases such as malaria and dengue fever with devastating efficiency. The mosquito Aedes aegypti provides one of the best examples of specialization on humans. It originated as a wild, animal-biting species in the forested areas of sub-Saharan Africa, where the subspecies Ae. aegypti formosus is still often found living in forests and biting non-human animals today2-4. The derived non-African subspecies Ae. aegypti aegypti, in contrast, has evolved to specialise in biting humans and thus has become the major worldwide vector of dengue and yellow fevers2-4."
For all the seemingly exotic origins of biting mosquitoes, it is well-documented that 250 years ago in Illinois, mosquitoes bearing malaria were a genuine problem for settlers. Yet even with eradication efforts in full swing around the world, the risk of disease mosquito-borne diseases has increased thanks to the effects of globalization and distribution of mosquito species around the world.
West Nile virus came to America from the Middle East. Its symptoms can be subtle for some people. The Illinois Department of Health notes: “Common symptoms include fever, nausea, headache and muscle aches. Symptoms may last from a few days to a few weeks. Four out of five people infected with West Nile virus will not show any symptoms. However, in rare cases, severe illness including meningitis or encephalitis, or even death, can occur.”
Indeed, one elderly Batavian became gravely ill from a West Nile virus infection. Recovery required weeks of medical treatment[LM1] . Since 2002, there have been more than 2000 cases of West Nile in Illinois, with some years numbering more than 100 cases while in other years, only a handful. Mosquito activity is highly weather dependent, and West Nile-carrying mosquitoes amplify the virus during hot, dry summers. The virus is now endemic in the northern Illinois region.
So the task of mosquito abatement is a serious situation in Fox Valley communities. That fact has been heightened in recent years by the arrival in the United States of a mosquito that bears a virus called Zika. Already there are locally transmitted cases of Zika in Florida and Texas. Travel-related cases have appeared in every state. This fact is a genuine threat to human populations because there is no known vaccination against the virus, which has disabling effects on children borne to women infected by the virus while pregnant. That is why mosquito prevention and abatement remains has become an even higher priority in areas where Zika has been detected.
But here’s the strange truth about Zika-bearing mosquitoes. The species of mosquito that bears the Zika virus typically breeds very close to the proximity of its birth. They actually don’t fly far to bite anyone. Their typical range is perhaps 1/8 of a mile. That[LM2] is why the Center for Disease Control issues warnings on how to control mosquitoes inside and outside your home. The Aedes aegypti mosquito (the primary vector for Zika) is very rarely found in the Chicago area, but the advice from the CDC is important to protect from all mosquito-borne disease.
- Use screens on windows and doors.
- Repair holes in screens to keep mosquitoes outside.
- Use air conditioning when available.
- Sleep under a mosquito bed net if air conditioned or screened rooms are not available or if sleeping outdoors.
- Once a week, empty and scrub, turn over, cover, or throw out items that hold water, such as tires, buckets, planters, toys, pools, birdbaths, flowerpots, or trash containers. Check inside and outside your home. Mosquitoes lay eggs near water.
Standing water and life cycles
Managing standing water is critical to mosquito abatement. In fact it drives much of the education provided by companies such as Clarke, a global mosquito abatement and aquatic services company headquartered in St. Charles, Illinois. Because while the company is paid to control mosquitoes, real results are just as likely gained through education about cleaning up standing water as through other means.
In urban areas, standing water is the key source of breeding potential for mosquitoes. In areas such as Batavia where Clarke is contracted to manage mosquito populations, the company seeks to educate the public on how and where mosquitoes breed. “One of the challenges is some people assume only notice swarming mosquitoes and think they are the most dangerous kind as they emerge from the woods. But many mosquitoes can breed right on a homeowner’s property. So we encourage people to survey their gutters, water features, even the downspouts where there are accordion-style crimps that catch water. Mosquitoes will breed anywhere they can find standing water.”
Understanding the life cycle of mosquitos is important to controlling their populations. Mosquitoes begin as eggs and go through larvae and pupae stages before emerging as flying adults. In some species, mosquito eggs are extremely durable and do not hatch for periods of up to three months. That means they can be transported long distances without detection or destruction. All it takes for a dangerous species to be transported from one part of the world to another is for eggs for larvae to go undetected in some international shipment, and the invasive species is unleashed in an entirely new environment.
Disease-bearing mosquitoes are a worldwide problem. Organizations including the Bill and Melinda Gates foundation provide massive amounts of money to fund disease prevention programs in developed and undeveloped countries. Strategies range from distribution of sleeping nets to chemical and natural mosquito abatement programs.
The science of mosquito abatement is continually evolving. Companies such as Clarke have invested in green chemistry products to replace conventional chemistries such as temephos, an organophosphate larvicide that had been in the company’s menu of products for more than 35 years. But the process of introducing greener products is not some overnight phenomenon. Generally it takes more than 10 years to bring a new product to market. The process includes chemical experiments, product engineering and tests, and regulatory reviews before a mosquito abatement product is even approved for use.
Those processes are closely married to the study of application strategies that make products safer and more effective for use in a broad spectrum of environments. Mosquito abatement products are categorized in segments such as natural or naturally-derived, biochemical, microbial and synthetic. All are used in specific applications.
In the case of Clarke, the company has created products under the banner EarthRight that use only products made from naturally derived OMRI (Organic Materials Review Institute) listed active ingredients.
Companies such as the power giant ComEd, whose workers often operate in situations where nuisance and disease-carrying mosquitoes are a problem, have adopted EarthRight products that help protect surrounding residential and natural environments.
To carry out these functions in line with an overall sustainability objective of its own, Clarke dispatches its own line of electric vehicles from its St. Charles campus. The power for the vehicles comes from 280 solar panels covering the roof of its 27,000 square foot facility. The panels actually returned power to the grid in 2015.
So the commitment to sustainability is considerable. And when Clarke associates fan out into the field to conduct community education or survey neighborhoods, they often do so on a fleet of bicycles which gives them a direct feel for the neighborhoods in which they’re operating.
The broader questions facing companies like Clarke are obvious when the use of pesticides and insecticides in the environment is a concern to many millions of people. The company questions use of some pesticides favored by agriculture, which do not always kill the insect pests they target, but instead wind up lingering in the environment where the insects that absorb traces of the chemicals actually build up resistance over time. “They actually become more difficult to kill,” notes researcher Julia Moore.
Which is why Clarke takes specificity so seriously. Their research lab breeds mosquitoes in-house to monitor and measure every aspect of the insect’s development and disease-carrying capacity. Clarke tests products not only for their chemical effectiveness, but for the best method of application. “When it comes to spraying for adult mosquitoes, first we push carbon dioxide out into the environment, which gets the insects flying. Then we introduce active ingredients targeted to specific aspects of the target mosquito’s physiology.”
Well fed species
Which explains why mosquitoes can be such a nuisance, and such a threat. Yet it is important to remember that mosquitoes have recently evolved in concert with human populations, and that means the destinies of the two species may be far more closely tied than we might like to believe. It is a symbiotic relationship in some respects.
So that buzz in your ear when a mosquito invades your bedroom or hovers near your ear at an evening picnic seeking a meal of human being could be seen as something of a love song from the mosquito’s perspective. The trick for the human race is to discourage these stalkers grin ruining our lives. It is a battle that is not likely to end anytime soon, and it all starts at home.