Impact of two rounds of mass drug administration using diethylcarbamazine combined with albendazole on the prevalence of Brugia timori and of intestinal helminths on Alor Island, Indonesia

Prevalence of zoonotic (brugian) filariasis in Asia: A proportional meta-analysis

Lymphatic filariasis is a public health problem and targeted for global elimination. WHO recommends mass drug administration to interrupt transmission of the parasites involved. There are concerns that transmission interruption may be difficult in areas of zoonotic filarial infections. This study aimed to estimate the pooled prevalence of zoonotic brugian filariasis, and to compare the pooled prevalence of brugian filariasis in human and animal populations in the same area based on available studies. A comprehensive literature search was conducted in health-related electronic databases (PubMed, Ovid MEDLINE, Index Medicus, google scholar). A random-effect meta-analysis of the pooled overall prevalence of filariasis in animal populations was conducted. Sixteen studies from four different Asian countries were identified. Studies were conducted most frequently in Thailand (n = 7), followed by Malaysia (n = 5), India (n = 3), and Sri Lanka (n = 1). Regardless of animal group, the pooled overall prevalence of animal Brugia infections was 13% (95%CI: 7-21%, I2:98%, 16 studies). On stratification, the pooled overall prevalence in the animal population was 19% (95%CI: 1-50%, I2: 99%, 3 studies) in India, 8% (95%CI: 2-7%, I2: 97%, 5 studies) in Malaysia, and 13% (95%CI: 7-20%, I2: 94%, 7 studies) in Thailand. The prevalence in the animal population was 17% (95%CI: 13-21%, 1 study) in Sri Lanka. The pooled overall prevalence of Brugia malayi was 13% (95%CI: 7-21%, I2:98%, 12 studies), while for Brugia pahangi this was 12% (95%CI: 7-19%, I2:86%, 7 studies). Regardless of animal group, geographic area, or diagnostic test, the prevalence of B. malayi was consistently high. On stratification by animal category, the pooled overall prevalence was 10% (95%CI: 6-14%, I2:92%, 13 studies) in cats, 12% (95%CI: 2-28%, I2: 99%, 6 studies) in dogs, and 55% (95%CI: 47-63%, 1 study) in leaf-eating monkeys. The findings show the extent of zoonotic Brugiainfections in domestic cats and dogs, suggesting that these animals are potential reservoirs for human brugian filariasis in the study countries. To substantiate this with more accuracy, future well designed whole genomic sequencing of individual mf collected from humans and B. malayi infected animals in the same area are needed.

The Impact of Mass Drug Administration on Lymphatic Filariasis

Mass drug administration (MDA) has made a significant impact on the control of lymphatic filariasis (LF) since the establishment of the Global Programme to Eliminate Lymphatic Filariasis. However, its implementation is associated with several challenges, hampering interruption of parasite transmission and LF elimination in endemic areas. This study assessed the impact of MDA by comparing baseline microfilaria and antigen prevalence with those after three years (mid-term) and ≥5 years of MDA implementation and their respective prevalence reductions and identified specific challenges that may hinder its effective implementation. Three years of MDA implementation were observed to have microfilaria prevalence reductions (88.54% to 98.66%) comparable to those of studies that implemented MDA for five to 10 years (≥5 years, 79.23% to 98.26%). Inadequate community understanding of and participation in the LF MDA programme are major drawbacks to its effective implementation. The implementation of MDA that incorporates community participation, incentivisation, education, and training strategies has the potential of increasing MDA coverage and compliance, thereby interrupting parasite transmission and reducing microfilarial prevalence to levels that warrant LF elimination.

Community perceptions and acceptability of mass drug administration for the control of neglected tropical diseases in Asia-Pacific countries: A systematic scoping review of qualitative research

Background

Preventative chemotherapy and mass drug administration have been identified as effective strategies for the prevention, treatment, control and elimination of several NTDs in the Asia-Pacific region. Qualitative research can provide in-depth insight into the social dynamics and processes underlying effective implementation of and adherence to mass drug administration programs. This scoping review examines published qualitative literature to examine factors influencing community perceptions and acceptability of mass drug administration approaches to control NTDs in the Asia-Pacific region.

