Control Of Lymphatic Filariasis Research Articles

Predictive Value of Microfilariae-Based Stop-MDA Thresholds After Triple Drug Therapy With IDA Against Lymphatic Filariasis in Treatment-Naive Indian Settings.

Mass drug administration (MDA) of antifilarial drugs is the main strategy for the elimination of lymphatic filariasis (LF). Recent clinical trials indicated that the triple-drug therapy with ivermectin, diethylcarbamazine, and albendazole (IDA) is much more effective against LF than the widely used two-drug combinations (albendazole plus either ivermectin or diethylcarbamazine). For IDA-based MDA, the stop-MDA decision is made based on microfilariae (mf) prevalence in adults. In this study, we assess how the probability of eventually reaching elimination of transmission depends on the critical threshold used in transmission assessment surveys (TAS-es) to define whether transmission was successfully suppressed and triple-drug MDA can be stopped. This analysis focuses on treatment-naive Indian settings. We do this for a range of epidemiological and programmatic contexts, using the established LYMFASIM model for transmission and control of LF. Based on our simulations, a single TAS, one year after the last MDA round, provides limited predictive value of having achieved suppressed transmission, while a higher MDA coverage increases elimination probability, thus leading to a higher predictive value. Every additional TAS, conditional on previous TAS-es being passed with the same threshold, further improves the predictive value for low values of stop-MDA thresholds. An mf prevalence threshold of 0.5% corresponding to TAS-3 results in ≥95% predictive value even when the MDA coverage is relatively low.

Mosquitoes, Lymphatic Filariasis, and Public Health: A Systematic Review of Anopheles and Aedes Surveillance Strategies.

Lymphatic Filariasis (LF) affects over 120 million people in 72 countries, with sub-periodic filariasis common in the Pacific. Wuchereria bancrofti has three physiological races, each with a unique microfilarial periodicity, and each race is isolated to a specific geographical region. Sub-periodic W. bancrofti is transmitted by various Aedes mosquito species, with Aedes polynesiensis and Aedes samoanus being the primary vectors in Samoa. The Aedes scutellaris and Aedes kochi groups are also important vectors in the South Pacific Islands. Anopheles species are important vectors of filariasis in rural areas of Asia and Africa. The Anopheles gambiae complex, Anopheles funestus, and the Anopheles punctulatus group are the most important vectors of W. bancrofti. These vectors exhibit indoor nocturnal biting behaviour and breed in a variety of habitats, including freshwater, saltwater, and temporary water bodies. Effective vector surveillance is central to LF control and elimination programs. However, the traditional Human Landing Collection (HLC) method, while valuable, poses ethical concerns and risks to collectors. Therefore, this review critically analyses alternative trapping tools for Aedes and Anopheles vectors in LF-endemic regions. We looked at 14 research publications that discussed W. bancrofti vector trapping methods. Pyrethrum Spray Catches (PSC), one of the seven traps studied for Anopheles LF vectors, was revealed to be the second most effective strategy after HLC, successfully catching Anopheles vectors in Nigeria, Ghana, Togo, and Burkina Faso. The PSC method has several drawbacks, such as the likelihood of overlooking exophilic mosquitoes or underestimating Anopheles populations. However, exit traps offered hope for capturing exophilic mosquitoes. Anopheles populations could also be sampled using the Anopheles Gravid Trap (AGT). In contrast, the effectiveness of the Double Net Traps (DNT) and the CDC Light Trap (CDC LT) varied. Gravid mosquito traps like the OviArt Gravid Trap (AGT) were shown to be useful tools for identifying endophilic and exophilic vectors during the exploration of novel collection techniques. The Stealth trap (ST) was suggested for sampling Anopheles mosquitoes, although specimen damage may make it difficult to identify the species. Although it needs more confirmation, the Ifakara Tent Trap C design (ITT-C) showed potential for outdoor mosquito sampling in Tanzania. Furvela tent traps successfully captured a variety of Anopheles species and are appropriate for use in a variety of eco-epidemiological settings. By contrast, for Aedes LF vectors, no specific sampling tool was identified for Aedes niveus, necessitating further research and development. However, traps like the Duplex cone trap, Resting Bucket Trap (RB), and Sticky Resting Bucket trap (SRB) proved effective for sampling Aedes albopictus, offering potential alternatives to HLC. This review emphasises the value of looking into alternative trapping methods for Aedes and Anopheles vectors in the LF-endemic region. Further research is required to determine the efficacy of novel collection techniques in various contexts, even if PSC and AGT show promise for sampling Anopheles vectors. The identified traps, along with ongoing research, provide valuable contributions to vector surveillance efforts in LF-endemic regions, enabling LF control and elimination strategies to advance.

