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.

How Does the Proportion of Never Treatment Influence the Success of Mass Drug Administration Programs for the Elimination of Lymphatic Filariasis?

BACKGROUND: Mass drug administration (MDA) is the cornerstone for the elimination of lymphatic filariasis (LF). The proportion of the population that is never treated (NT) is a crucial determinant of whether this goal is achieved within reasonable time frames. METHODS: Using 2 individual-based stochastic LF transmission models, we assess the maximum permissible level of NT for which the 1% microfilaremia (mf) prevalence threshold can be achieved (with 90% probability) within 10 years under different scenarios of annual MDA coverage, drug combination and transmission setting. RESULTS: For Anopheles-transmission settings, we find that treating 80% of the eligible population annually with ivermectin + albendazole (IA) can achieve the 1% mf prevalence threshold within 10 years of annual treatment when baseline mf prevalence is 10%, as long as NT <10%. Higher proportions of NT are acceptable when more efficacious treatment regimens are used. For Culex-transmission settings with a low (5%) baseline mf prevalence and diethylcarbamazine + albendazole (DA) or ivermectin + diethylcarbamazine + albendazole (IDA) treatment, elimination can be reached if treatment coverage among eligibles is 80% or higher. For 10% baseline mf prevalence, the target can be achieved when the annual coverage is 80% and NT ≤15%. Higher infection prevalence or levels of NT would make achieving the target more difficult. CONCLUSIONS: The proportion of people never treated in MDA programmes for LF can strongly influence the achievement of elimination and the impact of NT is greater in high transmission areas. This study provides a starting point for further development of criteria for the evaluation of NT.

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.

Coverage of preventive measures and surveillance for neglected tropical diseases in hard-to-reach communities in Ghana.

BACKGROUND: Neglected tropical diseases (NTDs) are a major public health burden which mainly affects poor populations living in tropical environments and hard-to-reach areas. The study sought to examine coverage of preventive efforts, and case surveillance for NTDs in hard-to-reach communities in Ghana. METHODS: The study investigated treatment efforts for lymphatic filariasis (LF), and onchocerciasis and schistosomiasis/soil transmitted helminths (SCH/STH) at household level, in difficult-to-access communities in Ghana. A total of 621 households were sampled from 6 communities in the Western, Oti and Greater Accra regions. RESULTS: Over 95% of the households surveyed were covered under mass drug administration (MDA) campaigns for lymphatic filariasis (LF) and onchocerciasis. More than 80% of households had received at least two visits by community drug distributors under the MDA campaigns in the last two years preceding the study. In addition, over 90% of households in the LF and onchocerciasis endemic communities had at least one member using anthelminthic medications under the MDA campaigns in the 12 months preceding the study. However, households where no member had taken anthelminthic medications in 12 months preceding the study were over 6 times likely to have someone in the household with LF. CONCLUSIONS: This study determined that SCH/STH, LF and onchocerciasis are of serious public health concern in some communities in Ghana. There is an urgent need for holistic practical disease control plan involving both financial and community support to ensure total control of NTDs in difficult-to-access communities is achieved.

Coverage and compliance of mass drug administration (MDA) programme for elimination of lymphatic filariasis in an endemic district of eastern Uttar Pradesh, India.

