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OBJECTIVES To inform next steps in pediatric diarrhea burden reduction by understanding the shifting enteropathogen landscape after rotavirus vaccine implementation. METHODS We conducted a case-control study of 1788 medically attended children younger than 5 years, with and without gastroenteritis, after universal rotavirus vaccine implementation in Peru. We tested case and control stools for 5 viruses, 19 bacteria, and parasites; calculated coinfection-adjusted attributable fractions (AFs) to determine pathogen-specific burdens; and evaluated pathogen-specific gastroenteritis severity using Clark and Vesikari scales. RESULTS Six pathogens were independently positively associated with gastroenteritis: norovirus genogroup II (GII) (AF 29.1, 95% confidence interval [CI]: 28.0–32.3), rotavirus (AF 8.9, 95% CI: 6.8–9.7), sapovirus (AF 6.3, 95% CI: 4.3–7.4), astrovirus (AF 2.8, 95% CI: 0.0–4.0); enterotoxigenic Escherichia coli heat stable and/or heat labile and heat stable (AF 2.4, 95% CI: 0.6–3.1), and Shigella spp. (AF 2.0, 95% CI: 0.4–2.2). Among typeable rotavirus cases, we most frequently identified partially heterotypic strain G12P[8] (54 of 81, 67%). Mean severity was significantly higher for norovirus GII–positive cases relative to norovirus GII–negative cases (Vesikari [12.7 vs 11.8; P < .001] and Clark [11.7 vs 11.4; P = .016]), and cases in the 6- to 12-month age range relative to cases in other age groups (Vesikari [12.7 vs 12.0; P = .0002] and Clark [12.0 vs 11.4; P = .0016]). CONCLUSIONS Norovirus is well recognized as the leading cause of pediatric gastroenteritis in settings with universal rotavirus vaccination. However, sapovirus is often overlooked. Both norovirus and sapovirus contribute significantly to the severe pediatric disease burden in this setting. Decision-makers should consider multivalent vaccine acquisition strategies to target multiple caliciviruses in similar countries after successful rotavirus vaccine implementation.

Feeding of infant formula using contaminated bottles may be an important transmission pathway of enteric pathogens during early life. Determinants of suboptimal bottle hygiene and the feasibility and acceptability of intervention strategies have not been well assessed. We evaluated the extent of bottle contamination, its contributing factors, and options for promoting improved bottle hygiene in a Peruvian shantytown. During Phase 1, we sampled from bottles and caregiver hands (n = 48) and processed for enumeration of total coliform and Escherichia coli colony-forming units. A semi-structured questionnaire captured bottle use and hygiene practices. Phase 2 involved the identification of candidate practices to recommend to caregivers. Phase 3 consisted of a behavioral trial in which 14 caregivers were educated about improved practices for bottle disinfection and later reported on their experiences implementing them. Fecal bacteria were detected in 43.8% of bottles sampled during Phase 1 and in 21.7% of hands. Caregivers overall did not use effective methods for disinfecting bottles, displayed misunderstandings surrounding hygienic practices, and few had ever discussed bottle hygiene with a health provider. Findings from the behavioral trial indicated that the improved practice of brushing the bottle with dish detergent for 30 seconds after every use is preferable to boiling the bottle for several minutes daily as caregivers reported that the brush was simple to use, efficient, and practical. The promotion of a bottle brush and detergent is a feasible and acceptable intervention strategy in peri-urban settings, and future research should evaluate its long-term effectiveness for reducing bottle contamination.

Antibiotic-resistant infections annually claim hundreds of thousands of lives worldwide. This problem is exacerbated by exchange of resistance genes between pathogens and benign microbes from diverse habitats. Mapping resistance gene dissemination between humans and their environment is a public health priority. Here we characterized the bacterial community structure and resistance exchange networks of hundreds of interconnected human faecal and environmental samples from two low-income Latin American communities. We found that resistomes across habitats are generally structured by bacterial phylogeny along ecological gradients, but identified key resistance genes that cross habitat boundaries and determined their association with mobile genetic elements. We also assessed the effectiveness of widely used excreta management strategies in reducing faecal bacteria and resistance genes in these settings representative of low- and middle-income countries. Our results lay the foundation for quantitative risk assessment and surveillance of resistance gene dissemination across interconnected habitats in settings representing over two-thirds of the world's population.

Background: More than one billion people worldwide live with a disability. Despite advances in recognising inequalities experienced by people with disabilities, barriers to services and stigmatisation still exist. The aims of this study were to explore: (1) perceptions and experiences of services specifically available to people with disabilities and their caregivers and (2) the perception of disability. Methods: In-depth interviews were conducted with 20 caregivers of persons with a disability and 14 key informants in two cities in Peru; Lima and Iquitos. The social-ecological model was used as a framework to analyse and present data, stratifying the key barriers and opportunities at each level. Results: At the individual level, interviewees reported a lack of support at the time of diagnosis, poor coping strategies, and communicated their desire for, and willingness to participate in support groups if they were established. On the community level, education and awareness were reportedly lacking and acts of discrimination and stigmatisation were common. Participants described opportunities for community-level campaigns to increase exposure and awareness of disability rights and inclusion. A dissatisfaction with government programmes was reported, as services were not available to everyone, in part due to geographical and socio-economic barriers. Conclusions: The main findings were the lack of emotional, informational, and tangible support available to caregivers of people with disabilities, often exacerbated by lower socio-economic status; a lack of transparency of care pathways available to people with disabilities; and a lack of visibility of people with disability in both Lima and Iquitos. Implications for Rehabilitation Support groups could offer additional support to caregivers of people with disabilities in Lima, mitigating existing gaps in services for people with disabilities, and their families. Education campaigns implemented on a community level could start to curb discrimination and stigmatisation of people with disabilities in Lima and Iquitos. A national census with inclusive language and methodology specifically designed to capture the percentage of the population currently living with a disability would give a real indication of what services are needed in Peru. The provision of clear, publically available routes of attention would assist caregivers and families to access services for people with disabilities.