Methodology

Twenty-four peer reviewed published papers reporting qualitative data from community members and stakeholders engaged in the implementation of mass drug administration programs were identified as eligible for inclusion.

Findings

This systematic scoping review presents available data from studies focussing on lymphatic filariasis, soil-transmitted helminths and scabies in eight national settings (India, Indonesia, Philippines, Bangladesh, Laos, American Samoa, Papua New Guinea, Fiji). The review highlights the profoundly social nature of individual, interpersonal and institutional influences on community perceptions of willingness to participate in mass drug administration programs for control of neglected tropical diseases (NTD). Future NTD research and control efforts would benefit from a stronger qualitative social science lens to mass drug administration implementation, a commitment to understanding and addressing the social and structural determinants of NTDs and NTD control in complex settings, and efforts to engage local communities as equal partners and experts in the co-design of mass drug administration and other efforts to prevent, treat, control and eliminate NTDs.

Conclusion

For many countries in the Asia-Pacific region, the “low hanging fruit has been picked” in terms of where mass drug administration has worked and transmission has been stopped. The settings that remain–such as remote areas of Fiji and Papua New Guinea, or large, highly populated, multi-cultural urban settings in India and Indonesia–present huge challenges going forward.

Qualitative research can provide in-depth insight into the social dynamics and processes underlying effective implementation of and adherence to mass drug administration programs. This scoping review examines published qualitative literature to examine factors influencing community perceptions and acceptability of mass drug administration approaches to control neglected tropical diseases (NTDs) in the Asia-Pacific region. Our analyses highlight the profoundly social nature of individual, interpersonal and institutional influences on community perceptions of willingness to participate in mass drug administration programs for control of NTDs. For many countries in the Asia-Pacific region, the “low hanging fruit has been picked” in terms of where mass drug administration has worked and transmission has been stopped. The settings that remain–e.g. remote areas of Fiji and Papua New Guinea, or large, highly populated, multi-cultural urban settings in India and Indonesia–present huge challenges going forward. Future NTD research and control efforts would benefit from a stronger qualitative social science lens to mass drug administration implementation, a commitment to understanding the socio-structural determinants of NTDs and NTD control in complex settings, and engaging local communities as equal partners and experts in the co-design of mass drug administration and other efforts to prevent, treat, control and eliminate NTDs.

Diethylcarbamazine citrate-fortified salt for lymphatic filariasis elimination in India

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

Elimination of lymphatic filariasis: current perspectives on mass drug administration

Following the London declaration on neglected tropical diseases (NTDs) in 2012 and inspired by the WHO 2020 roadmap to control or eliminate NTDs, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) intensified preventive chemotherapy and management of morbidity as the two main strategies to enhance progress towards the elimination of lymphatic filariasis (LF). This paper focuses on current perspectives of mass drug administration (MDA) towards the elimination of LF. The goal of MDA is to reduce the density of parasites circulating in the blood of infected persons and the intensity of infection in communities to levels where transmission is no longer sustainable by the mosquito vector. Three drugs, diethylcarbamazine, albendazole, and ivermectin are currently available for LF treatment, and their effectiveness and relative safety have opened the possibility of treating the entire population at risk. Currently, almost all LF endemic countries rely on the single-dose two-drug regimen recommended by the GPELF to achieve elimination. The 4th WHO report on NTDs has indicated that considerable progress has been made towards elimination of LF in some countries while acknowledging some challenges. In this review, we conclude that the 2020 elimination goal can be achieved if issues pertaining to the drug distribution, health system and implementation challenges are addressed.

Community Rates of IgG4 Antibodies to Ascaris Haemoglobin Reflect Changes in Community Egg Loads Following Mass Drug Administration

Background

Conventional diagnostic methods for human ascariasis are based on the detection of Ascaris lumbricoides eggs in stool samples. However, studies of ascariasis in pigs have shown that the prevalence and the number of eggs detected in the stool do not correlate well with exposure of the herd to the parasite. On the other hand, an ELISA test measuring antibodies to Ascaris suum haemoglobin (AsHb) has been shown to be useful for estimating transmission intensity on pig farms. In this study, we further characterized the AsHb antigen and screened samples from a population-based study conducted in an area that is endemic for Ascaris lumbricoides in Indonesia to assess changes in AsHb antibody rates and levels in humans following mass drug administration (MDA).

