Genetic portrait of the Amazonian communities of Peru and Bolivia: The legacy of the Takanan-speaking people.

During the colonial period in South America, many autochthonous populations were affected by relocation by European missionary reductions and other factors that impacted and reconfigured their genetic makeup. Presently, the descendants of some "reduced" and other isolated groups are distributed in the Amazonian areas of Peru, Bolivia, and Brazil, and among them, speakers of Takanan and Panoan languages. Based on linguistics, these peoples should be closely related, but so far no DNA comparison studies have been conducted to corroborate a genetic relationship. To clarify these questions, we used a set of 15 short tandem repeats of the non-recombining part of the Y-chromosome (Y-STRs) and mitochondrial DNA (mtDNA) control region sequence data. Paternal line comparisons showed the Takanan-speaking peoples from Peru and Bolivia descended from recent common ancestors; one group was related to Arawakan, Jivaroan, and Cocama and the other to Panoan speakers, consistent with linguistics. Also, a genetic affinity for maternal lines was observed between some Takanan speakers and individuals who spoke different Amazonian languages. Our results supported a shared ancestry of Takanan, Panoan, Cocama, and Jivaroan-speaking communities who appeared to be related to each other and came likely from an early Arawak expansion in the western Amazonia of South America.

In Vitro Benznidazole and Nifurtimox Susceptibility Profile of Trypanosoma cruzi Strains Belonging to Discrete Typing Units TcI, TcII, and TcV.

We ascertain the in vitro Benznidazole (BZN) and Nifurtimox (NFX) susceptibility pattern of epimastigotes, trypomastigotes, and amastigotes of 21 T. cruzi strains, from patients, reservoir, and triatomine bugs of various geographic origins. Using this panel of isolates, we compute the Epidemiological cut off value (COwt). Then, the frequency of the susceptible phenotype (Wild type) towards benznidazole (BZN) and nifurtimox (NFX) within this set of strains belonging to three discrete typing units (DTUs), TcI, TcII, and TcV, was deduced. We observed that the susceptibility status of individual T. cruzi isolates toward BZN and NFX is related to the genetic background and underlying factors that are probably related to the individual life trait history of each strain. Analyzing drug susceptibility in this conceptual framework would offer the possibility to evidence a link between isolates expressing a low susceptibility level (not wild-type) as defined by the COwt value and none-curative treatment. It will also permit us to track drug-resistant parasites in the T. cruzi population.

Lower urinary tract dysfunction in chronic Chagas disease: clinical and urodynamic presentation.

PURPOSE: To describe and give an estimation of the prevalence of urinary disorders in chronic Chagas disease, since most clinical research has been centered on the description of the cardiac and digestive forms. METHODS: To explore this topic, a cross-sectional study was conducted in 137 Bolivian adults of both sexes suffering from symptomatic chronic Chagas disease. All patients presenting confirmed chagasic cardiomyopathy, megacolon or both underwent a urologic symptom questionnaire, uroflowmetry, urinary tract ultrasonography and a creatinine assay. When urinary abnormality was detected, a complete urodynamic study was proposed including cystometry, pressure-flow studies and urethral pressure profile. RESULTS: Out of all study patients, 35 (26%) had a Chagas cardiomyopathy, 81 (59%) a megacolon, and 21 (15%) a megacolon associated with cardiomyopathy. In all, 63% presented urinary disorders defined by IPSS > 7 and/or ICIQ SF > 1. Among them, 62% were incontinent, mainly by bladder overactivity, and 45% presented grade 2 or 3 renal insufficiency. Of 49 patients, the urodynamic study identified 34 patients with detrusor overactivity (69%), mostly in those with Chagas megacolon. Median bladder functional capacity, urethral closure pressure and bladder compliance had normal values. Moreover, 36% of these patients presented moderate hypocontractility, without significant post-void residual. CONCLUSIONS: This study evidenced lower urinary tract dysfunction in a majority of chronic chagasic patients; those presenting megacolon were more likely to suffer from urinary incontinence. These results strongly suggest including routine urological clinical investigation in chronic Chagas patients, as urinary incontinence due to overactive bladder is frequently observed in this population.

Y Chromosome Sequences Reveal a Short Beringian Standstill, Rapid Expansion, and early Population structure of Native American Founders.

