In silico screening of flavonoid-based inhibitors targeting UDP-galactopyranose mutase of Brugia malayi for lymphatic filariasis drug design.

Review Objectives The objective of this systematic review is to understand the experiences of persons 15 years and older living with Chronic Lymphatic Filariasis (CLF) in developing countries. The specific review questions are: 1. What are the experiences of persons living with CLF? 2. What are the experiences of persons with CLF about strategies used to prevent/ treat the condition? 3. What is the influence of CLF on social relationships of persons affected? Inclusion criteria Types of Participants The review will consider publications that focus on developing countries and specifically include people of 15 years and older with manifestations of CLF. Phenomena of Interest The review will focus on studies that investigate the experience of living with manifestations of CLF. The review will also focus on studies that address the experiences and subjective opinions of persons that have employed various strategies of prevention/ treatment of the condition. The review will also consider studies that address the social relationships of persons living with CLF.

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

Lymphatic filariasis is a mosquito-borne neglected tropical disease caused by a group of nematodes (round worms), Wuchereria bancrofti, Brugia malayi and Brugia timori, which are transmitted by mosquito vectors. According to the recent fact sheet of World Health Organization, around 947 million people belonging to 54 countries are threatened by lymphatic filariasis infection. In the year 2000, over 120 million people were infected, with about 40 million disfigured and incapacitated by the disease globally. The disease results into a heavy socio-economic loss to the developing nations. The elimination of lymphatic filariasis relies on at least five effective annual rounds of mass drug administration program implemented in 422larger communities of endemic areas. It is done using oral medication of three drugs currently available for treatment: diethylcarbamazine, albendazole and ivermectin or a combination of albendazole and ivermectin. However, development of drug resistance is a reported phenomenon in nematodes. Also, these drugs act principally on larval stages (microfilariae) of the parasites and with limited or no effect on adult worms (macrofilariae). Thus, the biggest challenge is to combat adult parasites with a new and safe alternative which can be achieved only by developing newer chemotherapeutic agents against adult worms, a vaccine adjuvant or a prophylactic agent from natural flora. There are a number of plant species that are traditionally being used against many nematode infections; however the curative properties of these have not been explored much. The present review is an effort to collect the research outputs of various studies and approaches in the elimination of filariasis and gives detailed information about some of the major achievements in this area focusing on the development of prophylactic and chemotherapeutic agents from plants.

Lymphatic filariasis (LF), a morbid disease caused by the tissue-invasive nematodes Wuchereria bancrofti, Brugia malayi, and Brugia timori, affects millions of people worldwide. Global eradication efforts have significantly reduced worldwide prevalence, but complete elimination has been hampered by limitations of current anti-filarial drugs and the lack of a vaccine. The goal of this study was to evaluate B. malayi intestinal UDP-glucuronosyltransferase (Bm-UGT) as a potential therapeutic target. To evaluate whether Bm-UGT is essential for adult filarial worms, we inhibited its expression using siRNA. This resulted in a 75% knockdown of Bm-ugt mRNA for 6 days and almost complete suppression of detectable Bm-UGT by immunoblot. Reduction in Bm-UGT expression resulted in decreased worm motility for 6 days, 70% reduction in microfilaria release from adult worms, and significant reduction in adult worm metabolism as detected by MTT assays. Because prior allergic-sensitization to a filarial antigen would be a contraindication for its use as a vaccine candidate, we tested plasma from infected and endemic normal populations for Bm-UGT-specific IgE using a luciferase immunoprecipitation assay. All samples (n = 35) tested negative. We then tested two commercially available medicines known to be broad inhibitors of UGTs, sulfinpyrazone and probenecid, for in vitro activity against B. malayi. There were marked macrofilaricidal effects at concentrations achievable in humans and very little effect on microfilariae. In addition, we observed that probenecid and sulfinpyrazone exhibit a synergistic macrofilaricidal effect when used in combination with albendazole. The results of this study demonstrate that Bm-UGT is an essential protein for adult worm survival. Lack of prior IgE sensitization in infected and endemic populations suggest it may be a feasible vaccine candidate. The finding that sulfinpyrazone and probenecid have in vitro effects against adult B. malayi worms suggests that these medications have promise as potential macrofilaricides in humans.

