Chagas disease: current epidemiological trends after the interruption of vectorial and transfusional transmission in the Southern Cone countries

Chagas disease, named after Carlos Chagas who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, transmitted to humans by blood-sucking triatomine bugs and by blood transfusion. Chagas disease has two successive phases, acute and chronic. The acute phase lasts 6 to 8 weeks. After several years of starting the chronic phase, 20% to 35% of the infected individuals, depending on the geographical area will develop irreversible lesions of the autonomous nervous system in the heart, esophagus, colon and the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980's as a result of the demographically representative cross-sectional studies carried out in countries where accurate information was not available. A group of experts met in Brasília in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country program in the Southern Cone countries the transmission of Chagas disease by vectors and by blood transfusion has been interrupted in Uruguay in1997, in Chile in 1999, and in 8 of the 12 endemic states of Brazil in 2000 and so the incidence of new infections by T. cruzi in the whole continent has decreased by 70%. Similar control multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been recorded to ensure the interruption of the transmission of Chagas disease by 2005 as requested by a Resolution of the World Health Assembly approved in 1998. The cost-benefit analysis of the investments of the vector control program in Brazil indicate that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the program is a health investment with good return. Since the inception in 1979 of the Steering Committee on Chagas Disease of the Special Program for Research and Training in Tropical Diseases of the World Health Organization (TDR), the objective was set to promote and finance research aimed at the development of new methods and tools to control this disease. The well known research institutions in Latin America were the key elements of a world wide network of laboratories that received - on a competitive basis - financial support for projects in line with the priorities established. It is presented the time line of the different milestones that were answering successively and logically the outstanding scientific questions identified by the Scientific Working Group in 1978 and that influenced the development and industrial production of practical solutions for diagnosis of the infection and disease control.

Determinants and trends in perinatal human immunodeficiency virus type 1 (HIV-1) transmission in the metropolitan area of Belo Horizonte, Brazil: 1998 - 2005

Significant decrease in human immunodeficiency virus type 1 (HIV-1) vertical transmission has been observed worldwide in centers where interventions such as antiretroviral therapy (ART), elective cesarean section, and avoidance of breastfeeding have been implemented. This prospective cohort study aimed to assess the determinants of and the temporal trends in HIV-1 vertical transmission in the metropolitan area of Belo Horizonte, Brazil from January 1998 to December 2005. The rate of HIV-1 vertical transmission decreased from 20% in 1998 to 3% in 2005. This decline was associated with increased use of more complex ART regimens during pregnancy. Multivariate analysis restricted to clinical variables demonstrated that non ART, neonatal respiratory distress/sepsis and breastfeeding were independently associated with HIV-1 vertical transmission. When laboratory parameters were included in the model, high maternal viral load and non maternal ART were associated with HIV-1 vertical transmission. The results from this study confirm the impact of ART in the reduction of HIV-1 vertical transmission and indicate the need for improvement in the care and monitoring of mother and infant pairs affected by HIV-1.

Current epidemiological trends for Chagas disease in Latin America and future challenges in epidemiology, surveillance and health policy

Chagas disease, named after Carlos Chagas, who first described it in 1909, exists only on the American Continent. It is caused by a parasite, Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine bugs and via blood transfusion. Chagas disease has two successive phases: acute and chronic. The acute phase lasts six-eight weeks. Several years after entering the chronic phase, 20-35% of infected individuals, depending on the geographical area, will develop irreversible lesions of the autonomous nervous system in the heart, oesophagus and colon, and of the peripheral nervous system. Data on the prevalence and distribution of Chagas disease improved in quality during the 1980s as a result of the demographically representative cross-sectional studies in countries where accurate information was not previously available. A group of experts met in Brasilia in 1979 and devised standard protocols to carry out countrywide prevalence studies on human T. cruzi infection and triatomine house infestation. Thanks to a coordinated multi-country programme in the Southern Cone countries, the transmission of Chagas disease by vectors and via blood transfusion was interrupted in Uruguay in 1997, in Chile in 1999 and in Brazil in 2006; thus, the incidence of new infections by T. cruzi across the South American continent has decreased by 70%. Similar multi-country initiatives have been launched in the Andean countries and in Central America and rapid progress has been reported towards the goal of interrupting the transmission of Chagas disease, as requested by a 1998 Resolution of the World Health Assembly. The cost-benefit analysis of investment in the vector control programme in Brazil indicates that there are savings of US$17 in medical care and disabilities for each dollar spent on prevention, showing that the programme is a health investment with very high return. Many well-known research institutions in Latin America were key elements of a worldwide network of laboratories that carried out basic and applied research supporting the planning and evaluation of national Chagas disease control programmes. The present article reviews the current epidemiological trends for Chagas disease in Latin America and the future challenges in terms of epidemiology, surveillance and health policy.

