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Kaliappan S, Ramanujam K, Manuel M, Farzana J, Janagaraj V, Laxmanan S, Muliyil J, Sarkar R, Kang G, Walson J, Ajjampur S. Soil-transmitted helminth infections after mass drug administration for lymphatic filariasis in rural southern India. Trop Med Int Health 2021; 27:81-91. [PMID: 34704320 DOI: 10.1111/tmi.13697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Targeted deworming is the current strategy for control of morbidity associated with soil-transmitted helminths (STH) among at-risk populations: preschool-aged children, school-aged children and women of childbearing age. We report the prevalence and intensity of STH in a district after lymphatic filariasis (LF) mass drug administration (MDA) in southern India where albendazole was co-administered from 2001. METHODS Children aged 2 to 15 years and adults (defined as ≥15 years) in a rural administrative block of Tamil Nadu were recruited using a probability proportional to size method. Stool samples were screened and eggs per gram (EPG) determined by Kato-Katz method. Multilevel logistic regression (MLR) and multilevel negative binomial regression (MNBR) analyses were used to identify factors associated with infection and intensity, respectively. RESULTS Of 862 participants who provided samples, 60 (7.0%; 95% confidence interval (CI): 5.3-8.7) were positive for STH with a predominance of hookworm infections (n = 57, 6.6%; 95% CI: 5.0-8.3). Increasing age (odds ratio (OR): 1.09; 95% CI: 1.04-1.15) and regular usage of the toilet (OR: 0.32; 95% CI: 0.12-0.88) were independently associated with hookworm infection and age was significantly associated with increasing intensity of hookworm infection (infection intensity ratio (IIR): 1.28; 95% CI: 1.19-1.37). A brief review of STH prevalence in endemic settings before and after the stoppage of LF MDA indicated that, in most settings, a substantial reduction in STH prevalence is seen. CONCLUSION Community-wide MDA in all age groups in these post-LF MDA districts with low prevalence and light intensity infections could result in transmission interruption of STH.
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Affiliation(s)
- Saravanakumar Kaliappan
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Karthikeyan Ramanujam
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Malathi Manuel
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Jasmine Farzana
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Venkateshprabhu Janagaraj
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Selvi Laxmanan
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Jayaprakash Muliyil
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Rajiv Sarkar
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Gagandeep Kang
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
| | - Judd Walson
- Departments of Global Health, Medicine (Infectious Disease), Paediatrics & Epidemiology, University of Washington, Seattle, Washington, USA
| | - Sitara Ajjampur
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College Vellore, Tamil Nadu, India
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Ajjampur SSR, Kaliappan SP, Halliday KE, Palanisamy G, Farzana J, Manuel M, Abraham D, Laxmanan S, Aruldas K, Rose A, Kennedy DS, Oswald WE, Pullan RL, Galagan SR, Ásbjörnsdóttir K, Anderson RM, Muliyil J, Sarkar R, Kang G, Walson JL. Epidemiology of soil transmitted helminths and risk analysis of hookworm infections in the community: Results from the DeWorm3 Trial in southern India. PLoS Negl Trop Dis 2021; 15:e0009338. [PMID: 33930024 PMCID: PMC8184002 DOI: 10.1371/journal.pntd.0009338] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 06/07/2021] [Accepted: 03/29/2021] [Indexed: 12/17/2022] Open
Abstract
Since 2015, India has coordinated the largest school-based deworming program globally, targeting soil-transmitted helminths (STH) in ~250 million children aged 1 to 19 years twice yearly. Despite substantial progress in reduction of morbidity associated with STH, reinfection rates in endemic communities remain high. We conducted a community based parasitological survey in Tamil Nadu as part of the DeWorm3 Project—a cluster-randomised trial evaluating the feasibility of interrupting STH transmission at three geographically distinct sites in Africa and Asia—allowing the estimation of STH prevalence and analysis of associated factors. In India, following a comprehensive census, enumerating 140,932 individuals in 36,536 households along with geospatial mapping of households, an age-stratified sample of individuals was recruited into a longitudinal monitoring cohort (December 2017-February 2018) to be followed for five years. At enrolment, a total of 6089 consenting individuals across 40 study clusters provided a single adequate stool sample for analysis using the Kato-Katz method, as well as answering a questionnaire covering individual and household level factors. The unweighted STH prevalence was 17.0% (95% confidence interval [95%CI]: 16.0–17.9%), increasing to 21.4% when weighted by age and cluster size. Hookworm was the predominant species, with a weighted infection prevalence of 21.0%, the majority of which (92.9%) were light intensity infections. Factors associated with hookworm infection were modelled using mixed-effects multilevel logistic regression for presence of infection and mixed-effects negative binomial regression for intensity. The prevalence of both Ascaris lumbricoides and Trichuris trichiura infections were rare (<1%) and risk factors were therefore not assessed. Increasing age (multivariable odds ratio [mOR] 21.4, 95%CI: 12.3–37.2, p<0.001 for adult age-groups versus pre-school children) and higher vegetation were associated with an increased odds of hookworm infection, whereas recent deworming (mOR 0.3, 95%CI: 0.2–0.5, p<0.001) and belonging to households with higher socioeconomic status (mOR 0.3, 95%CI: 0.2–0.5, p<0.001) and higher education level of the household head (mOR 0.4, 95%CI: 0.3–0.6, p<0.001) were associated with lower odds of hookworm infection in the multilevel model. The same factors were associated with intensity of infection, with the use of improved sanitation facilities also correlated to lower infection intensities (multivariable infection intensity ratio [mIIR] 0.6, 95%CI: 0.4–0.9, p<0.016). Our findings suggest that a community-based approach is required to address the high hookworm burden in adults in this setting. Socioeconomic, education and sanitation improvements alongside mass drug administration would likely accelerate the drive to elimination in these communities. Trial Registration:NCT03014167. Approximately 1 in 5 people in India are infected with soil transmitted helminths (STH), leading to anaemia and malnutrition. To tackle this large burden of infection, the government of India launched one of the world’s largest school-based deworming programs in 2015 aiming to deworm all pre-school and school-aged children between 1 to 19 years of age twice yearly on the National Deworming Days. Deworming programs, including those in India, are focused on pre-school aged children, school aged children and women of reproductive age group. However, prevailing environmental and socioeconomic conditions, including poor sanitation, can contribute to high rates of reinfection from untreated adults and children. The DeWorm3 Project is a cluster-randomised trial evaluating the feasibility of interrupting STH transmission with community wide deworming of all individuals aged one to 99 years of age or older. As part of the study, we conducted a parasitological survey in the Deworm3 trial site in rural Tamil Nadu. Here we present the factors associated with STH infection and burden in these communities.