Aim To identify impairment in functional capacity associated with complicated and non-complicated diabetes using the 6-min walk distance test. Methods We enrolled 111 adults, aged ≥40 years, with Type 2 diabetes from a hospital facility and 150 healthy control subjects of similar age and sex from a community site in Lima, Peru. All participants completed a 6-min walk test. Results The mean age of the 261 participants was 58.3 years, and 43.3% were male. Among those with diabetes, 67 (60%) had non-complicated diabetes and 44 (40%) had complications such as peripheral neuropathy, retinopathy or nephropathy. The mean unadjusted 6-min walk distances were 376 m and 394 m in adults with and without diabetes complications, respectively, vs 469 m in control subjects (P

Population genetic studies have been used to understand the transmission of pathogens in humans and animals, especially the role of zoonotic infections and evolution and dispersal of virulent subtypes. In this study, we analysed the genetic diversity and population structure of Cryptosporidium meleagridis, the only known Cryptosporidium species that infects both avian and mammalian hosts and is responsible for approximately 10% of human cryptosporidiosis in some areas. A total of 62 C. meleagridis specimens from children, AIDS patients, and birds in Lima, Peru were characterised by sequence analysis of the ssrRNA gene and five minisatellite, microsatellite and polymorphic markers in chromosome 6, including the 60 kDa glycoprotein (gp60), 47 kDa glycoprotein (CP47), a serine repeat antigen (MSC6-5), retinitis pigmentosa GTPase regulator (RPGR) and thrombospondin protein 8 (TSP8). The multilocus sequence analysis identified concurrent infections with Cryptosporidium hominis in four AIDS patients and three children. Unique subtypes of C. meleagridis ranged from eight at the gp60 locus (gene diversity -Hd=0.651), three at the RPGR (Hd=0.556), three at the MSC6-5 locus (Hd=0.242), two at TSP8 (Hd=0.198), to one at CP47 (monomorphic), much lower than that of C. hominis in the same area. Intragenic linkage disequilibrium was strong and complete at all gene loci. Intergenic linkage disequilibrium was highly significant (P

Background. Human noroviruses are among the most common enteropathogens globally, and are a leading cause of infant diarrhea in developing countries. However, data measuring the impact of norovirus at the community level are sparse. Methods. We followed a birth cohort of children to estimate norovirus infection and diarrhea incidence in a Peruvian community. Stool samples from diarrheal episodes and randomly selected nondiarrheal samples were tested by polymerase chain reaction for norovirus genogroup and genotype. Excretion duration and rotavirus coinfection were evaluated in a subset of episodes. Results. Two hundred twenty and 189 children were followed to 1 and 2 years of age, respectively. By 1 year, 80% (95% confidence interval [CI], 75%–85%) experienced at least 1 norovirus infection and by 2 years, 71% (95% CI, 65%–77%) had at least 1 episode of norovirus-associated diarrhea. Genogroup II (GII) infections were 3 times more frequent than genogroup 1 (GI) infections. Eighteen genotypes were found; GII genotype 4 accounted for 41%. Median excretion duration was 34.5 days for GII vs 8.5 days for GI infection (P = .0006). Repeat infections by the same genogroup were common, but repeat infections by the same genotype were rare. Mean length-for-age z score at 12 months was lower among children with prior norovirus infection compared to uninfected children (coefficient: −0.33 [95% CI, −.65 to −.01]; P = .04); the effect persisted at 24 months. Conclusions. Norovirus infection occurs early in life and children experience serial infections with multiple genotypes, suggesting genotype-specific immunity. An effective vaccine would have a substantial impact on morbidity, but may need to target multiple genotypes.

Beta-defensins are a family of multifunctional genes with roles in defense against pathogens, reproduction, and pigmentation. In humans, six beta-defensin genes are clustered in a repeated region which is copy-number variable (CNV) as a block, with a diploid copy number between 1 and 12. The role in host defense makes the evolutionary history of this CNV particularly interesting, because morbidity due to infectious disease is likely to have been an important selective force in human evolution, and to have varied between geographical locations. Here, we show CNV of the beta-defensin region in chimpanzees, and identify a beta-defensin block in the human lineage that contains rapidly evolving noncoding regulatory sequences. We also show that variation at one of these rapidly evolving sequences affects expression levels and cytokine responsiveness of DEFB103, a key inhibitor of influenza virus fusion at the cell surface. A worldwide analysis of beta-defensin CNV in 67 populations shows an unusually high frequency of high-DEFB103-expressing copies in East Asia, the geographical origin of historical and modern influenza epidemics, possibly as a result of selection for increased resistance to influenza in this region. Hum Mutat 32:743–750, 2011. © 2011 Wiley-Liss, Inc.

and is a major impediment to the management of childhood diseases in developing coun- tries such as Peru. Although resistance in pathogenic organ- isms poses a distinct clinical challenge, commensal bacteria may play a crucial role in the spread of resistance within a community 3 by acting as a major reservoir for resistance genes. 4 Exposure of commensals such as Escherichia coli and Enterococcus faecium to antibiotics increases the car- riage levels of resistant organisms and, if plasmid-mediated, resistance might be transmitted to a more virulent acquired organism. 5 Abstract. Few studies have examined the influence of individual-, household-, and community-scale risk factors on carriage of resistant commensal bacteria. We determined children's medical, agricultural, and environmental exposures by household, pharmacy, and health facility surveys and Escherichia coli cultures of children, mothers' hands, household animals, and market chickens in Peru. Among 522 children with a positive stool culture, by log-binomial regression, using "any antibiotic" and 1-14 (versus 0) sulfa doses in the past 3 months increased children's risk, respectively, for ampicil- lin- and sulfamethoxazole-resistant E. coli carriage ( P = 0.01-0.02). Each household member taking "any antibiotic" increased children's risk for sulfamethoxazole- and multidrug-resistant E. coli carriage ( P < 0.0001). Residence in a zone where a larger proportion of households served home-raised chicken (as contrasted with intensively antibiotic-raised market chicken) protected against carrying E. coli resistant to all drugs ( P = 0.0004-0.04). Environmental contamination with drug-resistant bacteria appeared to significantly contribute to children's carriage of antibiotic-resistant E. coli .

Background Investigators use prospective community-based studies to collect longitudinal information on childhood diarrhea. The interval in which data are collected may affect the accuracy and interpretation of results. Our objective was to compare data of reported daily clinical symptoms from surveys conducted daily versus twice-weekly surveys. Methods We conducted our study in Lima, Peru, between October and December 2007. We asked 134 mothers to report daily symptoms by using a twice-weekly survey. We conducted daily surveys for the same data on 25% of participants randomly selected each day. We analyzed intersurvey variability by using Cohen's kappa and Signal Detection Theory (SDT). Results We collected 6157 and 1181 child-days of data through the twice-weekly and daily surveys, respectively. The prevalence of diarrhea, fever, vomiting, and cough were 6.4%, 1.6%, 2.1%, and 22.7% from the twice-weekly survey and, 6.4%, 2.0%, 2.4%, and 26% from the daily survey, respectively. Despite similar prevalence, 20% of days with reported diarrhea were discrepant between the two surveys, and agreement in the report of diarrhea decreased as time between the interviews increased ( p = .03). Conclusions Although twice-weekly surveys provide an adequate estimate of diarrheal prevalence compared with daily surveys, the prevalence of other symptoms based on dichotomous questions was lower under the former. Additionally, the agreement between the two surveys in the report of diarrhea decreased as the recall period increased, suggesting that data from daily interviews were of greater quality. Our analysis is a novel application of SDT to measure respondent certainty and bias, from which better inference about the quality of collected data may be drawn.

