--Eleven tips for operational researchers working with health programmes: our experience based on implementing differentiated tuberculosis care in south India

Due to the workload and lack of a critical mass of trained operational researchers within their ranks, health systems and programmes may not be able to dedicate sufficient time to conducting operational research (OR). Hence, they may need the technical support of operational researchers from research/academic organisations. Additionally, there is a knowledge gap regarding implementing differentiated tuberculosis (TB) care in programme settings. In this 'how we did it' paper, we share our experience of implementing a differentiated TB care model along with an inbuilt OR component in Tamil Nadu, a southern state in India. This was a health system initiative through a collaboration of the State TB cell with the Indian Council of Medical Research institutes and the World Health Organisation country office in India. The learnings are in the form of eleven tips: four broad principles (OR on priority areas and make it a health system initiative, implement simple and holistic ideas, embed OR within routine programme settings, aim for long-term engagement), four related to strategic planning (big team of investigators, joint leadership, decentralised decision-making, working in advance) and three about implementation planning (conducting pilots, smart use of e-tools and operational research publications at frequent intervals). These may act as a guide for other Indian states, high TB burden countries that want to implement differentiated care, and for operational researchers in providing technical assistance for strengthening implementation and conducting OR in health systems and programmes (TB or other health programmes). Following these tips may increase the chances of i) an enriching engagement, ii) policy/practice change, and iii) sustainable implementation.

The First Differentiated TB Care Model From India: Delays and Predictors of Losses in the Care Cascade

To reduce TB deaths in resource-limited settings, a differentiated care strategy can be used to triage patients with high risk of severe illness (i.e., those with very severe undernutrition, respiratory insufficiency, or inability to stand without support) at diagnosis and refer them for comprehensive assessment and inpatient care. Globally, there are few examples of implementing this type of strategy in routine program settings. Beginning in April 2022, the Indian state of Tamil Nadu implemented a differentiated care strategy called Tamil Nadu-Kasanoi Erappila Thittam (TN-KET) for all adults aged 15 years and older with drug-susceptible TB notified by public facilities. Before evaluating the impact on TB deaths, we sought to understand the retention and delays in the care cascade as well as predictors of losses. During April-June 2022, 14,961 TB patients were notified and 11,599 (78%) were triaged. Of those triaged, 1,509 (13%) were at high risk of severe illness; of these, 1,128 (75%) were comprehensively assessed at a nodal inpatient care facility. Of 993 confirmed as severely ill, 909 (92%) were admitted, with 8% unfavorable admission outcomes (4% deaths). Median admission duration was 4 days. From diagnosis, the median delay in triaging and admission of severely ill patients was 1 day each. Likelihood of triaging decreased for people with extrapulmonary TB, those diagnosed in high-notification districts or teaching hospitals, and those transferred out of district. Predictors of not being comprehensively assessed included: aged 25-34 years, able to stand without support, and diagnosis at a primary or secondary-level facility. Inability to stand without support was a predictor of unfavorable admission outcomes. To conclude, the first quarter of implementation suggests that TN-KET was feasible to implement but could be improved by addressing predictors of losses in the care cascade and increasing admission duration.

Diethylcarbamazine citrate-fortified salt for lymphatic filariasis elimination in India

Lymphatic filariasis (LF) is a vector-borne neglected tropical disease, causing permanent disability. The disease is debilitating and widespread, leading to tremendous productivity and economic loss. The Government of India (GOI) prioritized the elimination of LF through the annual mass drug administration (MDA) programme in 2004 and continued with a single dose of diethylcarbamazine citrate (DEC), 6 mg/kg of body weight, plus albendazole annually over a period of 5-6 years. The GOI had set the target to achieve LF elimination by 2015 and now by 2030. The progress so far has been suboptimal. Much remains to be done as about 84 per cent of the total 328 endemic districts are still under MDA. The major challenge in implementing MDA is poor compliance. It is necessary to have a feasible alternative strategy addressing the above challenge to achieve the desired goal of LF elimination. At this juncture, a well-researched approach, i.e. the use of DEC-fortified salt, also advocated by the World Health Organization, as a unique form of MDA, is proposed. As per this strategy, a low dose of DEC (0.2% w/w) is added to the cooking salt at the manufacturing facility of iodized salt and consumed by the LF-endemic communities for about two years. Many examples of successful use of this strategy for LF elimination in small- and large-scale trials have been documented in India and several other endemic countries in the world. Implementing DEC-iodine-fortified salt is a safe, less expensive, more efficient and prompt approach for achieving the elimination of LF in India. Adverse effects are none or minor and self-limiting. The DEC-fortified salt strategy can easily piggyback on the existing countrywide deployment of iodized salt under the National Iodine Deficiency Disorders Control Programme (NIDDCP), which has achieved a great success in reducing iodine-deficiency disorders such as hypothyroidism. This existing robust programme can be leveraged to launch DEC-fortified salt for the community. If implemented appropriately, this strategy will ensure the complete cessation of LF transmission within two years from its introduction. If the said strategy is implemented in 2022, it is expected that India will be able to achieve the LF elimination by 2024, much before the global target of 2030.