Immune Response Profiling of Cocktails of Brugia malayi Vaccine Candidates DIM-1, Calponin and Troponin 1in BALB/c Mice.

In search of a vaccine for the control of human lymphatic filariasis (LF) caused by Wuchereria bancrofti, Brugia malayi and B. timori, we identified three parasite-specific potential candidates: the disorganized muscle protein-1 (D), calponin (C) and troponin 1 (T) in B. malayi adult worm. In the present study, we investigated the immune response profile of the cocktails of the recombinant D, T and C proteins. Groups of BALB/c mice were immunized with individual rproteins or their cocktails DT, TC, DC and DTC, and the immunogen-specific IgG and its subclasses and IgE were determined. Cells from the immunized animals were challenged in vitro with the respective rproteins and cocktails and the release of nitric oxide (NO) from macrophages and Th1 and Th2 cytokines from splenocytes were determined. Among the immunized groups, DTC elicited comparatively a stronger response which included augmented release of NO, Th1 (IL-1β, IL-2, IFN-γ and TNF-α) and Th2 (IL-4, IL-6, IL-10 and TGF-β) cytokines, and increased levels of immunogen-specific IgG, IgG1 and IgG2b and low levels of immunogen-specific IgG2a and IgE and the Th2 cytokine IL-13. Immune responses that play important role in host protection were elicited strongly by DTC cocktail compared to the individual rproteins or DT, TC and DC cocktails. The findings provide a sound rationale for further studies on DTC cocktail as a vaccine candidate for the control of LF.

Knowledge and perceptions of lymphatic filariasis patients in selectedhotspot endemic communities in southern Ghana.

Lymphatic filariasis (LF) is a mosquito-borne neglected tropical disease that is one of the leading global causes of permanent disability. To date, LF interventions have been largely biomedical, focusing on drug treatments to disrupt parasite transmission and manage disease morbidity. Although important, these Mass Drug Administration (MDA) programs neglect the significance of socio-economic burden to the health of LF patients, which are compounded by social stigmatization, discrimination and associated depressive illnesses. The MDA program also typically fails to engage with local community beliefs and perceptions of LF, which may differ markedly from biomedical explanations and may have fueled non-compliance to treatments which is one of the major challenges of the Mass Drug Administration program. LF is not only a biomedical issue but also a social issue and LF interventions need to understand people's world views and the contexts through which they interpret bodily maladies. Hence, an effective LF intervention must bring together both the biomedical and the social components. The goal of this exploratory study was to assist in refining a large qualitative study (currently underway) that seeks to integrate culturally appropriate LF interventions into current LF control programs in Ghana. In this paper, we discuss the findings of a pre-intervention, exploratory study aimed at gaining a baseline grasp of a local culturally informed understanding of lymphatic filariasis and the knowledge gaps looking at three endemic Ghanaian communities in the Ahanta West District. A structured questionnaire was employed to assess the wellbeing, social inclusion, and cultural understanding of LF with a geographic focus within LF-endemic areas in Ghana. Interestingly, 45.8% of the 72 participants reported to have received information about LF from health care providers and the MDA program but only 5 out of the 72 (6.9%) respondents believed that LF was transmitted by mosquitos. This baseline study revealed several alternative interpretations and misconceptions about the disease, as well as the social and economic impacts, and importantly, the need to integrate qualitative research to develop culturally appropriate interventions and increase engagement with existing control programs.

Diethylcarbamazine elicits Ca2+ signals through TRP-2 channels that are potentiated by emodepside in Brugia malayi muscles.