Chapter 19 - Microfilaricidal efficacy of silver nanoparticles

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

Filariae are vector-borne nematodes responsible for an enormous burden of disease. Human lymphatic filariasis, caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori, and onchocerciasis (caused by Onchocerca volvulus) are neglected parasitic diseases of major public health significance in tropical regions. To date, therapeutic efforts to eliminate human filariasis have been hampered by the lack of a drug with sufficient macrofilaricidal and/or long-term sterilizing effects that is suitable for use in mass drug administration (MDA) programs, particularly in areas co-endemic with Loa loa, the causative agent of loiasis.Emodepside, a semi-synthetic cyclooctadepsipeptide, has been shown to have broad-spectrum efficacy against gastrointestinal nematodes in a variety of mammalian hosts, and has been approved as an active ingredient in dewormers for cats and dogs. This paper evaluates, compares (where appropriate) and summarizes the in vitro effects of emodepside against a range of filarial nematodes at various developmental stages.Emodepside inhibited the motility of all tested stages of filariae frequently used as surrogate species for preclinical investigations (Acanthocheilonema viteae, Brugia pahangi, Litomosoides sigmodontis, Onchocerca gutturosa, and Onchocerca lienalis), human-pathogenic filariae (B. malayi) and filariae of veterinary importance (Dirofilaria immitis) in a concentration-dependent manner. While motility of all filariae was inhibited, both stage- and species-specific differences were observed. However, whether these differences were detected because of stage- and/or species-specific factors or as a consequence of variations in protocol parameters among the participating laboratories (such as purification of the parasites, read-out units, composition of media, incubation conditions, duration of incubation etc.) remains unclear.This study, however, clearly shows that emodepside demonstrates broad-spectrum in vitro activity against filarial nematode species across different genera and can therefore be validated as a promising candidate for the treatment of human filariases, including onchocerciasis and lymphatic filariasis.

Lymphatic filariasis, generally called as elephantiasis, is a vector-borne infectious disease caused by the filarial nematodes, mainly Wuchereria bancrofti, Brugia malayi, and Brugia timori, which are transmitted through mosquitoes. The infection affects the normal flow of lymph leading to abnormal enlargement of body parts, severe pain, permanent disability, and social stigma. Due to the development of resistance as well as toxic effects, existing medicines for lymphatic filariasis are becoming ineffective in killing the adult worms. It is essential to search novel filaricidal drugs with new molecular targets. Asparaginyl-tRNA synthetase (PDB ID: 2XGT) belongs to the group of aminoacyl-tRNA synthetases that catalyze specific attachment of amino acids to their tRNA during protein biosynthesis. Plants and their extracts are well-known medicinal practice for the management of several parasitic infectious diseases including filarial infections. In this study, asparaginyl-tRNA synthetase of Brugia malayi was used as a target to perform virtual screening of plant phytoconstituents of Vitex negundo from IMPPAT database, which exhibits anti-filarial and anti-helminthic properties. A total of sixty-eight compounds from Vitex negundo were docked against asparaginyl-tRNA synthetase using Autodock module of PyRx tool. Among the 68 compounds screened, 3 compounds, negundoside, myricetin, and nishindaside, exhibited a higher binding affinity compared to standard drugs. The pharmacokinetic and physicochemical prediction, stability of ligand-receptor complexes via molecular dynamics simulation, and density functionality theory were done further for the top-scored ligands with receptor.

Lymphatic filariasis (LF) is a neglected tropical disease caused by threadlike worms (nematodes) that live in the lymphatic vessels of humans. Although three species of filarial parasites (Wuchereria bancrofti, Brugia malayi and Brugia timori) infect humans; 90% of infection is caused by Wuchereria Bancrofti and humans are its exclusive host. Nigeria is one of over 70 countries endemic for Lymphatic filariasis with an estimated 134 million people at the risk of infection. The Federal Capital Territory (FCT), which is endemic for LF, commenced mass drug administration (MDA) using ivermectin (IVM) and albendazole (ALB) in 2011. While MDA is continuing in two Area Councils, in 2020, we assessed the impact of MDA on LF prevalence in two area councils that had achieved five effective annual rounds of MDA. In 2010, a baseline mapping exercise was conducted in all six area councils of FCT-Abuja. The results revealed that four out of the six area councils were endemic for LF, with prevalence ranging from 1.0%-4.0%. The number of persons treated with ivermectin and albendazole in the four Area Councils was documented during annual MDA and population-based cluster surveys were conducted at least once in each area council during the five years of treatment, to verify the reported geographic and programme MDA coverage. This is the number treated divided by the total population eligible to receive treatment (usually <5years). The survey results confirmed that in two area councils (Abaji and Kuje) the coverage exceeded the target of 65% the while two other Councils did not reach the recommended coverage. A pre-transmission assessment survey (pre-TAS) was conducted in one sentinel site and at least one spot check site in Abaji and Kuje in 2019 and were found to have LF antigenemia (LF Ag) < 2% (range 0.0% to 1.99%). In 2020, transmission assessment surveys (TAS) were conducted in the two area councils that previously passed the Pre-transmission assessment survey. The results showed that the two Evaluation units had achieved the LF Ag threshold required to stop MDA. FCT has made significant progress towards LF elimination with two Area Councils qualifying to stop treatment. However, two other area councils still require a further two years of mass drug administration with effective MDA coverage before these area councils qualify for impact assessment.

