"Bed Bugs Invade New York City." "Bed Bugs Biting All Over US." "Bed Bugs Are Coming To Get You."

From the headlines, you might think America was under attack by an army of millimeter-sized parasites. Media reports have bed bug "epidemics" plaguing cities from New York City to Bloomington, Ind., to Los Angeles. Similar upticks in bed bug populations have been reported in recent years, an apparent resurgence after almost 50 years of relative quiet. So what's causing these infestations? And can they really be called "epidemics"?

Not really, said Alexis Barbarin, a doctoral candidate in entomology at Penn State. "Epidemic," she said, suggests "a mental picture of something huge, serious and possibly life-threatening." It grabs the reader's attention, but probably overstates the seriousness of the problem. The Centers for Disease Control has hesitated to call the bed bug problem an epidemic because they do not spread disease. "Have bed bug infestations reached epidemic proportions?" Barbarin asked. "In my opinion, no. But will they if we do not do anything about it? Probably so."

Most Americans have little understanding of bed bugs; that lack of education, Barbarin said, may be part of the problem. Contrary to popular imagination, infestations are not caused by poor housekeeping or hygiene, nor are the bugs found only in poor neighborhoods. Yet these commonly held misconceptions, she said, can prevent people from taking appropriate precautions. They also create a social stigma that can keep people from reporting infestations.

In fact, bed bugs -- small, elusive, parasitic insects that feed on the blood of warm-blooded animals -- have been found in New York City's highest-class hotels. "Bed bugs are not interested in the money you have in your pocket," Barbarin said, "but they are interested in the blood in your veins; rich or poor, we all make a decent meal."

Scientists have several hypotheses about the recent increase in bed bug populations. The affordability of air travel has made it easy to reach almost anywhere in the world quickly and cheaply. "Some travelers bring back unintended souvenirs," she said. Increased urbanization, too, has pushed people closer together, making it easy for infestations to spread if untreated.

Additionally, Barbarin said attitudes toward pesticides have changed. Routine pesticide spraying became less frequent as people became wary of its large-scale environmental effects (Rachel Carson's "Silent Spring" often is credited with this change in public consciousness). While today many consumers want "green" pest-control solutions, in a former era powerful pesticides such as DDT would have been on the front lines fighting bed bugs. Ecological concerns about its misuse led the Environmental Protection Agency to ban DDT for most uses in 1972. While some experts suggest bringing it back, Barbarin said that bed bugs had shown resistance to the chemical as early as 1946. Another class of pesticides, called pyrethroids, has largely replaced DDT -- but bed bugs also have shown resistance to these compounds. The only solution to the pesticide-resistance problem, Barbarin said, is more research and more public education.

In this case, adds, using a biological control is not really an option. Talk about a Catch-22 -- one of the bed bug’s fiercest natural enemies is the cockroach.