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Affiliation(s)
- Sitara S. R. Ajjampur
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
- * E-mail:
| | | | - Katherine E. Halliday
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America
| | - Gokila Palanisamy
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Jasmine Farzana
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Malathi Manuel
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Dilip Abraham
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Selvi Laxmanan
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Kumudha Aruldas
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Anuradha Rose
- Department of Community Medicine, Christian Medical College, Vellore, India
| | - David S. Kennedy
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - William E. Oswald
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rachel L. Pullan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sean R. Galagan
- The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
| | - Kristjana Ásbjörnsdóttir
- The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America
- Department of Epidemiology, University of Washington, Seattle, Washington, United States of America
| | - Roy M. Anderson
- School of Public Health, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Jayaprakash Muliyil
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Rajiv Sarkar
- Indian Institute of Public Health, Shillong, India
| | - Gagandeep Kang
- The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India
| | - Judd L. Walson
- The DeWorm3 Project, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Department of Medicine (Infectious Diseases) and Pediatrics, University of Washington, Seattle, Washington, United States of America
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Kwarteng A, Sylverken A, Asiedu E, Ahuno ST. Genome editing as control tool for filarial infections. Biomed Pharmacother 2021; 137:111292. [PMID: 33581654 DOI: 10.1016/j.biopha.2021.111292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 12/26/2022] Open
Abstract
Human filarial infections are vector-borne nematode infections, which include lymphatic filariasis, onchocerciasis, loiasis, and mansonella filariasis. With a high prevalence in developing countries, filarial infections are responsible for some of the most debilitating morbidities and a vicious cycle of poverty and disease. Global initiatives set to eradicate these infections include community mass treatments, vector control, provision of care for morbidity, and search for vaccines. However, there are growing challenges associated with mass treatments, vector control, and antifilarial vaccine development. With the emergence of genome editing tools and successful applications in other infectious diseases, the integration of genetic editing techniques in future control strategies for filarial infections would offer the best option for eliminating filarial infections. In this review, we briefly discuss the mechanisms of the three main genetic editing techniques and explore the potential applications of these powerful tools to control filarial infections.
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Affiliation(s)
- Alexander Kwarteng
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana; Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana.
| | - Augustina Sylverken
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana; Department of Theoretical and Applied Biology, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
| | - Ebenezer Asiedu
- Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
| | - Samuel Terkper Ahuno
- Department of Biochemistry and Biotechnology, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana; Kumasi Centre for Collaborative Research in Tropical Medicine, Kwame Nkrumah University of Science and Technology, KNUST, Kumasi, Ghana
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Kshirsagar NA, Gogtay NJ, Garg BS, Deshmukh PR, Rajgor DD, Kadam VS, Thakur PA, Gupta A, Ingole NS, Lazdins-Helds JK. Efficacy and tolerability of treatment with single doses of diethylcarbamazine (DEC) and DEC plus albendazole (ABZ) for three consecutive years in lymphatic filariasis: a field study in India. Parasitol Res 2017; 116:2683-2694. [PMID: 28785847 DOI: 10.1007/s00436-017-5577-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Accepted: 07/28/2017] [Indexed: 11/29/2022]
Abstract
Lymphatic filariasis (LF) affects 73 countries, causes morbidity and impedes socioeconomic development. We had found no difference in safety and micro (Mf) and macro filarial action of single-dose diethylcarbamazine (DEC) and DEC + albendazole (ABZ) in an F01 study done in India (year 2000). There was a programmatic need to evaluate safety and efficacy of multiple annual treatments (F02). Subjects (155) from the F01 study, meeting inclusion-exclusion criteria, were enrolled in F02 and treated with further two annual doses of DEC or DEC + ABZ. Efficacy was evaluated for Mf positivity by peripheral smear (PS) and nucleopore (NP) filter, circulating filarial antigen (CFA) and filarial dance sign (FDS) positivity and Mf count at yearly follow-up. Safety was assessed for 5 days after drug administration. Total of 139 subjects evaluated for efficacy (69 DEC and 70 DEC + ABZ group). Mf positivity prevalence declined progressively by 95% (PS), 66% (NP), and 95% (PS) and 86% (NP); CFA positivity prevalence declined by 15% and 9%; FDS by 100% each; Mf count declined by 75.5 and 76.9% with three annual treatment of DEC and DEC + ABZ, respectively. Addition of ABZ did not show any advantage over DEC given as three annual rounds for LF. DEC and DEC + ABZ were well tolerated. There was no correlation between result of CFA and FDS, (both claimed to be indicative of adult worm). Analysis of published studies and our data indicate that macrofilaricidal effect of DEC/DEC + ABZ may be seen in children and not adults, with three or more annual dosing.