BACKGROUND & OBJECTIVES: Lymphatic filariasis is targeted for elimination in India through mass drug administration (MDA) with diethylcarbamazine (DEC) combined with albendazole (ABZ). To assess the coverage, compliance and causes for non-compliance towards MDA in an endemic district of Uttar Pradesh (U.P.), north India. METHODS: A cross-sectional coverage evaluation survey was conducted in 24 rural and 6 urban clusters of Ghazipur district in eastern U.P. using multi-stage random sampling technique with probability proportional to estimated size (PPES). Data was collected in a semi-structured Performa from all the individuals in the selected households by interview technique. Bivariate analysis was performed to identify the factors associated with non-consumption of MDA drugs. RESULTS: A total of 1422 individuals were surveyed from 30 randomly selected subunits of which 1401 (98.5%) were eligible for MDA at the time of the round. Majority of the participants were in the age-group of 15-59 years (67.0%) and were males (53.3%). The overall coverage of MDA (both drugs) among the eligible population in Ghazipur district was 58.5%. Compliance among those who had received both the drugs was 61.6% with effective coverage of 36.0%. The coverage was significantly higher in rural areas compared to the urban clusters (p<0.0001). The most common reason quoted for not consuming drugs was fear of side effects (34.9%). However, the incidence of adverse events among those who consumed the drugs was only 2.5%. None of the socio-demographic variables showed a significant association with the compliance to the drugs. INTERPRETATION & CONCLUSION: Coverage and compliance of MDA in Ghazipur district of U.P., India was found to be below satisfactory levels. Targeted Information Education and Communication (IEC) campaigns focusing on the safety of drugs and the necessity of MDA, and mass mobilization with effective monitoring and supervision is the need of the hour for effective coverage of MDA Programme.

Semiannual Treatment of Albendazole Alone is Efficacious for Treatment of Lymphatic Filariasis: A Randomized Open-label Trial in Cote d'Ivoire.

BACKGROUND: Ivermectin (IVM) plus albendazole (ALB), or IA, is widely used in mass drug administration (MDA) programs that aim to eliminate lymphatic filariasis (LF) in Africa. However, IVM can cause severe adverse events in persons with heavy Loa loa infections that are common in Central Africa. ALB is safe in loiasis, but more information is needed on its efficacy for LF. This study compared the efficacy and safety of 3 years of semiannual treatment with ALB to annual IA in persons with bancroftian filariasis. METHODS: Adults with Wuchereria bancrofti microfilaremia (Mf) were randomized to receive either 3 annual doses of IA (N = 52), 6 semiannual doses of ALB 400 mg (N = 45), or 6 semiannual doses of ALB 800 mg (N = 47). The primary outcome is amicrofilaremia at 36 months. RESULTS: IA was more effective for completely clearing Mf than ALB 400mg or ALB 800mg (79%, 95% confidence interval [CI]: 67-91; vs 48%, 95% CI: 32-66 and 57%, 95% CI: 41-73, respectively). Mean percentage reductions in Mf counts at 36 months relative to baseline tended to be greater after IA (98%, 95% CI: 88-100) than after ALB 400 mg (88%, 95% CI: 78-98) and ALB 800 mg (89%, 95% CI: 79-99) (P = .07 and P = .06, respectively). Adult worm nest numbers (assessed by ultrasound) were reduced in all treatment groups. Treatments were well tolerated. CONCLUSIONS: Repeated semiannual treatment with ALB is macrofilaricidal for W. bancrofti and leads to sustained reductions in Mf counts. This is a safe and effective regimen that could be used as MDA to eliminate LF in areas where ivermectin cannot be used. CLINICAL TRIALS REGISTRATION: NCT02974049.

Multi-drug resistant bacteria isolates from lymphatic filariasis patients in the Ahanta West District, Ghana.

