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Biomedical subjects

K Krishnamoorthy

Publications and source records attributed to K Krishnamoorthy.

At least 19 recordsLinked to original sources
PubMed2006

School-based health education campaign--a potential tool for social mobilization to promote the use of DEC-fortified salt towards elimination of lymphatic filariasis.

Community compliance is crucial for the success of mass treatment using cooking salt fortified with diethylcarbamazine citrate (DEC) for the elimination of lymphatic filariasis (LF). We describe the role and effectiveness of school-based health education for social mobilization to promote the use of DEC salt, in an endemic district in India. Health education through classroom sessions was the main motivational strategy used. Community members were targeted to receive the message through children. The impact of this approach was assessed among students and community members using an interviewer-administered questionnaire and analysis of salt samples for DEC content from households. Significant improvement in awareness on LF among students and community respondents was observed. School health education (SHE) could promote the use of DEC salt by 19% points more in households with children in schools covered under health education campaign [campaign school (CS)] compared with others. Significantly higher proportion (72.7%) of samples from households with children in CS had detectable DEC, indicating the impact of the intervention on enhancing the use of DEC salt by the community. The results exemplify that SHE is a potential tool for improving and sustaining compliance, thus serving as part of a public health strategy to eliminate LF using DEC salt.

Diethylcarbamazine↗
PubMed2006

Health status of lymphatic filariasis assessed from patients using seven domains five levels (7D5L) instrument.

Health status is the standardized description of health condition of individuals either normal or ill due to diseases and is presented as multidimentional profiles. In an effort to develop an indicator to assess the impact of morbidity intervention against lymphatic filariasis (LF), we assessed the health status of seven different clinical manifestations (health states) of LF from the patient's perspective. One hundred and seventy-four filarial patients either with hydrocele or lymphoedema were involved in the study. Acute episode of adenolymphangitis (ADL) among chronic patients was considered as co-morbidity. Severity levels, focusing on physical, mental and social dimensions of health were defined and quantified, using seven domains and five levels (7D5L) instrument, an extended form of EuroQol (5D3L). All the seven domains of health are affected by filarial disease, with the levels of severity varying with health states. The mean severity score of ADL (25.8) was significantly higher compared to lymphoedema (10.7) and hydrocele (6.9) (P<0.05). In males, the mean score of lymphoedema (11.6) was significantly higher in comparison to hydrocele (P<0.05). The severity scores increase with the progression of filarial disease but independent of gender. The health states of LF were further classified based on the percentage of severity according to International Classification of Functioning, Disability and Health (ICF) on impairments. Lymphoedema grade 4 (oedema with skin changes) and ADL were ranked as severe. The importance of these findings is discussed in view of priority setting and evaluating the morbidity management under Global Programme for Elimination of Lymphatic Filariasis (GPELF).

Adolescent↗
PubMed2006

Generalized P-values and confidence intervals: a novel approach for analyzing lognormally distributed exposure data.

The problem of assessing occupational exposure using the mean of a lognormal distribution is addressed. The novel concepts of generalized p-values and generalized confidence intervals are applied for testing hypotheses and computing confidence intervals for a lognormal mean. The proposed methods perform well, they are applicable to small sample sizes, and they are easy to implement. Power studies and sample size calculation are also discussed. Computational details and a source for the computer program are given. The procedures are also extended to compare two lognormal means and to make inference about a lognormal variance. In fact, our approach based on generalized p-values and generalized confidence intervals is easily adapted to deal with any parametric function involving one or two lognormal distributions. Several examples involving industrial exposure data are used to illustrate the methods. An added advantage of the generalized variables approach is the ease of computation and implementation. In fact, the procedures can be easily coded in a programming language for implementation. Furthermore, extensive numerical computations by the authors show that the results based on the generalized p-value approach are essentially equivalent to those based on the Land's method. We want to draw the attention of the industrial hygiene community to this accurate and unified methodology to deal with any parameter associated with the lognormal distribution.

Air Pollutants, Occupational↗
PubMed2006

Operational feasibility of lot quality assurance sampling (LQAS) as a tool in routine process monitoring of filariasis control programmes.