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Affiliation(s)
- Nilima A Kshirsagar
- Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, New MS Building, 1st Floor, Parel, Mumbai, 400012, India. .,National Chair Clinical Pharmacology, ICMR Govt. of India, National Institute for Research in Reproductive Health (NIRRH), J. M. Street, Parel, Mumbai, 400012, India.
| | - N J Gogtay
- Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, New MS Building, 1st Floor, Parel, Mumbai, 400012, India
| | - B S Garg
- Department of Community Medicine, Mahatma Gandhi Institute of Medical Sciences, Wardha, 442102, India
| | - P R Deshmukh
- Department of Community Medicine, Mahatma Gandhi Institute of Medical Sciences, Wardha, 442102, India
| | - D D Rajgor
- Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, New MS Building, 1st Floor, Parel, Mumbai, 400012, India
| | - V S Kadam
- Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, New MS Building, 1st Floor, Parel, Mumbai, 400012, India
| | - P A Thakur
- Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, New MS Building, 1st Floor, Parel, Mumbai, 400012, India
| | - A Gupta
- Department of Clinical Pharmacology, Seth GS Medical College and KEM Hospital, New MS Building, 1st Floor, Parel, Mumbai, 400012, India
| | - N S Ingole
- Department of Pathology, Mahatma Gandhi Institute of Medical Sciences, Wardha, 442102, India
| | - J K Lazdins-Helds
- World Health Organization (WHO), Special Program for Research and Training in Tropical Diseases, Product Research and Development, 20 Avenue Appia, Geneva 27, 1211, Geneva, CH, Switzerland
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Ramaiah KD, Ottesen EA. Progress and impact of 13 years of the global programme to eliminate lymphatic filariasis on reducing the burden of filarial disease. PLoS Negl Trop Dis 2014; 8:e3319. [PMID: 25412180 PMCID: PMC4239120 DOI: 10.1371/journal.pntd.0003319] [Citation(s) in RCA: 204] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/06/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND A Global Programme to Eliminate Lymphatic Filariasis was launched in 2000, with mass drug administration (MDA) as the core strategy of the programme. After completing 13 years of operations through 2012 and with MDA in place in 55 of 73 endemic countries, the impact of the MDA programme on microfilaraemia, hydrocele and lymphedema is in need of being assessed. METHODOLOGY/PRINCIPAL FINDINGS During 2000-2012, the MDA programme made remarkable achievements - a total of 6.37 billion treatments were offered and an estimated 4.45 billion treatments were consumed by the population living in endemic areas. Using a model based on empirical observations of the effects of treatment on clinical manifestations, it is estimated that 96.71 million LF cases, including 79.20 million microfilaria carriers, 18.73 million hydrocele cases and a minimum of 5.49 million lymphedema cases have been prevented or cured during this period. Consequently, the global prevalence of LF is calculated to have fallen by 59%, from 3.55% to 1.47%. The fall was highest for microfilaraemia prevalence (68%), followed by 49% in hydrocele prevalence and 25% in lymphedema prevalence. It is estimated that, currently, i.e. after 13 years of the MDA programme, there are still an estimated 67.88 million LF cases that include 36.45 million microfilaria carriers, 19.43 million hydrocele cases and 16.68 million lymphedema cases. CONCLUSIONS/SIGNIFICANCE The MDA programme has resulted in significant reduction of the LF burden. Extension of MDA to all at-risk countries and to all regions within those countries where MDA has not yet reached 100% geographic coverage is imperative to further reduce the number of microfilaraemia and chronic disease cases and to reach the global target of interrupting transmission of LF by 2020.
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Affiliation(s)
- K. D. Ramaiah
- Consultant on Lymphatic Filariasis, Tagore Nagar, Pondicherry, India
| | - Eric A. Ottesen
- Neglected Tropical Disease Support Center, The Task Force for Global Health, Decatur, Georgia, United States of America
- ENVISION Project, RTI International, Washington, D.C., United States of America
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Sunish IP, Munirathinam A, Kalimuthu M, Ashok Kumar V, Tyagi BK. Persistence of lymphatic filarial infection in the paediatric population of rural community, after six rounds of annual mass drug administrations. J Trop Pediatr 2014; 60:245-8. [PMID: 24343822 DOI: 10.1093/tropej/fmt101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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.