Historical trends in the epidemiology of candidaemia: analysis of an 11-year period in a tertiary care hospital in Brazil

Candida species are an important cause of bloodstream infections (BSI). To evaluate the epidemiological, clinical and microbiological aspects of two cohorts {1994-1999 [period 1 (P1) ]; 2000-2004 [period 2 (P2) ]} of candidaemic patients, we performed a retrospective analysis from a laboratory-based survey. A total of 388 candidaemias were identified, with an incidence of 0.20/1,000 patient-days and a significant increase in P2 vs. P1 (0.25 vs. 0.15, p = 0.04). Cancer and prior antibiotic use were frequent and Candida albicans was the most prevalent species found (42.4%). Resistance to fluconazole was found in 2.47% of the strains. No differences were observed in the species distribution of Candida during the study periods. In the P2 cohort, there were higher prevalence of elderly individuals, cardiac, pulmonary and liver diseases, renal failure, central venous catheters and antibiotic therapy. In P1, there were higher prevalence of neurological diseases and chemotherapy. The crude mortality was 55.4%. In conclusion, our incidence rates remained high. Furthermore, the distribution pattern of Candida species and the fluconazole resistance profile remained unchanged. Moreover, we found a clear trend of higher prevalence of candidaemia among the elderly and among patients with comorbidities. Finally, it is necessary to discuss strategies for the prevention and control of Candida BSI in Brazil.

Genotyping Mycobacterium bovis from cattle in the Central Pampas of Argentina: temporal and regional trends

Mycobacterium bovis is the causative agent of bovine tuberculosis (TB), a disease that affects approximately 5% of Argentinean cattle. Among the molecular methods for genotyping, the most convenient are spoligotyping and variable number of tandem repeats (VNTR). A total of 378 samples from bovines with visible lesions consistent with TB were collected at slaughterhouses in three provinces, yielding 265 M. bovis spoligotyped isolates, which were distributed into 35 spoligotypes. In addition, 197 isolates were also typed by the VNTR method and 54 combined VNTR types were detected. There were 24 clusters and 27 orphan types. When both typing methods were combined, 98 spoligotypes and VNTR types were observed with 27 clusters and 71 orphan types. By performing a meta-analysis with previous spoligotyping results, we identified regional and temporal trends in the population structure of M. bovis. For SB0140, the most predominant spoligotype in Argentina, the prevalence percentage remained high during different periods, varying from 25.5-57.8% (1994-2011). By contrast, the second and third most prevalent spoligotypes exhibited important fluctuations. This study shows that there has been an expansion in ancestral lineages as demonstrated by spoligotyping. However, exact tandem repeat typing suggests dynamic changes in the clonal population of this microorganism.

Analysis of multi-scale systemic risk in Brazil's financial market

This work analyzes whether the relationship between risk and returns predicted by the Capital Asset Pricing Model (CAPM) is valid in the Brazilian stock market. The analysis is based on discrete wavelet decomposition on different time scales. This technique allows to analyze the relationship between different time horizons, since the short-term ones (2 to 4 days) up to the long-term ones (64 to 128 days). The results indicate that there is a negative or null relationship between systemic risk and returns for Brazil from 2004 to 2007. As the average excess return of a market portfolio in relation to a risk-free asset during that period was positive, it would be expected this relationship to be positive. That is, higher systematic risk should result in higher excess returns, which did not occur. Therefore, during that period, appropriate compensation for systemic risk was not observed in the Brazilian market. The scales that proved to be most significant to the risk-return relation were the first three, which corresponded to short-term time horizons. When treating differently, year-by-year, and consequently separating positive and negative premiums, some relevance is found, during some years, in the risk/return relation predicted by the CAPM. However, this pattern did not persist throughout the years. Therefore, there is not any evidence strong enough confirming that the asset pricing follows the model.

