TRIPS, patents & HIV/AIDS drugs.
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Biomedical subjects
Publications and source records attributed to K Satyanarayana.
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This study reports the knowledge and beliefs about filarial elephantiasis and hydrocele of people from an endemic area of Orissa, India. Both qualitative and quantitative data were collected from 12 villages, sampled from four blocks in the Khurda district of Orissa. This study found that people were aware of different manifestations of filariasis, and perceived them as problems in their community. A high proportion of people knew that mosquitoes are the reason for the spread of elephantiasis, but less people were aware of the cause of hydrocele and the association between elephantiasis and hydrocele. Only half of the respondents believed that elephantiasis is curable by modern medicines, and about 84% of respondents thought that surgery is the only method to cure hydrocele. About two-thirds of people know that avoiding mosquitoes can prevent elephantiasis. Age, gender, educational level and caste affiliation were identified as factors influencing awareness and knowledge. These findings may be used in the development of group-specific health education programmes to change health behaviour and to achieve higher involvement of the community in annual mass drug administration to eliminate lymphatic filariasis.
A two-arm community-based lymphatic filariasis elimination trial is being carried out in Tamil Nadu state, India to assess the effect of 2 annual single-dose mass drug administrations of diethylcarbamazine + albendazole (DEC + ALB) on microfilaraemia and antigenaemia in one arm, and diethylcarbamazine(DEC) alone in the other arm. In a cross-sectional survey at each time-point, 450-650 subjects in childhood (2-9 years old) and young adulthood (10-25 years old) were screened from each treatment arm. After 2 annual mass drug administrations, microfilaraemia prevalence in the 2-drug arm was reduced by 54% and 62% in the 2-9 year old and 10-25 year old groups respectively; and corresponding figures for the single-drug arm were 26% and 37%. Though higher reductions were recorded for geometric mean intensity of microfilaraemia in the 2-9 year old groups for both treatment arms, reduction was more pronounced in the 2-drug arm than the single drug arm (74% vs. 24%) in the 10-25 year old group. The reduction in the antigenaemia prevalence in the 2-9 year old group was evident in both treatment arms, but in the 10-25 year old group the reduction was only 16.8% in the 2-drug arm. Our results suggest that the annual, single-dose combination (DEC + ALB) mass treatment regimen has an enhanced effect against bancroftian filariasis compared to single-drug therapy.
A longitudinal community-trial on the control of soil-transmitted helminths (STHs), as part of a lymphatic filariasis elimination campaign, was taken up in two revenue blocks of southern India in the years 2001 and 2002 to assess the impact of two annual single-dose mass drug administration (MDA) of diethylcarbamazine (DEC) + albendazole (ALB) with that of DEC alone. The prevalences and intensities of STHs were studied among cross-sectional samples of school children aged 9-10 years by using the Kato-Katz technique at baseline and 11 months after each MDA. The combined drug mass treatment produced a higher reduction in the prevalence (RIP) (51-77%) and the egg reduction rate (ERR) (92-98%) compared with 12-15% RIP and 58-62% ERR of DEC alone mass treatment. The effect of two-drug therapy after two annual treatments was relatively long lasting as shown by RIP and ERR indicating that the reinfection rates were relatively lower in this approach than single-drug therapy. This study demonstrates that mass drug co-administration of DEC + ALB in Global Programme for Elimination of Lymphatic Filariasis (GPELF) targeted at the community had a synergistic and sustainable effect against soil-transmitted helminthiasis and provided considerable 'beyond filariasis' benefits. The additional advantages accrued to the community underscore the importance of scaling-up GPELF to cover the entire population at risk.
Culex quinquefasciatus and Mansonia annulifera are abundant in the rural areas of Kuttanadu, Kerala, India. Bloodmeal identification for individuals of these species collected in this region was determined by the agar-gel precipitin test. A total of 2,328 blood smears from Cx. quinquefasciatus (1,148) and Ma. annulifera (1,180) was tested. Results showed that Cx. quinquefasciatus and Ma. annulifera were highly anthropophilic and that human feeding accounted for 74 and 66% of the total bloodmeals tested. Feeding on cattle accounted for only 1.5 and 2.1% of Cx. quinquefasciatus and Ma. annulifera bloodmeals, respectively. This study showed the high anthropophilic feeding rates of Cx. quinquefasciatus and Ma. annulifera collected from an endemic belt of Malayan filariasis, where epidemiological studies revealed the coexistence of Bancroftian and Malayan filariasis.