Two major human diseases caused by filariid nematodes are onchocerciasis, or river blindness, and lymphatic filariasis, which can lead to elephantiasis. The drugs ivermectin, diethylcarbamazine (DEC), and albendazole are used in control programs for these diseases, but are mainly effective against the microfilarial stage and have minimal or no effect on adult worms. Adult Onchocerca volvulus and Brugia malayi worms (macrofilariae) can live for up to 15 years, reproducing and allowing the infection to persist in a population. Therefore, to support control or elimination of these two diseases, effective macrofilaricidal drugs are necessary, in addition to current drugs. In an effort to identify macrofilaricidal drugs, we screened an FDA-approved library with adult worms of Brugia spp. and Onchocerca ochengi, third-stage larvae (L3s) of Onchocerca volvulus, and the microfilariae of both O. ochengi and Loa loa. We found that auranofin, a gold-containing drug used for rheumatoid arthritis, was effective in vitro in killing both Brugia spp. and O. ochengi adult worms and in inhibiting the molting of L3s of O. volvulus with IC50 values in the low micromolar to nanomolar range. Auranofin had an approximately 43-fold higher IC50 against the microfilariae of L. loa compared with the IC50 for adult female O. ochengi, which may be beneficial if used in areas where Onchocerca and Brugia are co-endemic with L. loa, to prevent severe adverse reactions to the drug-induced death of L. loa microfilariae. Further testing indicated that auranofin is also effective in reducing Brugia adult worm burden in infected gerbils and that auranofin may be targeting the thioredoxin reductase in this nematode.

Lymphatic filariasis (LF) is one of the major health problems for the human kind in developing countries including India. LF is caused by three major nematodes namely Wuchereria bancrofti, Brugia malayi, and Brugia timori. The recent statistics of World Health Organization (WHO) showed that 51 million people were affected and 863 million people from 47 countries around worldwide remain threatened by LF. Among them, 90% of the filarial infection was caused by the nematode W. bancrofti. Approved drugs were available for the treatment of LF but many of them developed drug resistance and no longer effective in all stages of the infection. In the current research work, we explored the Glutathione S-transferase (GST) of W. bancrofti, the key enzyme responsible for detoxification that catalyzes the conjugation of reduced GSH (glutathione) to xenobiotic compounds. Initially, we analyzed the stability of the WbGST through 200 ns MD simulation and further structure-based virtual screening approach was applied by targeting the substrate binding site to identify the potential leads from small molecule collection. The in silico ADMET profiles for the top-ranked hits were predicted and the predicted non-toxic lead molecules showed the highest docking score in the range of -12.72 kcal/mol to -11.97 kcal/mol. The cross docking of the identified hits with human GST revealed the potential binding specificity of the hits toward WbGST. Through WbGST-lead complex simulation, the lead molecules were observed to be stable and also intactly bound within the binding site of WbGST. Based on the computational results, the five predicted non-toxic molecules were selected for the in vitro assay. The molecules showed significant percentage of inhibition against the filarial worm Setaria digitata which is the commonly used model organism to evaluate the filarial activity. In addition, the molecules also showed better IC50 than the standard drug ivermectin. The identified lead molecules will lay a significant insight for the development of new drugs with higher specificity and lesser toxicity to control and treat filarial infections.