The Americas were the last inhabitable continents to be occupied by humans, with a growing multidisciplinary consensus for entry 15-25 thousand years ago (kya) from northeast Asia via the former Beringia land bridge [1-4]. Autosomal DNA analyses have dated the separation of Native American ancestors from the Asian gene pool to 23 kya or later [5, 6] and mtDNA analyses to ∼25 kya [7], followed by isolation ("Beringian Standstill" [8, 9]) for 2.4-9 ky and then a rapid expansion throughout the Americas. Here, we present a calibrated sequence-based analysis of 222 Native American and relevant Eurasian Y chromosomes (24 new) from haplogroups Q and C [10], with four major conclusions. First, we identify three to four independent lineages as autochthonous and likely founders: the major Q-M3 and rarer Q-CTS1780 present throughout the Americas, the very rare C3-MPB373 in South America, and possibly the C3-P39/Z30536 in North America. Second, from the divergence times and Eurasian/American distribution of lineages, we estimate a Beringian Standstill duration of 2.7 ky or 4.6 ky, according to alternative models, and entry south of the ice sheet after 19.5 kya. Third, we describe the star-like expansion of Q-M848 (within Q-M3) starting at 15 kya [11] in the Americas, followed by establishment of substantial spatial structure in South America by 12 kya. Fourth, the deep branches of the Q-CTS1780 lineage present at low frequencies throughout the Americas today [12] may reflect a separate out-of-Beringia dispersal after the melting of the glaciers at the end of the Pleistocene.

Estudio epidemiológico, serológico y molecular de la enfermedad de chagas en la amazonía boliviana / Epidemiological, serological and molecular study of the chagas disease in the bolivian amazon

El presente estudio es parte del proyecto PIA-ACC.UMSA.01 Búsqueda de Nuevas Zonas Endémicas de la Enfermedad de Chagas en la Amazonía Boliviana como efecto del Cambio Climático, el cual nos ha permitido realizar el estudio epidemiológico - serológico y molecular de la enfermedad de Chagas en personas asintomáticas habitantes de seis regiones de la Amazonía Boliviana: Riberalta; Guayaramerín; Cobija; Trinidad; San Joaquín y San Borja, quienes en su mayoría pertenecían a los diversos pueblos indígenas, afectados por la pobreza. La exploración clínica y las pruebas de diagnóstico serológico y molecular de la enfermedad de Chagas se realizaron a la población de cada región sin costo. La participación de la gente fue coordinada con la Central de Pueblos Indígenas del Beni y mediante la firma del consentimiento informado se sometieron al estudio todos los participantes voluntarios. Un total de 338 muestras fueron procesadas con las pruebas serológicas de ELISA; HAI e IFI y la prueba molecular de la PCR en punto final. La seropositividad fue del 6,2% (21 casos) y la PCR fue positiva en 3,8% (13 casos). Del total de casos Chagas positivo, el 42% fueron casos de migrantes de regiones endémicas como Cochabamba, Santa Cruz, Chuquisaca y Yungas de La Paz, Asimismo, se identificaron a los principales factores de riesgo asociados a la enfermedad constatando entre otros aspectos que los habitantes de estas regiones tienen escaso conocimiento sobre la enfermedad de Chagas; sin embargo están conscientes sobre la aparición de enfermedades extrañas en estas regiones debido a las variaciones climatológicas detectadas en los últimos años y evidencian su preocupación sobre los efectos negativos del cambio climático

The present study is part of the project PIA-ACC.UMSA.01 Search for New Endemic Areas of Chagas Disease in the Bolivian Amazon as an effect of Climate Change, which has allowed us to carry out the epidemiological - serological and molecular study of Chagas disease in asymptomatic people living in six regions of the Bolivian Amazon: Riberalta; Guayaramerín; Cobija; Trinidad; San Joaquín and San Borja, who in their majority belonged to the diverse indigenous towns, affected by the poverty. Clinical exploration and serological and molecular diagnostic tests of Chagas disease were performed on the population of each region at no cost. The participation of the people was coordinated with the Central de Pueblos Indígenas del Beni (Central de Pueblos Indígenas del Beni) and by signing the informed consent all the volunteer participants were submitted to the study. A total of 338 samples were processed with the ELISA serological tests; HAI and IFI and the molecular test of the PCR at the end point. The seropositivity was 6.2% (21 cases) and the PCR was positive in 3.8% (13 cases). Of the total positive Chagas cases, 42% were cases of migrants from endemic regions such as Cochabamba, Santa Cruz, Chuquisaca and Yungas de La Paz. Likewise, the main risk factors associated with the disease were identified, noting among other aspects that inhabitants of these regions have little knowledge about Chagas disease; however, they are aware of the appearance of strange diseases in these regions due to the climatic variations detected in recent years and evidence their concern about the negative effects of climate change.