Chagas disease affects 8-11 million people throughout the Americas. Early detection is crucial for timely treatment and to prevent non-vectorial transmission. Recombinant antigen-based rapid tests had high sensitivity and specificity in laboratory evaluations, but no Peruvian specimens were included in previous studies. We evaluated Stat-Pak and Trypanosoma Detect rapid tests in specimens from Bolivia and Peru. Specimens positive by three conventional assays were confirmed positives; specimens negative by two or more assays were confirmed negatives. In Bolivian specimens, Stat-Pak and Trypanosoma Detect tests were 87.5% and 90.7% sensitive, respectively; both showed 100% specificity. Sensitivity in Peruvian specimens was much lower: 26.6-33.0% (Stat-Pak) and 54.3-55.2% (Trypanosoma Detect); both had specificities > 98%. Even in Bolivian specimens, these sensitivities are inadequate for stand-alone screening. The low sensitivity in Peru may be related to parasite strain differences. Chagas disease rapid tests should be field tested in each geographic site before widespread implementation for screening. Copyright

The efficiency of transmission of a pathogen within families compared with that between unrelated persons can affect both the strategies needed to control or eradicate infection and how the pathogen evolves. In industrialized countries, most cases of transmission of the gastric pathogen Helicobacter pylori seems to be from mother to child. An alternative model, potentially applicable among the very poor in developing countries, where infection is more common and the sanitary infrastructure is often deficient, invokes frequent transmission among unrelated persons, often via environmental sources. In the present study, we compared the genotypes of H. pylori from members of shantytown households in Peru to better understand the transmission of H. pylori in developing-country settings. H. pylori cultures and/or DNAs were obtained with informed consent by the string test (a minimally invasive alternative to endoscopy) from at least one child and one parent from each of 62 families. The random amplified polymorphic DNA fingerprints of 57 of 81 (70%) child-mother strain pairs did not match, nor did the diagnostic gene sequences (>1% DNA sequence difference), independent of the child's age (range, 1 to 39 years). Most strains from siblings or other paired family members were also unrelated. These results suggest that H. pylori infections are often community acquired in the society studied. Transmission between unrelated persons should facilitate the formation of novel recombinant genotypes by interstrain DNA transfer and selection for genotypes that are well suited for individual hosts. It also implies that the effective prevention of H. pylori infection and associated gastroduodenal disease will require anti- H. pylori measures to be applied communitywide.

One-sentence summary for table of contents: Different genotypes and subtypes are linked to different clinical manifestations., To determine whether clinical manifestations are associated with genotypes or subtypes of Cryptosporidium spp., we studied a 4-year longitudinal birth cohort of 533 children in Peru. A total of 156 infection episodes were found in 109 children. Data from first infections showed that C. hominis was associated with diarrhea, nausea, vomiting, general malaise, and increased oocyst shedding intensity and duration. In contrast, C. parvum, C. meleagridis, C. canis, and C. felis were associated with diarrhea only. C. hominis subtype families were identified (Ia, Ib, Id, and Ie); all were associated with diarrhea. Ib was also associated with nausea, vomiting, and general malaise. All C. parvum specimens belonged to subtype family IIc. Analysis of risk factors did not show associations with specific Cryptosporidium spp. genotypes or subtypes. These findings strongly suggest that Cryptosporidium spp. and subtypes are linked to different clinical manifestations in children.

Giardia intestinalis is a common gastrointestinal protozoan worldwide, but its effects on childhood growth in developing countries are not clearly understood. The authors aimed to describe its effects on child growth. They followed 220 Peruvian children daily for diarrhea, weekly for stool samples, and monthly for anthropometry. The authors modeled the effect of nutritional status on the risk of Giardia infection and the risk of diarrhea attributable to Giardia using negative binomial regression. They modeled the effects of Giardia infection on growth using linear regression, with 85% of children becoming infected with Giardia and 87% of these becoming reinfected. In multivariable analysis, the risk of Giardia infection did not vary with weight for age (relative risk = 1.00, 95% confidence interval: 0.89, 1.12) or height for age (relative risk = 0.92, 95% confidence interval: 0.82, 1.04). Giardiasis did not affect growth at 1 or 2 months following the first infection at any age interval. The longitudinal prevalence of Giardia between 6 and 24 months of age was not associated with height gain in that interval (p = 0.981). Giardia was not associated with an increased risk of diarrhea at any age interval. Study results question the importance of Giardia as a childhood pathogen in developing countries where giardiasis is hyperendemic.

We conducted a questionnaire-based case-control study to identify risk factors for cystic echinococcosis (CE) in Lima, Peru during July-December 2005. Data were obtained from 32 cases and 64 controls. Multivariate conditional logistic regression showed that having owned > or =10 dogs [adjusted odds ratio (AOR) 8.7, 95% CI 1.3-57.5) and raising sheep (AOR 5.9, 95% CI 1.2-28.1) were independently associated with CE. The belief that CE could be transmitted by food (AOR 0.1, 95% CI 0.01-0.7) and breeding goats (AOR 0.02, 95% CI 0.001-0.6) were protective factors against CE transmission. Our results suggest that preventive measures to decrease the transmission of echinococcosis to humans in Peru should include limiting the number of dogs owned and encouraging owners to restrict dogs' access to food and water used for human consumption.

We assessed fecal contamination of drinking water in households in 2 peri-urban communities of Lima, Peru. We measured Escherichia coli counts in municipal source water and, within households, water from principal storage containers, stored boiled drinking water, and water in a serving cup. Source water was microbiologically clean, but 26 (28%) of 93 samples of water stored for cooking had fecal contamination. Twenty-seven (30%) of 91 stored boiled drinking water samples grew E. coli. Boiled water was more frequently contaminated when served in a drinking cup than when stored (P < 0.01). Post-source contamination increased successively through the steps of usage from source water to the point of consumption. Boiling failed to ensure safe drinking water at the point of consumption because of easily contaminated containers and poor domestic hygiene. Hygiene education, better point-of-use treatment and storage options, and in-house water connections are urgently needed.

While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6–8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes.