BACKGROUND: Antimicrobial resistance is associated with increased morbidity in secondary infections and is a global threat owning to the ubiquitous nature of resistance genes in the environment. Recent estimate put the deaths associated with bacterial antimicrobial resistance in 2019 at 4.95 million worldwide. Lymphatic filariasis (LF), a Neglected Tropical Disease (NTD), is associated with the poor living in the tropical regions of the world. LF patients are prone to developing acute dermatolymphangioadenitis (ADLA), a condition that puts them at risk of developing secondary bacterial infections due to skin peeling. ADLA particularly worsens the prognosis of patients leading to usage of antibiotics as a therapeutic intervention. This may result in inappropriate usage of antibiotics due to self-medication and non-compliance; exacerbating antimicrobial resistance in LF patients. In this perspective, we assessed the possibilities of antimicrobial resistance in LF patients. We focused on antibiotic usage, antibiotic resistance in Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa isolates and looked at genes (mecA and Extended-spectrum beta-lactamase [blaCTX-M, blaSHV and blaTEM]) coding for resistance in multi-drug resistant (MDR) bacterial isolates. RESULTS: Of the sixty (60) participants, fifty-four (n = 54, 90%) were within 31-60 years of age, twenty (n = 20, 33.33%) were unemployed and thirty-eight (n = 38, 50.67%) had wounds aged (in months) seven (7) months and above. Amoxicillin (54%) and chloramphenicol (22%) were the most frequently used antibiotics for self-medication. Staphylococcus aureus isolates (n = 26) were mostly resistant to penicillin (n = 23, 88.46%) and least resistant to erythromycin (n = 2, 7.69%). Escherichia coli isolates (n = 5) were resistant to tetracycline (n = 5, 100%) and ampicillin (n = 5, 100%) but were sensitive to meropenem (n = 5, 100%). Pseudomonas aeruginosa isolates (n = 8) were most resistant to meropenem (n = 3, 37.50%) and to a lesser ciprofloxacin (n = 2, 25%), gentamicin (n = 2, 25%) and ceftazidime (n = 2, 25%). Multi-drug resistant methicillin resistant Staphylococcus aureus (MRSA), cephalosporin resistant Escherichia coli. and carbapenem resistant Pseudomonas aeruginosa were four (n = 4, 15.38%), two (n = 2, 40%) and two (n = 2, 25%) respectively. ESBL (blaCTX-M) and mecA genes were implicated in the resistance mechanism of Escherichia coli and MRSA, respectively. CONCLUSION: The findings show presence of MDR isolates from LF patients presenting with chronic wounds; thus, the need to prioritize resistance of MDR bacteria into treatment strategies optimizing morbidity management protocols. This could guide antibiotic selection for treating LF patients presenting with ADLA.

Efficacy and safety of triple therapy versus dual therapy for lymphatic filariasis: A systematic review and meta-analysis.

OBJECTIVE: Lymphatic filariasis is a serious public health issue. Recent studies showed that a single dosage of triple therapy (Ivermectin, Diethylcarbamazepine, and Albendazole) is more effective than dual therapy (Ivermectin plus Albendazole or Diethylcarbamazepine plus Albendazole) for clearing microfilaria from the blood. We aimed to evaluate the efficacy and safety of triple therapy versus dual therapy in patients infected with microfilaria and communities endemic to lymphatic filariasis. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, EMBASE, SCOPUS, Cochrane Central Register of Controlled Trials, and Web of Science until 24th June 2021. We included randomized control trials that compared triple with dual therapy given to patients with lymphatic filariasis or endemic communities. This study was registered with PROSPERO (CRD42021266724). RESULTS: We included eight articles after the screening process. Triple therapy caused more clearance of microfilaria in the blood (RR: 1.52; 95% CI: 1.15, 2.02; p = 0.003), while dual therapy caused more clearance of the circulating filariae antigen in the blood (RR: 0.76; 95% CI: 0.65, 0.88; p = 0.0003), both 12 months after drug administration. The triple therapy had a similar adverse effect compared with the dual therapy group. CONCLUSION: Based on the greater efficacy in the clearance of microfilaria and the safety of triple therapy, it constitutes a better strategy for the eradication programs of lymphatic filariasis in endemic regions. However, further studies are needed to confirm our results.

Soil-transmitted helminth infections after mass drug administration for lymphatic filariasis in rural southern India.

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.

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.

AWZ1066S, a highly specific anti-Wolbachia drug candidate for a short-course treatment of filariasis.