Estudio epidemiológico, serológico y molecular de la enfermedad de chagas en la amazonía boliviana / Epidemiological, serological and molecular study of the chagas disease in the bolivian amazon

El presente estudio es parte del proyecto PIA-ACC.UMSA.01 Búsqueda de Nuevas Zonas Endémicas de la Enfermedad de Chagas en la Amazonía Boliviana como efecto del Cambio Climático, el cual nos ha permitido realizar el estudio epidemiológico - serológico y molecular de la enfermedad de Chagas en personas asintomáticas habitantes de seis regiones de la Amazonía Boliviana: Riberalta; Guayaramerín; Cobija; Trinidad; San Joaquín y San Borja, quienes en su mayoría pertenecían a los diversos pueblos indígenas, afectados por la pobreza. La exploración clínica y las pruebas de diagnóstico serológico y molecular de la enfermedad de Chagas se realizaron a la población de cada región sin costo. La participación de la gente fue coordinada con la Central de Pueblos Indígenas del Beni y mediante la firma del consentimiento informado se sometieron al estudio todos los participantes voluntarios. Un total de 338 muestras fueron procesadas con las pruebas serológicas de ELISA; HAI e IFI y la prueba molecular de la PCR en punto final. La seropositividad fue del 6,2% (21 casos) y la PCR fue positiva en 3,8% (13 casos). Del total de casos Chagas positivo, el 42% fueron casos de migrantes de regiones endémicas como Cochabamba, Santa Cruz, Chuquisaca y Yungas de La Paz, Asimismo, se identificaron a los principales factores de riesgo asociados a la enfermedad constatando entre otros aspectos que los habitantes de estas regiones tienen escaso conocimiento sobre la enfermedad de Chagas; sin embargo están conscientes sobre la aparición de enfermedades extrañas en estas regiones debido a las variaciones climatológicas detectadas en los últimos años y evidencian su preocupación sobre los efectos negativos del cambio climático.

The present study is part of the project PIAACC.UMSA.01 Search for New Endemic Areas of Chagas Disease in the Bolivian Amazon as an effect of Climate Change, which has allowed us to carry out the epidemiological - serological and molecular study of Chagas disease in asymptomatic people living in six regions of the Bolivian Amazon: Riberalta; Guayaramerín; Cobija; Trinidad; San Joaquín and San Borja, who in their majority belonged to the diverse indigenous towns, affected by the poverty. Clinical exploration and serological and molecular diagnostic tests of Chagas disease were performed on the population of each region at no cost. The participation of the people was coordinated with the Central de Pueblos Indígenas del Beni (Central de Pueblos Indígenas del Beni) and by signing the informed consent all the volunteer participants were submitted to the study. A total of 338 samples were processed with the ELISA serological tests; HAI and IFI and the molecular test of the PCR at the end point. The seropositivity was 6.2% (21 cases) and the PCR was positive in 3.8% (13 cases). Of the total positive Chagas cases, 42% were cases of migrants from endemic regions such as Cochabamba, Santa Cruz, Chuquisaca and Yungas de La Paz. Likewise, the main risk factors associated with the disease were identified, noting among other aspects that inhabitants of these regions have little knowledge about Chagas disease; however, they are aware of the appearance of strange diseases in these regions due to the climatic variations detected in recent years and evidence their concern about the negative effects of climate change.

Divergent Mitochondrial Antioxidant Activities and Lung Alveolar Architecture in the Lungs of Rats and Mice at High Altitude.

