Filariasis Control Programmes Research Articles

Mass drug administration to eliminate lymphatic filariasis: a population-based coverage and compliance study in Eastern India

BackgroundNeglected tropical diseases (NTDs) like lymphatic filariasis (LF) affect over 1 billion people globally, with India being a significant hotspot. Challenges persist despite global and national efforts, including the WHO's Global Program to Eliminate Lymphatic Filariasis (GPELF) and India's National Filaria Control Programme. We conducted a study to assess MDA coverage and compliance to improve LF elimination efforts in the Khordha district of Odisha, India. MethodsA sample of 691 participants, including both males and females aged two years or older, was chosen through multistage stratified sampling. These participants were interviewed using a semi-structured questionnaire. Collected data regarding Socio-demographic characteristics, knowledge of filariasis, coverage and consumption of MDA drugs were analyzed. Descriptive statistics were applied to determine coverage and compliance, with results presented alongside a 95% confidence interval. ResultsIn our study, coverage and compliance rates were 86.36% and 91.12% for Albendazole, while 84.12% and 90.62% for DEC. Fear of side effects was the reason for most of the participants' non-consumption. The coverage rate was low in Urban areas because of gated communities and a lack of confidence in drug distributors. ConclusionThis recent round of MDA was effective but still Fear of side effects and lack of awareness were major challenges for the compliance of MDA drugs and need to be addressed for the complete eradication of LF.

Programmed cell death pathways as targets for developing antifilarial drugs: Lessons from the recent findings.

More than half a century has passed since the introduction of the National Filariasis Control Program; however, as of 2023, lymphatic filariasis (LF) still prevails globally, particularly in the tropical and subtropical regions, posing a substantial challenge to the objective of worldwide elimination. LF is affecting human beings and its economically important livestock leading to a crucial contributor to morbidities and disabilities. The current scenario has been blowing up alarms of attention to develop potent therapeutics and strategies having efficiency against the adult stage of filarial nematodes. In this context, the exploration of a suitable drug target that ensures lethality to macro and microfilariae is now our first goal to achieve. Apoptosis has been the potential target across all three stages of filarial nematodes viz. oocytes, microfilariae (mf) and adults resulting in filarial death after receiving the signal from the reactive oxygen species (ROS) and executed through intrinsic and extrinsic pathways. Hence, it is considered a leading target for developing antifilarial drugs. Herein, we have shown the efficacy of several natural and synthetic compounds/nanoformulations in triggering the apoptotic death of filarial parasites with little or no toxicity to the host body system.

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

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

Elimination of lymphatic filariasis as a public health problem from the Arab Republic of Egypt

Abstract Lymphatic filariasis (LF), caused by Wuchereria bancrofti infection, has probably occurred in Egypt since ancient times. In more recent years, LF was recognized as a major public health problem in the Nile delta since the early 1930s and Culex pipiens was identified as the major mosquito vector of transmission. Since then the Ministry of Health and Population (MoHP) took measures for control of the disease. During 1955-1965, a nationwide survey determined the size and extent of LF as a public health problem. The survey included all 20 governorates of the country, involved rural and urban areas. Over 0.5 million blood films were examined. The survey results indicated that LF was focally endemic in rural localities, concentrated in the eastern part of the Nile Delta mainly in Qalyubia, Sharqia, Dakahlia and Damietta governorates, and in Giza and Asyout in Upper Egypt. The LF prevalence was &amp;lt;1% in Behira, Cairo, Gharbia, Ismailia, Kafr El Sheikh, Menoufia, Port Said and Suez governorate. Six governorates In Upper Egypt were free of LF. In 1976, the National Filariasis Control Program was launched in Qalyubia governorate, and then gradually extended to cover 10 endemic governorates including: Asyout, Behira, Dakahlia, Damietta, Gharbia, Giza, Kafr El Sheikh, Menoufia, Qalyubia and Sharqia governorate. In 2000, Egypt was among the first countries to join the WHO global efforts and initiated a national LF elimination programme (NLFEP). The NLFEP programme adopted the WHO two objectives (1) elimination of LF as a public health problem based on annual mass drug distribution (MDA) of two drug regiments (DEC &amp; albendazole) to the entire eligible population living in areas where the disease was endemic (≥1%); (2) alleviate the suffering caused by LF through increased morbidity management and disability prevention (MMDP) activities. Intervention for interruption of transmission included several programme components. These included mapping of eligible MDA implementation units (IUs; villages); training of drug distributers on drug distribution activities; social mobilization using a variety of formal and informal channels to reach people with clear messages; directly observed drug distribution; treatment of adverse reactions; and monitoring and evaluation of MDA rounds. In 2005, after five effective MDA rounds (MDA coverage rate ≥80%), MDA was stopped in 92.5% of IUs, and continued in other IUs. In 2013, the last MDA round was implemented. In the 2014-2015 scholastic year, 10 years after stopping MDA in 166 villages, and more than six months after the last MDA implemented in 29 IUs during 2013, transmission assessment survey (TAS) was carried out according to WHO guidelines. In 2017, the last TAS was implemented. All TAS data clearly indicated that LF has likely been eliminated from Egypt. MMDP: five health centers, part of the primary health care system, are actively working with lymphoedema and elephantiasis affected people by providing skin care, necessary health care aids and information booklets. Thus, after over a decade of continued efforts, Egypt has successfully eliminated LF as a public health problem. In December 2017 the Director General of WHO congratulated Egypt for this historical achievement.