Methodology/Principal findings

We developed and evaluated an ELISA to detect human IgG4 antibodies to AsHb. We tested 1066 plasma samples collected at different times from 599 subjects who lived in a village in rural Indonesia that was highly endemic for ascariasis. The community received 6 rounds of MDA for lymphatic filariasis with albendazole plus diethylcarbamazine between 2002 and 2007. While the AsHb antibody assay was not sensitive for detecting all individuals with Ascaris eggs in their stools, the percentage of seropositive individuals decreased rapidly following MDA. Reductions in antibody rates reflected decreased mean egg output per person both at the community level and in different age groups. Two years after the last round of MDA the community egg output and antibody prevalence rate were reduced by 81.6% and 78.9% respectively compared to baseline levels.

Conclusion/Significance

IgG4 antibody levels to AsHb appear to reflect recent exposure to Ascaris. The antibody prevalence rate may be a useful indicator for Ascaris transmission intensity in communities that can be used to assess the impact of control measures on the force of transmission.

Ascariasis is a neglected tropical disease caused by the intestinal nematode Ascaris lumbricoides that affects hundreds of millions of people in the developing world. Current methods for diagnosis of this infection are based on detecting eggs in the stool that are excreted by adult Ascaris worms. However, these methods have limited sensitivity for recent infections, and they do not detect infections with immature parasite stages that do not always result in the establishment of adult worms in the human intestine. We have previously shown that an assay for antibodies to Ascaris hemoglobin in pig serum is useful for assessing transmission of Ascaris infections on pig farms. In this study, we developed and evaluated a similar antibody assay that is based on the detection of human IgG4 antibodies to Ascaris haemoglobin (AsHb). Community antibody rates decreased rapidly following mass drug administration of the anthelmintic drug albendazole, and this decrease reflected reduced Ascaris egg excretion at the community level. This antibody test may be a useful tool for assessing the impact of control measures on the transmission of new Ascaris infections in endemic populations.

Awareness and coverage of mass drug administration for elimination of lymphatic filariasis: a community based cross sectional study in Nepal

Lymphatic filariasis (LF) is among the major public health problems in Nepal. The disease is a major cause of morbidities primarily, lymphedema of legs and hydrocele and it impedes socio economic development in many endemic areas of the country. This study is aimed at exploring the understanding of people about mass drug administration (MDA) of the said disease and the status of compliance of MDA in Nepal. This study is a cross sectional study carried out among 894 household samples in three of the sixty LF endemic districts. The selected districts were Dhading, Kapilvastu and Kailali. The sentinel surveillance of sites in three districts constituted the sampling frame at the first stage. The peripheral health care centers in the sentinel sites constituted the sampling frame at the second stage of sampling. The coverage of MDA was 95.5 %. However, the compliance was less. Only 71.6 % of the respondents who took the drugs from health workers swallowed the diethyl carbamazine (DEC) completely, other did not swallow. In the present study, majority of respondents reported that they had heard or seen persons with side effects of DEC in their community. A total of 20 % of respondents reported that they had side effects after having DEC and only 3.9 % of these side effects were treated. The Female Community Health volunteers (FCHVs), health workers and radio/Television (TV) were the chief sources of MDA related information. This study recommends for a concerted public health action combining effective drug delivery mechanism and sound public awareness campaigns. The community people need to be made aware beforehand about the location, time of drug distribution. Also public awareness of the DEC should be conducted so that people would trust it and comply with the drug regime. Along with the health workers and radio/TV that has been used traditionally, we recommend mobilization of FCHVs in the public awareness campaigns the MDA campaigns.

Pilot assessment of soil-transmitted helminthiasis in the context of transmission assessment surveys for lymphatic filariasis in Benin and Tonga

Background

Mass drug administration (MDA) for lymphatic filariasis (LF) programs has delivered more than 2 billion treatments of albendazole, in combination with either ivermectin or diethylcarbamazine, to communities co-endemic for soil-transmitted helminthiasis (STH), reducing the prevalence of both diseases. A transmission assessment survey (TAS) is recommended to determine if MDA for LF can be stopped within an evaluation unit (EU) after at least five rounds of annual treatment. The TAS also provides an opportunity to simultaneously assess the impact of these MDAs on STH and to determine the frequency of school-based MDA for STH after community-wide MDA is no longer needed for LF.