Compared with mice, adult rats living at 3,600 m above sea level (SL-La Paz, Bolivia) have high hematocrit, signs of pulmonary hypertension, and low lung volume with reduced alveolar surface area. This phenotype is associated with chronic mountain sickness in humans living at high altitude (HA). We tested the hypothesis that this phenotype is associated with impaired gas exchange and oxidative stress in the lungs. We used rats and mice (3 months old) living at HA (La Paz) and SL (Quebec City, Canada) to measure arterial oxygen saturation under graded levels of hypoxia (by pulse oximetry), the alveolar surface area in lung slices and the activity of pro- (NADPH and xanthine oxidases-NOX and XO) and anti- (superoxide dismutase, and glutathione peroxidase-SOD and GPx) oxidant enzymes in cytosolic and mitochondrial lung protein extracts. HA rats have a lower arterial oxygen saturation and reduced alveolar surface area compared to HA mice and SL rats. Enzymatic activities (NOX, XO, SOD, and GPx) in the cytosol were similar between HA and SL animals, but SOD and GPx activities in the mitochondria were 2-3 times higher in HA vs. SL rats, and only marginally higher in HA mice vs. SL mice. Furthermore, the maximum activity of cytochrome oxidase-c (COX) measured in mitochondrial lung extracts was also 2 times higher in HA rats compared with SL rats, while there was only a small increase in HA mice vs. SL mice. Interestingly, compared with SL controls, alterations in lung morphology are not observed for young rats at HA (15 days after birth), and enzymatic activities are only slightly altered. These results suggest that rats living at HA have a gradual reduction of their alveolar surface area beyond the postnatal period. We can speculate that the elevation of SOD, GPx, and COX activities in the lung mitochondria are not sufficient to compensate for oxidative stress, leading to damage of the lung tissue in rats.

Genetic ancestry of families of putative Inka descent.

This study focuses on the descendants of the royal Inka family. The Inkas ruled Tawantinsuyu, the largest pre-Columbian empire in South America, which extended from southern Colombia to central Chile. The origin of the royal Inkas is currently unknown. While the mummies of the Inka rulers could have been informative, most were destroyed by Spaniards and the few remaining disappeared without a trace. Moreover, no genetic studies have been conducted on present-day descendants of the Inka rulers. In the present study, we analysed uniparental DNA markers in 18 individuals predominantly from the districts of San Sebastian and San Jerónimo in Cusco (Peru), who belong to 12 families of putative patrilineal descent of Inka rulers, according to documented registries. We used single-nucleotide polymorphisms and short tandem repeat (STR) markers of the Y chromosome (Y-STRs), as well as mitochondrial DNA D-loop sequences, to investigate the paternal and maternal descent of the 18 alleged Inka descendants. Two Q-M3* Y-STR clusters descending from different male founders were identified. The first cluster, named AWKI-1, was associated with five families (eight individuals). By contrast, the second cluster, named AWKI-2, was represented by a single individual; AWKI-2 was part of the Q-Z19483 sub-lineage that was likely associated with a recent male expansion in the Andes, which probably occurred during the Late Intermediate Period (1000-1450 AD), overlapping the Inka period. Concerning the maternal descent, different mtDNA lineages associated with each family were identified, suggesting a high maternal gene flow among Andean populations, probably due to changes in the last 1000 years.

Determinación del porcentaje de pacientes con enfermedad de chagas en la Amazonía Boliviana (parte i) / Determination of the percentage of patients with chagas disease in the Bolivian Amazon (part i)

OBJETIVO: Determinar la presencia de la enfermedad de Chagas en la Amazonía Boliviana mediante diagnóstico serológico y molecular en muestras de suero y sangre de pacientes de las regiones de Riberalta, Guayaramerín y Cobija. MATERIAL Y MÉTODOS: La población de estudio consistió en 192 personas mayores de edad habitantes de las regiones de Riberalta, Guayaramerín y Cobija quienes acudieron a los centros hospitalarios para una atención médica. Para el análisis de las muestras se utilizaron técnicas serológicas ELISA, HAI, IFI y la técnica molecular de la PCR en punto final. RESULTADOS: Los resultados reflejaron un porcentaje de infección del 4,08 por ciento del total de los pacientes de Cobija; 6,67 por ciento de los pacientes de Riberalta y 7,23 por ciento de los pacientes de Guayaramerín. Del total de los participantes el 74,48 por ciento fueron mujeres mayores de 17 años de edad. Los resultados de la PCR en punto final reflejaron un porcentaje de positividad general del 0,5 por ciento; los resultados de las pruebas serológicas reflejaron un porcentaje de positividad general del 6,25 por ciento.

