Detection of Wuchereria bancrofti infection in mosquitoes in areas co-endemic with Brugia malayi in Balasore district, Odisha, India.

Lymphatic filariasis (LF) is a crippling and disfiguring parasitic condition. India accounts for 55% of the world's LF burden. The filarial parasite Wuchereria bancrofti is known to cause 99.4% of the cases while, Brugia malayi accounts for 0.6% of the issue occurring mainly in some pockets of Odisha and Kerala states. The Balasore (Baleswar) district of Odisha has been a known focus of B. malayi transmission. We employed molecular xenomonitoring to detect filarial parasite DNA in vectors. In six selected villages, Gravid traps were used to collect Culex mosquitoes and hand catch method using aspirators was followed for collection of mansonioides. A total of 2903 mosquitoes comprising of Cx. quinquefasciatus (n = 2611; 89.94%), Cx. tritaeniorhynchus (n = 100; 3.44%), Mansonia annuliferea (n = 139; 4.78%) and Mansonia uniformis (n = 53; 1.82%) were collected from six endemic villages. The species wise mosquitoes were made into 118 pools, each with a maximum of 25 mosquitoes, dried and transported to the laboratory at VCRC, Puducherry. The mosquito pools were subjected to parasite DNA extraction, followed by Real-time PCR using LDR and HhaI probes to detect W. bancrofti and B. malayi infections, respectively. Seven pools (6.66%) of Cx. quinquefasciatus, showed infection with only W. bancrofti while none of the pools of other mosquito species showed infection with either W. bancrofti or B. malayi. Although the study area is endemic to B. malayi, none of the vectors of B. malayi was found with parasite infection. This study highlights the ongoing transmission of bancroftian filariasis in the study villages of Balasore district of Odisha and its implications for evaluating LF elimination programme.

Distinguishing recrudescence from reinfection in lymphatic filariasis.

BACKGROUND: The Global Program to Eliminate Lymphatic Filariasis (GPELF) is the largest public health program based on mass drug administration (MDA). Despite decades of MDA, ongoing transmission in some countries remains a challenge. To optimise interventions, it is critical to differentiate between recrudescence and new infections. Since adult filariae are inaccessible in humans, deriving a method that relies on the offspring microfilariae (mf) is necessary. METHODS: We developed a genome amplification and kinship analysis-based approach using Brugia malayi samples from gerbils, and applied it to analyse Wuchereria bancrofti mf from humans in Côte d'Ivoire. We examined the pre-treatment genetic diversity in 269 mf collected from 18 participants, and further analysed 1-year post-treatment samples of 74 mf from 4 participants. Hemizygosity of the male X-chromosome allowed for direct inference of haplotypes, facilitating robust maternal parentage inference. To enrich parasite DNA from samples contaminated with host DNA, a whole-exome capture panel was created for W. bancrofti. FINDINGS: By reconstructing and temporally tracking sibling relationships across pre- and post-treatment samples, we differentiated between new and established maternal families, suggesting reinfection in one participant and recrudescence in three participants. The estimated number of reproductively active adult females ranged between 3 and 11 in the studied participants. Population structure analysis revealed genetically distinct parasites in Côte d'Ivoire compared to samples from other countries. Exome capture identified protein-coding variants with ∼95% genotype concordance rate. INTERPRETATION: We have generated resources to facilitate the development of molecular genetic tools that can estimate adult worm burdens and monitor parasite populations, thus providing essential information for the successful implementation of GPELF. FUNDING: This work was financially supported by the Bill and Melinda Gates Foundation (https://www.gatesfoundation.org) under grant OPP1201530 (Co-PIs PUF & Gary J. Weil). B. malayi parasite material was generated with support of the Foundation for Barnes Jewish Hospital (PUF). In addition, the development of computational methods was supported by the National Institutes of Health under grants AI144161 (MM) and AI146353 (MM). The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

An automated, high-resolution phenotypic assay for adult Brugia malayi and microfilaria.

