I P Sunish

Indian Council of Medical Research, New Dilli, NCT, India

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Publications (29)160.04 Total impact

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    ABSTRACT: The National Programme for the Elimination of Lymphatic Filariasis is underway in the endemic districts of Tamil Nadu State, South India, since 2001. Annual mass drug administration (MDA) was carried out by the state health department to all eligible individuals. The impact of MDAs on transmission parameters was evaluated in 2 revenue blocks, viz, one with DEC alone and the other with a combination of albendazole. After 10 years with 6 annual MDAs, the transmission indices reached low levels in both treatment arms, but still persisted. However, the DEC alone arm showed higher transmission rates, compared to the DEC + ALB arm. Few villages which demonstrated persistent transmission need to be targeted with an additional control measure viz, vector control, to achieve LF elimination. It is evident from the 10 year period of the study that inclusion of albendazole along with DEC has significantly reduced the transmission indices to almost nil level, as compared to DEC alone.
    Parasitology International. 01/2014;
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    ABSTRACT: Under the Global Programme to Eliminate Lymphatic Filariasis (LF), mass drug administration (MDA) is being implemented in Tamil Nadu, south India, by the State health machinery. The impact of six annual rounds of MDA using diethylcarbamazine (DEC) with and without albendazole (ALB) on filarial infection (microfilaraemia prevalence-MFP; antigenaemia prevalence-AGP) in paediatric population of 2-9 years was determined in two revenue blocks, with a population of 321 000. After each MDA, 300-400 children were screened for filarial infection. After six MDAs, an overall MFP reduction of 84.67% and 57.95% was observed in DEC+ALB and DEC alone arms, respectively. Corresponding AGP reductions were 72.88% (p < 0.001) and 41.51% (p = 0.023). Observation of microfilaraemic children after six MDAs (0.32% in DEC+ALB; 0.75% in DEC alone), necessitates the need for supplementary control strategies (viz., vector control), in order to achieve the goal of LF elimination.
    Journal of Tropical Pediatrics 12/2013; · 1.01 Impact Factor
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    ABSTRACT: Background & objectives: Wolbachia are common intracellular bacteria that are found in arthropods and nematodes. These endosymbionts are transmitted vertically through host eggs and alter host biology in diverse ways, including the induction of reproductive manipulations, such as feminization, parthenogenesis, male killing and sperm-egg incompatibility. Since they can also move horizontally across species boundaries, Wolbachia is gaining importance in recent days as it could be used as a biological control agent to control vector mosquitoes or for paratransgenic approaches. However, the study of Wolbachia requires sophisticated techniques such as PCR and cell culture facilities which cannot be affordable for many laboratories where the diseases transmitted by arthropod vectors are common. Hence, it would be beneficial to develop a simple method to detect the presence of Wolbachia in arthropods. Method: In this study, we described a method of staining Wolbachia endobacteria, present in the reproductive tissues of mosquitoes. The reliability of this method was compared with Gram staining and PCR based detection. Results: The microscopic observation of the Gimenez stained smear prepared from the teased ovary of wild caught and Wolbachia (+) Cx. quinquefasciatus revealed the presence of pink coloured pleomorphic cells of Wolbachia ranging from cocci, comma shaped cells to bacillus and chain forms. The ovaries of Wolbachia (-) cured mosquito did not show any cell. Although Gram's staining is a reliable differential staining for the other bacteria, the bacterial cells in the smears from the ovaries of wild caught mosquitoes did not take the stain properly and the cells were not clearly visible. The PCR amplified product from the pooled remains of wild caught and Wolbachia (+) Cx. quinquefasciatus showed clear banding, whereas, no banding was observed for the negative control (distilled water) and Wolbachia (-) Cx. quinquefasciatus. Interpretation & conclusion: The Gimenez staining technique applied, could be used to detect the members of the endobacteria Wolbachia easily, even in a simple laboratory without any special facilities or even in the field condition and for handling large number of samples in a shorter duration.
