Scientific authorships and collaboration network analysis on Chagas disease: papers indexed in PubMed (1940-2009).

Chagas disease is a chronic, tropical, parasitic disease, endemic throughout Latin America. The large-scale migration of populations has increased the geographic distribution of the disease and cases have been observed in many other countries around the world. To strengthen the critical mass of knowledge generated in different countries, it is essential to promote cooperative and translational research initiatives. We analyzed authorship of scientific documents on Chagas disease indexed in the Medline database from 1940 to 2009. Bibliometrics was used to analyze the evolution of collaboration patterns. A Social Network Analysis was carried out to identify the main research groups in the area by applying clustering methods. We then analyzed 13,989 papers produced by 21,350 authors. Collaboration among authors dramatically increased over the study period, reaching an average of 6.2 authors per paper in the last five-year period. Applying a threshold of collaboration of five or more papers signed in co-authorship, we identified 148 consolidated research groups made up of 1,750 authors. The Chagas disease network identified constitutes a "small world," characterized by a high degree of clustering and a notably high number of Brazilian researchers.

Scientific authorships and collaboration network analysis on Chagas disease: papers indexed in PubMed (1940-2009) / Redes de colaboración y autorías científicas sobre la enfermedad de Chagas: análisis de las publicaciones indexadas en PubMed (1940-2009)

Chagas disease is a chronic, tropical, parasitic disease, endemic throughout Latin America. The large-scale migration of populations has increased the geographic distribution of the disease and cases have been observed in many other countries around the world. To strengthen the critical mass of knowledge generated in different countries, it is essential to promote cooperative and translational research initiatives. We analyzed authorship of scientific documents on Chagas disease indexed in the Medline database from 1940 to 2009. Bibliometrics was used to analyze the evolution of collaboration patterns. A Social Network Analysis was carried out to identify the main research groups in the area by applying clustering methods. We then analyzed 13,989 papers produced by 21,350 authors. Collaboration among authors dramatically increased over the study period, reaching an average of 6.2 authors per paper in the last five-year period. Applying a threshold of collaboration of five or more papers signed in co-authorship, we identified 148 consolidated research groups made up of 1,750 authors. The Chagas disease network identified constitutes a "small world," characterized by a high degree of clustering and a notably high number of Brazilian researchers.

La enfermedad de Chagas es una enfermedad parasitaria tropical, endémica en muchos países y regiones de América, si bien, los movimientos de población han incrementado su distribución geográfica y se han constatado casos en muchos países del mundo. En este sentido, resulta fundamental promover iniciativas de investigación cooperativas y transnacionales, con el propósito de aunar la masa crítica de conocimiento generada en los diferentes países. Se estudian las publicaciones científicas sobre la enfermedad de Chagas recogidas en la base de datos Medline entre 1940 y 2009. Mediante indicadores bibliométricos se han analizado los patrones de colaboración y se ha efectuado un Análisis de Redes Sociales para identificar los principales grupos de investigación. Se han analizado 13.989 documentos publicados por 21.350 autores. La evolución de la colaboración ha experimentado un notable crecimiento, alcanzando un promedio de 6,2 autores por trabajo en el último quinquenio. Aplicando un umbral de colaboración de 5 o más trabajos firmados en coautoría, se han identificado 148 grupos de investigación conformados por 1.750 autores. La red de Chagas identificada conforma un 'mundo pequeño' con un elevado grado de agrupamiento, destacando el elevado número de investigadores brasileños.

Mapping of Chagas disease research: analysis of publications in the period between 1940 and 2009 / Mapeamento de pesquisa da doença de Chagas: análise da produção de publicações no período entre 1940 e 2009

INTRODUCTION: Publications are often used as a measure of success in research work. Chagas disease occurs in Central and Southern America. However, during the past years, the disease has been occurring outside Latin America due to migration from endemic zones. This article describes a bibliometric review of the literature on Chagas disease research indexed in PubMed during a 70-year period. METHODS: Medline was used via the PubMed online service of the U.S. National Library of Medicine from 1940 to 2009. The search strategy was: Chagas disease [MeSH] OR Trypanosoma cruzi [MeSH]. RESULTS: A total of 13,989 references were retrieved. The number of publications increased steadily over time from 1,361 (1940-1969) to 5,430 (2000-2009) (coefficient of determination for linear fit, R²=0.910). Eight journals contained 25 percent of the Chagas disease literature. Of the publications, 64.2 percent came from endemic countries. Brazil was the predominant country (37 percent), followed by the United States (17.6 percent) and Argentina (14 percent). The ranking in production changed when the number of publications was normalized by estimated cases of Chagas disease (Panama and Uruguay), population (Argentina and Uruguay), and gross domestic product (Bolivia and Brazil). CONCLUSIONS: Several Latin American countries, where the prevalence of T. cruzi infection was not very high, were the main producers of the Chagas disease literature, after adjusting for economic and population indexes. The countries with more estimated cases of Chagas disease produced less research on Chagas disease than some developed countries.