OBJETIVE: To determine the presence of Chagas' disease in the Bolivian Amazon by serological and molecular diagnosis in serum and blood samples from patients from Riberalta, Guayaramerin and Cobija regions. MATERIAL AND METHODS: The study population was established by 192 elderly people living in the regions of Riberalta, Guayaramerin and Cobija who went to hospital for medical care. For the analysis of the samples serological techniques ELISA, HAI, IFI and the molecular technique of the PCR in end point were used. RESULTS: The results reflected a percentage of infection of 4,08 of the patients of Cobija, 6,67 percent of the patients of Riberalta and 7,23 percent of the patients of Guayaramerin. Of the total number of participants, 74,48 percent were women older than 17 years of age. The end-point PCR results showed a general positivity percentage of 0,5 percent the results of the serological tests reflected a general positive percentage of 6,25 percent.

A survey of the clinicopathological and molecular characteristics of patients with suspected Lynch syndrome in Latin America.

BACKGROUND: Genetic counselling and testing for Lynch syndrome (LS) have recently been introduced in several Latin America countries. We aimed to characterize the clinical, molecular and mismatch repair (MMR) variants spectrum of patients with suspected LS in Latin America. METHODS: Eleven LS hereditary cancer registries and 34 published LS databases were used to identify unrelated families that fulfilled the Amsterdam II (AMSII) criteria and/or the Bethesda guidelines or suggestive of a dominant colorectal (CRC) inheritance syndrome. RESULTS: We performed a thorough investigation of 15 countries and identified 6 countries where germline genetic testing for LS is available and 3 countries where tumor testing is used in the LS diagnosis. The spectrum of pathogenic MMR variants included MLH1 up to 54%, MSH2 up to 43%, MSH6 up to 10%, PMS2 up to 3% and EPCAM up to 0.8%. The Latin America MMR spectrum is broad with a total of 220 different variants which 80% were private and 20% were recurrent. Frequent regions included exons 11 of MLH1 (15%), exon 3 and 7 of MSH2 (17 and 15%, respectively), exon 4 of MSH6 (65%), exons 11 and 13 of PMS2 (31% and 23%, respectively). Sixteen international founder variants in MLH1, MSH2 and MSH6 were identified and 41 (19%) variants have not previously been reported, thus representing novel genetic variants in the MMR genes. The AMSII criteria was the most used clinical criteria to identify pathogenic MMR carriers although microsatellite instability, immunohistochemistry and family history are still the primary methods in several countries where no genetic testing for LS is available yet. CONCLUSION: The Latin America LS pathogenic MMR variants spectrum included new variants, frequently altered genetic regions and potential founder effects, emphasizing the relevance implementing Lynch syndrome genetic testing and counseling in all of Latin America countries.

Hypercapnic ventilatory response is decreased in a mouse model of excessive erythrocytosis.

The impact of cerebral erythropoietin (Epo) in the regulation of the hypercapnic ventilatory response (HcVR) is controversial. While we reported that cerebral Epo does not affect the central chemosensitivity in C57Bl6 mice receiving an intracisternal injection of sEpoR (the endogenous antagonist of Epo), a recent study in transgenic mice with constitutive high levels of human Epo in brain and circulation (Tg6) and in brain only (Tg21), showed that Epo blunts the HcVR, maybe by interacting with central and peripheral chemoreceptors. High Epo serum levels in Tg6 mice lead to excessive erythrocytosis (hematocrit ~80-90%), the main symptom of chronic mountain sickness (CMS). These latter results support the hypothesis that reduced central chemosensitivity accounts for the hypoventilation observed in CMS patients. To solve this intriguing divergence, we reevaluate HcVR in Tg6 and Tg21 mouse lines, by assessing the metabolic rate [O consumption (V̇) and CO production (V̇)], a key factor modulating ventilation, the effect of which was not considered in the previous study. Our results showed that the decreased HcVR observed in Tg6 mice (~70% reduction; < 0.01) was due to a significant decrease in the metabolism (~40%; < 0.0001) rather than Epo's effect on CO chemosensitivity. Additional analysis in Tg21 mice did not reveal differences of HcVR or metabolism. We concluded that cerebral Epo does not modulate the central chemosensitivity system, and that a metabolic effect upon CO inhalation is responsible for decreased HcVR observed in Tg6 animals. As CMS patients also show decreased HcVR, our findings might help to better understand respiratory disorders at high altitude.

New native South American Y chromosome lineages.

