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Chagas disease is primarily spread through insects. It occurs commonly in South and Central America. It is also referred as American trypanosomiasis, which is caused through protozoan parasite Trypanosoma cruzi. It is a vector-borne disease. These bugs are responsible for carrying the parasites occurring in the unhygienic environment of poverty ridden homes in rural or suburban areas. Generally, the bugs have been reported to disappear in daytime and resume activity at night while feeding on human blood. The bug bites the skin on face and defecates near the bite. The moment bite-ridden person scratches that region, parasites enter his body and the backdrop for infection is thus created.
According to recent research, T. cruzi was probably introduced to South America through bats nearly 7-10 million years ago with its roots in the Andean area at the time when first settlements in the coastal region of the Atacama Desert were formed. Another theory suggests that it affected wild animals approximately 9,000 years ago. It later extended to domestic animals and people. The large pool of T. cruzi parasites in wild animals of America implies that it is difficult to nullify the parasite.
Trypanosoma cruzi is a parasite, which is responsible for creating contagious sickness. It is spread through the bite of reduvid bugs and forms a major health problem in South America. The disease is known to affect people in the United States due activity of immigration.
Certain risk factors for Chagas disease have been underlined as follows:
- Inhabiting a hutment where reduvid bugs are found to exist in the walls.
- Consumption of food contaminated with T. cruzi.
- Blood transfusions or organ transplants from an infected person.
- Transmission through an infected mother to her newborn.
- Bio-hazard laboratory accidents.
Chagas disease occurs in two phases: acute and chronic. The acute phase shows no likelihood of symptoms or has very mild symptoms. During the acute stage, large numbers of parasites circulate in the blood. These symptoms are feverishness, swelling in the eye or any place where the bite occurs coupled with redness. The patient may experience an overall feeling of ill health. In less than half the population affected by the parasite, distinct visible signs are skin lesion or a purplish swelling of the eyelid.
Once the acute phase is over, the disease diminishes. Symptoms may fail to appear for years together. However, when the symptoms finally develop, they include constipation, pain in abdomen and digestive problems, heart failure, palpitations and extreme difficulty in swallowing. During the chronic phase, the parasites are hidden mainly in the heart and digestive muscle. About 30% of patients suffer from cardiac disorders and up to 10% suffer from digestive, neurological or mixed alterations. Eventually, the infection can result into sudden death or heart failure due to progressive destruction of the heart muscle.
Doctor may conduct physical examination to confirm the symptoms. Detection of enlarged liver and spleen; enlarged lymph nodes; irregular heartbeat and rapid heartbeat may confirm the physical diagnosis.
Following tests are undertaken by doctor to confirm the analysis:
- Blood culture to look for signs of infection
- Chest x-ray
- Electrocardiogram (ECG)
- Enzyme-linked immunoassay (ELISA) to look for signs of infection
- Blood test to detect cause of infection
The acute phase of the Chagas disease is mandatory to be treated. Treatment for infants carrying the infection since birth is required to be undertaken at the correct time. Delay in medication may lead to slower healing.
Treating the chronic phase, wherein symptoms fail to manifest, is most recommended for both children and adults. Drugs used to treat this infection are benznidazole and nifurtimox. Both medicines offer guaranteed cure if given soon after the onset of disease. The drugs have been reported to have side effects, particularly in older people. Nifurtimox is best avoided by patients with neurological or psychiatric disorders. Pregnant women and those with liver problems have been cautioned to stay away from these medications.
Side effects such as headaches, loss of appetite and weight loss, Neuropathy, insomnia and skin rashes have been noted.
Control And Prevention
Being a vector-borne disease, it is utmost important for fragile locations in Latin America to undertake preventive measure to avoid spread of infection causing parasites. So far, no vaccine exists for Chagas disease. Hence, vector control is most effective remediation step. On the basis of geographical area, World Health Organization (WHO) recommends maintenance of hygiene for prevention and control of disease. The measures include spraying of houses and surrounding areas with insecticides; use of bed nets; improvement of house to prevent vector infestation; practise of hygienic practices in food preparation, transportation, storage and consumption. The WHO lays emphasis on testing the donors and receivers of blood as well as organs, and also screening of newborns to conduct an early diagnosis.
1. Steverding, D. The history of Chagas disease. Parasites & Vectors 2014, 7:317. doi:10.1186/1756-3305-7-317
2. Teixeira, ARL, Hecht, M M., Guimaro, M., Sousa, AO., Nitz, N. Pathogenesis of Chagas’ Disease: Parasite Persistence and Autoimmunity. Clin. Microbiol. Rev. 2011, 24: 3 592-630. doi: 10.1128/CMR.00063-10