Methodology/Principal Findings

Pilot studies conducted in Benin and Tonga assessed the feasibility of a coordinated approach. Of the schools (clusters) selected for a TAS in each EU, a subset of 5 schools per STH ecological zone was randomly selected, according to World Health Organization (WHO) guidelines, for the coordinated survey. In Benin, 519 children were sampled in 5 schools and 22 (4.2%) had STH infection (A. lumbricoides, T. trichiura, or hookworm) detected using the Kato-Katz method. All infections were classified as light intensity under WHO criteria. In Tonga, 10 schools were chosen for the coordinated TAS and STH survey covering two ecological zones; 32 of 232 (13.8%) children were infected in Tongatapu and 82 of 320 (25.6%) in Vava'u and Ha'apai. All infections were light-intensity with the exception of one with moderate-intensity T. trichiura.

Conclusions

Synchronous assessment of STH with TAS is feasible and provides a well-timed evaluation of infection prevalence to guide ongoing treatment decisions at a time when MDA for LF may be stopped. The coordinated field experiences in both countries also suggest potential time and cost savings. Refinement of a coordinated TAS and STH sampling methodology should be pursued, along with further validation of alternative quantitative diagnostic tests for STH that can be used with preserved stool specimens.

Since 2000, some 2 billion preventive chemotherapy treatments have been delivered for lymphatic filariasis (LF), many in areas co-endemic for soil-transmitted helminthiasis (STH). A transmission assessment survey (TAS) is recommended to determine if such ‘mass drug administration (MDA)’ for LF can be stopped in a specified evaluation unit. The TAS also provides an opportune platform to simultaneously conduct STH assessments and make informed programmatic decisions about STH control. Through piloting this coordinated TAS and STH survey approach in Benin and Tonga, we found that after 5–6 rounds of annual MDA, STH prevalence was 4.2% in Benin and 13.8–25.6% in Tonga. All infections were light intensity except one moderate A. lumbricoides case in Tonga. Our study highlights that a coordinated strategy is operationally feasible, programmatically relevant, and potentially cost-effective. A more robust sampling methodology for coordinated TAS and STH surveys should be further explored, as well as alternative diagnostic tests for STH.

Impact of six rounds of mass drug administration on Brugian filariasis and soil-transmitted helminth infections in eastern Indonesia

BACKGROUND

The lymphatic filarial parasite Brugia timori occurs only in eastern Indonesia where it causes high morbidity. The absence of an animal reservoir, the inefficient transmission by Anopheles mosquitoes and the high sensitivity to DEC/albendazole treatment make this species a prime candidate for elimination by mass drug administration (MDA).

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated the effect of MDA using DEC and albendazole on B. timori and soil transmitted helminths (STH) in a cross-sectional study of a sentinel village on Alor Island annually over a period of 10 years. Pre-MDA the microfilaria (MF) prevalence was 26% and 80% of the residents had filaria-specific IgG4 antibodies. In 2010, 34 months after the 6(th) round of MDA, MF and antibody rates were only 0.17% and 6.4%, respectively. The MDA campaign had also a beneficial effect on STH. Baseline prevalence rates for Ascaris, hookworm and Trichuris were 34%, 28%, and 11%, respectively; these rates were reduced to 27%, 4%, and 2% one year after the 5(th) round of MDA. Unfortunately, STH rates rebounded 34 months after cessation of MDA and approached pre-MDA rates. However, the intensity of STH infection in 2009 was still reduced, and no heavy infections were detected.

CONCLUSIONS/SIGNIFICANCE

MDA with DEC/albendazole has had a major impact on B. timori MF and IgG4 antibody rates, providing a proof of principle that elimination is feasible. We also documented the value of annual DEC/albendazole as a mass de-worming intervention and the importance of continuing some form of STH control after cessation of MDA for filariasis.

