Combating the “Kiss” of Death
BY AWAKE! CORRESPONDENT IN BRAZIL
In the dead of night, while you are sound asleep, it draws ever closer. It does not wake you. Indeed, you do not even stir as you receive its harmful “kiss.”
THIS nocturnal intruder is the barber beetle—also called the kissing bug—which thrives in South America. The lingering “kiss” of this insect can last up to 15 minutes as the insect slowly draws your blood. In itself, the “kiss” will not harm you. But the feces left on your skin may contain a microorganism called Trypanosoma cruzi, or T. cruzi for short. If this parasite enters your body through the eyes, the mouth, or an open cut, it can cause American trypanosomiasis, better known as Chagas’ disease.
In its acute stage, the most recognizable symptom of Chagas’ disease is the swelling of an eye. Fatigue, fever, loss of appetite, or diarrhea may follow. Then, after a month or two, the symptoms usually disappear—even without treatment. But the worst may be yet to come. Some 10 to 20 years after infection, the victim may develop cardiac problems, including rhythm disturbances or even heart failure.a
It is estimated that up to 18 million people are infected with Chagas’ disease, and some 50,000 die from it each year. Not all victims are directly bitten by the bug. Some, for example, are breast-fed children who contracted the disease through an infected mother. A pregnant woman can even pass on the malady to her unborn child or infect her baby at the time of birth. Other means of transmission include blood transfusion and eating uncooked food that has been contaminated with T. cruzi.b
What is being done to combat Chagas’ disease? Insecticides have been effective in controlling the barber beetle population. But house spraying is unpleasant, and it must be repeated every six months. The Federal University of Rio de Janeiro has come up with an alternative—a paint that contains insecticide. The product was tested on 4,800 houses. The result? Two years later 80 percent of them were still bug free! Researchers have also discovered that the leaves of the neem, or Brazilian cinamomo, tree contain a nontoxic biodegradable substance (Azadirachtin) that not only cures infected beetles but also prevents healthy ones from becoming hosts.
Help for the Infected
Is there any hope for the millions of people who have been infected with Chagas’ disease? Yes. An international team of scientists is trying to unravel the secrets of the 10,000 genes of T. cruzi. This might make it possible to create diagnostic tests, vaccines, and more potent drugs.
In July 1997, scientists sent one of T. cruzi’s vital proteins into outer space on the space shuttle Columbia so that they could study its structure in microgravity. This is a fundamental step in developing drugs that match the structure of T. cruzi. The quest for new drugs is important, for once the disease reaches its later stages, no medication is currently effective.c
Recognizing the benefits of early treatment, Brazilian biologist Constança Britto developed the polymerase-chain-reaction test, which makes a diagnosis possible within two days. Unfortunately, though, many do not even know that they have the disease when it is in its early stages.
Prevention Is the Key
In conclusion, what precautions can you take if you are in a region that is home to the barber beetle?
▪ If you sleep in a mud or thatch house, try to use a bed net.
▪ Use insecticides. They lower the risk of transmission.
▪ Repair wall cracks and fissures, as these may be breeding sites for the barber beetle.
▪ Keep your home clean, including the areas behind pictures and furniture.
▪ Occasionally lay out mattresses and blankets in the sun.
▪ Remember that animals—wild and domesticated—can be carriers.
▪ If you suspect an insect to be a barber beetle, send it to the nearest health center for analysis.
a Symptoms vary, and some of them are not exclusive to Chagas’ disease. Hence, they are presented here merely as an overview and are not intended to serve as a basis for making a diagnosis. Many people do not experience any symptoms unless the disease reaches its chronic stage.
b The U.S. Centers for Disease Control and Prevention notes that in some countries the blood supply is not always screened for Chagas’ disease.
c Doctors use nifurtimox to treat T. cruzi, but it often has severe side effects.
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The Discovery of Chagas’ Disease
In 1909, Carlos Chagas, a Brazilian doctor, was working in Minas Gerais State, Brazil, where malaria was hindering the construction of a railroad. He observed many patients with symptoms unlike those of any known disease. He also noted that houses in the region were infested with insects called barber beetles, which feed on blood. On examining the contents of the insects’ intestines, Chagas discovered a new protozoan. He named it Trypanosoma cruzi, in honor of his friend, the scientist Oswaldo Cruz. The new disease was fittingly named after Carlos Chagas because of the depth of the research he did, which led to the discovery of this ailment.
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Rural dwellings are often infested with barber beetles
Photos: PAHO/WHO/P. ALMASY