Risk of Recrudescence of Lymphatic Filariasis after Post-MDA Surveillance in Brugia malayi Endemic Belitung District, Indonesia

Belitung district in Bangka-Belitung Province, Indonesia with a population of 0.27 million is endemic for Brugia malayi and 5 rounds of mass drug administration (MDA) were completed by 2010. Based on the results of 3 transmission assessment surveys (TAS), the district is declared as achieving elimination of lymphatic filariasis (LF) in 2017. The findings of an independent survey conducted by the National Institute of Health Research and Development (NIHRD) in the same year showed microfilaria (Mf) prevalence of 1.3% in this district. In 2019, NIHRD conducted microfilaria survey in 2 villages in Belitung district. Screening of 311 and 360 individuals in Lasar and Suak Gual villages showed Mf prevalence of 5.1% and 2.2% with mean Mf density of 120 and 354 mf/ml in the respective villages. Mf prevalence was significantly higher among farmers and fishermen compared to others and the gender specific difference was not significant. The results of a questionnaire based interview showed that 62.4% of the respondents reported to have participated in MDA in Lasar while it was 57.7% in Suak Gual village. About 42% of the Mf positive cases did not participate in MDA. Environmental surveys identified many swampy areas supporting the breeding of Mansonia vector species. Persistence of infection is evident and in the event of successful TAS3 it is necessary to monitor the situation and plan for focal MDA. Appropriate surveillance strategies including xenomonitoring in post-MDA situations need to be developed to prevent resurgence of infection. Possible role of animal reservoirs is discussed.

Scope of detectability of circulating antigens of human lymphatic filarial parasite Wuchereria bancrofti with smaller amount of serum by Og4C3 assay: its application in lymphatic filariasis elimination programme

Filarial antigen detection is an appropriate epidemiological indicator for mapping lymphatic filariasis and impact evaluation of filariasis elimination programme in view of low sensitivity of parasite detection. Monoclonal antibody-based Og4C3 immunological test requires 100 µl serum, which is difficult to collect by finger prick method during community based surveys. Hence, we tested lesser volume of serum compared to standard volume of 100 µl to compare its sensitivity and specificity in detecting the circulating filarial antigens. Blood samples were collected from individuals who tested positive [with titer groups 4 (border line positives), 6 (medium positives), and 8 (high positives)] and negative (titre group 3) for Og4C3 assay. Different volumes of serum samples were used to make-up required volume (100 µl) with appropriate dilutions and subjected to Og4C3 assay. The results showed that known negative samples tested negative at all the serum volumes tested. All positives (titer groups 6 and 8) showed positivity at all reduced volumes of serum sample. However one of the medium positive sample showed negative reaction in 5 µl volume of serum and two of the border line positives showed negative at all the serum volume tested. The results thus showed as less as 15 µl serum is adequate for use in Og4C3 assay. So the test can be performed without losing its sensitivity even with 5 µl serum samples at high titre of antigen (titre group 8) and 15 µl for other groups and this method has scope in programme evaluation.

A simple method for assessing occupational exposure via the one-way random effects model

A one-way random effects model is postulated for the log-transformed shift-long personal exposure measurements, where the random effect in the model represents an effect due to the worker. Simple closed-form confidence intervals are proposed for the relevant parameters of interest using the method of variance estimates recovery (MOVER). The performance of the confidence bounds is evaluated and compared with those based on the generalized confidence interval approach. Comparison studies indicate that the proposed MOVER confidence bounds are better than the generalized confidence bounds for the overall mean exposure and an upper percentile of the exposure distribution. The proposed methods are illustrated using a few examples involving industrial hygiene data.