Epidemiological assessment of neglected diseases in children: lymphatic filariasis and soil-transmitted helminthiasis

OBJECTIVE

To report the prevalence of lymphatic filariasis and intestinal parasitic infections in school-aged children living in a filariasis endemic area and discuss about the therapeutic regimen adopted in Brazil for the large-scale treatment of filariasis.

METHODS

A cross-sectional study including 508 students aged 5-18 years old, enrolled in public schools within the city of Olinda, Pernambuco. The presence of intestinal parasites was analyzed using the Hoffman, Pons and Janer method on 3 stool samples. The diagnosis of filarial infection was performed using the rapid immunochromatographic technique (ICT) for the antigen, and the polycarbonate membrane filtration for the presence of microfilariae. Descriptive statistics of the data was performed using EpiInfo version 7.

RESULTS

The prevalence of filariasis was 13.8% by ICT and 1.2% by microfilaraemia, while intestinal parasites were detected in 64.2% of cases. Concurrent diagnosis of filariasis and intestinal parasites was 9.4%, while 31.5% of students were parasite-free. Among individuals with intestinal parasites, 55% had one parasite and 45% had more than one parasite. Geohelminths occurred in 72.5% of the parasited individuals. In the group with filarial infection the prevalence of soil-transmitted helminthiasis was 54.5%.

CONCLUSIONS

The simultaneous diagnosis of filariasis and intestinal parasites as well as the high frequency of geohelminths justify the need to reevaluate the treatment strategy used in the Brazilian filariasis large-scale treatment program.

Regulatory T cells in human lymphatic filariasis: stronger functional activity in microfilaremics

Infection with filarial parasites is associated with T cell hyporesponsiveness, which is thought to be partly mediated by their ability to induce regulatory T cells (Tregs) during human infections. This study investigates the functional capacity of Tregs from different groups of filarial patients to suppress filaria-specific immune responses during human filariasis. Microfilaremic (MF), chronic pathology (CP) and uninfected endemic normal (EN) individuals were selected in an area endemic for Brugia timori in Flores island, Indonesia. PBMC were isolated, CD4CD25^hi cells were magnetically depleted and in vitro cytokine production and proliferation in response to B. malayi adult worm antigen (BmA) were determined in total and Treg-depleted PBMC. In MF subjects BmA-specific T and B lymphocyte proliferation as well as IFN-gamma, IL-13 and IL-17 responses were lower compared to EN and CP groups. Depletion of Tregs restored T cell as well as B cell proliferation in MF-positives, while proliferative responses in the other groups were not enhanced. BmA-induced IL-13 production was increased after Treg removal in MF-positives only. Thus, filaria-associated Tregs were demonstrated to be functional in suppressing proliferation and possibly Th2 cytokine responses to BmA. These suppressive effects were only observed in the MF group and not in EN or CP. These findings may be important when considering strategies for filarial treatment and the targeted prevention of filaria-induced lymphedema.

Lymphatic filariasis is a neglected disease still prominent in low-resource settings and is very disabling when it progresses to chronic pathology caused by lymphedema. Until now, studies on the contribution of Tregs to lymphocyte hyporesponsiveness in human filariasis have focused on frequency and phenotypic characteristics of these cells. We have looked at the functional consequence of the presence of Tregs in filaria-specific immune responses during different stages of human lymphatic filariasis. Proliferation of not only T cells, but also B cells, was decreased in patients with microfilaremia compared to uninfected individuals and chronic pathology (lymphedema) patients. The suppressed lymphocyte proliferative responses were increased after in vitro removal of Tregs in the microfilaria-positive group only, indicating the presence of filaria-specific functional Tregs in microfilaremic patients which are not as active in subjects with chronic pathology or without infection. Th2 cytokine responses were specifically enhanced in microfilaremics as well after Treg depletion, suggesting Treg-associated suppression of filaria-specific Th2 responses. Taken together, filaria-specific Treg contribute to immune modulation during microfilaremia and might need to be considered in therapeutic strategies to prevent chronic pathology induced by filarial infection.

