Tuberculin sensitivity in children in a rural area in Sharg El Niel Province .


Research type: Research Paper

Authors: El Nour, Hind Omer .

Abstract: Tuberculosis in many developing countries including Sudan remains a major health problem. It is endemic in some areas in Sudan; Childhood tuberculosis represents a hidden reservoir for infection. Inspite of this, research in this area including tuberculin sensitivity is meager. Objectives: the main objective is to determine tuberculin sensitivity in a representative sample of children and to find out any correlation with host and environmental factors. Methodology: Tuberculin survey was carried on a representative sample of children in a rural community in the East Nile Province selected by house to house survey for those 3 month to 6 years and school survey for those 7-15 years. 0.1 ml of tuberculin (one TU) was injected intradermally in the forcarm and read in 3-4 days. Results: A total of 1679 were tested, the results of 1367 were analysed. 82.6 percent received BCG vaccination, the majority within their first year of life and 80 percent were scar positive. Half of the children showed positive tuberculin reactions (5mm and more). 5-9 mm reactions constitute 40 percent while 10 mm and more reactions were 11 perecent. The tuberculin positivity after an initial increase up to the age of 7-10 years showed gradual decrease with age. History of contact with a tuberculous adult was associated with strong reactions (10 mm and more) while the sex and raw milk ingestion did not influence the tuberculin reactivily. The annual risk of infection was estimated as 2.35 with an estmated incidence of 234 per 100.000 population, labeling the area of the East Nile Province a high risk area of tuberculosis. Convlusion: BCG vaccination confirmed reasonable immunity up to the age of 7-10 years. there is good correlation between BCG scar and BCG vaccination and the rate of BCG vaccination coverage is comparable to that of the EPI figures. As a good BCG scar shwed direct relationship with tuberculin reactivity it is important to investigate post vaccination anergy in BCG vaccinated infants who did not show the scar within 3-6 months. Further evaluation of BCG vaccination especially considering the duration of immunity is needed in order to decide on revaccination of primary school leavers. A well integrated tuberculosis control programme including BCG vaccination, incorporated within the primary health care system is an urgent need.