    Journal of vector borne diseases 12/2012; 49(4):258-61. · 1.04 Impact Factor
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    ABSTRACT: Understanding Wolbachia mosquito interactions have been recognized as an important concept to develop novel vector control strategies. The prevalence of Wolbachia endobacteria in a natural population of the filariasis vector Culex quinquefasciatus was determined by the polymerase chain reaction method. Earlier workers had estimated the infection rates of Wolbachia with only one or very few individuals per species. In our study large number of specimens were assayed, and a total of 750 adult Culex quinquefasciatus mosquitoes were collected from three south Indian villages of Tirukoilur and Mugaiyur blocks, monthly for a period of five months (December 2006 to April 2007) and screened for the presence of Wolbachia. The percentage prevalence in adult males ranged from 88% to 96%; while in females from 84% to 100%. An overall prevalence of 91.2% was observed. There was no significant difference observed in the proportion of mosquitoes positive for Wolbachia between males and females, and also between different months of the survey; except during the month of February '07. The wsp gene sequence of the Wolbachia strain of Cx. quinquefasciatus detected was BLAST analysed and showed 99% sequence similarity with Wolbachia sp. of Culex pipiens isolated from different geographical regions. Phylogenetic analysis based on wsp gene fragments showed that the present Wolbachia isolate was closely related with Wolbachia from Culex pipens pipiens, Niphotettix virescens (Order: Hemiptera) and Cnaphalocrosis medinalis (Order: Lepidoptera).
    Tropical biomedicine 12/2011; 28(3):569-76. · 0.92 Impact Factor
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    ABSTRACT: The World Health Assembly in 1997 has targeted the elimination of lymphatic filariasis (LF) by 2020, and in India the goal has been set for the year 2015 by annual single dose mass drug administration (MDA). The role of community empowerment in enhancing the drug compliance and bringing out the function of various methods used to disseminate the information on MDA to the villagers is focused. A longitudinal survey was carried out in nine villages in Tirukoilur block of Villupuram district, Tamil Nadu for filarial infection variables like microfilaraemia, antigenaemia, transmission indices before and after each MDA, to determine the drug impact. Prior to each MDA, health education campaigns with different approaches were carried out with community as the leading player. These IEC approaches were assessed after 4 MDAs for its perception in the community. After four rounds of MDA, there was a significant decline in the filarial infection variables. The microfilaraemia and antigenaemia declined by 59% and 67% respectively. The transmission indices lowered by 89% and 94% (in resting and landing catch of mosquitoes respectively). The decline in these variables, with a drug consumption rate of >80% was achieved due to the effective IEC campaigns prior to each MDA. After 4 MDAs almost 97% of the respondents were aware of lymphatic filariasis. The KAP survey in the rural villages revealed that the dissemination of MDA message through autorickshaw was the most effective, followed by school students' rally. Empowerment of community through the members of women self help groups and school students were observed to be integral to mass drug administration campaigns for the enhancement of drug compliance, thus leading to LF elimination.
    Tropical biomedicine 04/2010; 27(1):68-78. · 0.92 Impact Factor
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    ABSTRACT: Antifilarial drug combinations including ivermectin provide antifilarial activity with ancillary benefits on intestinal helminths and ectoparasites, such as chiggers and lice. The impact of single oral dose of antifilarial drugs, viz; (1) diethylcarbamazine (DEC) alone, (ii) DEC + albendazole (ALB), (iii) ivermectin (IVR) + DEC and (iv) IVR + ALB, was determined, on the head louse (Pediculus humanus capitis) in primary school children in a rural community in south India. Primary school children (n = 534) of age 6-10 years from four villages of South India were examined for the presence of head lice before and after single dose of DEC + ivermectin drug combination. The effectiveness and the duration of cure sustained by these drugs were quantified. The head louse was examined by "combing method" during post-treatment periods at 15, 45, 60 and 75 days interval. The antifilarial drug consumption rate was similar (96-98%) in all treatment arms. In pre-treatment survey the prevalence of head lice in children administered with DEC, DEC + ALB, IVR + DEC and IVR + ALB arm was 86%, 80%, 87% and 80%, respectively, with the latter two arms demonstrating significant reduction in louse infestation (P < 0.05) for 60 days. Single dose with IVR combination demonstrates a greater impact in reducing head louse infestation in the endemic rural communities for nearly 60 days. Therefore, in regions such as Africa where ivermectin is part of the antifilariasis campaign, this drug will have an additional benefit in reducing head lice infestation.
