An ancient human scourge has returned to cause panic among home and property owners, home buyers and realtors. Bed bugs have invaded every state in the U.S. and reports of infestations have increased exponentially nationwide over the past few years. In a national survey of pest control companies conducted by noted bed bug authority Michael Potter for Pest Management Professional, Potter found, ?A whopping 91% of respondents reported their organizations had encountered bed bug infestations in the past two years. Only 37% said they encountered bed bugs more than 5 years ago.?

Until a few years ago, most pest control companies said it was unusual to receive even one or two calls a year about bed bugs. Since 2004, however, bed bug complaints have grown exponentially with pest control companies nationwide now averaging between 10 and 50 calls a week. In major metropolitan areas, some companies are fielding 100 or more bed bug complaints each week. Some experts are predicting that 2008 will be the Year of the Bed Bug. Cindy Mannes, spokesperson for the National Pest Management Association, said bed bugs have become a serious problem in every state, noting, ?There are some who call it the pest of the 21st century.?

Bed bugs are an equal opportunity pest. Infestations have occurred across the country in the tony co-ops of the rich and famous, in fashionable condominiums, in luxury apartments and in upscale suburban homes. Contrary to popular belief, bed bugs are not caused by filth or dirt. Like lice and fleas, bed bugs are creatures of convenience. A nuisance insect, they are not known to carry disease, but they can cause considerable discomfort, both mental and physical.

All but eradicated in the U.S. following World War II, the banning of powerful DDT-based pesticides, coupled with increased international travel, has brought about a nationwide resurgence of the annoying insect. Potter, an urban entomologist at the University of Kentucky, calls bed bugs the pre-eminent household pest in the U.S., on a par with cockroaches and rats. ?This is one serious issue,? he recently told the New York Times. ?This will be the pest of the 21st century ? no questions about it.?

If you're buying a house or looking for a new condo or apartment, take to heart the old adage Buyer Beware. You may be moving into a home that has been invaded by bed bugs. Most states require home sellers to provide buyers with an accurate statement disclosing the property's condition, including pest infestations. However, there are loopholes that should serve as a red flag to home buyers and their Realtors.

Most real estate disclosure statements are fairly broad and do not specifically ask about bed bug infestations. If any pest disclosure is specified, it's likely to be termites. Because bed bugs haven't been a problem in the United States for so many decades, few current state or municipal codes address them specifically. In many states, sellers can choose not to fill out the disclosure statement and instead pay a penalty which is credited to the buyer. For sellers with a bed bug problem, a several hundred dollar penalty may seem an acceptable price for making the sale.

Buyers and realtors should be aware that real estate disclosure laws that apply to home sales often don't apply to co-op and condo owners. Before you buy, check with the local building and health departments to find out what the regulations are in your area. Although some states are now considering adding specific bed bug regulations to their realty laws, at this point common law is generally on the side of the seller. As real estate attorney Edward Sumber of New York told the New York Times, ?Under the doctrine of caveat emptor ? let the buyer beware ? the seller has no affirmative obligation to reveal circumstances about the apartment to the buyer.?

However, disclosure laws in most states require the seller to answer honestly if specifically asked whether his home or apartment has been infected by bed bugs or other pests. Additionally, real estate brokers are usually obligated to reveal a bed bug problem to the buyer if they know about it. Unfortunately, in most states sellers are not required to tell their real estate brokers about bed bug problems. Essentially, that means buyers must rely on the integrity of sellers and landlords anxious to make a sale.

Many buyers shopping for a new home, apartment or condominium are now hiring a pest control company with an expertise in bed bug elimination to inspect the property before they buy. Some Realtors are recommending that sellers have their homes inspected for bed bugs before putting them on the market as both a reassurance and inducement to buyers.

What are bed bugs?

