Household Pests: The Top Risks to Public Health

Which common pests present the greatest health risks?

In the world on pest control, debate constantly rages regarding the appropriate use of pesticides, which pesticides are the most effective, which are the most dangerous to humans, etc. In conjunction with the US government (the EPA, specifically), the companies that produce these pesticides are required to identify the various pests that pose the most significant health risks to human beings. In an effort to more accurately and efficiently design pesticides to eliminate these pests, and to curtail the risk to humans with their use, this list enumerates the pests and vermin that represent the greatest physical health risks. Some entries on this list, like mice, mosquitoes, and bedbugs, have been discussed extensively on other posts.

Cockroaches:

Cockroaches rank among the most common household pests. Like other vermin, they feed on both unsupervised human and pet food. Cockroaches have been known to trigger asthma and have also been known to passively transport harmful microbes that can contaminate food supplies.

Body, head, and crab lice:

Lice are known to beset almost every mammal on earth. They are the hated cause of skin irritations and rashes on humans and, furthermore, are known vectors for diseases like epidemic typhus, trench fever, and epidemic relapsing fever. Human beings, as opposed to different types of animals, can host three different types of lice: head lice, body lice, and pubic lice.

Mosquitoes:

I’ve waxed lyrical about mosquitoes on this site in the past, and they’re recurring subjects of analysis precisely because they’re so dangerous. Yellow fever and Dengue fever have particularly affected travelers in the Caribbean, Central America, South America, and South Central Asia. Likewise, malaria is the most serious and widespread health concern caused by mosquitoes on a global level. West Nile virus is a health concern within the US, while Eastern equine encephalitis virus tends to afflict geographical regions in the eastern United States.

Ticks:

Like mites—and indeed, mosquitoes—ticks are particularly insidious pests, because they can stay latched onto their host, feeding on its blood and possibly transmitting diseases all the while, and remain undetected with ease. Ticks are vectors for a number of diseases that afflict both humans and other animals. Ticks can transmit Lyme disease, tick-bourn relapsing fever, ehrlichiosis, and Rocky Mountain spotted fever.

Bedbugs:

Bedbugs, too, have a particular prominence on this blog, partly because of their resurgence in urban areas, and partly because no-one wants to have their blood sucked while they’re sleeping—apart from vampire fetishists, I mean. Thankfully, bedbugs are incapable of transmitting blood-bourn diseases, but their bite can still cause significant allergic reactions, the severity of which depends on the host.

Rats and mice:

The chief concern with rodents like rats and mice are their ability to harbor fatal diseases and to contaminate human food supplies with those diseases. As is fairly common knowledge, rats were chiefly responsible for harboring and spreading the bubonic plague during the middle ages, and can also harbor diseases like Lassa fever, leptospirosis, and Hantavirus.

The Cost of Mice

 

What is the cost of a mouse infestation in both health and economic terms?

In the past, I’ve said that mice and other rodents can be spectacularly destructive pests—which is true, of course. However, what I’ve failed to elaborate on are the various ways in which mice can pose a threat to humans in both health and economic terms. The degree of potential damage that mice can pose naturally depends on the size of the infestation in question, but considering the fact that the typical house mouse can breed incredibly quickly, the initial presence of a few mice in the home can quickly lead to the appearance of dozens more in a surprisingly short amount of time. That said, dealing with a significant mouse infestation might seem like the perfect Sisyphean task on the surface, but the key to successfully getting a hold on the problem is to become familiar with the telltale signs of mouse incursions in the home and to catch them early on, before they have an opportunity to breed. Remember: an ounce of prevention is worth a pound of cure.

In a home or commercial environment, mice will always seek out stored foodstuffs or pet food; mice aren’t particularly picky eaters, it must be said. What’s more, the food that the mice don’t actually consume will likely become contaminated by their urine, droppings, or hair. While a single mouse might only consume around 8 pounds of food per year, they have the potential to render useless vastly more than that, thanks to their habit of nibbling on many pieces of food and discarding partially eaten items.