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Affiliation(s)
- I P Sunish
- Centre for Research in Medical Entomology (ICMR), No. 4 Sarojini Street, Chinna Chokkikulam, Madurai - 625 002, Tamil Nadu state, India
| | - A Munirathinam
- Centre for Research in Medical Entomology (ICMR), No. 4 Sarojini Street, Chinna Chokkikulam, Madurai - 625 002, Tamil Nadu state, India
| | - M Kalimuthu
- Centre for Research in Medical Entomology (ICMR), No. 4 Sarojini Street, Chinna Chokkikulam, Madurai - 625 002, Tamil Nadu state, India
| | - V Ashok Kumar
- Centre for Research in Medical Entomology (ICMR), No. 4 Sarojini Street, Chinna Chokkikulam, Madurai - 625 002, Tamil Nadu state, India
| | - B K Tyagi
- Centre for Research in Medical Entomology (ICMR), No. 4 Sarojini Street, Chinna Chokkikulam, Madurai - 625 002, Tamil Nadu state, India
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Ramaiah KD, Vanamail P. Surveillance of lymphatic filariasis after stopping ten years of mass drug administration in rural communities in south India. Trans R Soc Trop Med Hyg 2013; 107:293-300. [PMID: 23442572 DOI: 10.1093/trstmh/trt011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND While various studies provided insight into the impact of mass drug administration (MDA), information on the dynamics of the post-MDA threshold level lymphatic filariasis (LF) infection facilitates understanding its disappearance pattern and determining the duration of post-MDA monitoring and evaluation. METHODS The changes in microfilaraemia (Mf) prevalence and vector infection rates were monitored for four (2005-2008) and six years (2005-2010) respectively after stopping ten rounds of annual mass diethylcarbamazine (DEC) administration in a group of five villages located in South India. Four years after stopping MDA, circulating filarial antigenaemia (Ag) status among children and adults was also assessed in two villages. RESULTS Overall Mf prevalence (n = 700) and vector infection rates (n=803-3520) showed a declining trend. Two villages maintained zero Mf status in each of the four years, vector infection rate was zero from the third year onwards and Ag prevalence in adults was 0.4% (n = 226). In two other villages despite persistence of Mf and vector infection there was zero vector infectivity rate during the third to sixth year and Ag prevalence among children (n = 50) was nil. In the fifth village Mf prevailed at <1.0% and Ag prevalence among 1-7 year old children was 4.6% (n = 44) and vector infectivity rate during the sixth year was 0.1% (n = 852). CONCLUSION The incidence of sporadic new infections is evident in highly endemic communities such as the fifth village. However, there is uncertainty on the potential of the Ag positive children to reestablish infection. Six years of post-MDA monitoring and evaluation appears to be adequate to discern the status of transmission interruption and appropriate decision making.
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Affiliation(s)
- K D Ramaiah
- Vector Control Research Centre, Indian Council of Medical Research, Medical Complex, Indira Nagar, Pondicherry 605006, India
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Abstract
OBJECTIVE To review methods for the statistical analysis of parasite and other skewed count data. METHODS Statistical methods for skewed count data are described and compared, with reference to a 10-year period of Tropical Medicine and International Health (TMIH). Two parasitological datasets are used for illustration. RESULTS The review of TMIH found 90 articles, of which 89 used descriptive methods and 60 used inferential analysis. A lack of clarity is noted in identifying the measures of location, in particular the Williams and geometric means. The different measures are compared, emphasising the legitimacy of the arithmetic mean for the skewed data. In the published articles, the t test and related methods were often used on untransformed data, which is likely to be invalid. Several approaches to inferential analysis are described, emphasising (1) non-parametric methods, while noting that they are not simply comparisons of medians, and (2) generalised linear modelling, in particular with the negative binomial distribution. Additional methods, such as the bootstrap, with potential for greater use are described. CONCLUSIONS Clarity is recommended when describing transformations and measures of location. It is suggested that non-parametric methods and generalised linear models are likely to be sufficient for most analyses.
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Affiliation(s)
- Neal Alexander
- London School of Hygiene and Tropical Medicine, London, UK.
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Njenga SM, Mwandawiro CS, Muniu E, Mwanje MT, Haji FM, Bockarie MJ. Adult population as potential reservoir of NTD infections in rural villages of Kwale district, Coastal Kenya: implications for preventive chemotherapy interventions policy. Parasit Vectors 2011; 4:175. [PMID: 21917166 PMCID: PMC3212820 DOI: 10.1186/1756-3305-4-175] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 09/14/2011] [Indexed: 11/16/2022] Open
Abstract
Background Neglected tropical diseases (NTDs) are major public health problems in developing countries where they contribute to suffering of populations living in poor settings. As part of a research project started in September 2009 in Kwale district, Coast Region, Kenya, a baseline cross-sectional survey was conducted in 5 rural villages to provide information on the status of NTDs, including urinary schistosomiasis, soil-transmitted helminthiasis (STH), and lymphatic filariasis. This paper presents the results of a parasitological investigation among adults in the study villages. Methods A total of 599 adults in the 5 study villages were tested for NTD infections in urine, stool and blood. The presence of Schistosoma haematobium infection was determined by the urine filtration method. The presence of STH in stool was determined by Kato-Katz method while filarial antigenaemia was determined using immunochromatographic (ICT) test. Results The study revealed high prevalence of hookworm (41.7%) and schistosomiasis (18.2%) infections among adults in the study villages. Of the 599 individuals examined, 50.1% had one or more helminthic infections. There was low level of polyparasitism with helminthic NTDs in the study population with 9.5% and 1.7% of the participants having two and three infections, respectively. Conclusions In the current study, hookworm and schistosomiasis infections were identified as important infections among adults living in areas of high endemicity for these infections. Thus, if this section of the population is left untreated it may remain an important potential reservoir and a source of re-infection for school-age children treated in school deworming programmes. Therefore, there is a need to design novel strategies for preventive chemotherapy interventions that could allow inclusion of adults in an effort to reduce force of infection in high endemic communities.