Permanent demand excess as business strategy: an analysis of the Brazilian higher-education market

Many Higher Education Institutions (HEIs) establish tuition below the equilibrium price to generate permanent demand excess. This paper first adapts Becker’s (1991) theory to understand why the HEIs price in this way. The fact that students are both consumers and inputs on the education production process gives rise to a market equilibrium where some firms have excess demand and charge high prices, and others charge low prices and have empty seats.Second, the paper analyzes this equilibrium empirically. We estimated the demand for undergraduate courses in Business Administration in the State of São Paulo. The results show that tuition, quality of incoming students and percentage of lecturers holding doctorates degrees are the determining factors of students’ choice. Since the student quality determines the demand for a HEI, it is calculated what the value is for a HEI to get better students; that is the total revenue that each HEI gives up to guarantee excess demand. Regarding the “investment” in selectivity, 39 HEIs in São Paulo give up a combined R$ 5 million (or US$ 3.14 million) in revenue per year per freshman class, which means 7.6% of the revenue coming from a freshman class.

Effect of investments on fundamentals and market reaction on pre-operational and operational Brazilian companies for the period 2006-2012

ABSTRACT This paper provides evidence on the market reaction to corporate investment decisions whose shareholder value is largely attributed to growth options. The exploratory research raised pre-operational companies and their operational pairs on the same economy segments. It had the purpose of investigating the existence of statistical differentiation from financial indicators that reflect the installed assets and growth assets, and then study the market reaction to changes in fixed assets as a signaling element about investment decisions. The formation process of operational assets and shareholder value almost exclusively dependent on asset growth stands out in the pre-operational companies. As a result, differentiation tests confirmed that the pre-operational companies had their value especially derived on growth options. The market reaction was particularly bigger in pre-operational companies with abnormal negative stock returns, while the operational companies had positive returns, which may indicate that the quality of the investment is judged based on the financial disclosure. Additionally, operational companies' investors await the disclosure to adjust their prices. We conclude that the results are consistent with the empirical evidence and the participants in financial markets to long-term capital formation investments should give that special attention.

Expansion of undergraduate courses in nursing: dilemmas and contradictions facing the labor market

We sought to analyze, from the perspective of professors and students, the reasons and consequences of the expansion of undergraduate courses in nursing, discussing the dilemmas and the contradictions confronting the labor market. It was a qualitative study with data obtained from focus groups, conducted in 18 undergraduate nursing courses in the state of Minas Gerais, during the period of February to October of 2011. The narratives were submitted to critical discourse analysis. The results indicated that the education of the nurse was permeated by insecurity as to the future integration into the labor market. The insecurity translates into dilemmas that referred to employability and the precariousness of the working conditions. In this context, employment in the family health strategy emerges as a mirage. One glimpses the need for a political agenda with the purpose of discussion about education, the labor market and the determinants of these processes.

General trends in world biogeographic literature: a preliminary bibliometric analysis

Records with the search string biogeograph* were collected from the Science Citation Index (SCI). A total of 3456 records were downloaded for the 1945-2006 period from titles of articles and reviews, and 10,543 records were downloaded for 1991-2006, taking into consideration also abstracts and keywords. Temporal trends of publications, geographical and institutional distribution of the research output, authorship, and core journals were evaluated. There were as many as 122 countries carrying out biogeographic research; in the most recent period, USA is the top producing country, followed by the United Kingdom, Australia, France, Germany, Spain, and Canada. There were 17,493 authors contributing to the field. During 1991-2006 there were 4098 organizations with authors involved in biogeographic research; institutions with higher number of papers are the Natural History Museum (United Kingdom), the University of California, Berkeley (USA), the Museum National d'Histoire Naturelle (France), the Universidad Nacional Autónoma de México (Mexico), the American Museum of Natural History (USA) and the Russian Academy of Sciences (Russia). Research articles are spread over a variety of journals, with the Journal of Biogeography, Molecular Phylogenetics and Evolution, Molecular Ecology, and Biological Journal of the Linnean Society being the core journals. From 28,759 keywords retrieved those with the highest frequency were evolution, phylogeny, diversity, mitochondrial DNA, pattern(s), systematics, and population(s). We conclude that publications on biogeography have increased substantially during the last years, especially since 1998. The preferred journal for biogeographic papers is the Journal of Biogeography. Most frequent keywords seem to indicate that biogeography fits well within both evolutionary biology and ecology, with molecular biology and phylogenetics being important factors that drive their current development.