On farms, mice are particularly unwelcome, as they routinely destroy feed storage structures and feed transportation equipment; as one can easily imagine, the massive amount of food collected in a single location is nearly irresistible target. House mice living in fields will likewise have no problem digging up and feeding on newly planted grain; they may also damage crops before the harvest. However, losses to previously-stored food are significantly greater, and therefore pose a much more formidable economic threat. As mentioned previously, the real threat is widespread contamination of this feed with disease-causing urine and feces.

When mice decide to take up residence in a home, they almost always cause some degree of structural damage. Their near-constant gnawing and nest-building activities can destroy insulation inside walls and attics. Exacerbating the problem even more, mice like to make their homes inside electrical appliances and can chew through wires and cables with ease. As such, short-circuits and other fire hazards are very real and constant concerns. Even if good fortune prevails—for a time, anyway—these wires and other electrical equipment are often costly to replace, and will likely have to be carried out by and experienced professional. Mice living in attics or basements also have easy access to any antiques are heirlooms that may be stored there. If a mouse sees fit to damage these items, they may be extremely difficult or even impossible to replace.

Bedbugs: Identification and Extermination

How can I identify and kill bedbugs?

As I covered last week in my brief history of bedbugs, these insanely irritating insects have largely avoided the pest control industry’s attention since the 1960s, meaning that there’s a bit of a knowledge gap about how to get rid of and prevent a bedbug infestation.

The good news is that the world’s top minds are at work as we speak—or, as I write, rather—trying to figure out just how this plague on our nation came to be, and new information about this insidious pest is being published every day!

Firstly, it’s been recently discovered that bedbugs can’t climb up smooth vertical surfaces like glass and some plastics. However, scientists conducting an observational study on bedbug behavior were shocked to discover that, when confronted with a smooth, Pyrex glass bowl, a bedbug had seemingly little issue climbing up and out. It was later concluded that the bowl might have been covered in dust particles which the bedbug might have been able to use as a foothold, or that the glass had minute fissures in its surface that were undetectable with the naked eye. That said, it’s important to keep your pitfall-style traps clean and reasonably smooth.

Bedbugs aren’t the fastest insects in the world—it’s true—but when its prey is an immobile, sleeping human being, speed is hardly a necessity. Bedbugs can move at an average speed of about four feet per minute: that’s about a twenty-two hour mile for those interested.

Some recent research suggests that, while bedbugs are surprisingly hardy at low temperatures, they’re fairly defenseless against even the mildest heat treatment. Most studies agree that temperatures as low as 113 degrees Fahrenheit can fry bedbugs. Likewise, temperatures of about 120 degrees Fahrenheit can kill bedbugs, at all stages of development, in about a minute.

However, due to their tiny size—and the even smaller size of their eggs—it’s easy for bedbugs to hide in the folds and stitching of mattresses, meaning that getting rid of them might take a bit more muscle than running the casual heat lamp across the surface of your bed.

Mosquitoes and Feeding Habits

How do mosquitoes home in on their targets?

As I’ve mentioned before on this very blog, female mosquitoes bite because they need the protein in our blood to develop their eggs. But how do they choose their targets? What makes humans so special? Why can’t they just prey on dogs or cats—or other insects for that matter—and make the world a slightly happier place in the process?

Well, I’ll tell you. Mosquitoes choose their victims through a combination of smell, heat, and visual cues, and can continue sucking—either on the same host or a different one—until their abdomens are full of our sweet, delicious blood. The females (the only bloodsuckers, remember) can live up to about a month, and will generally feed every two to three nights during that period. Most, though not all, species of mosquito feed at dawn and dusk, and for a few hours into the evening.

Mosquitoes can detect the carbon dioxide expelled by humans when we breathe, and their highly sensitive antennae can detect these plumes of CO2 from hundreds of feet away. Once a mosquito has locked on to this carbon dioxide signal, it follows it to the source where it will look for a number of other chemical signals that it finds incredibly enticing. Human skin, for instance, produces an irresistible chemical cocktail of about 340 separate substances.

Interestingly, certain people do attract a larger number of mosquitoes, though scientists aren’t exactly sure why. It’s been observed that larger people and pregnant women tend to attract more mosquitoes, possibly because they expel more carbon dioxide. Likewise, colognes, lotions, perfumes, and other topical oils have been known to attract more mosquitoes.

