Relapses in multibacillary leprosy patients: a retrospective cohort of 11 years in Colombia.

OBJECTIVES: To determine the frequency and factors associated with relapse in multibacillary leprosy. DESIGN: We performed a retrospective cohort study on multibacillary leprosy patients treated at Centro Dermatologico Federico Lleras Acosta between January 1994 and December 2004. By survival analysis we studied the incidence density for recurrence and bacillary index conversion. The assessment of risk factors associated with the occurrence of relapse was constructed using a Cox regression model. RESULTS: We included 299 cases of which 243 received WHO-MB MDT on a regular basis, and followed them up to assess the frequency of relapses. We obtained 490 person-years of follow-up and an incidence density of 6.70 relapses/100 patient-years that was higher than most of the data reported in the literature. The relapse rate was 9.80 per 100 person-years when the initial bacillary index was > or = 2.0 and 5.60 relapses/100 patient-years when it was < 2 (P = 0.03). The relapse rate increased to 7.70/100 patient-years among those treated with WHO-MB 24 month fixed-dose, and it reduced to 5.70/100 patient-years when treated until smear negative. The variables that showed association with relapse were: initial bacillary index > or = 2.0, antireactional treatment and clinical classification of lepromatous leprosy. For each variable, the risk was four to five times more likely to present relapse. We also found that 21 patients' BI became negative per 100 treated for 1 year with WHO-MB MDT. CONCLUSIONS: We found a high relapse rate associated with initial high bacillary index in the Colombian population. Among the patients who received MDT on a regular basis 33 out of 165 (20%) relapsed.

Estudio de la tuberculosis aviar en un zoológico de la sabana de Bogotá, mediante la técnica de la tuberculinización y la vigilancia epidemiológica activa / Study of avian tuberculosis in a zoo at the Bogota savannah through tuberculin testing and active epidemiologic surveillance

El flujo de aves silvestres constituye una debilidad en la vigilancia epidemiológica, pues se desconoce su potencial como fuente de diseminación de enfermedades. Se hizo un seguimiento epidemiológico de la población aviar existente en un encierro mixto silvestre de un zoológico ubicado en la Sabana de Bogotá, donde tres aves murieron con diagnóstico presuntivo de tuberculosis. A fin de comprobar la presencia de Mycobacterium avium y proyectar las medidas para evitar los factores de riesgo, se utilizó un grupo control de exposición previa de cinco aves domésticas raza Hy line Brown, un grupo centinela de diez aves domésticas del mismo lote del grupo control, un grupo control externo, constituido por 102 aves de los encierros vecinos al área problema. Se realizaron estudios retrospectivos y prospectivos, mediante análisis histopatológicos, microbiológicos, epidemiológicos y moleculares. El 100% de las aves del encierro original que murieron se les confirmó genotípicamente tuberculosis, causada por Mycobacterium avium. Del grupo centinela, 35,5% resultaron afectadas por Mycobacterium avium, 28,6% por Mycobacterium gordonae, 14,3% por Mycobacterium chelonae y un 21,4% por una micobacteria de difícil clasificación. Los animales de fuera del encierro no mostraron ningún indicio de infección. Se concluye que el encierro problema se encuentra afectado por tuberculosis aviar y se constituye en un foco de alto riesgo, tanto para aves como para los humanos. También, las aves domésticas utilizadas como centinelas son muy buenos detectores de agentes infecciosos, en particular, de las microbacterias presentes en el medio ambiente y la prueba de tuberculinización es un buen indicador de infección con este tipo de microorganismos en aves domésticas.

The flow of wild birds is a weakness in epidemiologic surveillance because of its unknown potential as a source of disease dissemination. The investigation focused on an epidemiological tracking of the mixed wild bird population in a zoo in the Bogota Savannah, where three birds died with a presumptive diagnosis of tuberculosis. In order to verify the presence of Mycobacterium avium and to plan the required measures to avoid risk factors, a control group of five poultry birds of the Hy Line Brown variety that had already been exposed was used, as well as a sentinel group of the poultry birds from the same batch as the control group, and an external control group of 102 birds from cages near the area of the problem. Retrospective and prospective studies were carried out through histopathological, microbiological, epidemiological and molecular analysis. One hundred percent (100%) of the birds from the original cages that died were genotypically diagnosed with tuberculosis caused by Mycobacterium avium. Thirty-five percent (35.5%) of the sentinel group was affected by Mycobacterium avium, 28.6% by Mycobacterium gordonae, 14.3% by Mycobacterium chelonae and 21.4% by a mycobacterium that is very difficult to classify. The other animals outside the cage showed no evidence of infection. It is concluded that the problematic enclosure is affected by avian tuberculosis, which is of high risk both for birds and for humans. The poultry used as sentinels are excellent infective agent detectors, particularly of mycobacteria present in the environment, and the tuberculin test is a good indicator of infection with this type of microorganisms in poultry.