Capybaras (Hydrochoerus hydrochaeris) as amplifying hosts of Rickettsia rickettsii to Amblyomma sculptum ticks: Evaluation during primary and subsequent exposures to R. rickettsii infection.

Rickettsia rickettsii is the agent of Brazilian spotted fever (BSF), the most lethal tick-borne disease in the western hemisphere. Amblyomma sculptum is the main vector of R. rickettsii in southeastern Brazil. Capybaras act as primary hosts for this tick species, and as amplifying hosts for R. rickettsii, creating new infected lineages of A. sculptum in BSF-endemic areas. In a recent study, we demonstrated that capybaras successively exposed to R. rickettsii-infected A. sculptum ticks developed a mean rickettsemic period of 9.2 days during primary infection, but no rickettsemia during subsequent expositions, when capybaras were immune to R. rickettsii. During the primary and subsequent infections, capybaras were also infested with uninfected A. sculptum ticks. These infestations compose the present study, which aimed to evaluate: (i) if either rickettsemic or non-rickettsemic capybaras could serve as infection sources of R. rickettsii for A. sculptum larvae and nymphs; (ii) the vector competence of the subsequent nymphs and adults (molted from the engorged ticks collected from capybaras); and (iii) if there were R. rickettsii-acquisition by uninfected ticks co-feeding with infected ticks on immune capybaras (without rickettsemia). Through experimental infection of capybaras with R. rickettsii via tick feeding, simulating a natural condition, we demonstrated that primarily infected capybaras developed rickettsemia that resulted in successful acquisition feeding of larvae and nymphs of A. sculptum, since part of these ticks maintained R. rickettsii transstadially, and the resultant molted ticks (either nymphs or adults) successfully transmitted the bacterium by feeding on susceptible rabbits. Contrastingly, all rabbit infestations with ticks derived from acquisition feeding on R. rickettsii-immune capybaras (including when acquisition ticks fed in direct contact with donor ticks) evidenced absence of R. rickettsii transmission due to lack of clinical signs and antibody response in those rabbits. Our results indicate that capybaras could serve as R. rickettsii-amplifying hosts for A. sculptum ticks only during the capybara's primary infection, but not during subsequent infections on immune capybaras. Finally, the probable co-feeding nonsystemic transmission of R. rickettsii seems to be irrelevant in the context of BSF epidemiology, in areas where capybaras are incriminated as main amplifying hosts of R. rickettsii for A. sculptum ticks.

Influence of Body Dissatisfaction on the Self-Esteem of Brazilian Adolescents: A Cross-Sectional Study.

BACKGROUND: The present study investigated the influence of body dissatisfaction (BD) on the self-esteem of Brazilian adolescents. METHODS: A cross-sectional study was carried out with 1011 students at public and private schools in the city of Fortaleza, Brazil. The body shape questionnaire and the Rosenberg self-esteem scale were applied. Chi-square test, Student's t-test, Pearson's correlation, the odds ratio and binary logistic regression were used. RESULTS: The rate of low self-esteem was 33.8% in the adolescents; 27.8% of the adolescents presented some degree of BD, with severe BD in 5.8%. A significant low negative correlation was found between self-esteem and BD in all the adolescents. In the Odds Ratio analysis, it was observed that the odds of having low self-esteem increased in adolescents with BD as compared to adolescents without BD, being 3.85 times higher in females (CI 95%, 2.12-6.99), 2.83 times higher in males (CI 95%, 1.22-6.58), 5.79 times higher in adolescents attending public schools (CI 95% 2.06-16.26), and 2.96 times higher in adolescents attending private schools (CI 95%, 1.79-4.88). CONCLUSIONS: Low self-esteem affected one-third of the adolescents, both male and female. BD and education in public schools are predictor variables of low self-esteem in adolescents.

Author Correction: Clinical and serological evaluation of capybaras (Hydrochoerus hydrochaeris) successively exposed to an Amblyomma sculptum-derived strain of Rickettsia rickettsii.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Clinical and serological evaluation of capybaras (Hydrochoerus hydrochaeris) successively exposed to an Amblyomma sculptum-derived strain of Rickettsia rickettsii.

Brazilian spotted fever (BSF), caused by Rickettsia rickettsii, is the most lethal tick-borne disease in the western hemisphere. In Brazil, Amblyomma sculptum ticks are the main vector. Capybaras (Hydrochoerus hydrochaeris), the largest living rodents of the world (adults weighing up to 100 Kg), have been recognized as amplifying hosts of R. rickettsii for A. sculptum in BSF-endemic areas; i.e., once primarily infected, capybaras develop bacteremia for a few days, when feeding ticks acquire rickettsial infection. We conducted experimental infections of five capybaras with an A. sculptum-derived strain of R. rickettsii and performed clinical and bacteremia evaluation during primary and subsequent infections. Bacteremia was detected in all capybaras during primary infection, but not in subsequent infections. All animals seroconverted to R. rickettsii (titres range: 64-32,768), and remained seropositive throughout the study. Primary infection resulted in clinical spotted fever illness in four capybaras, of which two had a fatal outcome. Subsequent infections in seropositive capybaras resulted in no clinical signs. Capybaras developed a sustained immune response that prevented a second bacteremia. This condition may imply a high reproduction rate of capybaras in BSF-endemic areas, in order to continuously generate capybaras susceptible to bacteremia during primary infection.