Many single-nucleotide polymorphisms (SNPs) in the non-recombining region of the human Y chromosome have been described in the last decade. High-coverage sequencing has helped to characterize new SNPs, which has in turn increased the level of detail in paternal phylogenies. However, these paternal lineages still provide insufficient information on population history and demography, especially for Native Americans. The present study aimed to identify informative paternal sublineages derived from the main founder lineage of the Americas-haplogroup Q-L54-in a sample of 1841 native South Americans. For this purpose, we used a Y-chromosomal genotyping multiplex platform and conventional genotyping methods to validate 34 new SNPs that were identified in the present study by sequencing, together with many Y-SNPs previously described in the literature. We updated the haplogroup Q phylogeny and identified two new Q-M3 and three new Q-L54*(xM3) sublineages defined by five informative SNPs, designated SA04, SA05, SA02, SA03 and SA29. Within the Q-M3, sublineage Q-SA04 was mostly found in individuals from ethnic groups belonging to the Tukanoan linguistic family in the northwest Amazon, whereas sublineage Q-SA05 was found in Peruvian and Bolivian Amazon ethnic groups. Within Q-L54*, the derived sublineages Q-SA03 and Q-SA02 were exclusively found among Coyaima individuals (Cariban linguistic family) from Colombia, while Q-SA29 was found only in Maxacali individuals (Jean linguistic family) from southeast Brazil. Furthermore, we validated the usefulness of several published SNPs among indigenous South Americans. This new Y chromosome haplogroup Q phylogeny offers an informative paternal genealogy to investigate the pre-Columbian history of South America.Journal of Human Genetics advance online publication, 31 March 2016; doi:10.1038/jhg.2016.26.

The genetic history of indigenous populations of the Peruvian and Bolivian Altiplano: the legacy of the Uros.

The Altiplano region of the South American Andes is marked by an inhospitable climate to which the autochthonous human populations adapted and then developed great ancient civilizations, such as the Tiwanaku culture and the Inca Empire. Since pre-Columbian times, different rulers established themselves around the Titicaca and Poopo Lakes. By the time of the arrival of Spaniards, Aymara and Quechua languages were predominant on the Altiplano under the rule of the Incas, although the occurrence of other spoken languages, such as Puquina and Uruquilla, suggests the existence of different ethnic groups in this region. In this study, we focused on the pre-Columbian history of the autochthonous Altiplano populations, particularly the Uros ethnic group, which claims to directly descend from the first settlers of the Andes, and some linguists suggest they might otherwise be related to Arawak speaking groups from the Amazon. Using phylogeographic, population structure and spatial genetic analyses of Y-chromosome and mtDNA data, we inferred the genetic relationships among Uros populations (Los Uros from Peru, Uru-Chipaya and Uru-Poopo from Bolivia), and compared their haplotype profiles with eight Aymara, nine Quechua and two Arawak (Machiguenga and Yanesha) speaking populations from Peru and Bolivia. Our results indicated that Uros populations stand out among the Altiplano populations, while appearing more closely related to the Aymara and Quechua from Lake Titicaca and surrounding regions than to the Amazon Arawaks. Moreover, the Uros populations from Peru and Bolivia are genetically differentiated from each other, indicating a high heterogeneity in this ethnic group. Finally, our results support the distinctive ancestry for the Uros populations of Peru and Bolivia, which are likely derived from ancient Andean lineages that were partially replaced during more recent farming expansion events and the establishment of complex civilizations in the Andes.

A new subhaplogroup of native American Y-Chromosomes from the Andes.

The human Y chromosome contains highly informative markers for making historical inferences about the pre-Columbian peopling of Americas. However, the scarcity of these markers has limited its use in the inference of shared ancestry and past migrations relevant to the origin of the culturally and biologically diverse Native Americans. To identify new single nucleotide polymorphisms (SNPs) and increase the phylogenetic resolution of the major haplogroup Q found in the Americas, we have performed a search for new polymorphisms based on sequencing divergent Y chromosomes identified by microsatellite haplotype analysis. Using this approach, a new Y-SNP (SA01) has been identified in the Andean populations of South America, allowing for the detection of a new sublineage of Q1a3a. This sublineage displays a less complex phylogeographic network of associated microsatellites and more restricted geographic occurrence, and is given the designation Q1a3a4. This result indicates that our approach can be successfully used to identify sublineages of interest in a specific region that allow the investigation of particular histories of human populations.

