The Kiss of Death: Chagas' Disease in the Americas

 

 

 


Testing and Treatment of Chagas Disease

Trypanosomes of T. cruzi can be found in patients during the acute phase of Chagas' disease by direct examination of the blood and later by centrifugation of clotted blood, xenodiagnosis, and animal inoculation. One problem is the possible misidentification of parasites in examination of the blood - for example, the spirochete of syphilis has been confused with T. cruzi. If T. cruzi is reported in blood samples, retesting is recommended.

Xenodiagnosis

Xenodiagnosis is an effective technique that is akin to the technique of bloodletting with leeches that dates back to the Middle Ages. In this test, uninfected vinchucas are placed in a jar and tucked under the armpit of a patient suspected of being infected. The vinchucas are allowed to consume blood for thirty minutes, and their feces are examined for T. cruzi thirty and sixty days afterward. One problem with this test method is obtaining uninfected bugs. This technique is rarely xenodiagnosis is an effective method of testing for T. cruzi infectionused on children, and many adults have are hesitant in being willfully bitten by vinchucas. However, medical examinations can be as painful as the symptoms themselves. Xenodiagnosis can be an excellent examination for determining strains and populations of parasites.

ELISA testing

Indirect tests that look for T. cruzi antibodies have recently been devised. However, these tests aren't typically used during the acute phase of chagas because the immune system is producing chagasic antibodies. An ELISA test is similar to that used for AIDS and has been designed to to detect the presence of T. cruzi antibodies, though it sometimes does not differentiate T. cruzi antibodies from those produced in response to other less harmful or harmless parasites. Chronic patients should be tested by xenodiagnosis as well as ELISA, even when ELISA comes out negative, to ensure that the rate of infection is determined. People without noticeable signs of chagas who live in chagasic areas should be encouraged to have an ELISA test. If it comes out positive, xenodiagnosis is encouraged to help in determining the nature of the infection and form of treatment. ELISA testing is offered at a reasonable cost by the Ministry of Public Health and IBBA in Bolivia.

Nifurtimox and Benznidazole

The first chemical solutions against Chagas' disease with sufficient activity to justify clinical trials, the bisquinaldines, were not discovered until 1937. In 1972, the first drug to combat the disease, nifurtimox, was released for use in Latin America. Production of the drug was discontinued in 1997. Nifurtimox is administered as a yellow powder that a patient is to dissolve in water and drink three times a day after meals for sixty to ninety days at a dose of 8-10 mg/kg for adults, 15-20 mg/kg for children aged one to ten years, and 12.5-15 mg/kg for children aged eleven to sixteen years. Nifurtimox is readily absorbed and rapidly metabolizenifurtimoxd, with a peak plasma concentration at one to three hours, which declines to zero by twenty-four hours. The earlier the diagnosis is made and treatment initiated, the greater is the chance that the patient will be parasitologically cured. Good results can be seen in early treatment, circulating trypanosomes may disappear, and there may be a remission of chagasic symptoms. There may be occasional reversion to a serologically negative state. Negative side effects include nausea, skin rashes, peripheral neuritis, bone-marrow depression, weight loss, loss of memory, and sleeping disorders. Some patients discontinue this treatment if the side effects are too severe to tolerate.

Benznidazole was announced in 1974 and released in Latin America in 1978. Also a yellow powder, benznidazole, it is taken in water and is rapidly absorbed and distributed through the body tissues. Recommended dosage is 5 mg/kg/day for adults, 10 mg/kg/day for children for sixty days. It is claimed to be mobenznidazolere than eighty percent effective in curing acute and chronic chagas patients. There is no clear evidence that it has any advantage over nifurtimox. The efficacy of the two drugs are similar, though it has been claimed that benznidazole has less geographic variation in cure rates. Diverse side effects of benznidazole include vomiting, peripheral neuropathy, and skin reactions that may include erythematous light-sensitive skin rashes which can be severe.

None of these drugs is ideal, and our ability to control and treat, let alone eradicate, Chagas' disease is severely curtailed. The obstacles are formidable on the scientific side and relate not only to finding trypanosomes that lyse the parasites in their different stages and differing strains. There are problems getting the drug to the vicinity of the in vivo sites of trypanosomes without destroying human cells.

Natural treatments

Therapy for chagas comes in varying degrees - from controlling the parasite population in the body to completely eliminating it. Patients can be treated with Sangre de Drago (Croton roborensis HBK) which is sold in small bottles by herbal vendors throughout Bolivia. Though it is most effective against the symptoms, its parasiticide properties have not many natural treatments are effectivebeen verified in the laboratory. Chagasic heart disease can be treated with three flowers of retama (Spartum junceum) in maze (steeped in hot water), with two leaves of of cedron (Lippia triphylla Kunth). Ingredients may serve as a tranquilizer for heart attacks. Toronjil (Melissa officinalis L.) is also used for heart problems.

Restoration to complete health is an impossible dream for many peasants who lack the resources to pay for cures. They adapt through the use of household remedies, herbs, and rituals, which provide some level of relief and renewal. Until the problem is addressed by wealthier nations, the simple products of Mother Earth (Pachamama) remain their primary source.

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