The influence of physical activity and eating behaviour on body mass index in children and adolescents: A review the literature / Influencia de la práctica de la actividad física y del comportamiento dietético en el índice de masa corporal de niños y adolescentes: Revisión de literatura

ABSTRACT The object of the present study was to carry out a literature review to analyze the influence of physical activity and dietary behavior on body mass index in school-age children and adolescents. A search was carried out using the PubMed and LILACS databases, in which 1,412 articles were found. After application of inclusion and exclusion criteria, 17 studies were selected for qualitative analysis. Overweight and obesity were related with incorrect dietary habits (skipping breakfast, consumption of foods with high fat contents and high-sugar soft drinks), low levels of physical activity and long hours devoted to sedentary activities (playing video games or watching TV) were also related.

RESUMEN El objetivo de este estudio fue analizar, mediante una revisión de la literatura, la influencia de la práctica de actividad física y del comportamiento dietético sobre el índice de masa corporal de niños y adolescentes en fase escolar. Se realizó una búsqueda en las bases PubMed y LILACS. Se encontraron 1.412 artículos. Tras la aplicación de los criterios de inclusión y exclusión fueron seleccionados 17 estudios para realizar un análisis cualitativo. El sobrepeso y la obesidad están relacionadas a una alimentación in-adecuada (saltar el desayuno, consumo de alimentos con alto contenido de grasa y de bebidas azucaradas), niveles bajos de actividad física y longas horas realizando actividad sedentaria (jugando video-juegos o visualizando la TV).

Influence of the Mass Media and Body Dissatisfaction on the Risk in Adolescents of Developing Eating Disorders.

Media influence may lead adolescents to internalize patterns of physical beauty, resulting in dissatisfaction with their own bodies when they are unable to match up to these patterns. In the constant search for an 'ideal body', adolescents may begin to develop risk behaviors for the development of eating disorders (ED). The object of this study was to analyze the influence of the mass media on body dissatisfaction (BD) and on ED in adolescents, comparing genders. We also analyzed the influence of BD on the risk of developing unsuitable eating behaviors, with risk of ED, comparing genders. A cross-sectional study was carried out with 1011 adolescents: 527 girls and 484 boys. The BMI of each adolescent was determined, and the instruments EAT-26, Sociocultural Attitudes towards Appearance Questionnaire-3 (SATAQ-3), and body shape questionnaire (BSQ), were applied. For statistical analysis, we used Student's t-test, the chi-square test, Pearson's correlation test, the odds ratio, and hierarchical multiple linear regression. The influence of the mass media is associated with a greater probability of adolescents presenting BD. An increase in BD is associated with an increased risk of developing ED in adolescents of both genders but is greater in girls than in boys. Furthermore, the influence of the MM and BMI are predictors of BD in both genders; and BD is a predictor of ED risk in both girls and boys.

Removal of Capybara (Hydrochoerus hydrochaeris) population as measure to control Amblyomma tick population and reduce Brazilian Spotted Fever transmission risk in a Gated Community in Bragança Paulista (SP, Brazil) ­ Case Study / Remoção de capivaras (Hydrochoerus hydrochaeris) como ação para controle da população de carrapatos Amblyomma e redução do risco de transmissão da Febre Maculosa Brasileira em um Condomínio Residencial em Bragança Paulista (SP, Brasil) ­ Estudo de Caso

This study reports the factors which led a gated community located in Bragança Paulista (SP, Brazil), a non-endemic area for Brazilian Spotted Fever (BSF), to be classified as a Risk Area for transmission of this disease, showing that an increasing resident population of capybaras (Hydrochoerus hydrochaeris) in the area was likely responsible for a proliferation of Amblyomma sculptum ticks and acted as an amplifying host for Rickettsia rickettsii, the main etiologic agent of BSF. We report management actions proposed to control the local tick burden and reduce BSF risk, including measures to control parasitic and free-living tick populations and exclusion of the resident capybara population. Analyses of tick population data and R. rickettsii serology tests indicate that these measures were effective, greatly reducing the environmental burden of Amblyomma sculptum ticks and reducing the BSF transmission risk at the area.(AU)

Este estudo relata os fatores que levaram um Residencial localizado em Bragança Paulista (SP, Brasil), área não-endêmica para Febre Maculosa Brasileira (FMB), a ser classificado como Área de Risco para a doença, mostrando que uma crescente população residente de capivaras (Hydrochoerus hydrochaeris) na área era a provável responsável por uma proliferação de carrapatos Amblyomma sculptum e estava atuando como hospedeiro amplificador da bactéria Rickettsia rickettsii, principal agente etiológico da FMB. Relatamos as ações de manejo ambiental propostas para controlar a quantidade de carrapatos no local e reduzir o risco de transmissão da doença, incluindo medidas para o controle de populações de carrapatos parasíticas e no ambiente e a eliminação da população residente de capivaras. Análises de dados populacionais de carrapatos e testes serológicos para R. rickettsii indicaram que as medidas tomadas foram efetivas, causando grande redução da população de carrapatos no ambiente e reduzindo o risco de transmissão de FMB na área.(AU)