Filarial nematode infections are a major health concern in several countries. Lymphatic filariasis is caused by Wuchereria bancrofti and Brugia spp. affecting over 120 million people. Heavy infections can lead to elephantiasis, which has serious effects on individuals' lives. Although current anthelmintics are effective at killing microfilariae in the bloodstream, they have little to no effect against adult parasites found in the lymphatic system. The anthelmintic diethylcarbamazine is one of the central pillars of lymphatic filariasis control. Recent studies have reported that diethylcarbamazine can open transient receptor potential (TRP) channels in the muscles of adult female Brugia malayi, leading to contraction and paralysis. Diethylcarbamazine has synergistic effects in combination with emodepside on Brugia, inhibiting motility: emodepside is an anthelmintic that has effects on filarial nematodes and is under trial for the treatment of river blindness. Here, we have studied the effects of diethylcarbamazine on single Brugia muscle cells by measuring the change in Ca2+ fluorescence in the muscle using Ca2+-imaging techniques. Diethylcarbamazine interacts with the transient receptor potential channel, C classification (TRPC) ortholog receptor TRP-2 to promote Ca2+ entry into the Brugia muscle cells, which can activate Slopoke (SLO-1) Ca2+-activated K+ channels, the putative target of emodepside. A combination of diethylcarbamazine and emodepside leads to a bigger Ca2+ signal than when either compound is applied alone. Our study shows that diethylcarbamazine targets TRP channels to promote Ca2+ entry that is increased by emodepside activation of SLO-1 K+ channels.

The Prevalence of Lymphatic Filariasis Infection among Primary School Children (5-9 Years) of Infected Adults in Ihiala Local Government Area of Anambra State, Nigeria

Aims: To determine the prevalence of Lymphatic flariasis infection among primary school children and of infected adults in Ihiala LGA, Anambra State. Study design: Cross-sectional study. Place and Duration of Study: Department of the Ministry of Health Anambra State and a few selected primary school children in Ihiala Local Government Area between June 2021 and July 2022. Methodology: A total of 150 residents were examined for Lymphatic filariasis. In the Primary Health Centre, a screening for clinical manifestation was done among adults. Sample analysis was done using Filariasis Test Strip while Semi-structured questionnaires were used to collect data on knowledge, attitude and practices (KAP) among residents. Results: Out of 299 blood samples collected from school children and 150 questionnaires distributed to residents to ascertain the awareness of Lymphatic filariasis among residents in the study areas and also to evaluate the efficacy of Ivermectin and Albendazole distributed annually through Mass Drug Administration since 2014, Filariasis Test Strip (FTS) showed 0.0% prevalence of circulating filarial antigen among the school children while the total prevalence of clinical manifestations among residents was 43.33% with higher rate in males (57.33%) than females (42.67%) while forty to 49-year-olds recorded the highest prevalence (13.33%) of clinical manifestations. Statistical analysis was performed with ANOVA using SPSS package and the mean difference is significant at the .05 level that is the P value of the analysis is significant at ≥0.005 level. Conclusion: Our findings on Filariasis Test Strip (FTS) showed 0.0% prevalence of circulating filarial antigen among the school children implying that Lymphatic Filariasis transmissions is low in the study area, suggest the Ivermectin and Albendazole distributed through MDA since 2014 in the endemic areas of Anambra have been effective for Lymphatic filariasis control and should remain the recommended strategy for the elimination of Lymphatic filariasis.

Geospatial modelling of lymphatic filariasis and malaria co-endemicity in Nigeria.

Lymphatic filariasis (LF) and malaria are important vector-borne diseases that are co-endemic throughout Nigeria. These infections are transmitted by the same mosquito vector species in Nigeria and their transmission is similarly influenced by climate and sociodemographic factors. The goal of this study was to assess the relationship between the geospatial distribution of both infections in Nigeria to better coordinate interventions. We used national survey data for malaria from the Demographic and Health Survey dataset and site-level LF mapping data from the Nigeria Lymphatic Filariasis Control Programme together with a suite of predictive climate and sociodemographic factors to build geospatial machine learning models. These models were then used to produce continuous gridded maps of both infections throughout Nigeria. The R2 values for the LF and malaria models were 0.68 and 0.59, respectively. Also, the correlation between pairs of observed and predicted values for LF and malaria models were 0.69 (95% confidence interval [CI] 0.61 to 0.79; p<0.001) and 0.61 (95% CI 0.52 to 0.71; p<0.001), respectively. However, we observed a very weak positive correlation between overall overlap of LF and malaria distribution in Nigeria. The reasons for this counterintuitive relationship are unclear. Differences in transmission dynamics of these parasites and vector competence may contribute to differences in the distribution of these co-endemic diseases.