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Affiliation(s)
- Sammy M Njenga
- Eastern and Southern Africa Centre of International Parasite Control, Kenya Medical Research Institute, Mbagathi Road, Nairobi, Kenya.
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Wamae CN, Njenga SM, Ngugi BM, Mbui J, Njaanake HK. Evaluation of effectiveness of diethylcarbamazine/albendazole combination in reduction of Wuchereria bancrofti infection using multiple infection parameters. Acta Trop 2011; 120 Suppl 1:S33-8. [PMID: 20933491 DOI: 10.1016/j.actatropica.2010.09.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 06/24/2010] [Accepted: 09/17/2010] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To evaluate the effect of multiple rounds of annual single dose of DEC (6 mg/kg) or albendazole (400mg) given alone or in combination on Wuchereria bancrofti microfilaraemia, anti-filarial IgG1 and IgG4 and antigenaemia. METHODS A total of 170 participants were randomly assigned to albendazole (n = 62), DEC (n = 54), and DEC plus albendazole (DEC/ALB) combination (n = 54). Blood samples were collected at pre-treatment in 1998, at 1 week and 6 months after the first treatment and thereafter before subsequent treatments in 1999 and 2000. Effects of treatment on W. bancrofti infection were determined by changes in levels of microfilaraemia, antifilarial antibodies and circulating filarial antigen. RESULTS Comparison of geometric mean microfilariae intensities between DEC/ALB combination and DEC or albendazole single therapy groups after two rounds of annual treatment and 24 months follow-up showed that combination therapy resulted in a greater reduction of microfilaraemia than single therapy with either albendazole (p < 0.001) or DEC alone (p = 0.146). The overall levels of anti-filarial antibodies decreased significantly (p = 0.028 for IgG1 and p < 0.043 for IgG4) in all treatment groups at 24 months follow-up. Additionally, overall reduction in geometric mean circulating filarial antigen levels at 24 months was 44%, 60% and 85% for albendazole, DEC and DEC/ALB groups, respectively. CONCLUSIONS These study findings suggest that albendazole improved efficacy of DEC and mass administration of a combination of the two drugs would therefore enhance the interruption of transmission of W. bancrofti in endemic areas. This information has important implications for the ongoing Global Program for Elimination of Lymphatic Filariasis.
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Affiliation(s)
- C N Wamae
- Kenya Medical Research Institute, PO Box 54840-00200, Nairobi, Kenya.
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Mitjà O, Paru R, Hays R, Griffin L, Laban N, Samson M, Bassat Q. The impact of a filariasis control program on Lihir Island, Papua New Guinea. PLoS Negl Trop Dis 2011; 5:e1286. [PMID: 21886851 PMCID: PMC3160343 DOI: 10.1371/journal.pntd.0001286] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 07/06/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Annual mass drug administration (MDA) over five years is the WHO's recommended strategy to eliminate lymphatic filariasis (LF). Some experts, however, consider that longer periods of treatment might be necessary in certain high prevalence and transmission environments based upon past unsuccessful field experience and modelling. METHODOLOGY/PRINCIPAL FINDINGS To evaluate predictors of success in a LF control program we conducted an ecological study during a pre-existing MDA program. We studied 27 villages in Lihir Island, Papua New Guinea, from two areas with different infection rates before MDA. We undertook surveys to collect information on variables potentially having an influence on the outcome of the program, including epidemiological (baseline prevalence of infection, immigration rate), entomological (vector density) and operational (treatment coverage, vector control strategies) variables. The success in a village was defined using variables related to the infection (circulating filarial antigenemia prevalence < 1%) and transmission (antigenemia prevalence < 1 in 1000 children born since start of MDA). 8709 people were involved in the MDA program and average coverage rates were around 70%. The overall prevalence of filariasis fell from an initial 17.91% to 3.76% at round 5 (p < 0.001). Viewed on a village by village basis, 12/27 (44%) villages achieved success. In multivariate analysis, low baseline prevalence was the only factor predicting both success in reducing infection rates (OR 19,26; CI 95% 1,12 to 331,82) and success in preventing new infections (OR 27,44; CI 95% 1,05 to 719,6). Low vector density and the use of an optimal vector control strategy were also associated with success in reducing infection rates, but this did not reach statistical significance. CONCLUSIONS/SIGNIFICANCE Our results provide the data that supports the recommendation that high endemic areas may require longer duration MDA programs, or alternative control strategies.
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Affiliation(s)
- Oriol Mitjà
- Department of Medicine, Lihir Medical Centre, International SOS, Lihir Island, New Ireland Province, Papua New Guinea.