Brugia malayi are thread-like parasitic worms and one of the etiological agents of Lymphatic filariasis (LF). Existing anthelmintic drugs to treat LF are effective in reducing the larval microfilaria (mf) counts in human bloodstream but are less effective on adult parasites. To test potential drug candidates, we report a multi-parameter phenotypic assay based on tracking the motility of adult B. malayi and mf in vitro. For adult B. malayi, motility is characterized by the centroid velocity, path curvature, angular velocity, eccentricity, extent, and Euler Number. These parameters are evaluated in experiments with three anthelmintic drugs. For B. malayi mf, motility is extracted from the evolving body skeleton to yield positional data and bending angles at 74 key point. We achieved high-fidelity tracking of complex worm postures (self-occlusions, omega turns, body bending, and reversals) while providing a visual representation of pose estimates and behavioral attributes in both space and time scales.

Edge Artificial Intelligence (AI) for real-time automatic quantification of filariasis in mobile microscopy.

Filariasis, a neglected tropical disease caused by roundworms, is a significant public health concern in many tropical countries. Microscopic examination of blood samples can detect and differentiate parasite species, but it is time consuming and requires expert microscopists, a resource that is not always available. In this context, artificial intelligence (AI) can assist in the diagnosis of this disease by automatically detecting and differentiating microfilariae. In line with the target product profile for lymphatic filariasis as defined by the World Health Organization, we developed an edge AI system running on a smartphone whose camera is aligned with the ocular of an optical microscope that detects and differentiates filarias species in real time without the internet connection. Our object detection algorithm that uses the Single-Shot Detection (SSD) MobileNet V2 detection model was developed with 115 cases, 85 cases with 1903 fields of view and 3342 labels for model training, and 30 cases with 484 fields of view and 873 labels for model validation before clinical validation, is able to detect microfilariae at 10x magnification and distinguishes four species of them at 40x magnification: Loa loa, Mansonella perstans, Wuchereria bancrofti, and Brugia malayi. We validated our augmented microscopy system in the clinical environment by replicating the diagnostic workflow encompassed examinations at 10x and 40x with the assistance of the AI models analyzing 18 samples with the AI running on a middle range smartphone. It achieved an overall precision of 94.14%, recall of 91.90% and F1 score of 93.01% for the screening algorithm and 95.46%, 97.81% and 96.62% for the species differentiation algorithm respectively. This innovative solution has the potential to support filariasis diagnosis and monitoring, particularly in resource-limited settings where access to expert technicians and laboratory equipment is scarce.

Unpacking Immune Modulation as a Site of Therapeutics Innovation for Nematode Parasite Wuchereria bancrofti: A Temporal Quantitative Phosphoproteomics Profiling of Macrophage Migration Inhibitory Factor 2.

Nematode infections are common in both humans and livestock, with major adverse planetary health and economic impacts. Wuchereria bancrofti is a parasitic nematode that causes lymphatic filariasis, a neglected tropical disease that can lead to severe disability and deformity worldwide. For the long-term survival of the bancroftian parasites in the host, a complex immune invasion strategy is involved through immunomodulation. Therefore, immunomodulation can serve as a site of research and innovation for molecular targets. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine crucial to the host antimicrobial alarm system and stress response. Interestingly, the nematode parasite W. bancrofti also produces two homologs of MIF (Wba-MIF1 and 2). Using a mass spectrometry-based phosphoproteomics approach, we report new findings on the immunomodulatory effect and signaling mechanism of Wba-MIF2 in macrophage cells. Accordingly, we observed 1201 phosphorylated sites on 467 proteins. Out of the 1201 phosphorylated sites, 1075, 117, and 9 were found on serine (S), threonine (T), and tyrosine (Y) residues, respectively. Our bioinformatics analysis led to identification of major pathways, including spliceosomes, T cell receptor signaling pathway, Th17 differentiation pathway, interleukin-17 signaling pathway, and insulin signaling pathway upon Wba-MIF2 treatment. Wba-MIF2 treatment also enriched CDK4, CDK1, and DNAPK kinases. The comparison of the signaling pathway of Wba-MIF2 with that of human-MIF suggests both share similar signaling pathways. These findings collectively offer new insights into the role and mechanism of Wba-MIF2 as an immunomodulator and inform future diagnostics and drug discovery research for W. bancrofti.

