Tuberculin survey in Ethiopia

Kekkaku. 1992 Aug;67(8):539-44.

Abstract

For planning and implementation of effective national tuberculosis control programme (NTP) in Ethiopia, it is essential to know the real magnitude of tuberculosis problem. Previous tuberculin survey carried out during the period from 1953 to 1955 revealed the annual risk of infection 3.0%, and since then, there has been no survey. A new tuberculin survey was thus conducted during the period from December 1987 to April 1990. In order to get a sample of 47 previously BCG unvaccinated children, aged 6 to 10 years, selected from each 480 representative clusters of randomly selected 16 Woredas (districts), a total of 26,529 children, approximately 55 in each cluster, were given tuberculin intradermal injection, and the reaction was read in 26,269 children (99.0%). A scar survey was done, and 23,695 had no BCG scar, while 2,574 (10.1%) had BCG scar. Out of the former, 2,503 children (10.6%) were positive, and the annual risk of infection thus calculated was 1.4%. Out of the latter, 591 (23.0%) were positive. The results of these two surveys indicate that tuberculosis showed decline in the past 37 years with the annual reduction rate of 2.2%, however, the trend might change in the future due to present pandemic of HIV infection.

PIP: Between December 1987 and April 1990, health workers administered a tuberculin test to 26,529 6-to-10-year-old children in 16 districts (Woredas) of Ethiopia to obtain a sample of 47 children who had not received a BCG vaccination earlier. They were able to read the reaction in 99% of the children. 2574 (10.1%) children had a BCG scar and 591 (23%) of them tested positive for tuberculosis. 2503 (10.6%) of the 23,695 children who did not have a BCG scar tested positive for tuberculosis. Tuberculin positivity was highest in Deder Woreda (Harrarghe Region) and lowest in Wuchale Woreda (Shoa Region) (27.9% vs. 2%). In fact, prevalence was higher in urban areas than rural areas, suggesting overcrowding's effect on transmission. The last tuberculin survey in Ethiopia occurred in 1953-1955, at which time the prevalence was much higher than in 1988-1990 (30% vs. 10.6%). In addition, the annual risk of infection was higher (3% vs. 1.4%). Between the 2 surveys the prevalence of tuberculosis fell at a rate of 2.2%/year. Yet, the HIV infection pandemic in Ethiopia threatened that downward trend. The cost of chemoprophylactic drugs and lack of sufficient laboratory facilities posed a problem for Ethiopia's National Tuberculosis Control Programme.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • BCG Vaccine
  • Child
  • Cluster Analysis
  • Ethiopia / epidemiology
  • Humans
  • Prevalence
  • Risk
  • Tuberculin Test
  • Tuberculosis / epidemiology*
  • Tuberculosis / prevention & control
  • Vaccination

Substances

  • BCG Vaccine