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Effect of annual mass administration of diethylcarbamazine and albendazole on bancroftian filariasis in five villages in south India. Trans R Soc Trop Med Hyg 2011; 105:431-7. [PMID: 21601901 DOI: 10.1016/j.trstmh.2011.04.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 04/08/2011] [Accepted: 04/08/2011] [Indexed: 11/23/2022] Open
Abstract
Annual mass drug administration (MDA) is the recommended strategy for lymphatic filariasis (LF) elimination. We assessed the effect of six rounds of mass administration of diethylcarbamazine (DEC) and albendazole (ALB) on microfilaria (Mf) prevalence and intensity and vector infection and infectivity rates and circulating filarial antigenaemia (CFA) in a group of five villages in south India, endemic for Culex-transmitted bancroftian filariasis. During different rounds of MDA, 60-70% of the eligible population (>15 kg body weight) was treated. The MDA reduced the Mf prevalence from 8.10% (CI 6.18-10.01) to 1.01% (CI 0.31-1.71) (P<0.05) and geometric mean intensity of Mf from 0.31 (CI 0.22-0.40) to 0.02 (CI 0.00-0.04) (P<0.05), equivalent to a fall of 86% and 94% respectively. The vector infection and infectivity rates declined from 13.11% (CI 11.52-14.70) to 0.78% (CI 0.16-1.40) (P<0.05) and 1.04% (CI 0.56-1.52) to 0.13% (CI 0.00-0.39) (P<0.05), respectively. Four out of the five villages recorded <0.5% Mf prevalence and 0% vector infection rate. Circulating filarial antigenaemia (CFA) fell by 86% in the total population and 100% in 1-10 year old children. One of the five villages, which showed the highest baseline vector infection rate, showed >1.0% Mf rate. The results suggest that six rounds of mass administration of DEC and ALB, with 60-70% treatment coverage, is likely to achieve total interruption of transmission and elimination of LF in the majority of villages.
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Effects of albendazole on Litomosoides chagasfilhoi (Nematoda: Filarioidea) females in vivo. Parasitol Res 2010; 107:817-26. [PMID: 20585805 DOI: 10.1007/s00436-010-1934-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 05/24/2010] [Indexed: 10/19/2022]
Abstract
Gerbils (Meriones unguiculatus) experimentally infected with Litomosoides chagasfilhoi were treated with a single oral dose of 40 or 80 mg of albendazole, respectively. Observation of the microfilaremia after the treatment showed that both single oral doses of albendazole decreased the microfilaremia in L. chagasfilhoi infection. The body wall was composed of a cuticle, a hypodermis, and a muscular layer, and treated nematodes showed no morphological alterations. The ultrastructural alterations produced by treatment with 40 mg of albendazole included a higher number of membrane invaginations in the basal labyrinth of the uterine epithelium and the presence of myelin figures in this region. Inside the uterus, most embryos and microfilariae were disintegrated. The treatment with 80 mg of albendazole did not produce alterations in the uterine wall, and the number of vesicles near the microfilariae sheath was smaller than that observed in the untreated and in the 40-mg treatment groups. However, all the microfilariae observed in the uterus were extensively damaged with cytoplasmic vacuolization and cellular degeneration. No alterations in the intestinal cells were observed after treatment with 40 or 80 mg of albendazole. The present study contributes to the knowledge of albendazole's effects in filariids and demonstrates the potential embryotoxic and microfilaricidal consequences of this drug.
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Abstract
Filariasis is caused by thread-like nematode worms, classified according to their presence in the vertebrate host. The cutaneous group includes Onchocerca volvulus, Loa loa and Mansonella streptocerca; the lymphatic group includes Wuchereria bancrofti, Brugia malayi and Brugia timori and the body cavity group includes Mansonella perstans and Mansonella ozzardi. Lymphatic filariasis, a mosquito-borne disease, is one of the most prevalent diseases in tropical and subtropical countries and is accompanied by a number of pathological conditions. In recent years, there has been rapid progress in filariasis research, which has provided new insights into the pathogenesis of filarial disease, diagnosis, chemotherapy, the host–parasite relationship and the genomics of the parasite. Together, these insights are assisting the identification of novel drug targets and the discovery of antifilarial agents and candidate vaccine molecules. This review discusses the antifilarial activity of various chemical entities, the merits and demerits of antifilarial drugs currently in use, their mechanisms of action, in addition to antifilarial drug targets and their validation.