Platelet functions in lymphatic filariasis patients.

Filariasis is a chronic disease where parasitic worms survive in human hosts even for decades and lead to complications like lymphedema and elephantiasis. Despite the persistent existence of filarial parasites in human hosts, fatal and thrombotic complications are not known, unlike other parasitic diseases like malaria. This suggests that filarial parasites might be affecting the host's platelet functions. This study was conducted to examine platelet functions in confirmed filariasis patients and healthy controls. Results showed that filariasis patients had larger platelets, inhibited aggregation, and slower speed of aggregation, compared to controls. However, in vivo markers of platelet activation and degranulation (beta thromboglobulin and soluble P-selectin) were not affected. Observations suggested that there is increased platelet turnover, cellular apoptosis and inhibited platelet functions in filariasis patients compared to controls. Platelet function inhibition was not associated with the duration of disease, lymphedema-affected organs, or gender of patients. This study confirms that filarial parasites modulate platelet functions in human hosts.

A nationwide epidemiological and geodemographic analysis of lymphatic filariasis in Ecuador: a neglected and often forgotten disease in Ecuador.

Introduction: Lymphatic filariasis (LF) is a neglected parasitic disease transmitted by mosquitoes and affecting the lymphatic system. The aim of this study was to analyze the epidemiological and sociodemographic characteristics of patients with LF during the last 11 years of available data in Ecuador. Methods: A 11-year nationwide analysis of hospital admission and in-hospital mortality based on the National Institute of Statistics and Census (INEC) data was conducted in Ecuador from 2011 to 2021. The International Classification of Diseases 10th Revision (ICD-10) code for filariasis (ICD: B74) was used to retrieve information on severe LF as a proxy for incidence among 221 Ecuadorian cities. Results: A total of 26 hospital admissions and 3 deaths due to LF were registered. The highest mortality rate was found in populations over 80 years. Men accounted for 62.5% (n = 17) of total number of cases with an average incidence rate of 1.7 cases per/1,000,000, while females accounted for 34.6% (n = 9), representing 1 case per/1,000,000 woman. Cities located at lower altitude (459/1,000,000) reported higher incidence rates than those located at higher altitudes (7.4/1,000,000). Conclusion: This is the first study on LF in Ecuador. Although, Ecuador is not considered endemic for LF, we found evidence of the presence of this disease in recent years. The implementation and improvement of an adequate integrated epidemiological surveillance system will allow early identification of cases and therefore their respective treatment.

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.

Immunomodulatory effects of chitosan nanoparticles as vaccine delivery agent against lymphatic filariasis through mucosal immunization.

Lymphatic filariasis is a parasitic disease caused by nematodes affecting millions of individuals in the tropical region. The complex life cycle of the filarial parasite eludes protective measures such as chemotherapy and vector control. Vaccination through recombinant proteins stands as one of the safe and most effective methods. The filarial antigens Brugia malayi Thioredoxin (TRX) and abundant larval transcript-2 (ALT-2) can induce recognizable levels of protection in murine animal models. Chitosan is a safe, non-toxic material ubiquitously served as an efficient carrier and an adjuvant. The present study was attempted to enhance the immune efficacy of filarial antigens using chitosan nanoparticles (CN) through mucosal routes of immunization. Our study showed that oral immunization was able to produce enhanced humoral response and balanced Th1/Th2 antibody isotype response for the recombinant antigens compared to intranasal routes. A high level of splenocyte T cell proliferation (P < 0.01) was obtained for both routes. The cytokine analysis showed a high level of IFN-γ followed by IL-5 for the oral route, whereas a high level of IL-4 was observed for intranasal route. These results confirm the ability of chitosan nanoparticles to elevate the immune efficacy of the antigens through the oral route in mice.

Alteration of rhesus macaque serum N-glycome during infection with the human parasitic filarial nematode Brugia malayi.