Background. Gastric adenocarcinoma is associated with chronic infection by Helicobacter pylori and with the host inflammatory response triggered by it, with substantial inter-person variation in the immune response profile due to host genetic factors. Aim. To investigate the diversity of the proinflammatory genes IL8, its receptors and PTGS2 in Amerindians; to test whether candidate SNPs in these genes are associated with gastric cancer in an admixed population with high Amerindian ancestry from Lima, Peru; and to assess whether an IL8RB promoter-derived haplotype affects gene expression. Methods. We performed a Sanger-resequencing population survey, a candidate-gene association study (220 cases, 288 controls) and meta-analyses. We also performed an in vitro validation by a reporter gene assay of IL8RB promoter. Results. The diversity of the promoter of studied genes in Native Americans is similar to Europeans. Although an association between candidate SNPs and gastric cancer was not found in Peruvians, trend in our data is consistent with meta-analyses results that suggest PTGS2-rs689466-A is associated with H. pylori-associated gastric cancer in East Asia. IL8RB promoter-derived haplotype (rs3890158-A/rs4674258-T), common in Peruvians, was up-regulated by TNF-α unlike the ancestral haplotype (rs3890158-G/rs4674258-C). Bioinformatics analysis suggests that this effect stemmed from creation of a binding site for the FOXO3 transcription factor by rs3890158G>A. Conclusions. Our updated meta-analysis reinforces the role of PTGS2-rs689466-A in gastric cancer in Asians, although more studies that control for ancestry are necessary to clarify its role in Latin Americans. Finally, we suggest that IL8RB-rs3890158G>A is a cis-regulatory SNP.

Campylobacter jejuni is a major cause of diarrhea among children in developing countries. Since free-ranging chickens are a major source of Campylobacter infections, we hypothesized that corralling of these chickens would result in decreased rates of Campylobacter infections and Campylobacter-related diarrhea. We tested this hypothesis in Peruvian families in a periruban shantytown with free-ranging chickens and randomized by household using a (corralling) intervention versus control study design. Samples from participants and chickens were cultured for Campylobacter at the start of surveillance, and samples from children less than six years of age with diarrhea episodes and two sentinel chickens were cultured for Campylobacter monthly. Overall, 4,257 human stool specimens and 3,950 avian stool specimens were cultured over a 17-month period. Rates of Campylobacter-related diarrhea in children were significantly higher in the corral group, which demonstrated twice the incidence of Campylobacter diarrhea compared with controls overall, and seven times the rate of Campylobacter diarrhea versus controls in the subset with more than 20 household chickens. Rates of asymptomatic infection with Campylobacter were similar. Although corralling may be useful if corrals are distant from living quarters, it is not advisable as a control measure for Campylobacter in communities such as this.

Over the past decade, anti-malarial drug resistance has rapidly become a major public health problem in the Peruvian Amazon. This study compared polymerase chain reaction (PCR) to light microscopy for diagnosing and monitoring the parasitological response of malaria patients to anti-malarial chemotherapy in the Peruvian Amazon region of Iquitos. Typing of P. falciparum using MSP1, MSP2, and glutamine-rich protein distinguished among infecting parasites. Most (73%) P. falciparum patients were parasitologically resistant to sulfadoxine-pyrimethamine (RI = 10, RII = 1). Sensitivity of microscopy was lower than PCR (69% for P. vivax and 78% for P. falciparum), but parasite clearance times were comparable between microscopy and PCR. PCR sensitively and specifically detected mixed infections and low-level parasitemia indicative of drug resistance, making this approach of practical use for the control of malaria at the public health level. Genotyping malaria parasites will be useful to distinguish drug failure from new infections in clinical trials of anti-malarial drugs in the Peruvian Amazon region.

Cryptosporidium species are ubiquitous in the environment and are frequently detected in the stools of children who live where sanitation conditions are poor. To better characterize the immune response to these parasites, we monitored immunoglobulin G (IgG) antibody levels in a cohort of children from Lima, Peru. Two new enzyme-linked immunosorbent assays based on the C. parvum (bovine, subtype IIa) Iowa strain 17-kDa and 27-kDa antigens were used to measure IgG antibody levels in longitudinal serum samples. Antibody responses were detected during infections with C. parvum , C. felis , and C. meleagridis and with four different subtypes of C. hominis . We also noted that the magnitude of the antibody response was related to the number of previous infections and that older children generally had higher levels of antibodies to the two C. parvum antigens. Antibody responses were not associated with infections with either Cyclospora sp. or Giardia sp. We believe the antibody assays will be important tools for monitoring the success of future public health interventions.

Background. Polymorphisms in the gene that encodes the vitamin D receptor (VDR) may influence the host response to Mycobacterium tuberculosis infection. Methods. In a Peruvian community with a high incidence of tuberculosis (TB), VDR Taql and Fokl polymorphisms were compared among 103 patients with pulmonary TB and 206 matched healthy control subjects. Associations of VDR polymorphisms with treatment outcome were analyzed among 78 patients undergoing treatment of pulmonary TB. Results. Sputum mycobacterial culture and auramine stain conversions were significantly faster among participants with the Fokl FF genotype, compared with participants with the non-FF genotypes. Sputum culture conversion was faster among participants with the TaqI Tt genotype, compared with those with the TT genotype. Increased probability of culture conversion during TB treatment was independently associated with the TaqI Tt genotype (age- and sex-adjusted relative risk, 4.28; 95% confidence interval, 1.88-9.75; P =.001). VDR polymorphisms were not significantly associated with susceptibility to TB in the case-control study. Conclusions. VDR gene polymorphisms are associated with the time to sputum culture and auramine stain conversion during TB treatment. To our knowledge, the present study is the first report of a specific host gene influence on the outcome of TB treatment. These findings demonstrate the potential clinical relevance of immunomodulatory functions of vitamin D metabolites acting via the VDR in the host response against pulmonary TB.

Summary Background Inadequate water and sanitation adversely affect the health of children in developing countries. We aimed to assess the effects of water and sanitation on childhood health in a birth cohort of Peruvian children. Methods We followed up children once a day for diarrhoea and once a month for anthropometry, and obtained data for household water and sanitation at baseline. Findings At 24 months of age, children with the worst conditions for water source, water storage, and sanitation were 1·0 cm (95% CI 0·1–0·8) shorter and had 54% (−1 to 240) more diarrhoeal episodes than did those with the best conditions. Children from households with small storage containers had 28% (1–63) more diarrhoeal episodes than did children from households with large containers. Lack of adequate sewage disposal explained a height deficit of 0·9 cm (0·2–1·7) at 24 months of age. Better water source alone did not accomplish full health benefits. In 24-month-old children from households with a water connection, those in households without adequate sewage disposal and with small storage containers were 1·8 cm (0·1–3·6) shorter than children in households with sewage and with large storage containers. Interpretation Our findings show that nutritional status is a useful endpoint for water and sanitation interventions and underscores the need to improve sanitation in developing countries. Improved and more reliable water sources should discourage water storage at risk of becoming contaminated, decrease diarrhoeal incidence, and improve linear growth in children.