Onchocerciasis and lymphatic filariasis are two neglected tropical diseases that together affect ∼157 million people and inflict severe disability. Both diseases are caused by parasitic filarial nematodes with elimination efforts constrained by the lack of a safe drug that can kill the adult filaria (macrofilaricide). Previous proof-of-concept human trials have demonstrated that depleting >90% of the essential nematode endosymbiont bacterium, Wolbachia, using antibiotics, can lead to permanent sterilization of adult female parasites and a safe macrofilaricidal outcome. AWZ1066S is a highly specific anti-Wolbachia candidate selected through a lead optimization program focused on balancing efficacy, safety and drug metabolism/pharmacokinetic (DMPK) features of a thienopyrimidine/quinazoline scaffold derived from phenotypic screening. AWZ1066S shows superior efficacy to existing anti-Wolbachia therapies in validated preclinical models of infection and has DMPK characteristics that are compatible with a short therapeutic regimen of 7 days or less. This candidate molecule is well-positioned for onward development and has the potential to make a significant impact on communities affected by filariasis.

No evidence of lymphatic filariasis transmission in Bamako urban setting after three mass drug administration rounds.

Lymphatic filariasis (LF) elimination activities started in Mali in 2005 in the most endemic areas and reached countrywide coverage in 2009. In 2004, the district of Bamako was endemic for LF with a prevalence of 1.5%. The current study was designed to determine LF endemicity level in the urban area of Bamako after three rounds of ivermectin and albendazole mass drug administration (MDA). A cross-sectional study was conducted in 2011 in Bamako city, consisting of human prevalence and entomological surveys. Volunteers aged 14 years and above were invited to participate and tested for evidence of Wuchereria bancrofti using night time blood thick smear microfilarial count and blood spots for LF antibodies using the SD BIOLINE Oncho/LF IgG4 Biplex rapid test (Ov16/Wb123). Mosquitoes were collected using CDC light and gravid traps and tested using molecular methods. Poolscreen software v2.0 was used to estimate vector transmission potential. Of the 899 volunteers, one (0.11%) was found to be positive for LF using the Oncho/LF IgG4 Biplex rapid test, and none was found to have Wuchereria bancrofti microfilariae. No mosquitoes were found infected among 6174 Culex spp. (85.2%), 16 Anopheles gambiae s.l. (An. gambiae s.l.) (0.2%), 26 Aedes spp. (0.4%), 858 Ceratopogonidae (11.8%) and 170 other insects not identified (2.3%) tested. Our data indicate that there was no active LF transmission in the low prevalence urban district of Bamako after three MDA rounds. These data helped the National LF programme move forward towards the elimination goal.

Wuchereria Bancrofti Infection in Children Living in a Rubber Plantation Estate in South-South Nigeria.

BACKGROUND: Chronic manifestations of bancrofti filariasis can be debilitating. There is paucity of description of this disease in the childhood population, yet early detection can prevent disability such as elephantiasis. OBJECTIVE: The objective of the study was to determine the prevalence and clinical features of this infection among children in a plantation estate in Cross River State, Nigeria. METHODS: It was a cross-sectional study in subjects aged 1 to 18 years, recruited from the nine camps of the settlement, using multistage sampling technique. The presence of Circulating Filarial Antigen (CFA) was tested for using Immunochromatographic Card Technique (ICT). Simple proportions, percentages, Chi square and Fisher's exact tests were used to analyse the data. RESULTS: A total of 342 subjects were recruited into the study. One hundred and sixty three (47.7%) were males. The mean age was 8.52± 4.41years. Majority of the subjects, 316(92.4%), were from families of low socioeconomic status. Twenty of the 342 children (5.8%) were positive for microfilaria antigenaemia. Increasing age (p=0.006) and duration of stay in the estate (p=0.005) were positively associated with antigenaemia. None (0%) of the 55 subjects who used insecticide treated nets was positive for CFA, while 20 (6.97%) of the 287 who did not, were positive (p=0.03). Only ten (3.95%) of the 253 subjects who used insecticide spray vs 10 (11.0%) of the 89 who did not use spray were positive for CFA (p=0.016). Itching was the only significant symptom identified. CONCLUSION: The prevalence of Wuchereria bancrofti in the subjects was 5.8%, with increasing prevalence with age. Itching was the only significant clinical feature. The use of insecticide treated nets and insecticide sprays significantly reduced the chances of being infected. There is a need for elimination programme to be extended to the childhood population and to sub-urban areas.