Orthogonal Equivariant Minimax Estimatorsof Bivariate Normal Covariance Matrix and Precision Matrix

The scale and orthogonal equivariant minimax estimators are obtained for the bivariate normal covariance matrix and precision matrix under Selliah's (1964} and Stein's (1961) loss functions. These new estimators are better than Selliah's and Stein's minimax estimators. An unbiased estimator of the risk of the new estimator is obtained under Selliah's loss function using Haff's (1979) identity for the Wishart distribution. Simulation results seem to indicate that the new estimators dominate the corresponding Hatf's [(1979), (1980)] estimators. We also prove that, for p-2, Haff's estimators are not minimax.

Themed issue on "Organic field-effect transistors: interfacial phenomena and electronic properties"

This themed issue presents a collection of articles on organic field-effect transistors: interfacial phenomena and electronic properties.

Standardized likelihood ratio test for comparing several log-normal means and confidence interval for the common mean

Standardized likelihood ratio test (SLRT) for testing the equality of means of several log-normal distributions is proposed. The properties of the SLRT and an available modified likelihood ratio test (MLRT) and a generalized variable (GV) test are evaluated by Monte Carlo simulation and compared. Evaluation studies indicate that the SLRT is accurate even for small samples, whereas the MLRT could be quite liberal for some parameter values, and the GV test is in general conservative and less powerful than the SLRT. Furthermore, a closed-form approximate confidence interval for the common mean of several log-normal distributions is developed using the method of variance estimate recovery, and compared with the generalized confidence interval with respect to coverage probabilities and precision. Simulation studies indicate that the proposed confidence interval is accurate and better than the generalized confidence interval in terms of coverage probabilities. The methods are illustrated using two examples.

Posterior Reversible Encephelopathy Syndrome in Post-Streptococcal Glomerulonephritis

Posterior reversible encephalopathy syndrome (PRES) is a recognized brain disorder most commonly associated with hypertension, toxemia of pregnancy, or the use of immunosuppressive agents. Its clinical features include headache, decreased alertness, confusion, diminished spontaneity of speech, seizures, vomiting, and abnormalities of visual perception like cortical blindness. Magnetic resonance imaging shows edematous lesions primarily involving the posterior supratentorial white matter. We describe a 14-year-old boy who developed neurological symptoms of PRES during the course of acute post-streptococcal glomerulonephritis (APSGN).

Diurnally subperiodic filariasis among the Nicobarese of Nicobar district - epidemiology, vector dynamics & prospects of elimination

In India diurnally subperiodic filariasis (DspWB) is prevalent only in the Nicobar district of Andaman and Nicobar Islands. Studies undertaken at different points of time indicate that this form of filariasis is restricted to a small region in Nancowry group of islands where it is transmitted by mosquito Downsiomyia nivea, a day biting mosquito. Studies on prevalence, distribution, and assessment of endemicity status, vector incrimination, bioecology, host seeking behaviour, population dynamics of the vector, transmission dynamics and clinical epidemiology indicate the prevalence and persistence of this infection in the Nancowry group of islands with perennial transmission. There was no control programme in these islands, until the National programme to eliminate filariasis was launched in 2004. Eight rounds of annual mass drug administration (MDA) with diethyl carbamazine (DEC) + albendazole have been completed. Despite this, microfilaria prevalence remains at above one per cent, the level identified for initiating transmission assessment survey to decide on continuation of MDA further. This necessitates adjunct measures to the ongoing MDA programme in these islands. The vector control options could be an adjunct measure, but the vector is a forest dweller with a unique bio-ecology, therefore, not a technically feasible option. Use of DEC fortified salt for six months to one year could hasten the process of elimination. Although administration of DEC-fortified salt is simple, rapid, safe, and cost-effective, challenges are to be tackled for evolving operationally realistic strategy. Such a strategy requires commitment of all sections of the society, a distribution mechanism that ensures the use of DEC-fortified salt in the Nancowry islands. Here we discuss the plan of action to serve the indigenous communities and operationalizing DEC fortified salt strategy through an inter-sectoral approach involving multiple stakeholders.