Campylobacter jejuni is a major cause of pediatric diarrhea in developing countries-free-ranging chickens are presumed to be a common source. Campylobacter strains from monthly surveillance and diarrhea cases were compared by means of restriction-fragment length polymorphism (RFLP), rapid amplified polymorphic DNA, and Lior serotyping. RFLP analysis of 156 human and 682 avian strains demonstrated identical strains in chickens and humans in 29 (70.7%) of 41 families, and 35%-39% of human isolates from diarrhea and nondiarrhea cases were identical to a household chicken isolate. Isolation of the same RFLP type from a household chicken and a human within 1 month was highly protective against diarrhea (odds ratio, 0.07; P

We compared the epidemiologic characteristics of cyclosporiasis and cryptosporidiosis in data from a cohort study of diarrhea in a periurban community near Lima, Peru. Children had an average of 0.20 episodes of cyclosporiasis/year and 0.22 episodes of cryptosporidiosis/year of follow-up. The incidence of cryptosporidiosis peaked at 0.42 for 1-year-old children and declined to 0.06 episodes/child-year for 5- to 9-year-old children. In contrast, the incidence of cyclosporiasis was fairly constant among 1- to 9-year-old children (0.21 to 0.28 episodes/child-year). Likelihood of diarrhea decreased significantly with each episode of cyclosporiasis; for cryptosporidiosis, this trend was not statistically significant. Both infections were more frequent during the warm season (December to May) than the cooler season (June to November). Cryptosporidiosis was more frequent in children from houses without a latrine or toilet. Cyclosporiasis was associated with ownership of domestic animals, especially birds, guinea pigs, and rabbits.

Background Vector-borne transmission of Trypanosoma cruzi is seen exclusively in the Americas where an estimated 8 million people are infected with the parasite. Significant research in southern Peru has been conducted to understand T. cruzi infection and vector control, however, much less is known about the burden of infection and epidemiology in northern Peru. Methodology A cross-sectional study was conducted to estimate the seroprevalence of T. cruzi infection in humans (n=611) and domestic animals [dogs (n=106) and guinea pigs (n=206)] in communities of Cutervo Province, Peru. Sampling and diagnostic strategies differed according to species. An entomological household study (n=208) was conducted to identify the triatomine burden and species composition, as well as the prevalence of T. cruzi in vectors. Electrocardiograms (EKG) were performed on a subset of participants (n=90 T. cruzi infected participants and 170 age and sex-matched controls). The seroprevalence of T. cruzi among humans, dogs, and guinea pigs was 14.9% (95% CI: 12.2 – 18.0%), 19.8% (95% CI: 12.7- 28.7%) and 3.3% (95% CI: 1.4 – 6.9%) respectively. In one community, the prevalence of T. cruzi infection was 17.2% (95% CI: 9.6 - 24.7%) among participants < 15 years, suggesting recent transmission. Increasing age, positive triatomines in a participant's house, and ownership of a T. cruzi positive guinea pig were independent correlates of T. cruzi infection. Only one species of triatomine was found, Panstrongylus lignarius, formerly P. herreri. Approximately forty percent (39.9%, 95% CI: 33.2 - 46.9%) of surveyed households were infested with this vector and 14.9% (95% CI: 10.4 - 20.5%) had at least one triatomine positive for T. cruzi. The cardiac abnormality of right bundle branch block was rare, but only identified in seropositive individuals. Conclusions Our research documents a substantial prevalence of T. cruzi infection in Cutervo and highlights a need for greater attention and vector control efforts in northern Peru., Author Summary Chagas disease causes significant morbidity and mortality throughout Central and South America. The epidemiology and control of this disease is subject to unique regional particularities, including the behavior and ecology of the local insect vector species. Significant resources have been allocated towards research and control efforts in southern Peru, yet very little is known about the prevalence and epidemiology of Trypanosoma cruzi in northern Peru. Our study highlights significant T. cruzi infection in northern Peru and is one of the first to document substantial transmission by the insect Panstrongylus lignarius. Our results illustrate major gaps in knowledge and the need for public health interventions targeted at Chagas disease in the region of Cutervo Province of northern Peru.

Background Archaeology reports millenary cultural contacts between Peruvian Coast-Andes and the Amazon Yunga, a rainforest transitional region between Andes and Lower Amazonia. To clarify the relationships between cultural and biological evolution of these populations, in particular between Amazon Yungas and Andeans, we used DNA-sequence data, a model-based Bayesian approach and several statistical validations to infer a set of demographic parameters. Results We found that the genetic diversity of the Shimaa (an Amazon Yunga population) is a subset of that of Quechuas from Central-Andes. Using the Isolation-with-Migration population genetics model, we inferred that the Shimaa ancestors were a small subgroup that split less than 5300 years ago (after the development of complex societies) from an ancestral Andean population. After the split, the most plausible scenario compatible with our results is that the ancestors of Shimaas moved toward the Peruvian Amazon Yunga and incorporated the culture and language of some of their neighbors, but not a substantial amount of their genes. We validated our results using Approximate Bayesian Computations, posterior predictive tests and the analysis of pseudo-observed datasets. Conclusions We presented a case study in which model-based Bayesian approaches, combined with necessary statistical validations, shed light into the prehistoric demographic relationship between Andeans and a population from the Amazon Yunga. Our results offer a testable model for the peopling of this large transitional environmental region between the Andes and the Lower Amazonia. However, studies on larger samples and involving more populations of these regions are necessary to confirm if the predominant Andean biological origin of the Shimaas is the rule, and not the exception. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0174-3) contains supplementary material, which is available to authorized users.

Background: Longitudinal investigations into the origins of adult essential hypertension have found elevated blood pressure in children to accurately track into adulthood, however the direct causes of essential hypertension in adolescence and adulthood remains unclear. Methods: Cohort study, we revisited 152 Peruvian adolescents from a birth cohort evaluated with monthly anthropometric measurements between 1995 and 1998, and obtained anthropometric and blood pressure measurements 11 to 14 years later. We used multivariable regression models to study the effects of infantile and childhood growth trends on blood pressure and central obesity in early adolescence. Results: In regression models adjusted for childhood growth, each 0.1 SD increase in weight for length from 0 to 5 months of age, and 1 SD increase from 6 to 30 months of age, predicted decreased adolescent systolic blood pressure by 1.3 mm Hg (95% CI -2.4 to -0.1) and 2.5 mm Hg (95% CI -4.9 to 0.0), and decreased waist circumference by 0.6 (95% CI -1.1 to 0.0) and 1.2 cm (95% CI -2.3 to -0.1) respectively. Growth in infancy and early childhood was not a significant predictor of adolescent waist-to-hip ratio. Conclusions: Rapid compensatory growth in early life has been posited to increase the risk of long-term cardiovascular morbidities such that nutritional interventions may do more harm than good. However, we found increased weight growth during infancy and early childhood to predict decreases in adolescent systolic blood pressure and central adiposity.