The mosquito also relies on its large, photosensitive eyes to guide it towards its prey. Thermal sensors on the creature’s antennae also allow the mosquito to detect heat emanating from unprotected skin, which obviously makes it easier for it to get at the valuable blood underneath.

Once it lands, the mosquito will penetrate the skin with its serrated proboscis—which I discussed at length last week—and will proceed to feed until its abdomen is completely distended, whereupon it flies off, leaving its host with an irritating souvenir.

Ants: The Individual and the Colony

How do ant populations thrive without centralized leadership?

As human beings, we might find it remarkable that an ant colony is able so survive—and in many cases thrive—without any centralized leadership or any discernable hierarchal structure. Yet, as far as we know, ants always function primarily as individuals, though in service to the colony.

Although the term “queen” is used to describe the principle egg-laying female, it should be understood that the queen ant merely lays eggs and is, in turn, fed and cared for by the workers. She does not decide which worker fulfills what task and “issue orders,” as it were.

It’s precisely this absence of central control that has fascinated scientists for years. How is it that, despite this apparent setback, ants have achieved such a degree of evolutionary success? Could this same method be copied and applied to the intricacies of human society?

No individual ant has the capacity to know the global needs of the colony, or to know how many workers are engaged in a specific task at a given time. In short, the capacities of the individual are limited. That said, experts suggest that individual workers only need—and more to the point, are only capable of—making very simple decisions.

Accordingly, biologists have suggested that it should be possible to explain the state of an ant colony as a consequence of simple decisions made by individual ants. Given its inability to make complex decisions, it’s probably safe to assume that an ant’s behavior is based on what it perceives in its immediate surroundings.

Even on an individual level, an ant may not always respond the same way to the same stimuli. Rather, a given influence will increase the probability that an ant will act a certain way, which leads scientists to draw conclusions concerning ant behavior to fairly predictable tendencies as opposed to strictly deterministic outcomes.

Task allocation within ant communities is not strictly a black-or-white process. An ant may get swept along in a tide, so to speak, and find the immediate environment in inhabits requires a specific task. With each individual behaving in more or less this manner, the strength and success of a colony lies in the number of individuals.

The 10 Most Destructive Pests

How will YOU protect yourself from these pests?

Those zany kids at the National Pest Management Association are at it again with this list of the ten most destructive pests. In terms of both property damage and health risks, these household pests have been known to wreak havoc on even the most well protected homes.

Termites:

Like ants, termites are among the most successful groups of insects on earth, in as much as they’ve managed to colonize most landmasses, apart from Antarctica. Hundreds of species of termite are economically significant and can cause severe damage to buildings, crops, and forests.

Ticks:

Ticks are actually small arachnids that feed on the blood of mammals. That said, the principal threat that ticks pose is health-related. Ticks are dangerous vectors for Lyme disease (especially on the Eastern seaboard) and various other viruses and bacteria. Some ticks, such as the Australian paralysis tick, is intrinsically venomous and, as the name implies, can cause paralysis.

Carpenter Ants:

Like termites, carpenter ants are known for causing serious structural damage to buildings. However, carpenter ants don’t actually eat the wood they bore through. Rather, they drill elaborate tunnel systems for nesting and breeding purposes. Carpenter ants favor wooden structures with water damage, compounding an already serious and potentially fatal problem.

Aphids:

Aphids pose a mostly agricultural threat, as they feed on the fluids inside plants. Like ants and termites, aphids are hugely successful insects from a zoological standpoint, which is largely due to the fact that they can reproduce asexually. If left unchecked, the honeydew that aphids produce can turn into a mold fungus and can transmit viruses to other plants.

Yellowjackets:

Yellowjackets, along with hornets, paper wasps, and other stinging insects, are responsible for upwards of half a million ER visits every year. Yellowjackets, known colloquially as “wasps,” are known for their characteristic coloring, their occurrence only colonies, and their distinct side-to-side flight pattern prior to landing. Despite the threat they pose to humans, wasps are actually important predators in their own right, commonly hunting other varieties of household pests.

Moles:

These strange creatures like to feed on worms, grubs, and other insects beneath the surface of your lawn. Like many other destructive pests on this list, the mole is perfectly suited to its environment—that is, underground. For example, moles have been known to tolerate higher levels of carbon dioxide than other animals because of a special protein in the blood, allowing them to breathe underground with ease.