INTRODUÇÃO: Publicações são frequentemente utilizadas como uma medida de sucesso do trabalho de pesquisa. A doença de Chagas (DCh) ocorre na América Central e do Sul. Porém, durante os últimos anos, a doença tem ocorrido fora da América Latina, devido à migração das zonas endêmicas. Este artigo descreve uma análise bibliométrica da literatura sobre as pesquisas da doença de Chagas indexadas no PubMed, durante um período de 70 anos. MÉTODOS: O Medline foi usado através do serviço online da US PubMed da National Library of Medicine de 1940 a 2009. A estratégia de busca foi: Chagas disease [MeSH] OR Trypanosoma cruzi [MeSH]. RESULTADOS: Um total de 13.989 referências foi recuperado. O número de publicações aumentou de forma constante com 1.361 (1940-1969) para 5.430 (2000-2009) (coeficiente de determinação para o ajuste linear, R² = 0, 910). Oito revistas contiveram 25 por cento da literatura sobre a DCh. Um total de 64,2 por cento das publicações veio de países endêmicos. O Brasil foi o predominante (37 por cento), seguido pelos Estados Unidos da América (17,6 por cento) e Argentina (14 por cento). O ranking da produção foi alterado, quando o número de publicações foi normalizado por casos estimados da doença de Chagas (Panamá e Uruguai), população (Argentina e Uruguai), e Produto Interno Bruto (Bolívia e Brasil). CONCLUSÕES: Vários países da América Latina com uma prevalência não muito elevada de infecção pelo T. cruzi foram os principais produtores, após ajuste para os índices econômicos e populacionais. Os países com mais casos estimados da DCh produziu menos pesquisas em doença de Chagas que alguns países desenvolvidos.

Mapping of Chagas disease research: analysis of publications in the period between 1940 and 2009.

INTRODUCTION: Publications are often used as a measure of success in research work. Chagas disease occurs in Central and Southern America. However, during the past years, the disease has been occurring outside Latin America due to migration from endemic zones. This article describes a bibliometric review of the literature on Chagas disease research indexed in PubMed during a 70-year period. METHODS: Medline was used via the PubMed online service of the U.S. National Library of Medicine from 1940 to 2009. The search strategy was: Chagas disease [MeSH] OR Trypanosoma cruzi [MeSH]. RESULTS: A total of 13,989 references were retrieved. The number of publications increased steadily over time from 1,361 (1940-1969) to 5,430 (2000-2009) (coefficient of determination for linear fit, R²=0.910). Eight journals contained 25% of the Chagas disease literature. Of the publications, 64.2% came from endemic countries. Brazil was the predominant country (37%), followed by the United States (17.6%) and Argentina (14%). The ranking in production changed when the number of publications was normalized by estimated cases of Chagas disease (Panama and Uruguay), population (Argentina and Uruguay), and gross domestic product (Bolivia and Brazil). CONCLUSIONS: Several Latin American countries, where the prevalence of T. cruzi infection was not very high, were the main producers of the Chagas disease literature, after adjusting for economic and population indexes. The countries with more estimated cases of Chagas disease produced less research on Chagas disease than some developed countries.

Cyclosporiasis: a point source outbreak acquired in Guatemala.

BACKGROUND: Cyclosporiasis is a disease due to Cyclospora cayetanensis, an emerging coccidian parasite first described in 1979. It is an orally transmitted disease that is more frequent in tropical and subtropical areas. Cyclospora cayetanensis has been mainly described as a cause of travelers' diarrhea. This pathogen has given rise to a number of epidemic outbreaks attributable to ingestion of imported foods, particularly from tropical areas. METHODS: Descriptive study of clinical and epidemiological data of a small epidemic outbreak of C cayetanensis-induced gastroenteritis. RESULTS: Seven confirmed cases of C cayetanensis among Spanish nationals who had traveled to Antigua Guatemala are described. The incubation period was 6 days. Diarrhea, asthenia, anorexia, borborygmi, flatulence, and abdominal distension were present in all cases. Fever and heart burn in 85.7%. Weight loss in 71.4%. Abdominal pain, rectal tenesmus, and nausea in 42.8%. Vomiting and eructation in 14.2%. Heart burn was a frequent symptom, a finding not often previously described. The infection was probably acquired from raspberry juice. All cases improved with trimethoprim/sulphametoxazol. CONCLUSIONS: Cyclosporiasis is a cause of travelers' diarrhea. Parasitology laboratories must be advised of clinical suspicion of cyclosporiasis so that they can conduct a suitable targeted study; otherwise, false negative results may arise.

[Histoplasma capsulatum infection in a group of travelers to Guatemala]. / Infección por Histoplasma capsulatum en un grupo de cooperantes en Guatemala.

OBJECTIVE: To analyze the epidemiological and clinical characteristics of Histoplasma capsulatum infection in a group of volunteers who had traveled to Guatemala. METHODS: A review was performed of the clinical records of nine patients who consulted at the Tropical Medicine Outpatient Unit of Hospital Clinic in Barcelona, Spain. RESULTS. All patients were attended for travelers' diarrhea. In addition, one student had also presented with respiratory symptoms and fever while in Guatemala and her chest X-ray showed interstitial infiltrates. The epidemiological history recognized risk factors for histoplasmosis in all patients (all of them had been working in the reconstruction of an old school building). The intradermal histoplasmin test was performed and was positive in all nine patients. None of the students required treatment. CONCLUSIONS: Histoplasmosis should be included in the differential diagnosis of returning travelers' fever. The diagnosis would have been missed in all of our patients if not for a directed clinical history taking. It is important to reinforce prevention measures, e.g. the use of face masks, when working in an environment with a risk for acquiring histoplasmosis.