In order to determine the prevalence of high blood pressure and obesity in indigenous Ashaninkas, with limited contact with Western culture, a cross-sectional study was conducted in 2008 in five Ashaninka communities of the Junin region in the jungle of Peru. Individuals aged 35 or older were included. 76 subjects were evaluated (average age 47.4 years old, 52.6 % women) corresponding to 43.2% of the eligible population. The prevalence of hypertension was 14.5% (CI 95%: 6.4-22.6) and the prevalence of obesity, according to body mass index, was 4% (CI 95%: 0-8.4). No differences were observed in gender or in blood pressure levels by age group. Compared with previous studies in non-indigenous people of the Peruvian jungle, the prevalence of high blood pressure was higher while the prevalence of obesity was lower. Our findings are a call to be aware of the situation of chronic non-communicable diseases in indigenous populations in the Peruvian Amazon.

We analyzed the association between sub-scales developed with adolescents and the outcomes of precoital behaviors and vaginal sex in Lima, Peru. Adolescent participants in key informant sessions operationalized concepts identified during qualitative concept mapping into several sub-scales. Face and content validity testing and pilot application with respondent debriefing were used to refine the sub-scales. Three hundred 15-17 year olds were surveyed about the sub-scales, socio-demographics and sexual behaviors. Exploratory factor analysis confirmed six sub-scales, self-image, goals and decision-making, family education, parental rules/control, school support and peer support, which we regressed on the outcomes. Twice as many males as females reported more than three precoital behaviors and vaginal sex. Higher peer support reduced the likelihood of vaginal sex and precoital behaviors and higher family education reduced precoital behaviors. Results affirm the importance of including adolescents in the entire research process and of sex education with family- and peer-based strategies.

Background: We sought to determine if adult residents living at high altitude have developed sufficient adaptation to a hypoxic environment to match the functional capacity of a similar population at sea level. To test this hypothesis, we compared the 6-min walk test distance (6MWD) in 334 residents living at sea level vs. at high altitude. Methods: We enrolled 168 healthy adults aged ≥35 years residing at sea level in Lima and 166 individuals residing at 3,825 m above sea level in Puno, Peru. Participants completed a 6-min walk test, answered a sociodemographics and clinical questionnaire, underwent spirometry, and a blood test. Results: Average age was 54.0 vs. 53.8 years, 48% vs. 43% were male, average height was 155 vs. 158 cm, average blood oxygen saturation was 98% vs. 90%, and average resting heart rate was 67 vs. 72 beats/min in Lima vs. Puno. In multivariable regression, participants in Puno walked 47.6 m less (95% CI -81.7 to -13.6 m; p < 0.01) than those in Lima. Other variables besides age and height that were associated with 6MWD include change in heart rate (4.0 m per beats/min increase above resting heart rate; p < 0.001) and percent body fat (-1.4 m per % increase; p = 0.02). Conclusions: The 6-min walk test predicted a lowered functional capacity among Andean high altitude vs. sea level natives at their altitude of residence, which could be explained by an incomplete adaptation or a protective mechanism favoring neuro- and cardioprotection over psychomotor activity. © Caffrey et al.

BACKGROUND—In a previous study, we found that gallstones were a common occurrence in the high altitude villages of the Peruvian Andes. AIMS—To determine if high altitude (⩾ 1500 m) is a contributing risk factor for gallstone disease. METHODS—We conducted a cross sectional study in a periurban community in Lima, Peru, and compared the prevalence of gallstone disease between coastal natives, highland (Sierra) natives and Sierra natives who had migrated to the coast. We also compared the prevalence rates from this study with those from a previous study conducted at high altitude. We examined 1534 subjects >15 years of age for gallstone disease. Subjects were interviewed for the presence or absence of risk factors. RESULTS—Gallstone disease was more common in females (16.1 cases per 100, 95% CI 13.8-18.2) than in males (10.7 per 100, 95% CI 8.0-13.4). Females had a greater risk of gallstone disease, especially if they had used oral contraception and/or had four or more children. The age adjusted prevalence was not significantly different between coastal natives, Sierra migrants, and Andean villagers. The prevalence of gallstone disease was not associated with time since migration or with having native Sierra parents. After adjusting for other risk factors, Sierra natives who migrated to the coast had a lower prevalence of gallstone disease than coastal natives (odds ratio 0.74, 95% CI 0.58-0.94). CONCLUSIONS—This study indicates that high altitude is not a positive risk factor for gallstone disease and confirms that this disease is common in Peruvians, which may be attributable to Peruvian-Indian ethnicity. Keywords: gallstone disease; cholelithiasis; high altitude; risk factors; epidemiology; Peru

Lactobacillus GG (L-GG), an acid- and bile-resistant strain that colonizes the intestinal mucosa, has been used to manage diarrhea in children. Our objective was to evaluate the prophylactic use of L-GG to prevent diarrhea in children at high risk from a developing country in a randomized, placebo-controlled trial.Two hundred four undernourished children 6 to 24 months old from an indigent peri-urban Peruvian town received either L-GG or placebo in flavored gelatin once daily, 6 days a week, for 15 months. Episodes of diarrhea were documented by daily home visits, and diagnostic studies were done in a subset of cases. Recovery of L-GG in stool from subjects and from family contacts was examined.Subjects in the L-GG group had significantly fewer episodes of diarrhea (5.21 episodes diarrhea/child/year ['ecy'] L-GG group, 6. 02 ecy placebo group; P =.028). The decreased incidence of diarrhea in the L-GG group was greatest in the 18- to 29-month age group (P =. 004) and was largely limited to nonbreastfed children (Breastfed: 6. 59 ecy L-GG, 6.32 ecy placebo, P =.7; Nonbreastfed: 4.69 ecy L-GG, 5. 86 ecy placebo, P =.005). The duration of diarrhea episodes and the causes of diarrhea were similar in both groups, except adenovirus was more common in the placebo group.L-GG supplementation may be useful as a prophylactic measure to control diarrhea in undernourished children at increased risk, especially nonbreastfed children in the toddler age group.This article features a placebo-controlled trial of Lactobacillus GG (L-GG) for diarrhea prevention in undernourished children in Peru. The purpose of the study was to evaluate the use of L-GG as prophylactic treatment for diarrhea. The study population included 204 undernourished children aged 6-24 months, 99 of which were on L-GG and 105 on placebo. Subjects were followed by daily home visits to document diarrhea episodes and diagnostic studies were conducted. Results revealed that children receiving L-GG experienced fewer episodes of diarrhea, which were more pronounced among 18-29 month old children and largely limited to non-breast-fed children. Moreover, the duration of diarrhea episodes and its causes were similar in both groups, except that adenovirus was detected more frequently in the placebo group. In conclusion, L-GG supplementation would decrease diarrhea incidence in high-risk children.

