Direct drug susceptibility test for tubercle bacilli by the sputum swab culture method.

OBJECTIVE: To develop a simple, inexpensive method for testing direct drug susceptibility of tubercle bacilli to isoniazid (INH) and streptomycin (SM) which can be adopted for use even in remote parts of the world. DESIGN: Using 239 smear-positive sputum specimens obtained from an equal number of patients, a comparison was made between the direct swab susceptibility test and the standard indirect method for INH and SM using Löwenstein-Jensen (L-J) medium. RESULTS: There was 95% agreement of results for INH by 6 weeks and 90% for SM by 8 weeks; 96% of INH-resistant cultures could be detected in 5 weeks and 91% of SM-resistant cultures by 8 weeks. The discrepancies in the two tests were virtually symmetrically distributed at 6 and 8 weeks. The speed and efficiency of detection of resistance by the swab method was also assessed in relation to the standard indirect method. For INH, 96% of the cultures were detected by the fifth week, while 66% were detected as early as 2 weeks and 93% by 4 weeks. With SM, 84% were detected by 4 weeks, 89% by 5 weeks and 91% by 8 weeks. CONCLUSION: This study has indicated the usefulness of the swab method for testing the drug susceptibility of tubercle bacilli. As this method is simple and easy, and does not even require a centrifuge, it has the potential of application even in the remote parts of the world. The material used, Cetavlon (Cetrimide), is inexpensive and easily water soluble, and more importantly, aqueous solutions are self-sterilizing. It should be stressed, however, that the results obtained with this test take the same time as conventional methods, and it can therefore not be considered as a rapid test.

Some indices pertaining to the leprosy control programme in Tamil Nadu, based on data from a random sample of fourteen government control units.

From a random sample of 14 Government Leprosy Control Units in Tamil Nadu, information on the profile of the newly-diagnosed leprosy patients and some important aspects of the control programme in 1978-81 was collected when monotherapy with dapsone was the practice. Among the new patients, 55 per cent were males, 24 per cent were children, 6 per cent had lepromatous leprosy and 9 per cent had a deformity. About 65 per cent were detected by active case-finding methods and 25 per cent were voluntary referrals. Of the total diagnosed patients, only 68 per cent started treatment; further, of these, about 40 per cent collected drugs for at least 6 months in the first year of treatment. The average attendance at the clinic was 34 per cent of the due attendance. Coverage in the annual examination of family contacts was 57 per cent. During the 4 yr period, about 70 per cent of the villages had population surveys with a coverage of 75 per cent or more. The introduction of multi-drug therapy has provided a new impetus to the programme and therefore a similar study is called for to provide valuable information about the extent of improvement in completion rates and overall impact.

PIP: Researchers used 1978-1981 data from a random sample of 100 rural subcenters of 14 government leprosy control unites (LCUs) in Tamil Nadu, India to learn the status of indices of the National Leprosy Control Programme. The lepromatous rate stood at 6% (4-10% range) with males having a much higher percentage (8.6% vs. 3.9%) and children having a much lower percentage (.6% vs. 8.3%). It was highest for those who voluntarily reported their condition (10.4%) and lowest for those detected during a routine contact examination (2.5%). Active case finding techniques detected most new cases [65%; population survey (59%) and routine contact examination (6%)] followed by voluntary referrals (25%; 8-44% range) and miscellaneous sources. Only 68% (38-82%) of newly diagnosed cases started treatment in the same calendar year or the next. Indeed 46% of those detected by population survey and 37% of contact examination did not even register. Therefore the active case finding program does not bring full benefits to patients. It should undertake intense efforts to motivate all diagnosed patients to take treatment. Moreover, as many as 60% of patients did not collect the drugs needed for the multidrug therapy for =or + 6 months. Some of these did not even do so in the 1st year of treatment. As time passed, the levels of irregularity rose (65% in 2nd year and 71% in 3rd year). Perhaps LCU staff should use a group approach to motivate patients to collect the needed drugs rather than an individualizes approach. In addition, 18-89% of patients at time of registration had a bacteriological examination in 12 LCUs. The median stood at 69%. The percentage of patients who have a bacteriological examination must improve since the multidrug therapy regimen is dependent on the type of leprosy the patient has (multi or pauci bacillary leprosy).

Estimation of immunisation coverages in children by WHO 30-cluster survey.

A WHO 30-cluster survey for estimating immunisation coverages in infancy was undertaken in each of 5 districts in Tamil Nadu, strictly according to the specifications laid out in the WHO manual. The main aim was to examine whether the technique would provide estimates with the required degree of precision under Indian conditions. Of 60 sample survey estimates, 57 had the targeted degree of precision (i.e., 95% confidence limits of +/- 10 percentage points), which is in excellent agreement with expectation. The proportions of infants on whom immunisation was initiated, were very high for DPT vaccine (88-99%) and polio vaccine (85-99%); however, of those who had received the first dose, 23-39 per cent did not complete the 3-dose schedule. Estimated coverage with measles vaccine ranged from 15 to 54 per cent, while BCG coverage ranged from 53 to 97 per cent. Better health education regarding the need and correct age for immunisation, and more effective motivation at the time of administration of the first dose of DPT/polio vaccine, are recommended.

Confidence intervals in medical research.