Diagnosis of soil-transmitted helminthiasis in an Amazonic community of Peru using multiple diagnostic techniques

An observational descriptive study was conducted in a Shipibo-Conibo/Ese'Eja community of the rainforest in Peru to compare the Kato-Katz method and the spontaneous sedimentation in tube technique (SSTT) for the diagnosis of intestinal parasites as well as to report the prevalence of soil-transmitted helminth (STH) infections in this area. A total of 73 stool samples were collected and analysed by several parasitological techniques, including Kato-Katz, SSTT, modified Baermann technique (MBT), agar plate culture, Harada-Mori culture and the direct smear examination. Kato-Katz and SSTT had the same rate of detection for Ascaris lumbricoides (5%), Trichuris trichiura (5%), hookworm (14%) and Hymenolepis nana (26%). The detection rate for Strongyloides stercoralis larvae was 16% by SSTT and 0% by Kato-Katz, but 18% by agar plate culture and 16% by MBT. The SSTT also had the advantage of detecting multiple intestinal protozoa such as Blastocystis hominis (40%), Giardia intestinalis (29%) and Entamoeba histolytica/E. dispar (16%). The most common intestinal parasites found in this community were B. hominis, G. intestinalis, H. nana, S. stercoralis and hookworm. In conclusion, the SSTT is not inferior to Kato-Katz for the diagnosis of common STH infections but is largely superior for detecting intestinal protozoa and S. stercoralis larvae.

Evaluation of effectiveness of diethylcarbamazine/albendazole combination in reduction of Wuchereria bancrofti infection using multiple infection parameters

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.

Fermented soyabean and vitamin C-rich fruit: a possibility to circumvent the further decrease of iron status among iron-deficient pregnant women in Indonesia

Objective

Increasing the consumption of Fe-rich foods and thus improving Fe bioavailability without significantly increasing diet cost is the most sustainable intervention for improving Fe intake. We assessed the effect of supplementary food consisting of fermented soyabean (tempeh) and vitamin C-rich fruit consumed during pregnancy on maternal iron deficiency (ID).

Design

Pregnant women were randomly allocated by village into optimized diet and control groups. Supplementary food was given 6 d/week at home. The average weekly food provided comprised 600 g of tempeh, 30 g of meat, 350 g of guava, 300 g of papaya and 100 g of orange. Hb, ferritin and transferrin receptor (TfR) concentrations were measured at 12–20 and at 32–36 weeks of gestation.

Setting

Thirty-nine villages in Indonesia.

Subjects

Pregnant women (12–20 weeks of gestation, n 252).

Results

At baseline, mean Hb, ferritin and TfR concentrations and body Fe concentration were within the normal range and did not differ between groups. At near term, mean Hb, ferritin and body Fe decreased, whereas mean TfR increased significantly in both groups. The mean changes in Fe status were similar in both groups. In Fe-deficient women, consumption of an optimized diet was associated with smaller decreases in Hb (1·02 (95 % CI 0·98, 1·07) g/l; P = 0·058), ferritin (1·42 (95 % CI 1·16, 1·75) μg/l; P = 0·046) and body Fe (2·57 (95 % CI 1·71, 3·43) mg/kg; P = 0·073) concentrations, compared with a state of no intervention. Fe-deficient women at baseline benefited more from supplementary food compared with Fe-replete women.

Conclusions

Daily supplementary food containing tempeh and vitamin C-rich fruits during pregnancy might have positive effects on maternal ID.

Determinants of success in national programs to eliminate lymphatic filariasis: a perspective identifying essential elements and research needs

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in 2000. To understand why some national programs have been more successful than others, a panel of individuals with expertise in LF elimination efforts met to assess available data from programs in 8 countries. The goal was to identify: 1) the factors determining success for national LF elimination programs (defined as the rapid, sustained reduction in microfilaremia/antigenemia after repeated mass drug administration [MDA]); 2) the priorities for operational research to enhance LF elimination efforts. Of more than 40 factors identified, the most prominent were 1) initial level of LF endemicity; 2) effectiveness of vector mosquitoes; 3) MDA drug regimen; 4) population compliance. Research important for facilitating program success was identified as either biologic (i.e., [1] quantifying differences in vectorial capacity; [2] identifying seasonal variations affecting LF transmission) or programmatic (i.e., [1] identifying quantitative thresholds, especially the population compliance levels necessary for success, and the antigenemia or microfilaremia prevalence at which MDA programs can stop with minimal risk of resumption of transmission; [2] defining optimal drug distribution strategies and timing; [3] identifying those individuals who are "persistently non-compliant" during MDAs, the reasons for this non-compliance and approaches to overcoming it). While addressing these challenges is important, many key determinants of program success are already clearly understood; operationalizing these as soon as possible will greatly increase the potential for national program success.