An unusual Enterocytozoon bieneusi genotype was found in seven guinea pigs and a 2-year-old child in the same household. The genetic uniqueness of the parasite, its wide occurrence in other guinea pigs in the community, and its absence in other children in the community suggest the possibility of zoonotic transmission of the infection to the study child.

In a longitudinal cohort diarrhea study, a girl living in Lima, Peru, and her brother and dog were diagnosed with Cryptosporidium canis infections during the same period. Both children had transient diarrhea, but the dog was asymptomatic. This is the first report of possible transmission of cryptosporidiosis between humans and dogs.

This study investigated whether a child's first infection with Cryptosporidium parvum had an acute effect on weight gain. Specifically, the authors compared monthly rates of weight gain between C. parvum-infected and noninfected children. Over a 2-year period (1989-1991), a cohort of Peruvian children aged 0-3 months at recruitment were followed twice weekly for assessment of daily diarrheal status, weekly for C. parvum stool examinations, and monthly for anthropometric measurements. Data on 207 children permitted the authors to examine the effect of C. parvum infection on weight gain. During the 2-year study period, 45% (94/207) of the children became infected with C. parvum for the first time. Weight gain intervals in 57 of the 94 infected children met criteria for analysis. Of these, 63 percent (36/57) were asymptomatic (i.e., had no diarrhea). On average, children with symptomatic cryptosporidiosis gained (i.e., grew) 342 g less (95% confidence interval 167-517) during the first month of infection than did children without diarrhea who were not yet infected. The effect of asymptomatic cryptosporidiosis was less severe: On average, children with asymptomatic infection gained 162 g less (95% confidence interval 27-297) during the first month of infection than did children without diarrhea who were not yet infected. Symptomatic cryptosporidiosis retarded weight gain more than did asymptomatic cryptosporidiosis, but the latter was twice as common. Since asymptomatic cryptosporidiosis is more prevalent, it may have more of an overall adverse effect on child growth in the community than symptomatic cryptosporidiosis.During September 1989-November 1991 in Peru, 207 infants, 0-3 months old at enrollment and living in a periurban shanty town in Lima, were followed to determine whether a child's first infection with Cryptosporidium parvum had an adverse effect on weight gain during the first month of infection and whether poor nutritional status was a risk factor for C. parvum. Infection with C. parvum occurred at least once in 45% (97) of the infants. Median age at onset of a first C. parvum infection was 16 months. The growth interval of only 57 (61%) of C. parvum infected children was evaluated. 36 (63%) children were asymptomatic. The remaining 21 infected children had diarrhea. Children with cryptosporidiosis, whether symptomatic or asymptomatic, gained less weight during the first month of infection than children without cryptosporidiosis. Children with symptomatic cryptosporidiosis gained 184 g less weight during the first month of infection than did children with asymptomatic cryptosporidiosis. Children with symptomatic cryptosporidiosis gained 342 g less during the first month of infection than did children who were not infected with C. parvum and did not have diarrhea. Children with asymptomatic cryptosporidiosis gained 162 g less during the first month of infection than did children who were not infected with C. parvum and did not have diarrhea. The adverse effect of C. parvum on weight gain was strongest in children younger than 12 months. Neither wasting nor underweight was a significant risk factor for C. parvum infection. Stunting tended to increase the risk of C. parvum infection but the effect was not statistically significant. These findings show that C. parvum infection has an adverse effect on growth. Asymptomatic cryptosporidiosis is of special concern, since it was more prevalent and thus probably would have more of an overall adverse effect on child growth in the community.

A cross-sectional, community-based study was performed in 2012 with 428 residents of periurban shantytowns in Lima, Peru to study risk factors for and changes in latent tuberculosis infection in age-stratified groups compared with our data from the same region in 1990 (N = 219) and 2005 (N = 103). Tuberculin skin test positivity in these communities was highly prevalent at 52% overall, increased with age (P < 0.01) and was similar to 2005 (53%) and 1990 (48%). From 1990 to 2012, the prevalence of tuberculin positivity decreased in 5-14 and 15-24 year old groups (to 17% and 34%, respectively, both P < 0.05). However, this may be explained by cessation of Bacille Calmette-Guerin revaccination during this period, because Bacille Calmette-Guerin revaccination doubled tuberculin positivity. Over the same 22-year period, tuberculin positivity in the ≥ 25 year old group remained high (71%, P = 0.3), suggesting that prevalent latent tuberculosis infection persists in the adult population despite improving medical care and socioeconomic development in this region.

Background Tobacco smoking is an important public health concern worldwide leading to both chronic disease and early death. In Latin America, smoking prevalence is estimated at approximately 30% and prior studies suggest that the prevalence in Peru is 22% to 38%. We sought to determine the prevalence of daily smoking in a poor peri-urban community in Lima, Peru. Methods We conducted a cross-sectional survey in a random sample of adults ≥40 years of age living in Pampas de San Juan de Miraflores, Lima, Peru. We asked participants to respond to a survey that included questions on sociodemographics, tobacco use and dependence. Results We enrolled 316 participants. Average monthly household income was ≤ 400 USD and nearly all homes had running water, sewage, and electricity. Most individuals had not completed high school. Smoking prevalence was 16% overall, yet daily smoking prevalence was 1.9%. Former daily smokers comprised 3.8% of current nonsmokers and 9.1% current occasional smokers. Average scores for the Fagerstrom Test for Nicotine Dependence for daily smokers and occasional smokers were 1.5 and 0, respectively. Conclusions Daily use of tobacco is uncommon among adults in peri-urban communities of Lima, Peru, unlike their counterparts in Lima and other Latin American capital cities. Tobacco dependence is also low. Hence, efforts aimed at primary prevention are of utmost importance in these communities. This study provides an accurate baseline using an internationally recognized assessment tool (Global Adult Tobacco Survey), allowing for accurate assessment of tobacco control interventions over time.