Diagnosis and Control of Lymphatic Filariasis with Special Emphasis on Gene Editing Method

Diagnosis and Control of Lymphatic Filariasis with Special Emphasis on Gene Editing Method

Lymphatic Filariasis: Insightful Review of a Neglected Tropical Disease

Lymphatic filariasis (LF), a neglected tropical disease has currently infected at least 51 million individuals globally, disfigured and incapacitated about 36 million and placed over 882 million people at risk of infection. It is a painful and profoundly disfiguring disease that can lead to permanent disability. Victims of the disease do not only manifest physical disability, but suffer psychological, social and financial losses leading to stigmatisation and poverty. Regardless of the fact that LF has burdened the majority of individuals in endemic regions for many years, evidence shows that the disease has been poorly understood and its medical importance underestimated. For the past two decades or so, since the launching of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) by World Health Organization (WHO), there has been an avalanche of research works on the disease. This paper aims to provide a systematic and insightful review of the disease. The paper therefore provides a comprehensive outline of the global burden and distribution of LF, causative agents of human filariasis, life cycle of the parasite, clinical manifestations, diagnosis and control of LF.

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.

기생충 길들이기

Study of parasite control was a product of transnational interactions among scientists, activists, public, technologies and tools, as well as ecological environments such as parasites in the geopolitical context. This study critically reviews the previous historical analysis on public health programs, which was mainly looked at in a national context. Also, this study emphasizes that the practice of knowledge has been continuously transformed by social, cultural, and ecological factors that occur across the borders, with a specific example of Korea-Japan Joint research project in Jeju from 1970 to 1972 on the control of lymphatic filariasis. Endemic Burgia Malayi filaria provided a unique opportunity for both Korean and Japanese parasitologists to secure a valuable study object as well as model organism. The construction of knowledge about parasite control did not consist solely of research in a laboratory or university. Just as parasitologists continually engaged in the parasite control program and built up the knowledge and skills involved, these activities aimed to be applied to and practiced by the general public. In the process where knowledge constructed in a laboratory meets an external environment, researchers modified the practice according to appropriate social, cultural and ecological factors in local field of study sites.

Secreted filarial nematode galectins modulate host immune cells.

Lymphatic filariasis (LF) is a mosquito-borne disease caused by filarial nematodes including Brugia malayi. Over 860 million people worldwide are infected or at risk of infection in 72 endemic countries. The absence of a protective vaccine means that current control strategies rely on mass drug administration programs that utilize inadequate drugs that cannot effectively kill adult parasites, thus established infections are incurable. Progress to address deficiencies in the approach to LF control is hindered by a poor mechanistic understanding of host-parasite interactions, including mechanisms of host immunomodulation by the parasite, a critical adaptation for establishing and maintaining infections. The canonical type 2 host response to helminth infection characterized by anti-inflammatory and regulatory immune phenotypes is modified by filarial nematodes during chronic LF. Current efforts at identifying parasite-derived factors driving this modification focus on parasite excretory-secretory products (ESP), including extracellular vesicles (EVs). We have previously profiled the cargo of B. malayi EVs and identified B. malayi galectin-1 and galectin-2 as among the most abundant EV proteins. In this study we further investigated the function of these proteins. Sequence analysis of the parasite galectins revealed highest homology to mammalian galectin-9 and functional characterization identified similar substrate affinities consistent with this designation. Immunological assays showed that Bma-LEC-2 is a bioactive protein that can polarize macrophages to an alternatively activated phenotype and selectively induce apoptosis in Th1 cells. Our data shows that an abundantly secreted parasite galectin is immunomodulatory and induces phenotypes consistent with the modified type 2 response characteristic of chronic LF infection.