Impact of two rounds of mass treatment with diethylcarbamazine plus albendazole on Wuchereria bancrofti infection and the sensitivity of immunochromatographic test in Malindi, Kenya

Annual single-dose mass treatment of endemic populations with a combination of either diethylcarbamazine (DEC) or ivermectin plus albendazole is recommended as the mainstay of lymphatic filariasis elimination programmes. We evaluated the impact of two rounds of annual mass drug administration (MDA) of DEC and albendazole on bancroftian filariasis in a pilot elimination programme in an endemic area of Kenya. Overall prevalence of microfilaraemia decreased by 65.4%, whereas community microfilarial load decreased by 84% after the two MDAs. The prevalence of parasite antigenaemia determined by immunochromatographic test (ICT) declined significantly by 43.5% after the two MDAs. We also studied the effect of mass treatment on the sensitivity of the ICT. Although the sensitivity of the test before treatment was high (89.9%; kappa=0.909) sensitivity was lower after two MDAs (59.3%; kappa=0.644). The finding raises concern about the reliability of the ICT in long-term monitoring of infection and for establishing programmatic endpoints. The results of the present study indicate a relatively high effectiveness of MDA using a DEC/albendazole combination against Wuchereria bancrofti infection and, therefore, it may be a useful strategy to eliminate lymphatic filariasis in onchocerciasis-free areas.

Using knowledge, attitudes and practice (KAP) surveys on lymphatic filariasis to prepare a health promotion campaign for mass drug administration in Alor District, Indonesia

We report the results of two surveys of people's knowledge, attitudes and practices (KAP) regarding lymphatic filariasis (LF) in Alor District, eastern Indonesia. The results of the surveys were used to prepare and evaluate the social mobilization component of a pilot mass drug administration (MDA) in five villages. In the study area, the filarial parasites Brugia timori and Wuchereria bancrofti are highly endemic. Frequent and severe adverse reactions after MDA may occur especially in areas endemic for B. timori and therefore, a special communication strategy was designed to inform and to educate communities about LF and its control. The first KAP survey was conducted as a baseline pre-MDA with diethylcarbamazine and albendazole and the second as a post-intervention evaluation in order to obtain information on the impact of the communication campaign. Before the information campaign and the subsequent MDA, 54% of the study population had heard of one of the three main terms for LF, whereas after health education and MDA, 89% had heard of at least one of the three terms. Similarly, pre-MDA, 21% reported having had previously taken the treatment for filariasis, while post-MDA, 88% reported having taken the treatment during the pilot treatment period. The historical fears and traumatic experiences associated with past LF treatment campaigns in Indonesia were averted since both the communication campaign and the MDA were designed appropriately for and together with the community. As a result, compliance was sufficient in the first round to successfully begin the elimination process.

Controlling lymphatic filariasis and soil-transmitted helminthiasis together in South Asia: opportunities and challenges

Lymphatic filariasis (LF) and the major soil-transmitted helminth (STH) infections are co-endemic in many countries, particularly in Asia. Control strategies for both groups of infections have increasingly focused on the use of mass chemotherapy. With the use of albendazole, there is now a tool that is common to both. However, there are also important differences in their modes of transmission and epidemiology, and, as a result, in the overall control strategies. The Global Programme for the Elimination of Lymphatic Filariasis aims to eliminate LF through time-limited mass drug administration programmes. Control activities for STH are more diffuse, aiming to piggy-back de-worming onto existing services, such as school health activities; controlling morbidity, rather than eliminating infection, is the stated goal. In order to maximize health benefits to communities that are endemic for one or both of these infections, it is vitally important that policy makers and programme managers have a clear understanding of both commonalities and differences, and implement control strategies that allocate available resources in an optimal manner.