Lot quality assurance sampling (LQAS) with two-stage sampling plan was applied for rapid monitoring of coverage after every round of mass drug administration (MDA). A Primary Health Centre (PHC) consisting of 29 villages in Thiruvannamalai district, Tamil Nadu was selected as the study area. Two threshold levels of coverage were used: threshold A (maximum: 60%; minimum: 40%) and threshold B (maximum: 80%; minimum: 60%). Based on these thresholds, one sampling plan each for A and B was derived with the necessary sample size and the number of allowable defectives (i.e. defectives mean those who have not received the drug). Using data generated through simple random sampling (SRSI) of 1,750 individuals in the study area, LQAS was validated with the above two sampling plans for its diagnostic and field applicability. Simultaneously, a household survey (SRSH) was conducted for validation and cost-effectiveness analysis. Based on SRSH survey, the estimated coverage was 93.5% (CI: 91.7-95.3%). LQAS with threshold A revealed that by sampling a maximum of 14 individuals and by allowing four defectives, the coverage was >or=60% in >90% of villages at the first stage. Similarly, with threshold B by sampling a maximum of nine individuals and by allowing four defectives, the coverage was >or=80% in >90% of villages at the first stage. These analyses suggest that the sampling plan (14,4,52,25) of threshold A may be adopted in MDA to assess if a minimum coverage of 60% has been achieved. However, to achieve the goal of elimination, the sampling plan (9, 4, 42, 29) of threshold B can identify villages in which the coverage is <80% so that remedial measures can be taken. Cost-effectiveness analysis showed that both options of LQAS are more cost-effective than SRSH to detect a village with a given level of coverage. The cost per village was US dollars 76.18 under SRSH. The cost of LQAS was US dollars 65.81 and 55.63 per village for thresholds A and B respectively. The total financial cost of classifying a village correctly with the given threshold level of LQAS could be reduced by 14% and 26% of the cost of conventional SRSH method.

Adolescent↗
PubMed2005

A multivariate test for similarity of two dissolution profiles.

A multivariate test of size a for assessing the similarity of two dissolution profiles is proposed. The inferential procedure is developed by using the approach for the common mean problem in a multivariate setup due to Halperin (1961). The performance of the proposed method is compared with Intersection Union Test as well as f2 criterion recommended by the FDA through a simulation study. All the methods are illustrated with real examples.

Algorithms↗
PubMed2005

Physical and psychosocial burden due to lymphatic filariasis as perceived by patients and medical experts.

Patients with lymphatic filariasis (LF) face considerable physical, psychological and social disabilities. Morbidity management and control are important components of the Global Programme to Eliminate Lymphatic Filariasis. But information on the various disabilities caused by LF is scanty. We measured the severity levels of seven health states of LF in the physical and psychosocial domains of health from the perspective of patients and medical experts, using a 7-domain 5-level (7D5L) descriptive system. Adenolymphangitis had the highest severity levels in all domains of health followed by lymphoedema grade 4 (L4), lymphoedema grade 3 (L3), hydrocele grade 2 (H2), lymphoedema grade 2 (L2), lymphoedema grade1 (L1) and hydrocele grade 1 (H1). People with higher grades of lymphoedema and hydrocele had more severe psychosocial problems than physical ones. Severity levels assessed by medical experts were lower than those reported by sufferers. These findings indicate that LF has considerable impact on the physical, mental and social domains of health. Morbidity management programmes should be broadened to include counselling, rehabilitation and health education to manage the psychosocial problems caused by LF.

Activities of Daily Living↗
PubMed2004

The dynamics of Wuchereria bancrofti infection: a model-based analysis of longitudinal data from Pondicherry, India.