Lymphatic Filariasis Control: School-based One Health Initiative on The Usage of Local Plants as Alternative Mosquito Repellants in Timor Tengah Selatan, Nusa Tenggara Timur

Lymphatic filariasis is a mosquito-borne disease that poses a serious public health concern. The disease has spread to 28 Indonesian provinces, with NTT province being one of the 10 provinces with the highest incidence. Aside from being a major supporter of the annual mass drug administration program, the mosquito control initiative is also critical to the disease's eradication. However, today's mosquito control approaches depend primarily on synthetic moieties, which, unfortunately, have resulted in environmental problems and also resistance in important mosquito species. Consequently, developing alternative mosquito control strategies based on herbal components that are environmentally friendly, safe, and long-lasting is necessary. This one-health program aims to educate and raise public awareness of the importance of mosquito control and to inspire the community to utilize local plants as alternative mosquito repellents. This program is targeted high school students from the Timor Tengah Selatan regency. This regency is one of the NTT regencies with the highest risk of lymphatic filariasis. The approach method employed in this program was a series of presentations, discussions, and a demonstration of lymphatic filariasis and the selection of local plants that can be used as herbal repellents. Based on discussions with the students, it was discovered that after engaging in this activity, the participants had learned and recognized the dual function of various indigenous plants in their area as effective and cost-effective mosquito repellents. Furthermore, the students became more excited to learn and develop knowledge about the function of other local plants as efficient mosquito repellents.

Towards elimination of Lymphatic Filariasis in Kenya: improving advocacy, communication and social mobilization activities for mass drug administration, a qualitative study

IntroductionThe Kenya Breaking Transmission Strategy for Neglected Tropical Diseases (NTD) from 2019 to 2023 intensifies advocacy, coordination, and partnerships. The purpose of this study was to explore views and experiences of stakeholders and health workers on ways of improving the Advocacy, Communication and Social Mobilization (ACSM) activities of Mass Drug Administration (MDA) for Lymphatic Filariasis (LF) programs through participatory approaches in Kilifi County, Kenya.MethodsTwo wards were purposely selected in the Kaloleni sub-county, Kilifi County, where there was an average treatment coverage of 56% in 2015, 50.5% in 2016. Qualitative data collection methods were employed, which included participatory meetings with county stakeholders to understand their views, experiences, and suggestions on how ACSM strategies can be improved in MDA for LF. Twelve In-Depth Interviews (IDIs) were conducted (six with opinion leaders and six with Community Health Extension Workers (CHEWs) and two semi-structured interviews (SSIs) were held with county and sub-county coordinators involved in MDA administration. The aim was to better to understand their perceptions of the NTD program about ACSM, challenges to ACSM strategies, and ways to improve the strategies for ACSM in MDA for LF. The Data was organized and classified into codes and themes using QSR NVIVO version 12.ResultsThe study observed the low participation of stakeholders in the ACSM activities of MDA for LF and identified potential areas for stakeholders’ involvement to strengthen the activities. Challenges hindering effective implementation of ACSM activities include late delivery of Information, Educational and Communication (IEC) and few IEC materials, insufficient funding, inadequate time allocated to reach the assigned households with messages, messaging, and packaging of information for dissemination due to the vastness of the area. The stakeholders recommended innovative strategies and techniques to improve ACSM activities.Discussion and conclusionThe results of this study show key challenges to ACSM implementation of MDA for LF. Implementers need to pay attention to these challenges to enhance the effectiveness of MDA per the Kenya NTD Breaking Transmission Strategy. ACSM efforts in MDA for LF control and elimination should be linked with overarching efforts to mainstream partnerships and coordination in control and elimination.

Colorimetric and Real-Time Loop-Mediated Isothermal Amplification (LAMP) for Detection of Loa loa DNA in Human Blood Samples.