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Bhumiratana A, Pechgit P, Koyadun S, Siriaut C, Yongyuth P. Imported bancroftian filariasis: diethylcarbamazine response and benzimidazole susceptibility of Wuchereria bancrofti in dynamic cross-border migrant population targeted by the National Program to Eliminate Lymphatic Filariasis in South Thailand. Acta Trop 2010; 113:121-8. [PMID: 19835831 DOI: 10.1016/j.actatropica.2009.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 10/06/2009] [Accepted: 10/07/2009] [Indexed: 11/27/2022]
Abstract
The implementation on the Thailand-Myanmar border of annual mass drug administration (MDA) of a single 6 mg/kg dose of diethylcarbamazine (DEC) plus 400mg albendazole, part of the National Program to Eliminate Lymphatic Filariasis (PELF), has been challenging. In particular, chain migration of cross-border Myanmar workers at risk for nocturnally periodic Wuchereria bancrofti infection can lead to imported bancroftian filariasis (IBF) in Thailand. IBF is targeted for multiple-dose MDA with 300 mg DEC, in addition to what is recommended by the World Health Organization (WHO). The dynamic Myanmar migrants in Phang-nga, southern Thailand were sampled to test whether the responsible W. bancrofti has a genetic predisposition of benzimidazole exposure, and IBF exhibits DEC susceptibility. The long-term migrants had more access to DEC. IBF in W. bancrofti antigenemic (microfilaremic vs. amicrofilaremic) short-term migrants exhibited susceptibility to a 300-mg single-dose DEC treatment. During the course of a 3-month follow-up, antigenemia was significantly reduced, but microfilaremia was fluctuated. Surprisingly, a newly recognized Mansonella infection co-existing among W. bancrofti-affected Myanmar migrants elicited microfilaremia clearance within a month after treatment. As a result of the presence of genetically stable W. bancrofti beta-tubulin (Wbtubb) gene responsible for benzimidazole susceptibility, IBF did not possess a genetic predisposition for benzimidazole exposure. Point mutations at positions Phe167Tyr and Phe200Tyr were not detected by Wbtubb locus-specific nested PCR and sequencing. This study has the potential to help guide not only the Thai/Myanmar PELF surveillance and monitoring of mass treatment impacts on W. bancrofti, but also the other endemic countries allied with the Global Program to Eliminate Lymphatic Filariasis (GPELF).
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Affiliation(s)
- A Bhumiratana
- Department of Parasitology and Entomology, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand.
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Ramaiah KD. Lymphatic filariasis elimination programme in India: progress and challenges. Trends Parasitol 2009; 25:7-8. [DOI: 10.1016/j.pt.2008.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Revised: 10/10/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
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Dec Bronsvoort BM, Makepeace BL, Renz A, Tanya VN, Fleckenstein L, Ekale D, Trees AJ. UMF-078: A modified flubendazole with potent macrofilaricidal activity against Onchocerca ochengi in African cattle. Parasit Vectors 2008; 1:18. [PMID: 18570639 PMCID: PMC2464590 DOI: 10.1186/1756-3305-1-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Accepted: 06/20/2008] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Human onchocerciasis or river blindness, caused by the filarial nematode Onchocerca volvulus, is currently controlled using the microfilaricidal drug, ivermectin. However, ivermectin does not kill adult O. volvulus, and in areas with less than 65% ivermectin coverage of the population, there is no effect on transmission. Therefore, there is still a need for a macrofilaricidal drug. Using the bovine filarial nematode O. ochengi (found naturally in African cattle), the macrofilaricidal efficacy of the modified flubendazole, UMF-078, was investigated. METHODS Groups of 3 cows were treated with one of the following regimens: (a) a single dose of UMF-078 at 150 mg/kg intramuscularly (im), (b) 50 mg/kg im, (c) 150 mg/kg intraabomasally (ia), (d) 50 mg/kg ia, or (e) not treated (controls). RESULTS After treatment at 150 mg/kg im, nodule diameter, worm motility and worm viability (as measured by metabolic reduction of tetrazolium to formazan) declined significantly compared with pre-treatment values and concurrent controls. There was abrogation of embryogenesis and death of all adult worms by 24 weeks post-treatment (pt). Animals treated at 50 mg/kg im showed a decline in nodule diameter together with abrogated reproduction, reduced motility, and lower metabolic activity in isolated worms, culminating in approximately 50% worm mortality by 52 weeks pt. Worms removed from animals treated ia were not killed, but exhibited a temporary embryotoxic effect which had waned by 12 weeks pt in the 50 mg/kg ia group and by 24 weeks pt in the 150 mg/kg ia group. These differences could be explained by the different absorption rates and elimination half-lives for each dose and route of administration. CONCLUSION Although we did not observe any signs of mammalian toxicity in this trial with a single dose, other studies have raised concerns regarding neuro- and genotoxicity. Consequently, further evaluation of this compound has been suspended. Nonetheless, these results validate the molecular target of the benzimidazoles as a promising lead for rational design of macrofilaricidal drugs.
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Affiliation(s)
- Barend M Dec Bronsvoort
- Veterinary Parasitology, Liverpool School of Tropical Medicine/Faculty of Veterinary Science, University of Liverpool, Pembroke Place, Liverpool, UK.
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Ramaiah KD, Das PK, Vanamail P, Pani SP. Impact of 10 years of diethylcarbamazine and ivermectin mass administration on infection and transmission of lymphatic filariasis. Trans R Soc Trop Med Hyg 2007; 101:555-63. [PMID: 17374389 DOI: 10.1016/j.trstmh.2006.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 12/11/2006] [Accepted: 12/11/2006] [Indexed: 10/23/2022] Open
Abstract
The potential of repeated mass administration of diethylcarbamazine (DEC) and ivermectin to eliminate lymphatic filariasis has been examined in a study implemented in 10 villages with a population of 18415 in south India. During ten rounds of mass drug administration, 49-84% of the eligible population received treatment in different villages. Ten rounds of mass administration of DEC alone reduced the microfilaria (mf) prevalence and intensity by 93% and 97%, respectively, and the vector infection and infectivity rates by 91% and 89%, respectively. The corresponding figures with nine rounds of administration of ivermectin alone were 83%, 90%, 89% and 79%. Out of five villages in each treatment arm, the mf rate declined to <or=1% in four villages in the DEC arm and two villages in the ivermectin arm. No mosquitoes with infective-stage larvae were found in three of five villages in the DEC arm and two of five villages in the ivermectin arm. None of the children (n=130) were found to be positive for mf in either treatment arm. None of the 40 sampled children were found to be positive for circulating filarial antigenaemia in villages with lower endemicity in the DEC arm. The results suggest that ten rounds of DEC mass administration have the potential to interrupt transmission of infection in the majority of communities. The outcome was relatively less remarkable with ivermectin.
