Significant differences between Yemenite and Egyptian STR profiles and the influence on frequency estimations in Arabs

A population genetic study was performed on Yemenites using the set of nine short tandem repeat loci (STRs) D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820. Analysis of the data revealed that all loci were in Hardy-Weinberg equilibrium and evidence of linkage equilibrium was found for only 1 out of 36 locus pairs. At seven loci the allelic distributions found in the Yemenite sample were significantly different from those found for an Arab population sample from Egypt. Nevertheless, we assume that the Yemenite database can be used for Arabs of unknown or foreign (non-Yemenite) origin in the absence of population-specific databases without exerting a significant bias on the biostatistical interpretation. In an experimental set-up (ethnic profile frequency ratio test), the impact of calculating multi-locus profile frequencies for foreign Arab individuals (Egyptians) using the Yemenite database instead of a region-specific one was negligible. Received: 14 November 1999 / Accepted: 5 April 2000     

Evaluation of the National Tuberculosis Surveillance System in Sana’a,Yemen, 2018: Observational Study

BackgroundTuberculosis remains a public problem that is considered one of the top causes of morbidity and mortality worldwide. The National Tuberculosis Control Program in Yemen was established in 1970 and included in the national health policy under the leadership of the Ministry of Public Health and Population to monitor tuberculosis control. The surveillance system must be evaluated periodically to produce recommendations for improving performance and usefulness.ObjectiveThis study aims to assess the usefulness and the performance of the tuberculosis surveillance system attributes and to identify the strengths and weaknesses of the system.MethodsA quantitative and qualitative evaluation of the national tuberculosis surveillance system was conducted using the Centers for Disease Control and Prevention’s updated guidelines. The study was carried out in 10 districts in Sana’a City. A total of 28 public health facilities providing tuberculosis services for the whole population in their assigned catchment areas were purposively selected. All participants were interviewed based on their involvement with key aspects of tuberculosis surveillance activities.ResultsThe tuberculosis surveillance system was found to have an average performance in usefulness (57/80, 71%), flexibility (30/40, 75%), acceptability (174/264, 66%), data quality (4/6, 67%), and positive predictive value (78/107, 73%), and poor performance in simplicity (863/1452, 59%) and stability (15%, 3/20). In addition, the system also had a good performance in sensitivity (78/81, 96%).ConclusionsThe tuberculosis surveillance system was found to be useful. The flexibility, positive predictive value, and data quality were average. Stability and simplicity were poor. The sensitivity was good. The main weaknesses in the tuberculosis surveillance system include a lack of governmental financial support, a paper-based system, and a lack of regular staff training. Developing an electronic system, securing governmental finances, and training the staff on tuberculosis surveillance are strongly recommended to improve the system performance.