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New science indicates that Chagas infection in humans is at least 4500 years old if not 9000, and that infection occurred before domicilization of triatomine insects. Two types of T. cruzi display distinct characteristics and may one type appears to be transmitted orally, resulting in severe disease in children.

Chagas dz 1st described y Carlos Chagas 1909
endemic to Latin America
multinational control initiatives of 1990's-->reduced prevalence
control focussed on eliminating triatomines from homes
in 2006 Brazil declared free from T. cruzi transmission by Triatoma infestans

T. cruzi is a heterogeneous taxon
multiple mammal hosts and vectors
alternative routes of infection and infective forms
in Brazilian Amazon region (where domiciled triatomines have NOT been reported):
human cases of Chagas disease have been INCREASING
increase has been attributed to uncontrolled migration and deforestation
recent outbreaks of Chagas disease attributed to oral transmission in prev non–endemic areas
***a new epidemiologic profile is emerging in Brazil

T. cruzi has 2 main genotypes: I and II, with distinct biol, biochem, genetics

in Brazil, T. cruzi I is widespread among wild mammals and sylvatic vectors of all biomes
this genotype commonly isolated from humans and wild mammals in Amazon Basin

T. cruzi II
focal distribution in nature
the main agent of human infection in other Brazilian regions

T. cruzi found in human remains dating back 4,500–7,000
obtained from archeological site in 1985
recovered ancient DNA (aDNA) sequence corresponding to the parasite lineage type I
recovered via post-PCR in 2005, from a rib fragment
mummy called AM1: female approx 35yoa, hunter-gatherer
found in Abrigo do Malhador archeological site, Peruaçu Valley, Minas Gerais State
semiarid ecosystem: dry climate, karst relief, basic pH soil
(good conditions for preserving specimens)
T. cruzi was never studied in the labs used, and lab staff mitochondrial DNA was typed
to insure that the results were dt findings from old bone, not from lab or staff

clinical signs of T. cruzi seen in Chilean mummies from pre-Columbian times
a T. cruzi kinetoplast DNA region recovered in Chilean & Peruvian mummies
aged up to 9,000 years ago

current epidemiologic scenario in Brazil
seems to relate to nomad habits (prevent triatomine nesting, thus infx)

beginning of T. cruzi trans to humans attributed to domiciliation of T. infestans
in mud dwellings, built after European colonization

T. cruzi human infection in Brazil is ancient, dating back at least 4,500 years
occurred in hunter-gatherer populations preceding T. infestans domiciliation
presence of the T. cruzi I genotype in humans 4,500–7,000ya
in Minas Gerais State (where this genotype is currently absent)
-->distribution pattern of T. cruzi genotypes in humans has changed

current outbreaks of human T. cruzi infection
independent of triatomine domiciliation
mbdt reemergence of the ancient epidemiologic scenario of Chagas disease in Brazil

Int J Cardiol. 2006 Sep 10;112(1):132-3. Epub 2006 Apr 5.
The oral transmission of Chagas' disease: an acute form of infection responsible for regional outbreaks.
Benchimol Barbosa PR.
Orally transmitted Chagas' disease is an ordinarily rare form of Trypanosome cruzi transmission, and responsible for regional outbreaks. Ingestion of contaminated material is generally associated with massive parasitic transmission, ultimately leading to acute myocarditis, with more severe clinical presentation at younger ages, and high death rates. Close monitoring of regional outbreaks by health agencies is mandatory in order to prevent recrudescence of the disease.
PMID: 16600406 [PubMed - indexed for MEDLINE]

References from letter to the editor
1. Schofield CJ, Jannin J, Salvatella R. The future of Chagas disease control. Trends Parasitol. 2006;22:583–8.
2. Coura JR, Junqueira AC, Fernandes O, Valente SA, Miles MA. Emerging Chagas disease in Amazonian Brazil. Trends Parasitol. 2002;18:171–6.
3. Benchimol-Barbosa PR. The oral transmission of Chagas disease: an acute form of infection responsible for regional outbreaks. Int J Cardiol. 2006;112:132–3.
4. Prata A. Clinical and epidemiological aspects of Chagas disease. Lancet Infect Dis. 2001;1:92–100.
5. Prous A. Shlobach MC. Sepultamentos pré-históricos do vale do Peruaçú-MG. Revista do Museu de Arqueologia e Etnologia, São Paulo. 1997;7:3–21.
6. Fernandes O, Souto RP, Castro JÁ, Pereira JB, Fernandes NC, Junqueira AC, et al. Brazilian isalates of Trypanosoma cruzi from humans and triatomines classified into two lineages using mini-exon and ribosomal RNA sequences. Am J Trop Med Hyg. 1998;58:807–11.
7. Rothhammer F, Allison MJ, Nunez L, Standen V, Arriaza B. Chagas disease in pre-Columbian South America. Am J Phys Anthropol. 1985;68:495–8.
8. Ferreira LF, Britti C. Cardoso MA, Fernandes O, Reinhard K. Araújo A. Paleoparasitology of Chagas disease revealed by infected tissues from Chilean mummies. Acta Trop. 2000;75:79–84.
9. Aufderheide AC, Salo W, Madden M, Streitz J, Buikstra J, Guhl F, et al. A 9,000-year record of Chagas' disease. Proc Natl Acad Sci U S A. 2004;101:2034–9.
10. Briceño-León R. Chagas disease and globalization of the Amazon. Cad Saúde Pública. 2007;23:S33–40.

Lima VS, Iniguez AM, Otsuki K, Ferreira LF, Araújo A, Vicente ACP, et al. Chagas disease in ancient hunter-gatherer population, Brazil [letter]. Emerg Infect Dis [serial on the Internet].2008 Jun [date cited]. Available from http://www.cdc.gov/EID/content/14/6/1001.htm
(see link just above for links to sources)



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