Yield of screening for TB and HIV among children failing to thrive in Botswana.

BACKGROUND: Failure to thrive (FTT) is a sign of tuberculosis (TB) and human immunodeficiency virus (HIV) infection. We assessed TB and HIV prevalence in children with FTT at one clinic in Botswana. METHODS: In July 2010, we screened all children attending a 'Well Child' clinic for FTT. Children with FTT were referred to a paediatrician who: (i) assessed causes of FTT, (ii) evaluated for HIV and TB and (iii) reviewed the patient chart for evaluations for TB and HIV. RESULTS: Of 919 children screened, 176 (19%) had FTT. One hundred eighteen (67%) children saw a paediatrician, and of these, 95 (81%) completed the TB evaluation. TB was newly diagnosed in 6 of 95 (6%). At review, HIV status was known in 23 of 118 (19%). Ninety-five had an unknown HIV status. Forty-five (47%) tested for HIV; all tested HIV-negative. CONCLUSION: TB and HIV screening among children with FTT diagnosed TB in 6% of cases completing an evaluation, but no new HIV infections.

High rates of clustering of strains causing tuberculosis in Harare, Zimbabwe: a molecular epidemiological study.

We examined the pattern of tuberculosis (TB) transmission (i.e., reactivation versus recent transmission) and the impact of human immunodeficiency virus (HIV) infection in Harare, Zimbabwe. Consecutive adult smear-positive pulmonary TB patients presenting to an urban hospital in Harare were enrolled. A detailed epidemiological questionnaire was completed, and tests for HIV type 1 and CD4 cell counts were performed for each patient. Molecular fingerprinting of the genomic DNA recovered from cultures of sputum was performed by two molecular typing methods: spacer oligonucleotide typing (spoligotyping) and analysis of variable number of tandem DNA repeats (VNTRs). A cluster was defined as isolates from two or more patients that shared the same spoligotype pattern or the same VNTR pattern, or both. DNA suitable for typing was recovered from 224 patients. The prevalence of HIV infection was 79%. Of 187 patient isolates (78.6%) typed by both spoligotyping and analysis of VNTRs, 147 were identified as part of a cluster by both methods. By spoligotyping alone, 84.1% of patient isolates were grouped into 20 clusters. The cluster size was generally <8 patient isolates, although three large clusters comprised 68, 25, and 23 patient isolates. A total of 89.4% of the patient isolates grouped into 12 clusters defined by analysis of VNTRs, with 2 large clusters consisting of 127 and 13 patient isolates, respectively. Thirty-six percent of patient isolates with a shared spoligotype and 17% with a shared VNTR pattern were geographically linked within Harare, but they were not linked on the basis of the patient's home district. In a multivariate analysis, there were no independent predictors of clustering, including HIV infection status. Comparison with the International Spoligotype database (Pasteur Institute, Pointe a Pitre, Guadeloupe) demonstrated that our three largest spoligotype clusters are well recognized and ubiquitous in Africa. In this epidemiologically well characterized urban population with a high prevalence of HIV infection, we identified a very high level of strain clustering, indicating substantial ongoing recent TB transmission. Geographic linkage could be detected in a proportion of these clusters. A small group of actively circulating strains accounted for most of the cases of TB transmission.