This paper presents a model-based analysis of longitudinal data describing the impact of integrated vector management on the intensity of Wuchereria bancrofti infection in Pondicherry, India. The aims of this analysis were (1) to gain insight into the dynamics of infection, with emphasis on the possible role of immunity, and (2) to develop a model that can be used to predict the effects of control. Using the LYMFASIM computer simulation program, two models with different types of immunity (anti-L3 larvae or anti-adult worm fecundity) were compared with a model without immunity. Parameters were estimated by fitting the models to data from 5071 individuals with microfilaria-density measurement before and after cessation of a 5-year vector management programme. A good fit, in particular of the convex shape of the age-prevalence curve, required inclusion of anti-L3 or anti-fecundity immunity in the model. An individual's immune-responsiveness was found to halve in approximately 10 years after cessation of boosting. Explanation of the large variation in Mf-density required considerable variation between individuals in exposure and immune responsiveness. The mean life-span of the parasite was estimated at about 10 years. For the post-control period, the models predict a further decline in Mf prevalence, which agrees well with observations made 3 and 6 years after cessation of the integrated vector management programme.

Adolescent↗
PubMed2004

Vector survival and parasite infection: the effect of Wuchereria bancrofti on its vector Culex quinquefasciatus.

This paper investigates a cohort of 2187 laboratory reared Culex quinquefasciatus fed on 69 human volunteers, including 59 persons with different levels of Wuchereria bancrofti microfilariae and 10 without microfilaria. Mosquitoes were followed until death. Mosquito survival was analysed in relation to the level of microfilaria in the human and larval count in the dead mosquito. Vector mortality during the extrinsic incubation period (12 days post-engorgement) was significantly higher in mosquitoes fed on microfilaraemic volunteers (50%) than in those fed on amicrofilaraemics (29%). Both the percentage infected and the geometric mean parasite density was significantly higher among mosquitoes which died before 13 days (45% infected and 10 larvae per infected mosquito) than those surviving beyond 13 days (39% and 2.2), suggesting a parasite loss of more than 80% during the extrinsic incubation period. A large proportion (62%) of the mosquitoes that died during the early of phase of parasite development were infected (36% in low, 26% in medium and 90% in high human Mf-density). Survival analysis showed that the parasite load in mosquitoes and the human Mf-density for a given parasite load are independent risk factors of vector survival. Overall, the hazard of dying was found to be 11-15 times higher among mosquitoes fed on microfilaraemic volunteers than those fed on amicrofilaraemics. The hazard doubles for every increase of about 60-70 parasites in the vector. As a consequence of the parasite-induced reduction in vector survival, the transmission success of the parasite is reduced. The implication of the results on control/elimination of lymphatic filariasis using mass-drug administration is discussed.

Animals↗
PubMed2003

Treatment seeking behaviour and costs due to acute and chronic forms of lymphatic filariasis in urban areas in south India.

Previous estimates on the economic burden of lymphatic filariasis (LF) in India and elsewhere were primarily based on studies in rural areas. We investigated the treatment costs due to acute and chronic forms of LF in urban areas, where nearly one-third of the affected people live. Almost 98% of the patients with acute episodes of adenolymphangitis (ADL) underwent treatment and 49% of chronic patients also received treatment. The average treatment cost per ADL episode (n = 108) was Rs 22.21 +/- 53.84 (US dollars 0.46 +/- 1.12). The overall (n = 200) treatment costs incurred by a chronic patient per visit were Rs 16.71 +/- 62.36 (US dollars 0.35 +/- 1.30); for those who paid (n = 98) they were Rs 34.10 +/- 85.90 (US dollars$ 0.71 +/- 1.79). These costs are considerably higher than in rural areas. Government health centres and private practitioners were important sources of treatment. Treatments received from private practitioners were considerably more expensive than those from government health facilities. The cost of medicine accounted for 44% and 50% of the total expenditure on treatment for acute and chronic disease patients, respectively. The medical personnel from these treatment sources need to be trained on the new morbidity management methods, which are likely to be more effective than the current methods of treatment.

Acute Disease↗
PubMed2003

Inferences on the common mean of several normal populations based on the generalized variable method.

This article presents procedures for hypothesis testing and interval estimation of the common mean of several normal populations. The methods are based on the concepts of generalized p-value and generalized confidence limit. The merits of the proposed methods are evaluated numerically and compared with those of the existing methods. Numerical studies show that the new procedures are accurate and perform better than the existing methods when the sample sizes are moderate and the number of populations is four or less. If the number of populations is five or more, then the generalized variable method performs much better than the existing methods regardless of the sample sizes. The generalized variable method and other existing methods are illustrated using two examples.