Loiasis, caused by the filarial nematode Loa loa, is endemic in Central and West Africa. Loa loa has been associated with severe adverse reactions in high Loa-infected individuals receiving ivermectin during mass drug administration programs for the control of onchocerciasis and lymphatic filariasis. Diagnosis of loiasis still depends on microscopy in blood samples, but this is not effective for large-scale surveys. New diagnostics methods for loiasis are urgently needed. Previously, we developed a colorimetric high-sensitive and species-specific LAMP for Loa loa DNA detection. Here, we evaluate it in a set of 100 field-collected clinical samples stored as dried blood spots. In addition, Loa loa-LAMP was also evaluated in real-time testing and compared with microscopy and a specific PCR/nested PCR. A simple saponin/Chelex-based method was used to extract DNA. Colorimetric and real-time LAMP assays detected more samples with microscopy-confirmed Loa loa and Loa loa/Mansonella perstans mixed infections than PCR/nested-PCR. Samples with the highest Loa loa microfilariae counts were amplified faster in real-time LAMP assays. Our Loa loa-LAMP could be a promising molecular tool for the easy, rapid and accurate screening of patients for loiasis in endemic areas with low-resource settings. The real-time testing (feasible in a handheld device) could be very useful to rule out high-microfilariae loads in infected patients.

Community-based trial assessing the impact of annual versus semiannual mass drug administration with ivermectin plus albendazole and praziquantel on helminth infections in northwestern Liberia

We assessed the impact of three annual vs five semiannual rounds of mass drug administration (MDA) with ivermectin plus albendazole followed by praziquantel for the control or elimination of lymphatic filariasis (LF), onchocerciasis, soil-transmitted helminth (STH) infections and schistosomiasis in Lofa County, Liberia. The study started in 2012 and was interrupted in 2014 during the Ebola virus outbreak. Repeated cross-sectional surveys were conducted in individuals 5 years and older to measure infection markers. Wuchereria bancrofti antigenemia prevalences decreased from 12.5 to 1.2% (90% reduction) and from 13.6 to 4.2% (69% reduction) one year after three rounds of annual or five rounds of semiannual MDA, respectively. Mixed effects logistic regression models showed decreases in odds of antigenemia positivity were 91 and 74% at that time in the annual and semiannual treatment zones, respectively (p < 0.001). Semiannual MDA was slightly more effective for reducing Onchocerca volvulus microfiladermia prevalence and at follow-up 3 were 74% (from 14.4 to 3.7%) and 83% (from 23.6 to 4.5%) in the annual and semiannual treatment zones, respectively. Both treatment schedules had similar beneficial effects on hookworm prevalence. Thus, annual and semiannual MDA with ivermectin and albendazole had similar beneficial impacts on LF, onchocerciasis, and STH in this setting. In contrast, MDA with praziquantel had little impact on hyperendemic Schistosoma mansoni in the study area. Results from a long-term follow-up survey showed that improvements in infection parameters were sustained by routine annual MDA provided by the Liberian Ministry of Health after our study endpoint.

Spatial transcriptomics reveals antiparasitic targets associated with essential behaviors in the human parasite Brugia malayi.

Lymphatic filariasis (LF) is a chronic debilitating neglected tropical disease (NTD) caused by mosquito-transmitted nematodes that afflicts over 60 million people. Control of LF relies on routine mass drug administration with antiparasitics that clear circulating larval parasites but are ineffective against adults. The development of effective adulticides is hampered by a poor understanding of the processes and tissues driving parasite survival in the host. The adult filariae head region contains essential tissues that control parasite feeding, sensory, secretory, and reproductive behaviors, which express promising molecular substrates for the development of antifilarial drugs, vaccines, and diagnostics. We have adapted spatial transcriptomic approaches to map gene expression patterns across these prioritized but historically intractable head tissues. Spatial and tissue-resolved data reveal distinct biases in the origins of known drug targets and secreted antigens. These data were used to identify potential new drug and vaccine targets, including putative hidden antigens expressed in the alimentary canal, and to spatially associate receptor subunits belonging to druggable families. Spatial transcriptomic approaches provide a powerful resource to aid gene function inference and seed antiparasitic discovery pipelines across helminths of relevance to human and animal health.

Long-term consequences of the misuse of ivermectin data

Ivermectin is an oral anti-infective medicine that is integral to neglected tropical disease programmes. It is safe and effective for the treatment and control of lymphatic filariasis, scabies, and onchocerciasis, sometimes as part of a mass drug administration, as recognised in the WHO road map for neglected tropical diseases 2021–30.1 The WHO essential medicines list provides recommendations for minimum medicine needs for a basic health-care system, which includes ivermectin as an anthelmintic, antifilarial, and antiectoparasitic treatment.