Comparison of School-Based and Community-Wide Mass Drug Administration for Schistosomiasis Control in an Area of Western Kenya with High Initial Schistosoma mansoni Infection Prevalence: A Cluster Randomized Trial.

.We conducted a cluster randomized trial comparing the target population and timing of mass drug administration (MDA) with praziquantel for control of schistosomiasis in villages in western Kenya with high initial prevalence (> 25%) according to a harmonized protocol developed by the Schistosomiasis Consortium for Operational Research and Evaluation. A total of 150 villages were randomized into six treatment arms (25 villages per arm), were assessed at baseline, and received two or four rounds of MDA using community-wide (CWT) or school-based (SBT) treatment over 4 years. In the fifth year, a final evaluation was conducted. The primary outcomes were prevalence and intensity of Schistosoma mansoni infections in children aged 9–12 years, each year their village received MDA. Baseline and year 5 assessments of first-year students and adults were also performed. Using Poisson and negative binomial regression with generalized estimating equations, we found similar effects of CWT and SBT MDA treatment strategies in children aged 9–12 years: significant reductions of prevalence of infection in all arms and of heavy-intensity (≥ 400 eggs/gram) infections in most arms but no significant differences between arms. Combined arms of villages that received four rounds of treatment had greater reduction than villages in arms that only received two rounds of treatment. Surprisingly, we also found benefits of SBT for first-year primary students and adults, who never received treatment in those arms. Our data support the use of annual SBT for control programs when coupled with attention to infections in younger children and occasional treatment of adults.

Mapping the baseline prevalence of lymphatic filariasis across Nigeria

IntroductionThe baseline endemicity profile of lymphatic filariasis (LF) is a key benchmark for planning control programmes, monitoring their impact on transmission and assessing the feasibility of achieving elimination. Presented in this work is the modelled serological and parasitological prevalence of LF prior to the scale-up of mass drug administration (MDA) in Nigeria using a machine learning based approach.MethodsLF prevalence data generated by the Nigeria Lymphatic Filariasis Control Programme during country-wide mapping surveys conducted between 2000 and 2013 were used to build the models. The dataset comprised of 1103 community-level surveys based on the detection of filarial antigenemia using rapid immunochromatographic card tests (ICT) and 184 prevalence surveys testing for the presence of microfilaria (Mf) in blood. Using a suite of climate and environmental continuous gridded variables and compiled site-level prevalence data, a quantile regression forest (QRF) model was fitted for both antigenemia and microfilaraemia LF prevalence. Model predictions were projected across a continuous 5 × 5 km gridded map of Nigeria. The number of individuals potentially infected by LF prior to MDA interventions was subsequently estimated.ResultsMaps presented predict a heterogeneous distribution of LF antigenemia and microfilaraemia in Nigeria. The North-Central, North-West, and South-East regions displayed the highest predicted LF seroprevalence, whereas predicted Mf prevalence was highest in the southern regions. Overall, 8.7 million and 3.3 million infections were predicted for ICT and Mf, respectively.ConclusionsQRF is a machine learning-based algorithm capable of handling high-dimensional data and fitting complex relationships between response and predictor variables. Our models provide a benchmark through which the progress of ongoing LF control efforts can be monitored.