A detailed study on the thermal, photo-physical and electrochemical properties and OFET applications of D–π–A–π–D structured unsymmetrical diketopyrrolopyrrole materials

Seven unsymmetrical DPP-derivatives with a D–π–A–π–D architecture have been synthesized and the effect of the electron donating ability and extent of electronic conjugation of the end capping units on their properties are explored.

Closed-form fiducial confidence intervals for some functions of independent binomial parameters with comparisons

Approximate closed-form confidence intervals (CIs) for estimating the difference, relative risk, odds ratio, and linear combination of proportions are proposed. These CIs are developed using the fiducial approach and the modified normal-based approximation to the percentiles of a linear combination of independent random variables. These confidence intervals are easy to calculate as the computation requires only the percentiles of beta distributions. The proposed confidence intervals are compared with the popular score confidence intervals with respect to coverage probabilities and expected widths. Comparison studies indicate that the proposed confidence intervals are comparable with the corresponding score confidence intervals, and better in some cases, for all the problems considered. The methods are illustrated using several examples.

Impact of MDA and the prospects of elimination of the lone focus of diurnally sub periodic lymphatic filariasis in Nicobar Islands, India

Mass Drug Administration is being carried out in Andaman and Nicobar Islands, India since 2004. Cross sectional microfilaria (Mf) survey was conducted in Nancowry group of islands, the lone foci of diurnally sub periodic form of bancroftian filariasis in Nicobar district, to examine its eligibility for Transmission Assessment Survey (TAS). A total of 2561 individuals (coverage: 23.9%) were screened from five islands. The overall Mf prevalence was 3.28%. Except one island, all other islands recorded Mf prevalence >1%, ranging from 2.5% to 5.3%, indicating persistence of infection despite six annual rounds of MDA. Mf prevalence was age dependent and was higher among males, but not significantly different between genders. Age and gender specific analysis showed a significant reduction in all the age classes among females vis a vis pre-MDA prevalence while the reduction was significant only in 21-30 and 41-50 age classes in males. Exposure to day biting and forest dwelling Downsiomyia nivea can be attributed for the persistent infection besides non-compliance for MDA. Based on fits of modified negative binomial distribution, true prevalence of Mf carriers in the community was estimated to be 4.74%, which is markedly higher (about 24%) than the observed prevalence of 3.28%. Follow up of cohorts showed evidence of continued persistence of infection and acquisition of new infections post six rounds of MDA. As the Mf prevalence was above >1% in four of the five islands, this area is not eligible for TAS, warranting continuation of MDA. Mass DEC fortified salt is suggested as an adjunct to hasten elimination of infection.

Comparison of means of two lognormal distributions based on samples with multiple detection limits

The problem of comparing the means of two lognormal distributions based on samples with multiple detection limits is considered. Tests and confidence intervals for the ratio of the two means, based on pivotal quantities involving the maximum likelihood estimators, are proposed. The merits of the proposed approaches are evaluated by Monte Carlo simulation. Simulation study indicates that the procedures are satisfactory in terms of coverage probabilities of confidence intervals, and powers of tests. The proposed approach can also be applied to find confidence intervals for the difference between the means of the two lognormal distributions. Illustrative examples with a real data set and with a simulated data set are given.

Survival of diurnally sub periodic Wuchereria bancrofti in Downsiomyia nivea (Diptera: Culicidae): a density dependent factor from Andaman & Nicobar Islands

BACKGROUND & OBJECTIVES

In India, diurnally sub periodic Wuchereria bancrofti transmitted by Downsiomyia nivea is prevalent only in the Nicobar district of Andaman and Nicobar Islands. The ongoing LF elimination programme aims at transmission interruption by bringing down the microfilarie (mf) load in the community, which has implication on the parasite load in mosquito vector. Therefore, understanding density dependent constraints on transmission assumes significance from control perspective. The present study was undertaken in Teressa Island to understand the density dependent parasite mortality and survival probability of the parasite Do. nivea.

METHODS

The entomological data collected from Teressa Island, endemic for the diurnally sub periodic form of W. bancrofti were used to examine the parasite loss and its survival up to infectivity. Patterns of parasite distribution in Do. nivea were examined.

RESULTS

Distribution patterns of microfilariae were found to be over dispersed in Do. nivea. The later stages of the parasite in the vector were randomly distributed. Distribution pattern of various filarial larval stages suggested that the loss of parasites occurred as development progressed and was maximal between the first and second stages. Further, both the prevalence of infection and the degree of parasite aggregation in the vector population have fallen significantly with development of parasite stage.