Larval habitat diversity and Anopheles mosquito species distribution in different ecological zones in Ghana

BackgroundUnderstanding the ecology of larval malaria and lymphatic filariasis mosquitoes in a changing environment is important in developing effective control tools or programmes. This study characterized the breeding habitats of Anopheles mosquitoes in rural communities in different ecological zones in Ghana during the dry and rainy seasons.MethodsThe spatio-temporal distribution, species composition, and abundance of larval Anopheles mosquitoes in breeding habitats were studied in five locations in three ecological zones of Ghana. These were Anyakpor (coastal savannah area), Duase (forest area), and Libga, Pagaza, and Kpalsogu (Sahel savannah area). Larvae were collected using standard dippers and were raised in the insectary for identification.ResultsOut of a total of 7984 mosquito larvae collected, 2152 (27.26%) were anophelines and were more abundant in the rainy season (70.82%) than in the dry season (29.18%). The anophelines comprised 2128 (98.88%) An. gambiae s.l., 16 (0.74%) An. rufipes, and 8 (0.37%) An. pharoensis. In the coastal savannah and forest zones, dug-out wells were the most productive habitat during the dry (1.59 larvae/dip and 1.47 larvae/dip) and rainy seasons (11.28 larvae/dip and 2.05 larvae/dip). Swamps and furrows were the most productive habitats in the Sahel savannah zone during the dry (0.25 larvae/dip) and rainy (2.14 larvae/dip) seasons, respectively. Anopheles coluzzii was the most abundant sibling species in all the ecological zones. Anopheles melas and An. arabiensis were encountered only in the coastal savannah and the Sahel savannah areas, respectively. Larval habitat types influenced the presence of larvae as well as larval density (p < 0.001). The land-use type affected the presence of Anopheles larvae (p = 0.001), while vegetation cover influenced larval density (p < 0.05).ConclusionThe most productive habitats were dug-out wells in the coastal savannah and forest zones, and furrows from irrigated canals in the Sahel savannah zone. Anopheles coluzzii was the predominant vector species in all the ecological zones. The abundance of Anopheles breeding habitats and larvae were influenced by anthropogenic activities. Encouraging people whose activities create the larval habitats to become involved in larval source management such as habitat manipulation to stop mosquito breeding will be important for malaria and lymphatic filariasis control.

Individual Efficacy and Community Impact of Ivermectin, Diethylcarbamazine, and Albendazole Mass Drug Administration for Lymphatic Filariasis Control in Fiji: A Cluster Randomized Trial.

Bancroftian filariasis remains endemic in Fiji despite >10 years of mass drug administration (MDA) using diethylcarbamazine and albendazole (DA). The addition of ivermectin to this combination (IDA) has improved efficacy of microfilarial clearance at 12 months in individually randomized trials in nocturnal transmission settings, but impact in a setting of diurnally subperiodic filarial transmission has not been evaluated. This cluster randomized study compared the individual efficacy and community impact of IDA vs DA as MDA for lymphatic filariasis in 35 villages on 2 islands of Fiji. Participants were tested at enrollment for circulating filarial antigen and, if positive, for microfilariae. Weight-dosed treatment was offered according to village randomization. Communities were visited at 12 months and retested for lymphatic filariasis. Infected individuals from Rotuma were retested at 24 months. A total of 3816 participants were enrolled and 3616 were treated. At 12 months, microfilariae clearance was achieved in 72 of 111 participants detected with infection at baseline, with no difference in efficacy between treatment groups: DA, 69.2% (95% confidence interval [CI], 57.2%-79.1%) vs IDA, 62.5% (95% CI, 43.6%-78.2%); risk difference, 11.3 % (95% CI, -10% to 32.7%); P = .30. There was no difference between treatment groups in community prevalence of microfilariae at 12 months or individual clearance at 24 months. We found no difference between IDA and DA in individual clearance or community prevalence of lymphatic filariasis at 12 months, and no improved efficacy following a second annual round of IDA. Possible explanations for the apparent lack of benefit of IDA compared to DA include drug and parasite factors affecting clearance, and higher than expected reinfection rates. Clinical Trials Registration: NCT03177993 and Australian New Zealand Clinical Trial Registry: N12617000738325.