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Affiliation(s)
- K D Ramaiah
- Vector Control Research Centre (Indian Council of Medical Research), Medical Complex, Indira Nagar, Pondicherry 605 006, India.
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Efficacy and safety of drug combinations in the treatment of schistosomiasis, soil-transmitted helminthiasis, lymphatic filariasis and onchocerciasis. Trans R Soc Trop Med Hyg 2007; 101:747-58. [PMID: 17481681 DOI: 10.1016/j.trstmh.2007.03.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 03/05/2007] [Accepted: 03/05/2007] [Indexed: 11/28/2022] Open
Abstract
This review concerns the efficacy and safety of combinations of various drugs, including albendazole (ALB), diethylcarbamazine (DEC), ivermectin (IVM), mebendazole and praziquantel (PZQ). There were no significant pharmacokinetic interactions when ALB-PZQ, ALB-DEC, ALB-IVM or ALB-IVM-PZQ were co-administered. ALB did not add to the cure rate of PZQ in the treatment of Schistosoma japonicum, S. mansoni and S. haematobium. ALB and DEC in combination and alone were ineffective against S. haematobium infections. No combinations (ALB-PZQ, ALB-IVM and ALB-DEC) were superior to ALB against Ascaris lumbricoides and hookworm infections, whilst IVM, but not PZQ or DEC, added to the effect of ALB in the treatment of Trichuris trichiura. Results with ALB added to single-drug therapy with IVM or DEC against lymphatic filariasis were inconclusive, but DEC and IVM in combination appeared to be superior to DEC or IVM alone. None of the drug combinations against lymphatic filariasis showed more adverse reactions than single-drug therapy. In onchocerciasis patients, ALB and IVM were safe in those also infected with lymphatic filariasis, but were not superior to IVM alone. Existing policies are based on limited knowledge. Well conducted, comparative, randomised controlled studies would greatly aid in the future use of these drug combinations.
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Burkot TR, Durrheim DN, Melrose WD, Speare R, Ichimori K. The argument for integrating vector control with multiple drug administration campaigns to ensure elimination of lymphatic filariasis. FILARIA JOURNAL 2006; 5:10. [PMID: 16914040 PMCID: PMC1560133 DOI: 10.1186/1475-2883-5-10] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Accepted: 08/16/2006] [Indexed: 11/22/2022]
Abstract
BACKGROUND There is a danger that mass drug administration campaigns may fail to maintain adequate treatment coverage to achieve lymphatic filariasis elimination. Hence, additional measures to suppress transmission might be needed to ensure the success of the Global Program for the Elimination of Lymphatic Filariasis. DISCUSSION Vector control successfully eliminated lymphatic filariasis when implemented alone or with mass drug administration. Challenges to lymphatic filariasis elimination include uncertainty of the exact level and duration of microfilarial suppression required for elimination, the mobility of infected individuals, consistent non-participation of some infected individuals with mass drug administration, the possible development of anti-filarial drug resistance and treatment strategies in areas co-endemic with loasis. Integration of vector control with mass drug administration can address some of these challenges. The potential benefits of vector control would include: (1) the ability to suppress filariasis transmission without the need to identify all individual 'foci of infection'; (2) minimizing the risk of reestablishment of transmission from imported microfilaria positive individuals; and (3) decreasing the risk of dengue or malaria transmission where, respectively, Aedes or Anopheles are lymphatic filariasis vectors. SUMMARY With adequate sustained treatment coverage, mass drug administration should meet the criteria for elimination of lymphatic filariasis. However, it may be difficult to sustain sufficiently high mass drug administration coverage to achieve lymphatic filariasis elimination in some areas, particularly, where Aedes species are the vectors. Since vector control was effective in controlling and even eliminating lymphatic filariasis transmission, integration of vector control with mass drug administration will ensure the sustainability of transmission suppression and thereby better ensure the success of national filariasis elimination programs. Although trials of some vector control interventions are needed, proven vector control strategies are ready for immediate integration with mass drug administration for many important vectors. Vector control is the only presently available additional lymphatic filariasis control measure with the potential for immediate implementation.
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Affiliation(s)
- TR Burkot
- Centers for Disease Prevention and Control, Division of Parasitic Diseases, 4770 Buford Highway, Mailstop F42, Atlanta, Georgia 03041, USA
| | - DN Durrheim
- WHO Lymphatic Filariasis Collaborating Center, James Cook University, Townsville, QLD, 4811, Australia
- Hunter New England Population Health, Locked Bag 10, Wallsend New South Wales 2287, Australia
| | - WD Melrose
- WHO Lymphatic Filariasis Collaborating Center, James Cook University, Townsville, QLD, 4811, Australia
| | - R Speare
- WHO Lymphatic Filariasis Collaborating Center, James Cook University, Townsville, QLD, 4811, Australia
| | - K Ichimori
- PacELF, World Health Organization, PO Box 113, Suva, Fiji Islands
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