While their adorable name is due to the way they come out of midnight and kisses around human mouth and eyes, kissing insects actually pose the greatest threat to humans through their feces. After closing their lips with their sleeping victims, these one-inch-long insects take a delicate dump at the crime scene. And this repulsive encounter is worse than unhygienic: those feces spread microscopic parasites that cause Chagas disease.
Fortunately, scientists at the University of Texas A & M have a new weapon against these and other disease-carrying insects. As reported today in the Journal of Medical Entomology, the movement of elusive kissing insects with radio transmitters can now be traced, allowing researchers to be equipped with new profitable tools to stop the spread of insect-borne diseases.
Chagas disease is more prevalent in Central and South America, where it currently affects up to 8 million people. But it has also been increasingly identified in the southern United States: in Texas, 50 percent of the captured bugs test positive for the parasites that spread the disease, and up to one million Americans may be currently suffering from Chagas. "Up to now, in the United States, bugs and Chagas disease have been somewhat neglected and uninformed," says the study's lead author, Gabriel Hamer, an entomologist at the University of Texas A & M. In recent years, this is changing and the medical community and the general public are increasing recognition that bugs are found in the United States. "
When the bugs kiss the infected people, they transfer the parasites that cause the disease to their next victims. Due to this, and because Chagas can not be transmitted directly from person to person, knowing the movements of the bugs is fundamental to stop the spread of the disease. (Many of the infected remain asymptomatic and unknowingly harbor the disease, but carriers can still transmit parasites if they are bitten again.) Animals, including pets, are also vulnerable to infection, putting their owners at greater risk if they are bitten. for another insect kiss).
If kissing feces are rubbed into the mouth, eyes or any break in the skin, including the recent bite mark of the parasite, the parasites can enter the body and spread rapidly through the tissues and blood. The disease causes a mild fever-like syndrome that can permanently compromise organ function if left untreated.
Control of bed bug populations is considered the most effective method to prevent Chagas disease, which is considered an unattended tropical disease and accumulates about $ 270 million in medical costs each year. While insects are susceptible to insecticides and confused in front of nets, their minute size, nocturnal habits and neutral coloration make them difficult to detect. Little is known about their movements and dispersion, but what we do know is this: they thrive best in the nooks and crannies of old and poorly constructed buildings, which are common in countries where Chagas runs rampant.
For entomologists, Kisses present another challenge: their populations may be rare, particularly in the United States. Their lone and agoraphobic lifestyle makes them frustratingly difficult to trace by conventional methods, such as identification and release studies common in other insects.
Discover the daily movements of kisses, a team led by Gabriel Hamer and veterinary ecologist Sarah Hamer of Texas A & M University chose an unconventional technique, taking advantage of state-of-the-art radiotelemetry technology to track the locations of insects . The couple, who are married, partnered with Texas owners who are currently fighting bug infestations to carry out their field work. They chose three private residences that covered different landscapes, which allowed the team to study two different species of kissing insects.
After capturing a handful of kissing critters in each residence, the researchers placed tiny transmitters on the back of super-stinging insects. The transmitters sent radio signals that reported the location of the insects to the recipients of the equipment, which allowed the researchers to remotely spy on the scams of the insects.
"This technology allows us to track bugs in a way that is not visually possible." Says Matthew Siderhurst, an entomologist at Eastern Mennonite University who also uses radio telemetry in his work, but was not affiliated with the study. "This is a way of answering many questions … like, what is the insect doing when we are not looking? & # 39;"
The Hamer monitored a total of 18 movements in 11 kissing insects. Under radio surveillance, the insects were quite inactive, sneaking an average of only 12.5 feet at a time. In addition, nocturnal insects tended to return to the constant hovels to rest and relax during the day.
In one of their experimental sites, the researchers collaborated with owners who had previously lost several dogs against Chagas disease. To protect themselves and their pets, Texas residents had actively started to eliminate kissing insects from the property, accumulating hundreds of insects for Hamer's research over the course of four years.
The usefulness of radio transmitters shone when a female was revealed. The besucona bug was embedded in a small crack between the upper and lower halves of a plastic doghouse, a place revealed only by the dismantling of the structure. "It's something we would have missed through routine cleaning and spraying," explains lead author Sarah Hamer. "If we know these places, we can pay attention to them, but otherwise we do not think twice."
Radio telemetry has been used successfully to track wildlife for decades. Recent technological advances, including the compaction of transmitters, have even allowed their use with insects in the context of pollination, crop pests and conservation. But Hamers' work is the first to implement technology to track insect vectors of diseases. These early successes can pave the way for tracking insects by kissing on a more global scale.
There are drawbacks: transmitters the size of an error have weak ranges and short battery lives, limiting the range of each tracker to a maximum of two weeks and 300 feet. And even at 0.2 grams, each transmitter weighs almost as much as an individual kiss insect. But Sarah Hamer knew that kissing insects were not oblivious to weight fluctuations, since even an average blood meal can also double its load. Then, she and her team will test whether supporting the transmitter has a negative impact on insect behavior.
Sarah Hamer, who previously worked extensively with radio telemetry in birds and mammals, hopes that technology will continue to advance with the times. "Years ago, I was working with transmitters that weighed two grams, which was cutting-edge at the time," he says. "The ones we use with the bugs are a tenth of that, we were pushing the boundaries with the birds, and now we run into the insects."
For now, radio transmitters have already expanded the options for disease specialists. infectious and entomologists with the hope of obtaining information about the covert lives of kissing insects. In their fieldwork, Hamer and his colleagues found that all the specimens they had marked at a residence had died, which was unexpected and revealed the effectiveness of the insecticide treatment performed by a pest management company a few months earlier. This opens the door to testing the potency of different chemical products against these insects, a topic that is especially relevant in the US. UU., Where currently there is no specifically labeled insecticide to use against bugs.
In addition, through their work with private citizens of Texas, researchers hope to continue to involve the public in the prevention of Chagas disease. "We are empowering these citizen scientists," says Sarah Hamer. Homeowners like those who participated in this study are some of the most important sources of Hamer's wild kissers, and will continue to provide specimens for future work.
For diseases such as Chagas that exist in the human-wildlife interface, knowing the risks and vulnerabilities on both sides are critical. Modern technology now has an increasingly important role in stopping the spread of infectious diseases, and in the future, these tracking tools will reveal much more than what insects are fooling themselves.