Objectives According to a large-scale international survey, Peru has one of the highest prevalences of asthma worldwide; however, data from this survey were limited to participants from urban Lima. The authors sought to characterise the epidemiology of asthma in Peru in two regions with disparate degrees of urbanisation. In this manuscript, the authors summarise the study design and implementation. Design A cross-sectional study. Participants Using census data of 13–15-year-old adolescents from two communities in Peru, the authors invited a random sample of participants in Lima (n=725) and all adolescents in Tumbes (n=716) to participate in our study. Primary and secondary outcome measures The authors asked participants to complete a questionnaire on asthma symptoms, environmental exposures and socio-demographics and to undergo spirometry before and after bronchodilator, skin allergy testing and exhaled nitric oxide testing. The authors obtained blood samples for haematocrit, total IgE levels, vitamin D levels and DNA in all participants and measured indoor particulate matter concentrations for 48 h in a random subset of 70–100 households at each site. Results Of 1851 eligible participants, 1441 (78%) were enrolled and 1159 (80% of enrolled) completed all physical tests. 1283 (89%) performed spirometry according to standard guidelines, of which 86% of prebronchodilator tests and 92% of postbronchodilator tests were acceptable and reproducible. 92% of allergy skin tests had an adequate negative control. The authors collected blood from 1146 participants (79%) and saliva samples from 148 participants (9%). Overall amounts of DNA obtained from blood or saliva were 25.8 μg, with a 260/280 ratio of 1.86. Conclusions This study will contribute to the characterisation of a variety of risk factors for asthma, including urbanisation, total IgE levels, vitamin D levels and candidate genes, in a resource-poor setting. The authors present data to support high quality of survey, allergic, spirometric and genetic data collected in our study., Article summary Article focus We sought to characterise the epidemiology of asthma in Peru by studying two regions with disparate degrees of urbanisation. We summarise the study design, implementation and standard operating procedures and provide quality control data for important outcome and exposure variables. Key messages We present data to support high quality of survey, allergic, spirometric and genetic data collected in our study. Strengths and limitations of this study This study will contribute to the characterisation of a variety of risk factors for asthma, including urbanisation, total IgE levels, vitamin D levels and candidate genes, in a resource-poor setting. This study is cross-sectional and therefore does not track symptoms over time to directly determine causality. In addition, we did not collect stool samples to assess parasitic infections nor do we have information on respiratory infections in early childhood.

Estimates of the percentage of women who have had Pap smears in Peru vary between 7% and 43%. This study explores what women know about cervical cancer and Pap smears, as well as their barriers to obtaining Pap smears. Focus group discussions (FGD) were conducted with a total of 177 women in four Peruvian cities. Discussions reveal that most women did not know what causes cervical cancer. Most women did not know the purpose of Pap smears, although knowledge about Pap smears was higher than knowledge about cervical cancer. Fear, embarrassment, and lack of knowledge were the main barriers identified for not getting Pap smears. Programs and policies aiming to increase Pap smear coverage must start by educating women on cervical cancer and its prevention in order to improve women's perceptions about the screening test and increase Pap smear seeking behaviors in the long term.

The association of wealth and infections with Giardia, Cryptosporidium, Cyclospora, and microsporidia were examined in a longitudinal cohort conducted in Peru from 2001 to 2006. Data from 492 participants were daily clinical manifestations, weekly copro-parasitological diagnosis, and housing characteristics and assets owned (48 variables), and these data were used to construct a global wealth index using principal component analysis. Data were analyzed using continuous and categorical (wealth tertiles) models. Participant's mean age was 3.43 years (range = 0–12 years), with average follow-up of 993 days. Univariate and multivariate analyses identified significant associations between wealth and infections with Giardia and microsporidia. Participants with greater wealth indexes were associated with protection against Giardia (P < 0.001) and persistent Giardia infections (> 14 days). For microsporidia, greater wealth was protective (P = 0.066 continuous and P = 0.042 by tertiles). Contrarily, infections with Cryptosporidium and Cyclospora were independent of wealth. Thus, subtle differences in wealth may affect the frequency of specific parasitic infections within low-income communities.

Chagas disease affects an estimated 8 million people in Latin America. Infected individuals have 20–30% lifetime risk of developing cardiomyopathy, but more subtle changes in autonomic responses may be more frequent. We conducted a matched case-control study of children in Arequipa, Peru, where triatomine infestation and Trypanosoma cruzi infection are emerging problems. We collected data on home environment, history, physical examination, electrocardiogram, and autonomic testing. Signs of triatomine infestation and/or animals sleeping in the child's room and household members with Chagas disease were associated with increased infection risk. Electrocardiogram findings did not differ between cases and controls. However, compared with control children, infected children had blunted autonomic responses by three different measures, the Valsalva maneuver, the cold pressor test, and the orthostatic test. T. cruzi-infected children show autonomic dysfunction, although the prognostic value of this finding is not clear. Sustained vector control programs are essential to decreasing future T. cruzi infections.

Admixture occurs when individuals from parental populations that have been isolated for hundreds of generations form a new hybrid population. Currently, interest in measuring biogeographic ancestry has spread from anthropology to forensic sciences, direct-to-consumers personal genomics, and civil rights issues of minorities, and it is critical for genetic epidemiology studies of admixed populations. Markers with highly differentiated frequencies among human populations are informative of ancestry and are called ancestry informative markers (AIMs). For tri-hybrid Latin American populations, ancestry information is required for Africans, Europeans and Native Americans. We developed two multiplex panels of AIMs (for 14 SNPs) to be genotyped by two mini-sequencing reactions, suitable for investigators of medium-small laboratories to estimate admixture of Latin American populations. We tested the performance of these AIMs by comparing results obtained with our 14 AIMs with those obtained using 108 AIMs genotyped in the same individuals, for which DNA samples is available for other investigators. We emphasize that this type of comparison should be made when new admixture/population structure panels are developed. At the population level, our 14 AIMs were useful to estimate European admixture, though they overestimated African admixture and underestimated Native American admixture. Combined with more AIMs, our panel could be used to infer individual admixture. We used our panel to infer the pattern of admixture in two urban populations (Montes Claros and Manhuacu) of the State of Minas Gerais (southeastern Brazil), obtaining a snapshot of their genetic structure in the context of their demographic history.

Information on one Ecuadorian and three Peruvian Amerindian populations for 11 autosomal short tandem repeat (STR) loci is presented and incorporated in analyses that includes 26 other Native groups spread all over South America. Although in comparison with other studies we used a reduced number of markers, the number of populations included in our analyses is currently unmatched by any genome-wide dataset. The genetic polymorphisms indicate a clear division of the populations into three broad geographical areas: Andes, Amazonia, and the Southeast, which includes the Chaco and southern Brazil. The data also show good agreement with proposed hypotheses of splitting and dispersion of major language groups over the last 3,000 years. Therefore, relevant aspects ofNative American history can be traced using as few as 11 STR autosomal markers coupled with a broad geographic distribution of sampled populations. Am J Phys Anthropol, 2011. © 2011 Wiley-Liss, Inc.