Bernatas J J, Mohamed Ali I, Ali Ismaël H, Barreh Matan A
Centre Paul Faure, Programme National de Lutte contre la Tuberculose, MSAS, République de Djibouti.
Med Trop (Mars). 2008 Dec;68(6):611-6.
The purpose of this report was to describe a tuberculin survey conducted in 2001 to assess the trend in the annual risk for tuberculosis infection in Djibouti and compare resulting data with those obtained in a previous survey conducted in 1994. In 2001 cluster sampling allowed selection of 5599 school children between the ages of 6 and 10 years including 31.2% (1747/5599) without BCG vaccination scar. In this sample the annual risk of infection (ARI) estimated using cutoff points of 6 mm, 10 mm, and 14 mm corrected by a factor of 1/0.82 and a mode value (18 mm) determined according to the "mirror" method were 4.67%, 3.64%, 3.19% and 2.66% respectively. The distribution of positive tuberculin skin reaction size was significantly different from the normal law. In 1994 a total of 5257 children were selected using the same method. The distribution of positive reactions was not significantly different from the gaussian distribution and 28.6% (1505/5257) did not have a BCG scar. The ARI estimated using cutoff points of 6 mm, 10 mm, and 14 mm corrected by a factor of 1/0.82 and a mode value (17 mm) determined according to the "mirror" method were 2.68%, 2.52%, 2.75% and 3.32 respectively. Tuberculin skin reaction size among positive skin test reactors was correlated with the presence of a BCG scar, and its mean was significantly higher among children with BCG scar. The proportion of positive skin test reactors was also higher in the BCG scar group regardless of the cutoff point selected. Comparison of prevalence rates and ARI values did not allow any clear conclusion to be drawn, mainly because of a drastic difference in the positive reaction distribution profiles between the two studies. The distribution of the skin test reaction's size 1994 study could be modelized by a gaussian distribution while it could not in 2001. A partial explanation for the positive reaction distribution observed in the 2001 study might be the existence of cross-reactions with environmental mycobacteria.
本报告的目的是描述2001年进行的一项结核菌素调查，以评估吉布提结核病感染年风险的趋势，并将所得数据与1994年进行的前一次调查所获数据进行比较。2001年采用整群抽样法选取了5599名6至10岁的学童，其中31.2%（1747/5599）没有卡介苗接种疤痕。在这个样本中，使用6毫米、10毫米和14毫米的截断点，并通过1/0.82的系数进行校正，以及根据“镜像”法确定的众数（18毫米）来估计的年感染风险（ARI）分别为4.67%、3.64%、3.19%和2.66%。结核菌素皮肤反应阳性大小的分布与正态分布有显著差异。1994年，采用相同方法共选取了5257名儿童。阳性反应的分布与高斯分布无显著差异，28.6%（1505/5257）没有卡介苗疤痕。使用6毫米、10毫米和14毫米的截断点，并通过1/0.82的系数进行校正，以及根据“镜像”法确定的众数（17毫米）来估计的ARI分别为2.68%、2.52%、2.75%和3.32%。结核菌素皮肤试验阳性反应者的皮肤反应大小与卡介苗疤痕的存在相关，且有卡介苗疤痕儿童的反应平均值显著更高。无论选择何种截断点，卡介苗疤痕组中皮肤试验阳性反应者的比例也更高。患病率和ARI值的比较无法得出任何明确结论，主要是因为两项研究中阳性反应分布情况存在巨大差异。1994年研究中皮肤试验反应大小的分布可用高斯分布建模，而2001年则不行。2001年研究中观察到的阳性反应分布的部分解释可能是与环境分枝杆菌存在交叉反应。