Albumins↗
PubMed2002

Cost-effectiveness of the use of vector control and mass drug administration, separately or in combination, against lymphatic filariasis.

The costs and effects of two intervention strategies for the control of bancroftian filariasis-annual mass drug administrations (MDA) with a combination of diethylcarbamazine and ivermectin, with or without integrated vector control (VC)-were estimated in rural villages in South India. The aim was to compare the cost-effectiveness of MDA alone with that of MDA plus VC. Control of the local vector, Culex quinquefasciatus, was based on the application of polystyrene beads to cesspits, the treatment of drains with larvicidal Bacillus sphaericus and the stocking of wells with larvivorous fish. An itemized cost menu was used to cost MDA and MDA + VC, retrospectively. The annual transmission potential was used to assess the direct outcome of the disease-control methods, whereas the prevalence and intensity of microfilaraemia were used as indicators of the impact of each method. The per-capita costs were 1.49 U.S. dollars for two rounds of MDA, 1.70 U.S. dollars for 2 years of VC and, therefore, 3.19 U.S. dollars for 2 years of MDA + VC. Integration of VC with MDA did not appear to be cost-effective: it cost an estimated 1.80 U.S. dollars to stop an infective mosquito biting a villager using MDA alone but 3.32 U.S. dollars to achieve the same result using MDA + VC. Similarly, the cost to reduce the prevalence of microfilaraemia in a three-village group by 1% was only 96.62 U.S. dollars for MDA alone but 201.16 U.S. dollars when vector control was integrated. The implications of these results for the control and elimination of filariasis in Indian village communities, and the options for sharing and minimizing costs, are discussed.

Animals↗
PubMed2001

Detection of Brugia malayi in laboratory and wild-caught Mansonioides mosquitoes (Diptera: Culicidae) using Hha I PCR assay.

An Hha 1 based polymerase chain reaction (PCR) assay developed for the detection of Brugia malayi, the causative agent of Brugian lymphatic filariasis, was evaluated for its sensitivity in the laboratory and for its usefulness in measuring changes in transmission of the disease in the field. Laboratory studies showed that the new assay was highly sensitive in comparison with the standard dissection and microscopy technique. The assay can detect as little as 4 pg of parasite DNA or a single microfilaria in pools of up to 100 mosquitoes. The optimum pool size for convenience was found to be 50 mosquitoes per pool. The efficacy of PCR assay was evaluated in filariasis control programmes in operation in endemic areas of Kerala State, South India. The infection rates obtained by the Hha I PCR assay and the conventional dissection and microscopy technique were 1.2% and 1.7% respectively in operational areas and 8.3% and 4.4% respectively, in check areas, which were not significantly different (P < 0.05). Thus, the Hha I PCR assay was found to be as sensitive as the conventional technique and hence it can be used as a new epidemiological tool for assessing parasite infection in field-collected mosquitoes.

Aedes↗
PubMed2000

Cost of mass annual single dose diethylcarbamazine distribution for the large scale control of lymphatic filariasis.

Economic analysis of the revised strategy to control lymphatic filariasis with mass annual single dose diethylcarbamazine (DEC) at 6 mg/kg body weight launched in one of the districts of Tamil Nadu in 1996 was carried out. This exploratory study, proposed for five years in 13 districts under 7 states on a pilot scale through the Department of Public Health is an additional input of the existing National Filaria Control Programme in India. A retrospective costing exercise was undertaken systematically from the provider's perspective following the completion of the first round of drug distribution. The major activities and cost components were identified and itemized cost menu was prepared to estimate the direct (financial) and indirect (opportunity) cost related to the implementation of the Programme. The total financial cost of this Programme to cover 22.7 lakh population in the district was Rs. 22.05 lakhs. The opportunity cost of labour and capital investment was calculated to be Rs. 7.98 lakhs. The total per capita cost was Rs. 1.32, with Rs. 0.97 and Rs. 0.35 as financial and opportunity cost respectively. Based on these estimates, the implementation cost of the Programme at Primary Health Centre (PHC) level was calculated and projected for five years. The additional financial cost for the existing health care system is estimated to be Rs. 27,800 per PHC every year. DEC tablets (50 mg) was the major cost component and sensitivity analysis showed that the cost of the Programme could be minimized by 20 per cent by switching over to 100 mg tablets. The analysis indicates that this Programme is a low-cost option and the results are discussed in view of its operational feasibility and epidemiological impact.