Human lymphatic filariasis is a mosquito-vectored disease caused by the nematode parasites Wuchereria bancrofti, Brugia malayi and Brugia timori. These are relatively large roundworms that can cause considerable damage in compatible mosquito vectors. In order to assess how mosquitoes respond to infection in compatible mosquito-filarial worm associations, microarray analysis was used to evaluate transcriptome changes in Aedes aegypti at various times during B. malayi development. Changes in transcript abundance in response to the different stages of B. malayi infection were diverse. At the early stages of midgut and thoracic muscle cell penetration, a greater number of genes were repressed compared to those that were induced (20 vs. 8). The non-feeding, intracellular first-stage larvae elicited few differences, with 4 transcripts showing an increased and 9 a decreased abundance relative to controls. Several cecropin transcripts increased in abundance after parasites molted to second-stage larvae. However, the greatest number of transcripts changed in abundance after larvae molted to third-stage larvae and migrated to the head and proboscis (120 induced, 38 repressed), including a large number of putative, immunity-related genes (∼13% of genes with predicted functions). To test whether the innate immune system of mosquitoes was capable of modulating permissiveness to the parasite, we activated the Toll and Imd pathway controlled rel family transcription factors Rel1 and Rel2 (by RNA interference knockdown of the pathway's negative regulators Cactus and Caspar) during the early stages of infection with B. malayi. The activation of either of these immune signaling pathways, or knockdown of the Toll pathway, did not affect B. malayi in Ae. aegypti. The possibility of LF parasites evading mosquito immune responses during successful development is discussed.

Inter and intra-specific diversity of parasites that cause lymphatic filariasis

Lymphatic filariasis and onchocerciasis caused by filarial nematodes are important diseases leading to considerable morbidity throughout tropical countries. Diethylcarbamazine (DEC), albendazole (ALB), and ivermectin (IVM) used in massive drug administration are not highly effective in killing the long-lived adult worms, and there is demand for the development of novel macrofilaricidal drugs affecting new molecular targets. A Ca2+ binding protein, calumenin, was identified as a novel and nematode-specific drug target for filariasis, due to its involvement in fertility and cuticle development in nematodes. As sterilizing and killing effects of the adult worms are considered to be ideal profiles of new drugs, calumenin could be an eligible drug target. Indeed, the Caenorhabditis elegans mutant model of calumenin exhibited enhanced drug acceptability to both microfilaricidal drugs (ALB and IVM) even at the adult stage, proving the roles of the nematode cuticle in efficient drug entry. Molecular modeling revealed that structural features of calumenin were only conserved among nematodes (C. elegans, Brugia malayi, and Onchocerca volvulus). Structural conservation and the specificity of nematode calumenins enabled the development of drugs with good target selectivity between parasites and human hosts. Structure-based virtual screening resulted in the discovery of itraconazole (ITC), an inhibitor of sterol biosynthesis, as a nematode calumenin-targeting ligand. The inhibitory potential of ITC was tested using a nematode mutant model of calumenin.

Background: Lymphatic filariasis is a parasitic infection caused by nematodes such as filaria Wuchereria bancrofti, Brugia malayi, and Brugia timori. These parasites can be transmitted through mosquito bites such as several species of mosquitoes, particularly Anopheles, Aedes, Culex, and Mansonia with geographical variations in the dominant vector identity. The main strategy used consists of community-wide mass drug administration (MDA) for the entire population at risk to stop disease transmission and prevent infectious morbidity. WHO recommends the use of annual medication in combination with the triple drug ivermectin therapy. Objective: To compare DEC and albendazole (IDA) versus the two drugs albendazole and diethycarbamazine or albendazole and ivermectin therapy. Methods: The literature search was carried out independently by the researcher using the Sciencedirect, Pubmed, and Cochrane online databases without limiting the type of study or the year of publication. The keywords used in this study were combined with the Boolean operator, namely "AND" namely ((((Lymphatic filariasis) AND (albendazole)) AND (diethylcarbamazine)) AND (ivermectin)) AND (compare). Results: Where triple drug therapy was significantly better in reducing and clearing microfilariae and worm nests in patients with lymphatic filariasis compared to two drug therapy alone. However, side effects occur more frequently in the combination of three therapies. The average side effects were low, such as headaches, joint pain, fatigue, and nausea. Conclusion: although it has relatively low side effects that occur in three drug combinations rather than two drug combination therapy, triple therapy combination therapy is more effective than two drug therapy in treating lymphatic filariasis disease.