Serum N-glycan profiling studies during the past decades have shown robust associations between N-glycan changes and various biological conditions, including infections, in humans. Similar studies are scarcer for other mammals, despite the tremendous potential of serum N-glycans as biomarkers for infectious diseases in animal models of human disease and in the veterinary context. To expand the knowledge of serum N-glycan profiles in important mammalian model systems, in this study, we combined MALDI-TOF-MS analysis and HILIC-UPLC profiling of released N-glycans together with glycosidase treatments to characterize the glycan structures present in rhesus macaque serum. We used this baseline to monitor changes in serum N-glycans during infection with Brugia malayi, a parasitic nematode of humans responsible for lymphatic filariasis, in a longitudinal cohort of infected rhesus macaques. Alterations of the HILIC-UPLC profile, notably of abundant structures, became evident as early as 5 weeks post-infection. Given its prominent role in the immune response, contribution of immunoglobulin G to serum N-glycans was investigated. Finally, comparison with similar N-glycan profiling performed during infection with the dog heartworm Dirofilaria immitis suggests that many changes observed in rhesus macaque serum N-glycans are specific for lymphatic filariasis.

Canine filaria species in selected lymphatic filariasis endemic and non-endemic areas in Sri Lanka.

Subperiodic brugian filariasis and dirofilariasis show a rising trend in Sri Lanka posing a threat to public health. As information was limited on canine filaria species in Sri Lanka, we studied the filaria parasites among dog populations in lymphatic filariasis (LF) endemic and non-endemic regions by microscopy and molecular methods. Thick blood smears (TBSs) were performed among 295 dogs presenting to veterinary clinics for surgical or sterilization procedures in Galle (LF endemic) and Mullaitivu (LF non-endemic) districts, of which 55.6% were positive for any microfilariae. We identified Dirofilaria repens (50.8%) and Brugia spp. (20.6%) by microscopy, which, included mono-infections (D. repens 35.3% and Brugia spp. 5%) and co-infections (15.6%). Infections in Galle and Mullaitivu were 61% and 44.9% respectively. The brugian filariasis rate was significantly higher among canines in LF endemic Galle district (29.9%) than in Mullaitivu (LF non-endemic) (1.1%) (P < 0.001), while D. repens infections were comparable in both districts. Genomic DNA extracted from 10% of microfilariae positive TBSs was amplified using pan-filarial primers targeting the internal-transcriber-spacer region-2 (ITS-2). Sequencing of amplicons confirmed the presence of D. repens (89.28%), Brugia pahangi (7.14%) and B. malayi (3.57%) infections. The phylogeny constructed and analysed in MEGA X indicated genetic variability among D. repens and B. pahangi isolates from Sri Lanka. With this study, we were able to report B. pahangi infections for the first time in Sri Lanka.

Characterization of a novel microfilarial antigen for diagnosis of Wuchereria bancrofti infections.

BACKGROUND: Lymphatic filariasis (LF) is a neglected tropical disease caused by the filarial nematodes Wuchereria bancrofti, Brugia malayi and Brugia timori. The Global Program to Eliminate LF uses mass drug administration (MDA) of anti-filarial drugs that clear microfilariae (Mf) from blood to interrupt transmission by mosquitos. New diagnostic tools are needed to assess the impact of MDA on bancroftian filariasis, because available serologic tests can remain positive after successful treatment. METHODOLOGY/PRINCIPAL FINDINGS: We identified Wb-bhp-1, which encodes a W. bancrofti homologue of BmR1, the B. malayi protein used in the Brugia Rapid antibody test for brugian filariasis. Wb-bhp-1 has a single exon that encodes a 16.3 kD protein (Wb-Bhp-1) with 45% amino acid identity to BmR1. Immunohistology shows that anti-Wb-Bhp-1 antibodies primarily bind to Mf. Plasma from 124 of 224 (55%) microfilaremic individuals had IgG4 antibodies to Wb-Bhp-1 by ELISA. Serologic reactivity to Wb-Bhp-1 varied widely with samples from different regions (sensitivity range 32-92%), with 77% sensitivity for 116 samples collected from microfilaremic individuals outside of sub-Saharan Africa. This variable sensitivity highlights the importance of validating new diagnostic tests for parasitic diseases with samples from different geographical regions. Individuals with higher Mf counts were more likely to have anti-Wb-Bhp-1 antibodies. Cross-reactivity was observed with a minority of plasma samples from people with onchocerciasis (17%) or loiasis (10%). We also identified, cloned and characterized BmR1 homologues from O. volvulus and L. loa that have 41% and 38% identity to BmR1, respectively. However, antibody assays with these antigens were not sensitive for onchocerciasis or loiasis. CONCLUSIONS: Wb-Bhp-1 is a novel antigen that is useful for serologic diagnosis of bancroftian filariasis. Additional studies are needed to assess the value of this antigen for monitoring the success of filariasis elimination programs.

