Risk-benefit assessment of Bacillus Calmette-Guérin vaccination, anti-phenolic glycolipid I serology, and Mitsuda test response: 10-year follow-up of household contacts of leprosy patients

Abstract: INTRODUCTION: Despite multidrug therapy, leprosy remains a public health issue. The intradermal Bacillus Calmette-Guérin (BCG) vaccine, Mitsuda test (lepromin skin test), and anti-phenolic glycolipid I (PGL-I) serology are widely used in leprosy studies and have shown great epidemiological value. METHODS: This longitudinal study evaluated the relative risks and benefits of these three tools by comparing results observed in household contacts (HHCs) of leprosy patients who developed leprosy with those of HHCs who did not in a population of 2,992 individuals monitored during a 10-year period. RESULTS : Seventy-five (2.5%) new leprosy cases were diagnosed, including 28 (0.9%) co-prevalent cases. Therefore, for the risk-benefit assessment, 47 (1.6%) HHCs were considered as truly diagnosed during follow-up. The comparison between healthy and affected contacts demonstrated that not only did BCG vaccination increase protection, but boosters also increased to 95% relative risk (RR) reduction when results for having two or more scars were compared with having no scars [RR, 0.0459; 95% confidence interval (CI), 0.006-0.338]. Similarly, Mitsuda reactions >7mm in induration presented 7-fold greater protection against disease development compared to reactions of 0-3mm (RR, 0.1446; 95% CI, 0.0566-0.3696). In contrast, anti-PGL-I ELISA seropositivity indicated a 5-fold RR increase for disease outcome (RR, 5.688; 95% CI, 3.2412-9.9824). The combined effect of no BCG scars, Mitsuda reaction of <7mm, and seropositivity to anti-PGL-I increased the risk for leprosy onset 8-fold (RR, 8.109; 95% CI, 5.1167-12.8511). CONCLUSIONS: The adoption of these combined assays may impose measures for leprosy control strategies.

Behavioral alterations induced by absence of circadian light rhythm: effects of constant light or constant dark on depression-like behaviors and locomotor activity in rats / Alterações comportamentais induzidas pela ausência do ritmo circadiano de luz: efeitos da luz constante ou escuro constante em comportamentos relacionados à depressão e na atividade locomotora em ratos

Affective disorders have been linked to abnormal biological rhythms. Depression- and anxietyrelated behaviors can be altered following changes of daily periods of environmental light. The aim of this study was to investigate the effect of daily light cycle on both anxiety- and depressive-like behaviors of rats. Wistar male rats were exposed to constant dark or constant light during one week and compared to control animals exposed to 12/12h light/dark cycle regarding to anxiety-like behaviors and general activity on open field test and depressive-like behaviors on the forced swimming test. Data showed that rats exposed to one week of constant light exhibited increased number of quadrants crossed in the open field. No change on anxiety-like behaviors (time and quadrants crossed in the center of apparatus) was observed in the open field test. One week of constant dark increased the time of immobility behavior in the forced swimming test relative to control 12/12h light/dark treatment. Therefore, one week of continuous light induced locomotor hyperactivity and one week of continuous dark induced depressive-like behaviors following reestablishment of normal 12/12h light/dark cycle. Such data demonstrate the importance of light/dark environmental rhythm on mood changes and the significance of light/dark cycle control on behavioral studies.

Os transtornos afetivos têm sido relacionados a anormalidades dos ritmos biológicos. Comportamentos relacionados à depressão e ansiedade podem ser alterados depois de mudanças dos períodos diários de luz ambiental. O objetivo desse estudo foi investigar o efeito de alterações no ritmo diário de luz em ambos os comportamentos relacionados à ansiedade e depressão em ratos. Ratos Wistar machos foram expostos a um ambiente com escuro constante ou claro constante durante uma semana e foram comparados aos animais controle (12h claro / 12h escuro) quanto aos comportamentos relacionados à ansiedade e atividade geral no teste de campo aberto e quanto aos comportamentos relacionados à depressão no teste de nado forçado após o restabelecimento do ritmo normal de claro/escuro. Os resultados mostraram que ratos expostos por uma semana no claro constante apresentaram aumento dos quadrantes percorridos no teste de campo aberto se comparados aos ratos controle. Nenhuma alteração dos comportamentos relacionados à ansiedade (tempo e locomoção no centro do aparato) foi observada no teste do campo aberto. Além disso, uma semana no escuro constante aumentou o tempo de imobilidade dos animais no teste de nado forçado quando comparados aos animais controle. Portanto, uma semana de claro constante induziu hiperatividade locomotora e uma semana de escuro constante induziu comportamentos relacionados à depressão depois do restabelecimento do ritmo normal (12/12h) de claro e escuro. Tais resultados demonstram a importância do ritmo claro/escuro ambiental nas alterações de humor e a importância do controle do ciclo claro/escuro em estudos comportamentais.