Isolation of Trypanosoma cruzi DNA in 4,000-year-old mummified human tissue from northern Chile

Paleoparasitologia no Brasil

Neste artigo faz-se uma revisão sobre o início da paleoparasitologia no Brasil e seu desenvolvimento. A pesquisa de parasitos em vestígios humanos pode trazer informações sobre questões tais como a origem e antiguidade da relação parasito-hospedeiro, distribuição de parasitos através do tempo e migrações humanas pré-históricas. O estudo de seqüências de ADN de parasitos encontrados em tecidos mumificados e coprólitos pode ser uma importante fonte de informação para filogenia e co-evolução parasito-hospedeiro. A análise de ácidos nucléicos de parasitos encontrados em material arqueológico (paleoparasitologia molecular) abre novas perspectivas para estudos sobre evolução ao nível molecular.

Detection of kinetoplast DNA of Trypanosoma cruzi from dried feces of triatomine bugs by PCR

It is important to clarify the distribution of infected triatomine bugs in the endemic area of Chagas' disease for proper control. In the present study, we tried to detect T. cruzi kinetoplast DNA by PCR from dried triatomine feces collected from the house wall of an endemic area to assess the distribution of infected bugs more easily. The primers (P35/P36) were chosen to amplify the conserved region within the minirepeats of T. cruzi kinetoplast minicircle DNA. The kinetoplast DNA of T. cruzi could be actually detected in the dried feces collected from the wall of a brick-built house in Santa Cruz, Bolivia. Next, we examined the stability of T. cruzi kinetoplast DNA in the feces exposed to artificial environments. T. cruzi DNA was also detected by PCR in the feces left for 26 weeks at 25 degrees C and in those left for 4 weeks at 40 degrees C. The present study indicates that examination of dried feces on the wall can be an effective tool for surveillance of the natural infection of triatomine bugs that live in houses.

Paleo-parasitology and the antiquity of human host-parasite relationships

Paleo-parasitology may be developed as a new tool to parasite evolution studies. DNA sequences dated thousand years ago, recovered from archaeological material, means the possibility to study parasite-host relationship coevolution through time. Together with tracing parasite-host dispersion throughout the continents, paleo-parasitology points to the interesting field of evolution at the molecular level. In this paper a brief history of paleo-parasitology is traced, pointing to the new perspectives opened by the recent techniques introduced.

Molecular evidence of bacteremia by gastrointestinal pathogenic bacteria in an infant mummy from ancient Egypt

In this study, we describe an infant mummy from ancient Egypt that showed macromorphologic signs of chronic anemia and vitamin C deficiency. From this infant, we have obtained a sterile sample from a metatarsal bone to extract ancient bacterial DNA. Following polymerase chain reaction amplification and subcloning of the amplicons, the sequence of the 16S ribosomal DNA was determined in several resulting clones. The presence of pathogenic and apathogenic bacteria, such as Escherichia coli, are indicated by our result, providing evidence of bacteremia, which probably contributed to death due to septicemia. These findings suggest that the infant, who already had chronic anemia and vitamin C deficiency, acquired a gastrointestinal infection, which finally led to a systemic spread. To our knowledge, this is the first case identifying potentially septicemic bacterial dissemination in an ancient Egyptian mummy. Using our approach, we hope to investigate distinct paleomicrobiological aspects of ancient populations, which will potentially enlighten our understanding of the development and evolution of pathogenic bacteria.

Chagas disease and human migration

Human Chagas disease is a purely accidental occurrence. As humans came into contact with the natural foci of infection might then have become infected as a single addition to the already extensive host range of Trypanosoma cruzi that includes other primates. Thus began a process of adaptation and domiciliation to human habitations through which the vectors had direct access to abundant food as well as protection from climatic changes and predators. Our work deals with the extraction and specific amplification by polymerase chain reaction of T. cruzi DNA obtained from mummified human tissues and the positive diagnosis of Chagas disease in a series of 4, 000-year-old Pre-Hispanic human mummies from the northern coast of Chile. The area has been inhabited at least for 7,000 years, first by hunters, fishers and gatherers, and then gradually by more permanent settlements. The studied specimens belonged to the Chinchorro culture, a people inhabiting the area now occupied by the modern city of Arica. These were essentially fishers with a complex religious ideology, which accounts for the preservation of their dead in the way of mummified bodies, further enhanced by the extremely dry conditions of the desert. Chinchorro mummies are, perhaps, the oldest preserved bodies known to date.

Paleoparasitology of Chagas disease revaled by infected tissues from Chilean mummies

Mummified tissues were sampled from bodies stored at the Museo Arqueologico de San Pedro de Atacama, northern Chile, dated from 2000 years BP-1400 AD, and Trypanosoma cruzi DNA was recovered using polymerase chain reaction (PCR) methodology. Amplification of the conserved region of the minicircle molecule of T. cruzi was achieved in four of the six samples tested. Amplified products corresponding to genetic fragments of the parasite were tested by hybridization experiments with positive results for T. cruzi specific molecular probe. The origin and dispersion of T. cruzi human infection is discussed as well as the molecular paleoparasitological approach, and what it may represent in an evolutionary perspective.