Safety and efficacy of mass drug administration with a single-dose triple-drug regimen of albendazole + diethylcarbamazine + ivermectin for lymphatic filariasis in Papua New Guinea: An open-label, cluster-randomised trial.

BACKGROUND: Papua New Guinea (PNG) has a high burden of lymphatic filariasis (LF) caused by Wuchereria bancrofti, with an estimated 4.2 million people at risk of infection. A single co-administered dose of ivermectin, diethylcarbamazine and albendazole (IDA) has been shown to have superior efficacy in sustained clearance of microfilariae compared to diethylcarbamazine and albendazole (DA) in small clinical trials. A community-based cluster-randomised trial of DA versus IDA was conducted to compare the safety and efficacy of IDA and DA for LF in a moderately endemic, treatment-naive area in PNG. METHODOLOGY: All consenting, eligible residents of 24 villages in Bogia district, Madang Province, PNG were enrolled, screened for W. bancrofti antigenemia and microfilaria (Mf) and randomised to receive IDA (N = 2382) or DA (N = 2181) according to their village of residence. Adverse events (AE) were assessed by active follow-up for 2 days and passive follow-up for an additional 5 days. Antigen-positive participants were re-tested one year after MDA to assess treatment efficacy. PRINCIPAL FINDINGS: Of the 4,563 participants enrolled, 96% were assessed for AEs within 2 days after treatment. The overall frequency of AEs were similar after either DA (18%) or IDA (20%) treatment. For those individuals with AEs, 87% were mild (Grade 1), 13% were moderate (Grade 2) and there were no Grade 3, Grade 4, or serious AEs (SAEs). The frequency of AEs was greater in Mf-positive than Mf-negative individuals receiving IDA (39% vs 20% p<0.001) and in Mf-positive participants treated with IDA (39%), compared to those treated with DA (24%, p = 0.023). One year after treatment, 64% (645/1013) of participants who were antigen-positive at baseline were re-screened and 74% of these participants (475/645) remained antigen positive. Clearance of Mf was achieved in 96% (52/54) of infected individuals in the IDA arm versus 84% (56/67) of infected individuals in the DA arm (relative risk (RR) 1.15; 95% CI, 1.02 to 1.30; p = 0.019). Participants receiving DA treatment had a 4-fold higher likelihood of failing to clear Mf (RR 4.67 (95% CI: 1.05 to 20.67; p = 0.043). In the DA arm, a significant predictor of failure to clear was baseline Mf density (RR 1.54; 95% CI, 1.09 to 2.88; p = 0.007). CONCLUSION: IDA was well tolerated and more effective than DA for clearing Mf. Widespread use of this regimen could accelerate LF elimination in PNG. TRIAL REGISTRATION: Registration number NCT02899936; https://clinicaltrials.gov/ct2/show/NCT02899936.

Mass Spectrometric and Glycan Microarray-Based Characterization of the Filarial Nematode Brugia malayi Glycome Reveals Anionic and Zwitterionic Glycan Antigens.