CONTEXTE: Les manifestations chroniques de la filariose de bancrofti peuvent être débilitantes. Il existe peu de descriptions de cette maladie dans la population infantile, mais une détection précoce peut prévenir des handicaps tels que l'éléphantiasis. OBJECTIF: L'objectif de l'étude était de déterminer la prévalence et caractéristiques cliniques de cette infection chez les enfants d'une plantation dans l'État de Cross River, au Nigéria. METHODES: Il s'agissait d'une étude transversale chez des sujets âgés de 1 à 18 ans, recrutés dans les neuf camps de la colonie, en utilisant la technique d'échantillonnage à plusieurs degrés. La présence d'antigène filarien circulant (CFA) a été testée à l'aide de la technique de carte immunochromatographique (ICT). Des proportions simples, des pourcentages, le Chi carré et des tests exacts de Fisher ont été utilisés pour analyser les données. RESULTATS: Un total de 342 sujets ont été recrutés dans l'étude. Cent soixante trois (47,7 %) étaient des hommes. L'âge moyen était de 8,52 ± 4,41 ans. La majorité des sujets, 316 (92,4 %), provenaient de familles de faible statut socio-économique. Vingt des 342 enfants (5,8 %) étaient positifs pour l'antigénémie des microfilaires. L'augmentation de l'âge (p = 0,006) et de la durée de séjour dans le domaine (p = 0,005) était positivement associée à l'antigénémie. Aucun (0%) des 55 sujets qui ont utilisé des moustiquaires imprégnées d'insecticide n'était positif pour le CFA, tandis que 20 (6,97%) des 287 qui n'en avaient pas étaient positifs (p=0,03). Seuls dix (3,95 %) des 253 sujets qui ont utilisé un insecticide contre 10 (11,0 %) des 89 qui n'ont pas utilisé de spray étaient positifs pour le CFA (p = 0,016). Les démangeaisons étaient le seul symptôme significatif identifié. CONCLUSION: La prévalence de Wuchereria bancrofti chez les sujets était de 5,8 %, avec une prévalence croissante avec l'âge. Les démangeaisons étaient la seule caractéristique clinique significative. L'utilisation de moustiquaires imprégnées d'insecticide et de pulvérisations d'insecticide a considérablement réduit les risques d'infection. Il est nécessaire d'étendre le programme d'élimination à la population infantile et aux zones suburbaines. Mots clés: Filariose de Bancrofti, Enfants, Zone d'Endémie.

Evaluating the Diagnostic Test Accuracy of Molecular Xenomonitoring Methods for Characterizing Community Burden of Lymphatic Filariasis.

BACKGROUND: Molecular xenomonitoring (MX), the detection of pathogen DNA in mosquitoes, is a recommended approach to support lymphatic filariasis (LF) elimination efforts. Potential roles of MX include detecting presence of LF in communities and quantifying progress towards elimination of the disease. However, the relationship between MX results and human prevalence is poorly understood. METHODS: We conducted a systematic review and meta-analysis from all previously conducted studies that reported the prevalence of filarial DNA in wild-caught mosquitoes (MX rate) and the corresponding prevalence of microfilaria (mf) in humans. We calculated a pooled estimate of MX sensitivity for detecting positive communities at a range of mf prevalence values and mosquito sample sizes. We conducted a linear regression to evaluate the relationship between mf prevalence and MX rate. RESULTS: We identified 24 studies comprising 144 study communities. MX had an overall sensitivity of 98.3% (95% confidence interval, 41.5-99.9%) and identified 28 positive communities that were negative in the mf survey. Low sensitivity in some studies was attributed to small mosquito sample sizes (<1000) and very low mf prevalence (<0.25%). Human mf prevalence and mass drug administration status accounted for approximately half of the variation in MX rate (R2 = 0.49, P < .001). Data from longitudinal studies showed that, within a given study area, there is a strong linear relationship between MX rate and mf prevalence (R2 = 0.78, P < .001). CONCLUSIONS: MX shows clear potential as tool for detecting communities where LF is present and as a predictor of human mf prevalence.