Adolescent↗
PubMed1998

The relationship between microfilarial load in the human host and uptake and development of Wuchereria bancrofti microfilariae by Culex quinquefasciatus: a study under natural conditions.

The uptake of Wuchereria bancrofti microfilariae (Mf) by Culex quinquefasciatus and their development in relation to human Mf density were quantified by allowing a total of 1096 wild mosquitoes to feed on 13 volunteers sleeping under partially open bed-nets. For each volunteer, each hour between 18.00 and 06.00 h the Mf density in finger-prick blood was determined and engorged mosquitoes collected. Each hourly collection of mosquitoes was kept separately. Half of them was dissected within 18 h post-feeding for the presence of ingested Mf, the other half was reared for 12 days to allow for the development of L3 larvae. About 20% of the latter mosquitoes died during these 12 days and these harboured significantly more larvae than the surviving ones, which could be an indication of excess-mortality among heavily infected mosquitoes. Assuming that variability in Mf uptake and in the number of developed L3 larvae can be described by a negative binomial distribution, a maximum-likelihood procedure was applied to estimate the relationship between human Mf density and both the arithmetic mean Mf uptake and L3 development. Both were adequately described by a saturating hyperbolic function that significantly differed from linearity. The saturation level for Mf was estimated at 29 (CI: 20-54) and for L3 larvae at 6.6 (CI: 4.3-17.0). Next, the L3 yield was related to Mf uptake indicating that the W. bancrofti-C. quinquefasciatus complex shows 'limitation', i.e. a decreasing yield for an increasing uptake. Both the number of Mf ingested and the number of L3 larvae developing per mosquito were found to be highly aggregated, with the level of aggregation decreasing in a non-linear way with human Mf density.

Adolescent↗
PubMed1997

Current status of filariasis in Chavakad taluk, Trichur district, Kerala.

A sample survey using parasitological, clinical and entomological indicators was carried out in all the 18 administrative units of Chavakad taluk, Trichur district, Kerala, India to assess the current filariasis situation. Cluster sampling procedure was followed to screen individuals. Both Wuchereria bancrofti and Brugia malayi species were found to be prevalent in this taluk. Microfilaria (mf) carriers with W. bancrofti were detected in eight areas while B. malayi was recorded only from one area. The two species were found to co-exist in another area. The highest infection rate registered for W. bancrofti was 1.51 while it was 0.3 for B. malayi. Infection due to W. bancrofti constituted 87.88% of the total 33 microfilaria cases. Prevalence of B. malayi was very low. Cases with clinical manifestation of filariasis were recorded in all the four areas surveyed. The present trend in the prevalence of infection (mf) and disease showed a decline in both the species when compared to earlier surveys of 1960s. At least 11 areas are still endemic for filariasis in this taluk. Although prevalence of mf was recorded for the first time in one of the areas viz., Elavalli, the rate was only 0.16%. Entomological surveys revealed the presence of 14 mosquito species, of which Culex quinquefasciatus contributed 84.85% and Mansonia 0.77%. While C. quinquefasciatus was recorded in all the 18 areas, Mansonia spp were found only in 8 areas. Only C. quinquefasciatus was found to harbour different developmental stages of W. bancrofti, with overall infection and infectivity rates of 1.94 and 0.97 respectively. The possible reason for the decline in vector density and infection in man are postulated.

Adolescent↗
PubMed1996

Exact confidence intervals for the common mean of several normal populations.

The problem of interval estimation of the common mean of several normal populations when the variances are unknown and unequal is considered. Some new confidence intervals are proposed. One of them is centered at the well-known Graybill-Deal estimator of the common mean. These new intervals and an existing exact confidence interval are numerically compared with respect to their expected lengths. Based on comparison studies, some recommendations are made regarding the choice of the intervals to be used in applications.

Animals↗