Evolved from bird and bat nest parasites, Climex lectaularius, the common bed bug, is a tiny nocturnal insect that hides in dark crevices during the day and feeds on human blood during the night. Their oval bodies are flattened and wingless and a light to reddish-brown in color. Adult bed bugs are 1/4 to 3/8 inch long or about the size of an apple seed. Before feeding, the bed bugs are as flat as paper, becoming dark red and bloated with blood as they feed, much like a tick. As they puncture the skin to feed -- usually for 3 to 10 minutes -- they eject an anesthetic that can cause an allergic reaction and the symptomatic itchy, red welts that bedevil their hosts. However, welts may take a day or two to develop and not all bed bug sufferers react to their bites, which can delay detection.

A female bed bug can produce up to 500 eggs during its average one-year lifespan, laying about 5 eggs per day. Difficult to detect without magnification, the eggs are whitish, pear-shaped and about the size of a pinhead. The female lays her sticky eggs in bedding and carpets or cements them into cracks and crevices near the bed to ensure a food source when the nymphs hatch. Nymphs, which are lighter in color and look like slightly smaller adults, hatch in 4 to 12 days and begin to feed immediately. Bed bugs progress through five nymphal stages, molting after each stage. The whitish carapaces they shed are a telltale sign of bed bug infestation. It takes 5 to 8 weeks for nymphs to reach maturity. Since several generations of bed bugs can be produced in a year, all stages of growth can be found in an infested room.

Bed bugs feed every 3 to 5 days and must feed at least once to develop to the next stage and to reproduce. They often void while feeding, leaving telltale rusty or tarry spots on sheets and in hiding places. Bed bugs can survive for 1 to 7 months without a blood meal and have been known to live in an abandoned house for as long as a year. They give off a distinctive musty, sweet odor often likened to ripe red raspberries or coriander.

Bed bugs will readily travel 10 to 15 feet to feed but have been observed traveling more than 100 feet from their established harborage to feed on a host. Once established, infestations can spread rapidly to adjoining rooms or units through crawl spaces, wall voids and electrical and plumbing conduits. Adept hitchhikers, bed bugs can easily enter your home on clothing, bedding, luggage, used furniture, cardboard boxes, etc. They can be brought home from a hotel stay or by sitting in a car, cab, bus, train or plane recently inhabited by an infested person.

What to look for

Bed bugs may be tiny but they leave telltale traces. Look most closely near beds and in bedrooms where bed bugs feed. Look for these telltale signs of bed bug activity:

A heavily infested room may have a characteristic musty or sweet odor like the scent of fresh red raspberries or coriander; however, the odor may not be obvious.

Look for active, crawling bugs on bed linens, carpet and furniture near the bed.

Look for dark fecal and blood stains on bed linens; carpets and carpet welting; and in the seams, creases, tufts and folds of mattresses and box springs.

You should also look for fecal smears or pea-sized pearly egg deposits behind headboards; along baseboards and door and window casings; around electrical plates; in plaster cracks; and under loose wallpaper, paintings and posters.

Look for whitish nymph molts and old exoskeletons under area rugs, at the edges of carpets, and in under-the-bed storage containers.

Beware of bats in the attic or eaves. Quite often bed bugs feeding on bats in the attic of a house will migrate to the living area in search of an easier food source, humans.

Buyer beware!

Bites, odor and voiding smears are indicators of a bed bug problem. However, these insects often go undetected when symptoms are not obvious. Bed bugs are also easily confused with other nuisance bugs like carpet beetles, bird and rodent mites, shiny spider beetles, parasitic wasps, even lint by the more paranoid, making definitive diagnosis a job for bed bug experts.

Before you buy a new home, ask the owner if there has ever been a bed bug problem. In co-ops, condos, apartments and any multi-unit residence, ask the property owner whether bed bugs have been reported in any unit. Before they buy, many home buyers are now requiring a pest inspection by a bed bug expert in addition to the traditional home inspection. When it's buyer beware, it makes sense to protect yourself.