A dengue case was reported for the 1st time in a rural area of Kurnool District, Andhra Pradesh, India. Entomological and serological investigations were carried out to determine the prevalence of dengue vectors and dengue virus. Aedes aegypti was recorded for the 1st time in rural areas of Andhra Pradesh. Breeding of Ae. aegypti was observed only in containers with nonpotable water. Cement cisterns and tanks, stone tubs, and clay pots were the major breeding habitats of Ae. aegypti. Larval indices for Ae. aegypti ranged as follows: house index 28-40%, container index 13-37%, and Breteau index 32-60. A serological survey indicated that humans in Kurnool District have been exposed to dengue virus infections. The potential threat of an outbreak of dengue fever in rural areas because of the prevalence of the vector (Ae. aegypti) and dengue virus is discussed.
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Japanese encephalitis (JE) is endemic in Cuddalore district, Tamil Nadu, where Culex tritaeniorhynchus Giles was the major vector. We screened 45 100 adult female Cx. tritaeniorhynchus (902 pools) by enzyme-linked immunosorbent assay and isolated and confirmed JE virus (JEV) by using an insect bioassay system. We had 69 isolates of which 62 (90%) were identified as JEV. The average vector abundance per man hour for Cx. tritaeniorhynchus was 324.5 per month for the period June 1998-May 2000. The average minimum infection rate (MIR) per month in Cx. tritaeniorhynchus was 1.4 (range 0.0-5.6). Every year, a new batch of goats, 20 in the first year and 31 in the second year, born during the non-JE transmission period (January-June), aged <6 months and negative for haemagglutination inhibition (HI) antibodies were procured and placed in the villages as sentinels. Fortnightly, blood specimens were collected from these goats and tested for JE antibodies by HI test. Seroconversions (SCs) were recorded in 14 goats (70%) in the first year and 23 goats (74%) in the second year. JE HI antibody titres in goats were low (1:10-1:80) and these levels declined to undetectable levels in about 4 weeks following SCs. The time sequence of events indicated that four of five peaks of MIR in mosquitoes were followed 1-3 months later by peaks in the proportion of seroconverted goats. We suggest the screening of goats and cattle as a more feasible tool to stratify areas according to JE infection risk to the human population through the regular health system rather than screening mosquitoes using monoclonal antibodies, which is possible only in specialized laboratories.
Annual 2-drug, single-dose mass drug administration (MDA) to 80-90% of the eligible population for 4-6 years are pre-requisites for the successful elimination of lymphatic filariasis (LF) from endemic communities by interruption of transmission and eventual elimination of new infections. In an experimental intervention project on the control of LF in Villupuram district of Tamil Nadu state, India, migration patterns of the villagers were investigated to determine the appropriate timing to implement MDA in order to attain high coverage in a village-level study. Between January and December 1997, 16 observations took place at 3-week intervals, following MDA with two drugs viz., diethylcarbamazine and ivermectin, in July-August 1996. The migrants from the village constituted 17-27% at different points of time and both short-term and long-term migrating patterns were observed. More villagers were available during the agricultural season (September-January), peaking around mid-January [83%; significantly higher (P < 0.05)] than during most of the remaining months, including a substantial portion of the migrant population. There is an urgent need to reschedule the yearly MDA in this area to take place in January and to plan mopping up operations by involving local self-help groups to include migrants (both short-term and long-term) in the LF elimination efforts.
We conducted longitudinal studies on filariasis control in Villupuram district of Tamil Nadu, south India, between 1995 and 2000. Overall, 23 entomological (yearly) data sets were available from seven villages, on indoor resting collections [per man hour (PMH) density and transmission intensity index (TII)] and landing collections on human volunteers [PMH and annual transmission potential (ATP)]. All four indices decreased or increased hand-in-hand with interventions or withdrawal of inputs and remained at high levels without interventions under varied circumstances of experimental design. The correlation coefficients between parameters [PMH: resting vs. landing (r = 0.77); and TII vs. ATP (r = 0.81)] were highly significant (P < 0.001). The former indices from resting collections stand a chance of replacing the latter from landing collections in the evaluation of global filariasis elimination efforts. The TII would appear to serve the purpose of a parameter that can measure infection pressure per unit time in the immediate household surroundings of human beings and can reflect the success or otherwise of control/elimination efforts along with human infection parameters. Moreover, it will not pose any additional risk of new infection(s) and avoids infringement of human rights concerns by the experimental procedures of investigators, unlike ATP that poses such a risk to volunteers.