Prevalence of soil transmitted nematodes on Nukufetau, a remote Pacific island in Tuvalu

Background

The population of Nukufetau, a remote coral atoll island in Tuvalu in the Western Pacific, received annual mass drug administration (MDA) of diethylcarbamazine and albendazole under the Pacific Elimination of Lymphatic Filariasis program in 2001, 2002 and 2003, with the last MDA occurring six months before a cross-sectional survey of the whole population for soil transmitted helminths (STH).

Methods

A cross-sectional survey in May 2004 recruited 206 residents (35.2% of the population) who provided a single faecal sample that was preserved, concentrated and examined microscopically.

Results

Overall prevalence of STH was 69.9%; only hookworm and Trichuris trichiura were diagnosed. Trichuris was present in 68.4% with intensity of infection being light in 56.3%, medium in 11.7% and heavy in 0.5%. Hookworm occurred in 11.7% with intensity of infection 11.2% being light and medium in 0.5%. Twenty individuals (9.7%) had dual infections. The prevalence of Trichuris was constant across all ages while the prevalence of hookworm was significantly lower in residents below 30 years of age. In the age group 5–12 years comparison of results with a 2001 survey [1] suggested that the prevalence of STH has declined minimally, due to sustained high prevalence of Trichuris, while hookworm has declined dramatically from 34.4% to 1.6%.

Conclusion

The results of this survey suggest that although the MDA appears to have reduced hookworm prevalence in residents below 30 years of age, there has been minimal effect on Trichuris prevalence. An integrated program to control STH is required.

Community-based study to assess the efficacy of DEC plus ALB against DEC alone on bancroftian filarial infection in endemic areas in Tamil Nadu, south India

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.

Progress towards eliminating lymphatic filariasis in Zanzibar: a model programme

Programmes to eliminate lymphatic filariasis are underway in ten countries of sub-Saharan Africa, and in several programmes outside Africa five rounds of mass drug administration (MDA) are being completed. In Africa, Egypt and Zanzibar have completed five rounds of MDA. Zanzibar was the first country to complete five rounds of treatment using a combination of albendazole and ivermectin, reducing both the prevalence and intensity of Wuchereria bancrofti. Characteristics of the Zanzibar programme serve as a model for other countries: factors crucial to its success include high-level political commitment, the development of appropriate social mobilization strategies, the involvement of communities in drug distribution, and the introduction of morbidity management for individuals with lymphoedema.

A blueprint for success: integration of neglected tropical disease control programmes

The rapid expansion of chemotherapy-based control programmes for neglected tropical diseases has been catalysed by funding from the Bill and Melinda Gates Foundation, donations of several drugs from pharmaceutical manufacturers, and the reduced price of the drug praziquantel. Focussing on lymphatic filariasis, schistosomiasis and soil-transmitted helminthiasis, we review here the progress made to date with the implementation and integration of large-scale control programmes. Unresolved issues include a means for rapid identification of communities at highest risk of co-morbidity, cost-effective approaches for integrating the technical interventions into setting-specific packages, and determination of the most appropriate and sustainable delivery systems.

Estimation of the prevalence of lymphatic filariasis by a pool screen PCR assay using blood spots collected on filter paper

The prevalence of lymphatic filariasis was estimated by PCR-based pool screening of night blood collected from 865 individuals living in ten areas endemic for Wuchereria bancrofti, Brugia malayi or B. timori in Indonesia. A total of 232 microfilaraemics were identified by filtration of 1 ml of blood. The microfilaria (mf) prevalence ranged from 6% to 54%, and the mf density in microfilaraemics ranged from 1 mf/ml to 6028 mf/ml. PCR assays both for W. bancrofti or Brugia spp. detected a single mf present on a 30 microl dried filter paper blood spot. One hundred and seventy-eight pools of five blood spots in each pool (pool-5) were tested by PCR and 101 (57%) pools were positive. When pool size was increased to 10 spots per pool (pool-10), 65 (70%) of 93 pools were positive. Pearson's correlation and linear regression showed a strong correlation between filtration and pool screen PCR results for pool-10 (r=0.835) and pool-5 (r=0.695). Based on the determination coefficient (R), the results of pool-10 PCR (R=0.697) gave a better prediction compared with pool-5 PCR (R=0.483). This study suggests that pool screen PCR may be a useful tool for monitoring the Global Program to Eliminate Lymphatic Filariasis.