TUBERCULIN SURVEY IN GOVERNMENT HIGH SCHOOL OF DHARAN MUNICIPALITY

This survey was done in 682 out of 1672 children tested with Batch of Tuberculin used for Testing (PPD RT 23 with Tween 80) in Jan. 1997 with financial research grant of B.P. Koirala Institute of Health Sciences, Dharan. Dharan City is situated in Eastern Development Region (EDR) of Nepal where a high percentage of migrated population is residing with very high number of sputum positive cases. The majority of population are from high hills and mountain region where the Annual Risk of Infection (ARI) is less. This survey was done to know the epidemiological situation of Tuberculosis (TB) in Dharan. Tuberculin survey was done in Eastern Development Region (EDR) (1994) by National Tuberculosis Centre (NTC)/Japan International Cooperation Agency (JICA) in Saptari and Morang. The reported result of average Annual Risk of Infection (ARI) is 2.49% and 2.38% respectively. The mean age of surveyed population was 14.8 yrs. The Bacilli Calmette Guerin (BCG) coverage (scar rate) was 38.3% and BCG 4-8 age group 83.3% was highest and it gradually decreased to 37.5% in 12 + age group. The average 23 Tween-8-Batch of Tuberculin used for Testing (PPD) positive is 33.6% with 10 mm induration as cutoff line. Annual Risk of Infection (ARI) based on above was 2.7% in 9-11 age group and 1.31% in 12 + age group. This survey is suggestive of tuberculosis being highly prevalent in Dharan. The survey also showed average ARI to be 2.44% in Dharan in 10-15 yrs age group. The finding is suggestive of high ARI although the populations has migrated from hill and mountain. Previous report of average ARI in this area was 2.5% (Morang and Saptari). The survey result suggests that high priority, effective tuberculosis program is necessary and intensive control program can only give impact to control of tuberculosis in Dharan.

B.P. Koirala Institute of Health Sciences (BPKIHS) caters to population of lower hills as well as terai. The Tuberculosis (TB) clinic regularly detects 260 -270 sputum positive cases from Dharan municipality annually (1994 -1997).
As Mass Miniature Radiography (MMR) for prevalence survey was not possible & sputum examination is more difficult due to social factor; therefore tuberculin survey was the best alternative applied. 1  Earlier, more number of schools were planned for survey. However, our survey team encountered difficulty in their work due to reluctance showed by the school principals (poor response) & also due to general ignorance. So, the survey was limited to one big public school of Dharan municipality to assess the following: a. Extent of tuberculosis; estimate incidence and prevalence as compared to the reported incidence. b. BCG coverage. c. Have base line data for the trend of tuberculosis by repeating the survey at different intervals (5 -10 years). The following data were recorded in each case: Injection day (1st day) -Injection date, name, age/sex , class, date of reading induration in mm, roll no., Bacilli Calmette Guerin (BCG) scar size in mm.

MATERIAL & METHOD
Reading day (3rd or 4th day) -PPD induration in mm measured in transverse direction, reading date by trained technician supervised by senior author (N. K.).

RESULT
There were 1672 students studying in Public Madhyamic Vidyalaya, Dharan. 682 children were selected from all classes according to population proportion by simple random sampling. All 682 students received 1 TU PPD and were analyzed for tuberculin reaction.
The age distribution of 682 children ranged from 0 -18 yrs with a mean age 14.8 ± 2.42 years given in figure 1. Figure 1a (Table I).
The PPD induration size is shown in Figure 2 for all children.
The mean PPD (sensitive) induration size in BCG scar positive children was (5.16.±2.67) mm. and in non vaccinated (-ve scar) was (8.03 ± 4.52). Taking 10 mm as cut -off point, tuberculin positive rate was 33.6% and average ARI was 2.44% (95% confidence levels 1.90% to 2.98%). Table I & II show the prevalence rate and average ARI in each age group of this study and average Annual Risk of Infection (ARI) of schools in Saptari (2.49%) and Morang (2.38%) compared with earlier report.

Average ARI
The average ARI is 2.44% which suggests that tuberculosis is highly epidemic in this area. Table III shows ARI data of other districts. Although Dharan is having migratory population, poor hygienic condition and over-crowding exists in households.
Population density may be one factor which influences tuberculosis in this area.

Recommendation
Tuberculin survey is required in Sunsari district area. Follow up survey is also suggested in Dharan as this survey was limited to only one school due to various reasons. Intensive tuberculosis programme is necessary to give impact to tuberculosis control as this city may be a focal point of transmission to tuberculosis infection due to high migratory population.
Short course chemotherapy is being given to all sputum +ve cases in Dharan under close supervision, so the survey should be repeated to see the impact of program in coming years.
Nation Tuberculosis Centre (NTC) should co-operate with B.P. Koirala Institute of Health Sciences, Dharan for further research.