An investigation in a referral pediatric hospital has indicated that during a recent dengue outbreak in Chennai, Tamil Nadu, India, dengue in infancy constituted 20% of total dengue virus infections with low mortality rates in this hospital. In developing countries, strengthening of dengue management capabilities at hospitals can prevent dengue-related deaths in infants.
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The paper attempts to report the factors responsible for the coverage and compliance of mass diethylcarbamazine citrate (DEC) administration, during the programme to eliminate lymphatic filariasis in the East Godavari District of Andhra Pradesh, India. The evaluation survey indicates that single dose DEC was received by 77% and taken by 64% of eligible people. Reasons for non-reception and non-consumption of the drug at household level were identified. The factors that influenced the coverage and compliance of treatment are broadly categorized as health services related, community related and drug related factors. The study identified some key factors to be followed for the success of the programme.
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Seven village units endemic for filariasis were assigned randomly into three arms with different intervention strategies in the years 1995 and 1996. Villages in Group A received two annual mass drug administrations (MDAs) of diethylcarbamazine (DEC) plus ivermectin (IVR). Group B received the same MDAs in combination with vector control; in Group C only placebo was administered. Post-treatment evaluation in 1997 revealed marked reductions in microfilaraemia prevalences (MFP) and geometric mean intensities (GMI). Subsequently, vector control in Group B was continued by the community. Groups A and B received no MDAs between 1997 and 1999 and were re-evaluated in 1999. During this evaluation, antigenaemia prevalence (AGP) was estimated along with MFP, using immunochromatographic test (ICT) kits. The gains of the MDAs were sustained in Group B, while resurgences occurred in Group A, where annual transmission potential (ATP) rose from 21 to 631.6 and MFP doubled. Group C continued to have high ATPs (1057-1617), while Group B had very low ATPs (0-63). After Mulla's corrections, the reductions in MFP were 62.7 and 83.5% and for GMI 72.1 and 91.4% in Group A and B, respectively, compared with Group C. Vector control preserved the gains of MDAs and accounted for 55.8% and 67.1% reductions in MFP and GMI in Group B compared with Group A. The reductions in AGP were 29.4% in Group A and 39.2% in Group B against Group C. The differences between MFP and AGP were nearly uniform across all villages and there was a significant correlation (r=0.98) between the two variables. A similar significant relationship was observed between MFP and AGP values across age groups (r=0.95). Prediction of AGP values from MFP values was proposed with regression equations. We conclude that vector control would be useful as an adjuvant to chemotherapy to prevent resurgences.
The efficacy of single-dose combination drug therapy with diethylcarbamazine (DEC) plus albendazole (ALB), and single-drug therapy with DEC alone against geohelminths was compared as part of a mass drug administration (MDA) for elimination of filariasis. This study was conducted in two blocks of Villupuram District of Tamil Nadu State, India, covering a population of 321 000 including about 100 000 children 1-15 years of age. Prevalence and intensity of geohelminth infection were determined by the Kato-Katz technique immediately before and 3 weeks after the MDA. A pre-treatment cross-sectional survey was undertaken in 18 statistically selected villages out of 204 villages, including 646 school children. About 60% were infected with one or more geohelminths. The overall prevalence rates were 53.9%, 12.4% and 5.7% for Ascaris lumbricoides, hookworms and Trichuris trichiura, respectively. Combination therapy (DEC + ALB) produced a cure rate of 74.3% and an egg reduction rate of 97.3% for geohelminths, which were higher than the corresponding rates (30.4% and 79.0%) observed in the single drug therapy arm with DEC alone. The odds of cure with combination therapy were significantly higher for roundworm (5.3 times) and hookworms (3.5 times), then odds of cure with DEC alone. Both therapies were equally effective against trichuriasis, recording cure rates >77% and egg reduction rates >83%. In combination therapy, 53.5% of the children noticed expulsion of worms after MDA, while in single drug therapy only 20.9% did. Our study indicated that MDA of combination therapy was operationally feasible at the community level, and it may secure higher community compliance because of its perceived benefits and enhanced efficacy against geohelminths than single-drug therapy.