Infección por Histoplasma capsulatum en un grupo de cooperantes en Guatemala / Histoplasma capsulatum infection in a group of travelers to Guatemala

Objetivo. Analizar las características epidemiológicas y clínicas de un grupo de cooperantes que presentó infección por H. capsulatum después de un viaje a Guatemala. Métodos. Revisión de historias clínicas de 9 pacientes atendidos en la Consulta de Medicina Tropical del Hospital Clínic. Resultados. El motivo de consulta fue diarrea del viajero en todos los casos, aunque una de las pacientes presentó sintomatología respiratoria y fiebre durante su estancia en Guatemala con infiltrados intersticiales en la radiología de tórax. La encuesta epidemiológica detectó factores de riesgo para la adquisición de Histoplasma (todos habían trabajado en la rehabilitación de una escuela vieja), motivo por el cual se realizó la prueba de histoplasmina, que resultó positiva en los 9 casos. Ningún paciente necesitó tratamiento. Conclusiones. La histoplasmosis debe incluirse en el diagnóstico diferencial de la fiebre del viajero. En nuestro grupo el diagnóstico hubiese pasado desapercibido en ausencia de una anamnesis dirigida. Es importante no olvidar y reforzar las medidas de prevención de la enfermedad en viajeros (p. ej., utilización de mascarillas de protección respiratoria si se trabaja en un entorno de riesgo) (AU)

Objective. To analyze the epidemiological and clinical characteristics of Histoplasma capsulatum infection in a group of volunteers who had traveled to Guatemala. Methods. A review was performed of the clinical records of nine patients who consulted at the Tropical Medicine Outpatient Unit of Hospital Clinic in Barcelona, Spain. Results. All patients were attended for travelers' diarrhea. In addition, one student had also presented with respiratory symptoms and fever while in Guatemala and her chest X-ray showed interstitial infiltrates. The epidemiological history recognized risk factors for histoplasmosis in all patients (all of them had been working in the reconstruction of an old school building). The intradermal histoplasmin test was performed and was positive in all nine patients. None of the students required treatment. Conclusions. Histoplasmosis should be included in the differential diagnosis of returning travelers' fever. The diagnosis would have been missed in all of our patients if not for a directed clinical history taking. It is important to reinforce prevention measures, e.g. the use of face masks, when working in an environment with a risk for acquiring histoplasmosis (AU)

Aeromonas spp. and traveler's diarrhea: clinical features and antimicrobial resistance.

Traveler's diarrhea is the most common health problem of international travelers. We determined the prevalence of Aeromonas spp. associated with traveler's diarrhea and analyzed the geographic distribution, clinical features, and antimicrobial susceptibility. Aeromonas spp. were isolated as a cause of traveler's diarrhea in 18 (2%) of 863 patients. A. veronii biotype sobria was isolated in nine patients, A. caviae in seven patients, and A. jandaei and A. hydrophila in one patient each. Aeromonas spp. were isolated with a similar prevalence in Africa, Latin America, and Asia. Watery and persistent diarrhea, fever, and abdominal cramps were common complaints. All strains were resistant to ampicillin; showed variable resistance to chloramphenicol, tetracycline, and cotrimoxazole; and were susceptible to cefotaxime, ciprofloxacin, and nalidixic acid. The persistence of symptoms made antimicrobial treatment necessary.

[Imported diseases in African immigrants in Spain: study of 1,321 patients]. / Enfermedades importadas en inmigrantes Africanos: estudio de 1.321 pacientes.

BACKGROUND: Immigrants can carry diseases characteristic from their countries of origin. These are known as imported diseases (ID) and can be classified into tropical diseases (TD) or cosmopolitan diseases (CD). The aim of this study was to analyse the ID in African immigrants and evaluate their repercussion in the Spanish Public Health. PATIENTS AND METHOD: Observational study, retrospective protocol, carried from 1984 to 1994 in African immigrants seen in a reference Hospital. Not infectious chronic ID were excluded. The repercussion in public health was divided in 3 categories according to transmission risk to the host population: a) ID without current risk; b) ID with potential risk and, c) ID of risk. RESULTS: 1,321 African immigrants were considered. Most of them were from Sub-Saharan Africa. The most frequent TD were helminthiases and among CD, tuberculosis, sexually transmitted diseases and parasitoses. ID without transmission risk were 26.7% (2.4% CD and 24.3% TD), ID with potential risk 35.2% (33.6% CD and 1.6% TD) and ID with risk 38% (all CD). CONCLUSIONS: The CD and their association with poverty suppose a higher risk of transmission to the host country population. Global policies of helping social and economic insertion of immigrant populations, combined with international health collaboration, will rebound positively in the general population's health.