Implementación de la Técnica Reacción en Cadena de la Polimerasa en el Diagnóstico de Salmonella y Shigella directamente de muestras fecales / Implementation of the Technical Polymerase Chain Reaction in the Diagnosis of `Salmonella` and Shigella directly of fecal samples

Las diarreas causadas por bacterias son las que potencilamente suponene un mayor riesgo vital para el paciente, siendo los patógenos más importantes Shiggella y Salmonella que se ubican entre las causas principales de muerte en niños menores de cinco años, e spor esto que resulta de vital importancia realizar un diagnóstico rápido y preciso, junto a un tratamiento efectivo.

Polymerase chain reaction detection and serologic follow-up after treatment with benznidazole in Bolivian children infected with a natural mixture of Trypanosoma cruzi I and II.

Thirty-five Bolivian children (5-10 years of age) seropositive for infection with T. cruzi underwent specific chemotherapy with benznidazole. Before treatment, 57.1% had a positive parasitologic diagnosis. Some patients presented an early conversion by polymerase chain reaction of blood samples, while others were still positive four and seven months after the end of the treatment, which indicated an absence of parasite clearance. Strain typing showed that most patients were infected by a mixture of clones I and II of T. cruzi. Serologic conversion in conventional tests and antibodies to shed acute-phase antigen were observed in two and four patients, respectively. For the other patients, the average rate of antibody decay was half the initial rate. The parasitologic and serologic data indicated that chemotherapy acts throughout the course of infection in a long-lasting process in which the decrease of specific antibody production is related to the reduction of the live parasite load.

Serodiagnosis of chronic and acute Chagas' disease with Trypanosoma cruzi recombinant proteins: results of a collaborative study in six Latin American countries.

An enzyme-linked immunosorbent assay to diagnose Chagas' disease by a serological test was performed with Trypanosoma cruzi recombinant antigens (JL8, MAP, and TcPo). High sensitivity (99.4%) and specificity (99.3%) were obtained when JL8 was combined with MAP (JM) and tested with 150 serum samples from chagasic and 142 nonchagasic individuals. Moreover, JM also diagnosed 84.2% of patients in the acute phase of T. cruzi infection.

Chagas' disease diagnosis: a multicentric evaluation of Chagas Stat-Pak, a rapid immunochromatographic assay with recombinant proteins of Trypanosoma cruzi.

A rapid serologic test for diagnosis of T. cruzi infection (Chagas Stat Pak) was developed using recombinant proteins in an immunochromatographic assay. This cassette format test was evaluated first in blind with a panel of 393 coded serum samples. The Chagas Stat-Pak identified 197 infected (98.5% sensitivity) and 183 non-infected individuals (94.8% specificity). A second evaluation was performed with 352 sera from four Latin America countries tested independently in each country, showing a sensitivity of 100% and specificity of 98.6%. A third set of tests comparing sera with plasma and eluates from filter paper as well as serum preserved in 50% glycerol did show identical results as those obtained with serum. This rapid test (15 min) uses one device per sample, does not require refrigeration nor a laboratory structure or specialized skills to be performed, accepts different types of samples and may be stored for long periods of time for result checking and documentation. These attributes together with the high sensitivity and specificity demonstrated herein, make this test a suitable tool for field studies, small laboratories and emergencies at blood banks in the countryside of endemic areas.

Analisis genetico poblacional de 9 Y-SRs en grupo etnico de Bolivia / Population genetic Analisys of 9 Y-TRs in etnico group of Bolivia

En Bolivia la población ameriñdia de la Amazonia, contiene cierto número de pequeños grupos humanos, que mantienen poco o ningún contacto con otros pueblos indígenas o con grupos humanos civilizados. Los estudios de la variabilidad del cromosoma Y, en poblaciones amerindias nativas han sido provechosos para comprender algunos aspectos de la historia genética. Con el objeto de investigar las posibles relaciones entre las distintas etnias que habitan Bolivia, se analizaron 9 marcadores microsatélites del cromosoma Y, (DYS393, DYS39O, DYS394, DYS392, DYS391, DYS385 1-II, DYS389 1-II). De esta manera se obtuvo 23 haplotipos diferentes y una alta frecuencia de algunos alelos, como el 13 para el locus DYS393 y DYS394. Estos resultados posiblemente se deban al componente amerindio, como lo indican otros estudios similares en este mismo tipo de poblaciones del continente americano