Deer:

As your author can attest, deer love to snack on expensive flowers and other outdoor ornamentals. Besides tearing up landscaping, deer can also carry deer ticks, which, in turn, can carry Lyme disease. In some parts of the US, deer populations have escalated unchecked, and have now reached pest-levels.

Mosquitoes:

We all know about the health risks posed by mosquitoes: malaria, west Nile virus, yellow fever, dengue fever, filariasis, and other arboviruses, making them one of the deadliest animals in the world. Mosquitoes can breed in as little as a bottle-cap’s worth of standing water, meaning that homeowners should diligently check their property for potential mosquito breeding locations.

Slugs:

Like worms, slugs play an important role in the ecosystem by eating and decomposing dead plant and animal matter. That said, they’ll just as soon eat live plants as dead ones, and frequently present agricultural problems for farmers and gardeners. Slugs can destroy plants faster than they can grow and bore holes in fruits and vegetables, making them unfit for sale or consumption.

Japanese Beetles:

As the name suggests, Japanese beetles are invasive pests that were initially found in the US sometime in the 1910s. They feed by skeletonizing plants, meaning that they consume only the leaf material between the veins, while leaving the veins themselves relatively untouched.

Mice: Just the Facts

How much do you really know about mice?

As a lover of trivia, I like to take it upon myself to spread knowledge to the masses—specifically, knowledge of household pests that you may find yourself combatting at some point in your life.

Mice are extremely common pests that can be found throughout the United States. They’re remarkably adaptable creatures, and can thrive in even the most adverse conditions. In order to best rid yourself of the rodent menace, it helps to become familiar with some of the mouse’s basic attributes.

Here are the facts:

Mice have scales on their tails, which aid in climbing and balancing.

– The average weight of a mouse is between 0.5 and 1 ounce.

– A group of mice is self-evidently referred to as a “mischief.”

– A mouse can jump or fall unharmed from a height of 12 feet.

– Mice typically traverse the same, predictable routes in and out of a given area.

– Mice will usually stay within 15 to 20 feet of the nest, even when searching for food.

– According to University of Florida researchers, mice can give birth to a new litter every three weeks.

– Mice can get pregnant again within 48 hours of giving birth to a litter.

– Male mice are referred to as bucks.

– Females are called does.

– The common house mouse is usually around three to four inches long, though some can grow up to seven inches, depending on the species.

– Mice communicate with one another using ultrasonic sounds.

– Mice metabolize incredibly quickly and, if given optimal access to resources, will eat around 15 to 20 times a day.

– A female mouse can become pregnant at two months of age.

Interestingly, and despite their contemporary reputation as ridiculously irritating pests, mice have a long and storied history in a number folk cultures. The ancient Egyptians, for example, had a story about a mouse serving as vizier to the pharaoh. Likewise, several cultures in the Balkans celebrate “Mouse Day,” the purpose of which was to prevent mice from stealing produce and otherwise ruin manufactured goods.

A Brief History of Bedbugs

They’ve been feeding on us ALL ALONG!

It’s no secret that bedbugs have been a problem for humans for thousands of years. Records indicate that Aristotle mentioned the pests as early as 400 BC in ancient Greece. Likewise, the famed naturalist and Roman military commander cited bedbugs as a treatment for snakebites in ear infections in his seminal work, Natural History. (Author’s note: do not stick bedbugs in your ears to try to cure an infection.)

Bedbugs were then referenced throughout the middle ages and up until 1670, though they remained fairly rare through European countries. A whole slew of urban legends and old wives tales concerning the optimal ways to remove bedbugs abound, including the use of black pepper, wild mint, herb and seeds of cannabis, smoke from peat fires, and the use of predatory insects such as centipedes, ants, and spiders. (Author’s note: do not release centipedes into your home in order to get rid of bedbugs.)

In the mid-twentieth century, the bedbug population allegedly flourished. Many experts have suggested that the reason for the population boom was the advent of indoor heating—a definite possibility, since bedbugs are known to prefer warm environments. Interestingly, the proliferation of bedbug populations seems to have dropped off after the later half of the twentieth century, presumably due to the development of new, powerful pesticides that had not been previously available.