Millions of people worldwide are infected with filarial nematodes, responsible for lymphatic filariasis (LF) and other diseases causing chronic disablement. Elimination programs have resulted in a substantial reduction of the rate of infection in certain areas creating a need for improved diagnostic tools to establish robust population surveillance and avoid LF resurgence. Glycans from parasitic helminths are emerging as potential antigens for use in diagnostic assays. However, despite its crucial role in host-parasite interactions, filarial glycosylation is still largely, structurally, and functionally uncharacterized. Therefore, we investigated the glycan repertoire of the filarial nematode Brugia malayi. Glycosphingolipid and N-linked glycans were extracted from several life-stages using enzymatic release and characterized using a combination of MALDI-TOF-MS and glycan sequencing techniques. Next, glycans were purified by HPLC and printed onto microarrays to assess the host anti-glycan antibody response. Comprehensive glycomic analysis of B. malayi revealed the presence of several putative antigenic motifs such as phosphorylcholine and terminal glucuronic acid. Glycan microarray screening showed a recognition of most B. malayi glycans by immunoglobulins from rhesus macaques at different time points after infection, which permitted the characterization of the dynamics of anti-glycan immunoglobulin G and M during the establishment of brugian filariasis. A significant level of IgG binding to the parasite glycans was also detected in infected human plasma, while IgG binding to glycans decreased after anthelmintic treatment. Altogether, our work identifies B. malayi glycan antigens and reveals antibody responses from the host that could be exploited as potential markers for LF.

Giant scrotal elephantiasis in a migrant from Niger.

We hereby describe the case of a giant scrotal elephantiasis due to infection by Wuchereria bancrofti, imported in Belgium. We briefly discuss diagnostic methods, their subtlety, and therapeutic possibilities.

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.

Prevalence of soil-transmitted helminth infections, schistosomiasis, and lymphatic filariasis before and after preventive chemotherapy initiation in the Philippines: A systematic review and meta-analysis.

OBJECTIVE: To estimate the impact of preventive chemotherapy on the prevalence and intensity of soil-transmitted helminth (STH) infections, schistosomiasis, and lymphatic filariasis in the Philippines, using systematic review and meta-analysis. METHODS: We included reports reporting prevalence of STH infections, schistosomiasis, or lymphatic filariasis in the Philippines published until 31 March 2021. Peer-reviewed studies were identified in electronic databases. Grey literature reports by the University of the Philippines and the Department of Health were also included. Pooled infection prevalence, before and after the initiation of preventive chemotherapy, stratified by age group, was calculated using the inverse variance heterogeneity model. FINDINGS: A total of 109 reports were included in the review and meta-analysis. Overall prevalence of moderate-heavy intensity Ascaris lumbricoides (6.6%) and Trichuris trichiura (2.7%) infection after initiation of preventive chemotherapy were significantly lower than the prevalence prior to initiation (23.6% for A. lumbricoides and 12.2% for T. trichiura). Prevalence reductions were also found in school and preschool-age children for A. lumbricoides and T. trichiura. Studies conducted after preventive chemotherapy initiation had significantly lower overall prevalence of moderate-heavy intensity schistosomiasis (3.1% vs 0.2%) and of schistosomiasis in school-age children (30.5% vs 1%). Pooled prevalence of lymphatic filariasis prior to preventive chemotherapy initiation was 3.2% across 12 provinces, while currently only two provinces still have prevalence of more than 1%. There were no published studies reporting prevalence of lymphatic filariasis after initiation of preventive chemotherapy. Heterogeneity was high with I2 mostly above 90%. CONCLUSION: The burden of STH infections and schistosomiasis in children were significantly lower in studies conducted following the initiation of preventive chemotherapy. Eliminating morbidity and interrupting transmission, however, may require expanded control initiatives including community-wide treatment, and improved water, sanitation, and hygiene. Lymphatic filariasis burden has decreased since the implementation of preventive chemotherapy, with all but two provinces having reached the elimination of lymphatic filariasis as a public health problem.

Computational screening of potential inhibitors targeting MurF of Brugia malayi Wolbachia through multi-scale molecular docking, molecular dynamics and MM-GBSA analysis.