Results From 2 Cohort Studies in Central Africa Show That Clearance of Wuchereria bancrofti Infection After Repeated Rounds of Mass Drug Administration With Albendazole Alone Is Closely Linked to Individual Adherence.

BACKGROUND: Two community trials conducted from 2012 to 2018 in the Republic of Congo and the Democratic Republic of the Congo demonstrated the efficacy of semiannual mass drug administration (MDA) with albendazole (ALB) alone on lymphatic filariasis (LF). However, a high interindividual heterogeneity in the clearance of infection was observed. METHODS: We analyzed trial data to assess the effect of individual adherence to ALB MDA on clearance of circulating filarial antigenemia (CFA) and microfilaremia. Community residents were offered a single dose of ALB every 6 months and tested for LF with a rapid test for CFA at baseline and then annually. CFA test results were scored on a semiquantitative scale. At each round, microfilaremia was assessed in CFA-positive individuals. All CFA-positive individuals for whom at least 1 follow-up measure was available were included in the analyses. Parametric survival models were used to assess the influence of treatment adherence on LF infection indicators. RESULTS: Of 2658 individuals enrolled in the trials, 394 and 129 were eligible for analysis of CFA and microfilaremia clearance, respectively. After adjusting for age, sex, and initial CFA score, the predicted mean time for clearing CFA was shorter in persons who had taken 2 doses of ALB per year (3.9 years) than in persons who had taken 1 or 0 dose (4.4 and 5.3 years; P < .001 for both). A similar pattern was observed for microfilaremia clearance. CONCLUSIONS: These results demonstrate a clear dose-response relationship for the effect of ALB on clearance of CFA and microfilaremia.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Serological Evaluation of Onchocerciasis and Lymphatic Filariasis Elimination in the Bakoye and Falémé Foci, Mali.

BACKGROUND: Ivermectin-based onchocerciasis elimination, reported in 2009-2012, for Bakoye and Falémé, Mali, supported policy-shifting from morbidity control to elimination of transmission (EOT). These foci are coendemic with lymphatic filariasis (LF). In 2007-2016 mass ivermectin plus albendazole administration was implemented. We report Ov16 (onchocerciasis) and Wb123 (LF) seroprevalence after 24-25 years of treatment to determine if onchocerciasis EOT and LF elimination as a public health problem (EPHP) have been achieved. METHODS: The SD Bioline Onchocerciasis/LF Ig[immunoglobulin]G4 biplex rapid diagnostic test (RDT) was used in 2186 children aged 3-10 years in 13 villages (plus 2 hamlets) in Bakoye and in 2270 children in 15 villages (plus 1 hamlet) in Falémé. In Bakoye, all-age serosurveys were conducted in 3 historically hyperendemic villages (1867 individuals aged 3 -78 years). RESULTS: In Bakoye, IgG4 seropositivity was 0.27% (95% confidence interval [CI] = .13%-.60%) for both Ov16 and Wb123 antigens. In Falémé, Ov16 and Wb123 seroprevalence was 0.04% (95% CI = .01%-.25%) and 0.09% (95% CI = .02%-.32%), respectively. Ov16-seropositive children were from historically meso/hyperendemic villages. Ov16 positivity was <2% in ≤14 year-olds, and 16% in ≥40 year-olds. Wb123 seropositivity was <2% in ≤39 year-olds, reaching 3% in ≥40 year-olds. CONCLUSIONS: Notwithstanding uncertainty in the biplex RDT sensitivity, Ov16 and Wb123 seroprevalence among children in Bakoye and Falémé is consistent with EOT (onchocerciasis) and EPHP (LF) since stopping treatment in 2016. The few Ov16-seropositive children should be skin-snip polymerase chain reaction tested and followed up.