Be that as it may, bedbug populations seem to have made a comeback in recent years, beginning in the 1980s. Fast foreword to today, and it seems as though we’ve got a serious bedbug problem on our hands again. Our old friends as the National Pest Management Association has reported a 71% increase in bedbug-related calls between 2000 and 2005.

It’s worth noting, however, that the appearance of bedbugs in the home is not necessarily an indication of uncleanliness. Since bedbugs are attracted by the presence of human hosts, it seems as though the only real criteria for a possible bedbug infestation is the presence of a human to feed on.

Mosquitoes: No True Parasite?

Mosquitoes: Perfectly Evolved to Suck

Of all the blood-sucking parasites the torment the realms of man, the mosquito, perhaps, sucks the most. Insect puns aside, the mechanism with which a mosquito actually withdraws blood from a body is remarkably complex, and really is a testament to its perfectly evolved purpose and form.

The mosquito possesses an intricate proboscis consisting of six different stylets—that is, a hard, sharp anatomical structure—each with a specific purpose: making the initial incision, inserting anti-coagulant and digestive enzymes, and withdrawing the blood itself. These different stylets are protected by a protective sheath formed by the creature’s lower lip, which is subsequently retracted up and out of the way during blood extraction.

Interestingly, each species of blood-sucking parasite produces its own anti-coagulant, which is a vital factor in the prevention of the host’s blood-clotting; without it, the parasite’s mouth-parts would inevitably become blocked and unworkable before it could enjoy the first drop of our sweet, delicious blood.

It’s fairly common knowledge that female mosquitoes mainly aggrieve humans, as they’re the ones responsibly for providing nutrients for their larvae. Male mosquitoes are generally content to feed on nectar—a much less risky proposition, to be sure.

We all know that a mosquito is a parasite, but parasites themselves can be split into two main categories: True parasites only rarely kill their hosts, although they can cause extreme physical discomfort or even transmit diseases eventually resulting in the host’s death. Parasitoids, on the other hand, are basically predators living within the tissues of their hosts—usually other insects—in such a way that the host’s expiration is postponed until the parasite has successfully reproduced.

That said, the mosquito is not necessarily a true parasite, as it merely visits a mammal for a meal it its expense, then moves on. Small comfort to an individual beset by a horde of mosquitoes, though, who, along with your author, would submit that the only good parasite is a dead one.

Ants: The Exclusively-Terrestrials

Ever seen a flying ant?

It’s a widely agreed-upon fact among experts that ants are the most populous insects on earth, with each colony having the potential to support literally millions of members. It’s curious, though, that ants have been able to proliferate so proficiently without the benefit of wings or other notable locomotive facilities.

One major difference between ants and other so-called “social insects” such as wasps and bees is the marked absence of wings. Interestingly, ants have mostly dispensed with flight as a means of foraging. Worker ants are always wingless and, moreover, queens and males possess wings only during the reproductive period.

Although ants have been known to build nests in nearly every ground-level habitat imaginable, only few have elevated themselves—quite literally—into trees. Only a few species, such as the carpenter ant, commonly hollow out tree trunks into a complex network of passages. The real problem, of course, is when such species decide to construct their elaborate nests in the wooden foundations of houses—which can very easily lead to a complete collapse.

On the other side of the coin, the slightly more exotic weaver-ants, often found in Asia, Australia, and Africa, are known to construct nests—as the name implies—by weaving together leaves and other foliage using silk produced by their larvae. The behaviors of these ants, naturally, are born of the necessity to adapt to their surroundings.

One of the more fascinating species—in your author’s opinion, at least—is the much-feared army-ant, which is most commonly found in Africa, South America, and India. The army-ant, like those species mentioned above, is completely terrestrial but, in contrast, has no permanent nest. Instead, it prefers to move restlessly about in search of food. When their resources in a given location are finally exhausted, they move on, advancing in vast, spreading columns, the center consisting principally of workers, while the flanks consist of their huge soldiers; their jaws held aloft like sickles. Ahead of the column march advance “scouts” which lay down scent-trails for the colony to follow.

Adaptability is the name of the game with any species of insect, but the amazing versatility and remarkable organization of these creatures has no doubt aided in their massive populations as well as their ability to thrive in nearly all environments.