Lymphatic filariasis is a parasitic disease caused by the worms Wuchereria bancrofti, Brugia malayi and Brugia timori. Three anti-filarial drugs namely Diethylcarbamazine, Ivermectin and Albendazole and their combinations are used as the control strategies for filariasis. The disease has received much attention in drug discovery due to the unavailability of vaccines and the toxic pharmaceutical properties of the existing drugs. In Wolbachia endosymbiont Brugia malayi, the UDP-N-acetylmuramoyl-tripeptide-d-alanyl-d-alanine ligase (MurF) plays a key role in peptidoglycan biosynthesis pathway and therefore can be considered as effective drug target against filariasis disease. Therefore, in the present study, MurF was selected as the therapeutic target to identify specific inhibitors against filariasis. Homology modeling was performed to predict the three-dimensional structure of MurF due to the absence of the experimental structure. Further molecular dynamics simulation and structure-based high throughput virtual screening with three different chemical databases (Zinc, Maybridge and Specs) were carried out to identify potent inhibitors and also to check their conformations inside the binding site of MurF, respectively. Top three compounds with high docking score and high relative binding affinity against MurF were selected. Further, validation studies, including predicted ADME (Absorption, Distribution, Metabolism, Excretion) assessment, binding free energy using MM-GBSA (Molecular Mechanics Generalized Born Surface Area) and DFT (Density Functional Theory) calculations were performed for the top three compounds. From the results, it was observed that all the three compounds were predicted to show high reactivity, acceptable range of pharmacokinetic properties and high binding affinity with the drug target MurF. Overall, the results could provide more understanding on the inhibition of MurF enzyme and the screened compounds could lead to the development of new specific anti-filarial drugs.

Recombinant antigens used as diagnostic tools for lymphatic filariasis.

Lymphatic filariasis (LF) is a parasitic disease caused by the worms Wuchereria bancrofti, Brugia malayi, or Brugia timori. It is a tropical and subtropical illness that affects approximately 67 million people worldwide and that still requires better diagnostic tools to prevent its spread and enhance the effectiveness of control procedures. Traditional parasitological tests and diagnostic methods based on whole protein extracts from different worms are known for problems related to sample time collection, sensitivity, and specificity. More recently, new diagnostic tools based on immunological methods using recombinant antigens have been developed. The current review describes the several recombinant antigens used as tools for lymphatic filariasis diagnosis in antigen and antibody capture assays, highlighting their advantages and limitations as well as the main commercial tests developed based on them. The literature chronology is from 1991 to 2021. First, it describes the historical background related to the identification of relevant antigens and the generation of the recombinant polypeptides used for the LF diagnosis, also detailing features specific to each antigen. The subsequent section then discusses the use of those proteins to develop antigen and antibody capture tests to detect LF. So far, studies focusing on antibody capture assays are based on 13 different antigens with at least six commercially available tests, with five proteins further used for the development of antigen capture tests. Five antigens explored in this paper belong to the SXP/RAL-2 family (BmSXP, Bm14, WbSXP-1, Wb14, WbL), and the others are BmShp-1, Bm33, BmR1, BmVAH, WbVAH, BmALT-1, BmALT-2, and Wb123. It is expected that advances in research with these antigens will allow further development of tests combining both sensitivity and specificity with low costs, assisting the Global Program to Eliminate Lymphatic Filariasis (GPELF).

Molecular Characterization of a Reemergent Brugia malayi Parasite in Sri Lanka, Suggestive of a Novel Strain.

Sri Lanka achieved elimination status for lymphatic filariasis in 2016; still, the disease remains a potential public health issue. The present study is aimed at identifying a subperiodic Brugia sp. parasite which has reemerged in Sri Lanka after four decades via molecular-based analysis. Polymerase chain reaction performed with pan-filarial primers specific for the internal transcribed spacer region-2 (ITS-2) of the rDNA of Brugia filarial parasites isolated from human, canine, and feline blood samples yielded a 615 bp band establishing the species identity as Brugia malayi. Comparison of the ITS2 sequences of the reemerged B. malayi isolates with GenBank sequences revealed a higher sequence homology with B. pahangi than B. malayi with similar phylogenetic evidence. However, the mean interspecies Kimura-2-parameter pairwise divergence between the generated Brugia sequences with B. malayi and B. pahangi was less than 3%. During the analysis of parsimony sites of the new ITS2 sequences, substitutions at A36T, A296G, T373A, and G482A made the sequences different from both B. pahangi and B. malayi suggesting the possibility of a new genetic variant or a hybrid strain of B. malayi and B. pahangi. Mosquito dissections and xenomonitoring identified M. uniformis and M. annulifera as vectors of this novel strain of B. malayi circulating among cats, dogs, and humans in Sri Lanka.