    International journal of dermatology 11/2009; 48(11):1201-5. · 1.18 Impact Factor
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    ABSTRACT: The first chikungunya outbreak occurred in Kerala during 2006 affecting 14 districts, followed by another during May 2007 affecting almost whole of the State. Four of the worst affected districts viz, Pathanamthitta, Idukki, Kottayam and Thrissur were surveyed during 2007 to understand the magnitude of the problem of chikungunya fever, particularly clinical signs and symptoms. A total of 1265 persons from 310 houses were surveyed door-to-door in 20 different localities representing four affected districts. The history and examination findings from 354 clinically diagnosed chikungunya cases were recorded. The symptoms recorded were fever, headache, myalgia, arthralgia, itch/rash, oedema, eye congestion, eye pain, oral ulcers, distaste, nausea, vomiting and haemorrhage. The major symptoms were fever (100%), headache (97.5%), arthralgia (99.4%) and myalgia (99.4%). A significant difference was observed in oedema, distaste, nausea and headache among different age groups and these symptoms were reported to be lower (12.2-89.8%) in younger age group than in older age group (90.4-100%). No genderwise difference was observed for any of the symptoms. In clinically diagnosed chikungunya cases higher age group (>35 years) found with higher rate of severity with symptoms of oedema, distaste, nausea and headache when compared with lower age group (1-35 yr). Chikungunya invaded Kerala State for the first time in 2006 and continues to be a major vector borne disease in the State. The clinical symptoms in affected cases highlighted high fever, sever myalgia and prolonged arthralgia, with occasional history of skin itch/rash (petechiae).
    The Indian Journal of Medical Research 03/2009; 129(3):311-5. · 2.06 Impact Factor
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    ABSTRACT: To determine the role of vector control in further decreasing the transmission of bancroftian filariasis achieved by mass drug administration and the long-term impact on filariometric indices. Three rounds of annual mass drug administration, with diethylcarbamazine and ivermectin, were complemented by vector control (mainly using polystyrene beads) in villages of Tirukoilur, south India, during 1995-99. Subsequently, drug administration is being carried out with diethylcarbamazine and albendazole or diethylcarbamazine alone. We evaluated the impact of mass drug administration used alone or in conjunction with vector control (from 1995 to 2005) on vector transmission indices (such as transmission intensity index, monthly biting rate, monthly transmission potential and annual transmission potential). We analysed data on filarial infection in the community to estimate the prevalence of microfilaraemia and antigenaemia using chi2 analysis and Fisher's exact test. Vector density greatly decreased in villages where vector control was used as an adjunct to mass drug administration and almost no infective mosquitoes were found in the small numbers still remaining. Filarial antigenaemia was low and continued to decrease significantly in the age group 15-25 years in villages receiving mass drug administration with vector control in contrast to villages receiving only mass drug administration. The gains of mass drug administration were sustained only with the integration of vector control measures. We advocate the incorporation of vector control in the Global Programme to Eliminate Lymphatic Filariasis as it can potentially decrease the time required for eliminating lymphatic filariasis.
    Bulletin of the World Health Organisation 03/2007; 85(2):138-45. · 5.25 Impact Factor
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    ABSTRACT: The impact of single dose mass drug administration of diethylcarbamazine (DEC), DEC with albendazole (ALB), and ivermectin (IVR) with albendazole, was examined on the human bancroftian filarial infections in village scale trials in south India, from a follow-up study after 2 years. The treatment arms administered with DEC alone and DEC+ALB demonstrated long-term benefits in reducing microfilaraemia significantly (P<0.05), while antigenaemia reduction was negligible. The arm with ALB+IVR did not show such reductions. Among the antigenaemic and microfilaraemic individuals, 87% became amicrofilaraemic in DEC+ALB arm, which were higher than that observed in the other 2 treatment arms. Among amicrofilaraemics (but Ag+), nearly 35% cleared of infection in DEC+ALB, while 26% and 6% in DEC alone and IVR+ALB arms, respectively. The drug combination DEC+ALB was observed to demonstrate a significant impact in reducing filarial infection even after 2 years post treatment.
    Parasitology International 10/2006; 55(3):233-6. · 2.30 Impact Factor
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    ABSTRACT: As part of the Global Programme for Elimination of Lymphatic Filariasis (GPELF), India is implementing mass drug administration (MDA) with annual single dose of diethylcarbamazine (DEC) with and without albendazole (ALB). The impact of MDAs on filarial infections and soil-transmitted helminth (STH) infections was assessed during a 3-year period in two communities, one with DEC + ALB and the other with DEC alone. Prior to each MDA (during 2001, 2002 and 2003), filarial indices (microfilaraemia and antigenaemia) were assessed from blood samples of 450-650 persons aged 2-25 years and STH infections in stool samples (Kato-Katz method) from 325 to 500 children aged 9-10 years. Mosquitoes resting indoors were collected to determine the filarial infection status. The microfilaraemia prevalence decreased significantly (P < 0.05) in both arms, with the highest decline in the DEC + ALB arm (72%vs. 51%). Decline in micrefilaria intensity was also higher in the DEC + ALB arm (81.4%vs. 48.5%). In this arm alone, the antigenaemia prevalence was reduced significantly (62%; P < 0.001). The reduction in STH prevalence was lower in the DEC alone arm (6.5%; NS) than in the DEC + ALB arm (70.9%; P < 0.001). Also, the egg reduction in DEC alone arm was only half that of DEC + ALB arm (49%vs. 97%). Our community-based follow-up study showed higher and sustained benefits with regard to filarial and STH infections for the two-drug arm over the DEC alone arm. The trends suggest that at least 10 MDAs may be necessary to achieve the goal of elimination.