Population Pharmacokinetics of Diethylcarbamazine in Patients with Lymphatic Filariasis and Healthy Individuals.

Diethylcarbamazine (DEC) is a drug of choice to treat lymphatic filariasis (LF) either used alone or in combination as mass drug administration (MDA) preventive strategies. The objective of this study was to develop a population pharmacokinetics (PK) model for DEC in subjects infected with lymphatic filariasis (LF) compared to healthy individuals, and to evaluate the effect of covariates on the volume of distribution (V/F) and oral clearance (CL/F) of DEC. This was an open-label cohort study of treatment-naive Wuchereria bancrofti-infected (n = 32) and uninfected (n = 24) adults residing in the Agboville District of Côte d'Ivoire. The population pharmacokinetics model for DEC was built using Phoenix NLME 8.0 software. The covariates included in the model-building process were age, gender, body weight, infection status, creatinine clearance (CLCR), and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. A total of 56 adults were enrolled in the study, and a total of 728 samples were obtained over 168 h. A one-compartment linear pharmacokinetics model with first-order absorption with an absorption lag time (Tlag) best described the data. After determining the pharmacokinetics (PK) parameters of DEC, body weight and gender were found to be the significant covariates for DEC V/F. The final population pharmacokinetics model adequately described the pharmacokinetics of DEC in the studied population. Model-based simulation indicated that the body weight significantly impacted the exposure in both the male and female populations. This analysis may further support the drug-drug interaction model development of DEC with different coadministered drugs or agents in disease control programs. (This study is registered at clinicaltrials.gov under identifier NCT02845713.).

A Trial of a Triple-Drug Treatment for Lymphatic Filariasis.

BACKGROUND: The World Health Organization has targeted lymphatic filariasis for global elimination by 2020 with a strategy of mass drug administration. This trial tested whether a single dose of a three-drug regimen of ivermectin plus diethylcarbamazine plus albendazole results in a greater sustained clearance of microfilariae than a single dose of a two-drug regimen of diethylcarbamazine plus albendazole and is noninferior to the two-drug regimen administered once a year for 3 years. METHODS: In a randomized, controlled trial involving adults from Papua New Guinea with Wuchereria bancrofti microfilaremia, we assigned 182 participants to receive a single dose of the three-drug regimen (60 participants), a single dose of the two-drug regimen (61 participants), or the two-drug regimen once a year for 3 years (61 participants). Clearance of microfilariae from the blood was measured at 12, 24, and 36 months after trial initiation. RESULTS: The three-drug regimen cleared microfilaremia in 55 of 57 participants (96%) at 12 months, in 52 of 54 participants (96%) at 24 months, and in 55 of 57 participants (96%) at 36 months. A single dose of the two-drug regimen cleared microfilaremia in 18 of 56 participants (32%) at 12 months, in 31 of 55 participants (56%) at 24 months, and in 43 of 52 participants (83%) at 36 months (P=0.02 for the three-drug regimen vs. a single dose of the two-drug regimen at 36 months). The two-drug regimen administered once a year for 3 years cleared microfilaremia in 20 of 59 participants (34%) at 12 months, in 42 of 56 participants (75%) at 24 months, and in 51 of 52 participants (98%) at 36 months (P=0.004 for noninferiority of the three-drug regimen vs. the two-drug regimen administered once a year for 3 years at 36 months). Moderate adverse events were more common in the group that received the three-drug regimen than in the combined two-drug-regimen groups (27% vs. 5%, P<0.001). There were no serious adverse events. CONCLUSIONS: The three-drug regimen induced clearance of microfilariae from the blood for 3 years in almost all participants who received the treatment and was superior to the two-drug regimen administered once and noninferior to the two-drug regimen administered once a year for 3 years. (Funded by the Bill and Melinda Gates Foundation; ClinicalTrials.gov number, NCT01975441 .).