Chagas disease.In this study, investigators reconstructed the behavior of Chagas disease (American trypanosomiasis African trypanosomiasis human trypanosomiasis endemic in areas of tropical Africa, due to infection with Trypanosoma gambiense (Gambian t.) or T. rhodesiense (Rhodesian t.); it is transmitted by the bite of species of Glossina (tsetse flies) and in advanced stage attacks the central nervous system, resulting in meningoencephalitis that leads to lethargy, tremors, convulsions, and eventually coma and death.) in the Atacama Desert Atacama Desert (ätäkä`mä), arid region, c.600 mi (970 km) long, N Chile, extending south from the border of Peru. The desert itself, c.2,000 ft (610 m) above sea level, is a series of dry salt basins flanked on the W by the Pacific coastal range, averaging c.2,500 ft (760 m) high, and on the E by the Andes. over the past 9,000 years. The researchers analyzed ancient DNA to identify kinetoplast kinetoplast /ki·ne·to·plast/ (ki-net´o-plast) a structure associated with the basal body in many protozoa, primarily the Mastigophora; it is rich in DNA and, like the basal body, it replicates independently. ki·net·o·plast (k DNA of Trypanosoma Trypanosoma /Try·pano·so·ma/ (tri?pan-o-so´mah) a genus of protozoa parasitic in the blood and lymph of invertebrates and vertebrates, including humans. T. bru´cei gambien´se and T. bru´cei rhodesien´se cause types of African trypanosomiasis and T. cru´zi causes Chagas' disease. cruzi, the disease's infectious agent transmitted by the insect vector, a triatomid bug. Specimens analyzed were from muscle and visceral tissues in excavated, naturally mummified human bodies buried in that hyperarid desert during the past 9 millennia. Results indicated that 41% of these bodies were infected by T. cruzi at the time of death. Among the 11 represented populations, no statistically significant differences in prevalence rates could be demonstrated when studied by the time period, sex, or age, except for lower rates (28%) for infants. Such prevalence rates are similar to those of modern T. cruzi-endemic areas. These results demonstrated the well-established presence of Chagas disease in this region among wild forest animals when the first humans (the Chinchorro) arrived. By settling this region, the new arrivals initially and inadvertently exposed themselves to the triatomid bug transmitting this disease, and joined the wild animals as part of the disease's reservoir. At some undetermined time during this 9,000-year interval, a few of the vector species became adapted to the thatched roof and other features of the region's human dwellings and initiated the independent domestic cycle involving only humans and their domesticated animals. The study also suggests that, given available specimens, the history of other infectious diseases can be similarly reconstructed. Aufderheide AC, Salo W, Madden M, Streitz J, Buikstra J, Guhl F, et al. A 9,000-year record of Chagas' disease Chagas' disease, disease of South and Central America caused by the parasite Trypanosoma cruzi Trypanosoma cru·zi (kr   z )n. . It usually affects children and young adults and is transmitted by the feces of infected insects, typically the assassin bug. Most of those infected have mild symptoms, such as fever and swelling and redness around the eyes, but from 10% to 30% develop chronic disease that may result in serious or fatal inflammation of the brain and heart tissues.. Proc Natl Acad Sci U S A. 2004;101:2034-9. Epub 2004 Feb 06.
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