    Tropical Medicine & International Health 07/2006; 11(6):851-61. · 2.94 Impact Factor
  • The Lancet Infectious Diseases 04/2006; 6(3):125-6. · 19.97 Impact Factor
  • I P Sunish, R Reuben, R Rajendran
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    ABSTRACT: The development and survival of immatures of Culex vishnui (Diptera: Culicidae) complex, vectors of Japanese encephalitis virus, were studied in transplanted rice, Oryza savita L., fields during three crop growing seasons. The total duration of development from the first instar to adult emergence varied from 6 to 8 d. Survival rate estimates ranged from 0.003 to 0.524, but they generally were <0.1. Unusually high survival rates (0.192-0.524) were observed in summer and long-term monsoon crop seasons during 1993. A multiple regression method using backward elimination was used to analyze the factors responsible for these variations. The model identified nine parameters related with survival rates that explained 99% of the variance. Area of water surface and hardness were negatively related, whereas green algae, notonectid adults, anisopterans, dytiscids, salinity, water depth, and dissolved oxygen were positively associated with immature survival.
    Journal of Medical Entomology 04/2006; 43(2):185-91. · 1.86 Impact Factor
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    ABSTRACT: 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.
    Tropical Medicine & International Health 10/2004; 9(9):1030-5. · 2.94 Impact Factor
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    ABSTRACT: 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.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 04/2004; 98(3):174-81. · 1.82 Impact Factor
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    I P Sunish, R Rajendran, R Reuben
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    ABSTRACT: The effect of urea on the oviposition behaviour of culicine vectors of Japanese encephalitis was studied in rice fields. Gravid females had a strong preference for oviposition in urea treated areas in rice fields, while no such preference was exhibited in untreated areas. The egg laying declined in the area where urea treated water surface had a mechanical barrier, which allowed volatile fractions to escape, but prevented contact with the water. Urea was shown to act as an oviposition attractant/stimulant for Culex tritaeniorhynchus, but its role was not clear for Cx. vishnui, as the number of egg rafts obtained for the latter species was low.
    Memórias do Instituto Oswaldo Cruz 10/2003; 98(6):789-91. · 1.36 Impact Factor
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    ABSTRACT: 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.
    Tropical Medicine & International Health 09/2003; 8(9):812-9. · 2.94 Impact Factor
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    ABSTRACT: 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.
    Tropical Medicine & International Health 05/2003; 8(4):316-21. · 2.94 Impact Factor
  • R Rajendran, I P Sunish, T R Mani
    New England Journal of Medicine 04/2003; 348(12):1179-81; author reply 1179-81. · 51.66 Impact Factor
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    ABSTRACT: 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.
    Annals of Tropical Medicine and Parasitology 01/2003; 96 Suppl 2:S77-90. · 1.31 Impact Factor
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    ABSTRACT: We evaluated the long-term impact of single-dose diethylcarbamazine plus albendazole combination therapy with that of diethylcarbamazine alone on the control of soil-transmitted helminths (STH) in 2 blocks (revenue units) of Villupuram district, south India, as part of an ongoing mass drug administration (MDA) campaign for the elimination of lymphatic filariasis in 2001. The prevalence and intensities of STHs were studied in 287 children, aged 9 and 10 years (136 in the combination therapy cohort and 151 in the diethylcarbamazine alone cohort), using the Kato-Katz technique to examine stool samples at 4 time-points (baseline, and 3 weeks, 6 months and 11 months after MDA). The combination therapy showed long-term efficacy against STHs and the magnitude of control remained at a moderate and significant level for 11 months after MDA compared with the moderate gains of diethylcarbamazine alone. Single-dose MDA with albendazole and diethylcarbamazine combination therapy may prove to be a good strategy in treating multiple parasitic infections in endemic communities.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 01/2003; 97(3):355-9. · 1.82 Impact Factor