The utility of confidence intervals in a wide variety of situations in the medical field is re-emphasized, with examples drawn from controlled clinical trials, disease control programmes, vaccine trials and laboratory studies. It is shown that the confidence interval approach is more informative than a mere test of statistical significance, and should therefore be employed as an useful adjuvant. Since proportions are widely quoted in medical literature and as the determination of the exact confidence limits for a binomial proportion is iterative and time-consuming, an assessment is made of 15 published methods which provide approximate confidence limits; the 'Square root transformation' method is recommended since it is accurate and the computation of limits is relatively easy. In the case of a difference between two proportions, the usual method may be employed if sample sizes exceed 75; for smaller sample sizes (even for sizes of 5), the Jeffreys-Perks method is very satisfactory and is therefore recommended.

Evaluation of a modified medium for the one hour urease test for Helicobacter pylori infection.

The biopsy urease test is a simple and rapid method for the diagnosis of Helicobacter pylori infection; results are obtained within 4 h to 24 h. Various modifications of the media used in this test have been tried, to improve the accuracy and speed of the test. We compared the yield obtained with two media: the standard Christensen's urea medium and a modified plain urea medium (without the nutrients glucose and peptone); the result was read upto 1 h. In the first 53 cases, culture was obtained when either of the media gave a negative result. There was no difference in false positives in the two media, while there were more false negatives with the plain urea medium (4) compared to the Christensen's medium (1). In the latter 69 patients, we determined the accuracy of the two media by obtaining culture in all cases. The Christensen's medium had a sensitivity of 100% and a specificity of 92.1%, while the plain urea medium had a sensitivity of 96.7% and a specificity of 92.1%. The speed of reaction in both media was similar. We conclude that the Christensen's urea medium gives accurate results even when read at 1 h; the plain urea medium gives similar results.

Effect of vitamin A supplementation to mother and infant on morbidity in infancy.

OBJECTIVES: To assess the impact of Vitamin A supplementation to the mother soon after delivery and to the infant at six months on morbidity in infancy. DESIGN: Randomized double blind placebo controlled field trial. SETTING: 51 villages in two contiguous Primary Health Centers in Villupuram Health Unit District of Tamil Nadu, South India. SUBJECTS: 909 newly delivered mother-and-infant pairs. INTERVENTIONS: Both mother and infant received Vitamin A (300,000 IU for mothers and 200,000 IU for children) in 311 instances (AA); mother received Vitamin A but infant received Placebo in 301 instances (AP); and both mother and infant received Placebo in the remaining 297 instances (PP). MAIN OUTCOME MEASURES: Incidence of diarrhea and Acute Respiratory Infection (ARI); distributions of infants by frequency of episodes and number of infected days. RESULTS: 233 in the AA Group and 228 each in the AP and PP Groups were followed up regularly. The incidence of diarrhea in these infants was 97.4%, 96.9% and 94.7% in the three groups, mean number of diarrheal episodes was 4.4, 4.6 and 4.2 and median number of days in infancy with diarrhea was 26, 26 and 22 days, respectively. For ARI, the incidences were 96.6%, 95.6% and 96.1%, means were 4.8, 5.1 and 4.8 episodes, and the medians were 32, 34 and 34 days, respectively. CONCLUSIONS: Prophylactic administration of mega doses of Vitamin A to the mother soon after delivery and to the infant at six months do not have any beneficial impact on the incidence of diarrhea and ARI in infancy.

A concurrent comparison of a WHO-recommended 30-cluster survey and a modified version of it under Indian conditions in the estimation of immunization coverages.

A concurrent comparison of the WHO 30-cluster sample survey method for estimating immunization coverages (DPT, Polio, BCG, Measles) and an Indian modification of (GOI) was undertaken in five districts in South India. The essential difference between the two methods is the manner in which the first household is selected in the chosen clusters. With the WHO method, it is chosen clusters. With the WHO method, it is chosen at random, whereas with the GOI method it is often close to the village centre. Estimates with the required degree of precision, i.e., 95% confidence limits of +/- 10 percentage points, were provided in 18 (90%) of 20 instances by the WHO method and in 19 (95%) by the GOI method, findings which are in accordance with expectation. The estimated coverages were, however, higher by the GOI method than by the WHO method in two districts, lower in one district, and in the remaining two districts there was no clear pattern. On the average, there was a suggestion that the GOI method yielded slightly higher coverages, but the differences were not statistically significant.

A 20-year study of the Leprosy Control Programme at the Hemerijckx Leprosy Centre in Polambakkam in South India.

The Hemerijckx leprosy centre at Polambakkam in South India covers a rural population of about 800,000 and has treated over 40,000 cases of leprosy during the period 1955-75. Based on a stratified random sample of 25% of the case records, information was obtained about the profile of newly-detected cases in various cohorts (1955-57, 1958-60, 1961-64, 1965-69, 1970-75), regularity in drug collection and response to treatment. In newly-detected cases, the ratio of males to females was stable (3:2), but the proportion of adults aged 45 years or more increased from 15% in 1958-60 to 20% in 1970-75 and the lepromatous rate decreased from 9% to 6%; the proportion deformed at the time of diagnosis ranged from 11% to 15%. Regularity in drug collection was unsatisfactory even in the first year of treatment, with less than half the patients making 6 (or more) of the 12 monthly drug collections. The clinical status at 4-6 years was known for 70-75% of the patients who started treatment and of those approximately 60% had inactive or arrested disease. Data from population surveys was sparse; about 60% of the expected numbers were initiated and less than 30% of these had a coverage of 75% or more. The limited evidence, however, showed a decline in the prevalence of about 2 per thousand per annum. Field studies to evolve strategies for better motivation of patients, introduction of short-course regimens, and continuous monitoring of the programme are urgently needed.