INTERPRETATION & CONCLUSIONS

Results indicate the operation of parasite density dependent mortality of vectors or parasite loss or combination of both. The present study with Aedes transmitted filariasis conducted before launching LF elimination programme in the study area indicates a comparable level of parasite regulation in the vector which has similar implications on the transmission threshold. Thus, the consideration of Aedes with Culex in deriving the critical level of antigen positive for making decisions on cessation of mass drug administration (MDA) can be justified. However, with MDA aiming at reducing parasite load in the community, the operation of density dependent factor in the transmission becomes less pronounced in the subsequent rounds of MDA.

Towards elimination of lymphatic filariasis: social mobilization issues and challenges in mass drug administration with anti-filarial drugs in Tamil Nadu, South India

India is a signatory to World Health Assembly resolution for elimination of lymphatic filariasis (LF) and National Health Policy has set the goal of LF elimination by 2015. Annual mass drug administration (MDA) is ongoing in endemic districts since 1996-97. Compliance rate is a crucial factor in achieving elimination and was assessed in three districts of Tamil Nadu for 10th and 11th treatment rounds (TRs). An in-depth study assessed the impact of social mobilization by drug distributors (DDs) in two areas from each of the three districts. Overall coverage and compliance for assessed TRs were 76.3 and 67.7% which is below the optimum level to achieve LF elimination. Modifiable determinants continue to be the reason for non-consumption even in the 11th TR and 20.8% were systematic non-compliers. In 76.4% of the cases, DDs failed to adhere to three mandatory visits as per the guidelines. Number of visits by DDs in relation to low and high MDA coverage areas showed a significant relationship (P ≤ 0.000). MDA is limited to drug distribution alone and efforts by DDs in preparing the community were inadequate. Probable means to meet the challenges in preparation of the community is discussed.

Impact of education campaign on community-based vector control in hastening the process of elimination of lymphatic filariasis in Tamil Nadu, South India

Globally mosquito-borne lymphatic filariasis (LF) is targeted for elimination by 2020. Towards this goal, the scope of community-based vector control as a supplementary strategy to mass drug administration (MDA) was assessed through an intensive education campaign and evaluated using pre- and post-educational surveys in an intervention and comparison village in Tamil Nadu, South India. Environmental and entomological indicators for breeding sites and mosquito density were examined before and after the intervention. Significant (P < 0.05) increase in knowledge was observed in intervention area with regard to transmission and control of LF. Relative change between intervention and comparison villages before and after intervention was also significant (z = >1.96). Multiple mosquito control and personal protection methods were in use during the post-intervention assessment and was evident from the significantly (P < 0.05) higher average score. Breeding sources declined significantly (P < 0.05) in the intervention village with a significant relative change (z = 4.32). Significant reduction in per man-hour indoor resting density of mosquitoes was observed in the intervention area compared to baseline. The per capita cost for reducing 87% of the mosquito density was $ 0.32 indicating the effectiveness of community-based approach. The usefulness of this strategy in the elimination of LF is discussed.

Rural-urban population movement, community context and impact on DEC fortified salt program to eliminate lymphatic filariasis

Diethylcarbamazinecitrate (DEC) salt in conjunction with annual single-dose mass drug administration (MDA) with DEC tablets can be considered as potential option to hasten the process of Lymphatic Filariasis (LF) elimination. Consumption of DEC tablet/salt by at least 80% of the endemic population is crucial in achieving elimination in five years. This study examines the determinants of rural-urban population movement and its implication on DEC fortified salt program to control LF. Data was collected through questionnaire from 150 each movers and non-movers from 10 randomly selected villages and also using Key informant (KI) interviews in Villupuram district in Tamil Nadu. Households with at least one family member engaged in movement at any point of time in the previous year, range from 24 - 43% in different villages. Knowledge on cause, control, ongoing LF elimination programs and compliance with DEC tablets (28.7%) and salt (30%) were significantly higher (p < 0.05) among non-movers than movers (4.7% and 3.3% respectively). In order to achieve the goal of elimination of LF by 2020, measures need to be undertaken to ensure that the social mobilization activities and LF intervention programs need to cover the 24-43% of mobile population.