Prevalence, Intensity of Soil-Transmitted Helminths, and Factors Associated with Infection: Importance in Control Program with Ivermectin and Albendazole in Eastern Côte d'Ivoire.

Evaluation of soil-transmitted helminths (STHs) and implementation of additional interventions are required in the region of a filariasis control program, given that antifilariasis drugs also have a beneficial effect on STHs. Thus, this study determines the extensive epidemiology of STHs to improve their successful control. Stool samples were analyzed using the Kato-Katz method. Chi-squared and Kruskal-Wallis tests were used to measure differences in infection rates and intensities, respectively, and logistic regression identified the risks of infection. The main intestinal helminths (A. lumbricoides, hookworm [N. americanus], S. mansoni, and T. trichiura) were found in the population. The overall prevalence of STHs was 19.5%. The prevalence of hookworm, the predominant species, ranged from 2% (n=6) to 28% (n=97). The overall prevalence of the other intestinal helminths was less than 6% (n=18). Intensity of hookworm was mostly light with a range from 1.6% (n=5) to 25.9% (n=90). However, the intensity of the species was significantly greater in Soribadougou compared to the other localities. Heavy infection was found in old children and adults but not in young children. Open defecation (OR=3.23, p≤0.05), dog/cat raising (OR=1.94, p≤0.05), farming (OR=14.10, p≤0.05), and irrigated culture (OR=3.23, p≤0.05) were positively associated with hookworm. It was observed that the participants missed the follow-up examinations due to trip (32.7%) or misunderstanding (15%) and lack of information (11.8%) of the purpose of the survey. Thus, to sustain the control of STHs, the MDA program should target the entire community and add education about the use of toilets, best practices of farming, and dog/cat raising.

Environmental factors associated with the distribution of Loa loa vectors Chrysops spp. in Central and West Africa: seeing the forest for the trees

BackgroundLoiasis is caused by the filarial parasite Loa loa, which is widespread through Central and West Africa and largely confined the tropical equatorial rainforests. The tabanid flies Chrysops silacea and Chrysops dimidiata are the main vectors driving transmission. This study aimed to better define the spatial distribution and ecological niche of the two vectors to help define spatial-temporal risk and target appropriate, timely intervention strategies for filariasis control and elimination programmes.MethodsChrysops spp. distributions were determined by collating information from the published literature into a database, detailing the year, country, locality, latitude/longitude and species collected. Environmental factors including climate, elevation and tree canopy characteristics were summarised for each vector from data obtained from satellite modelled data or imagery, which were also used to identify areas with overt landcover changes. The presence of each Chrysops vector was predicted using a maximum entropy species distribution modelling (MaxEnt) method.ResultsA total of 313 location-specific data points from 59 published articles were identified across seven loiasis endemic countries. Of these, 186 sites were included in the climate and elevation analysis, and due to overt landcover changes, 83 sites included in tree canopy analysis and MaxEnt model. Overall, C. silacea and C. dimidiata were found to have similar ranges; annual mean temperature (24.6 °C and 24.1 °C, respectively), annual precipitation (1848.6 mm and 1868.8 mm), elevation (368.8 m and 400.6 m), tree canopy cover (61.4% and 66.9%) and tree canopy height (22.4 m and 25.1 m). MaxEnt models found tree canopy coverage was a significant environmental variable for both vectors.ConclusionsThe Chrysops spp. database and large-scale environmental analysis provides insights into the spatial and ecological parameters of the L. loa vectors driving transmission. These may be used to further delineate loiasis risk, which will be important for implementing filariasis control and elimination programmes in the equatorial rainforest region of Central and West Africa.

From Colonoscope to Microscope: the Diagnosis of Trichuris Trichiura

Soil Transmitted Helmenthiasis (STH) is a major public health problem in the developing countries. Trichuriasis is one of the common prevalent parasitic infestations in the tropical and sub-tropical countries across the globe incuding India. However, there has been a steady decline of STH in the last five years where there has been success of albendazole with Mass Drug Administration (MDA) in National Filariasis Control Program and Kerala state has been one of them. We report a case of whipworm infection that was incidentally diagnosed by colonoscopy where repeated stool microscopy was uncontributory. The worm can be overlooked, particularly if colon preparation is not good.

Mansonellosis, the most neglected human filariasis.

Human mansonellosis is caused by M. perstans, M. ozzardi and M. streptocerca, the three main filarial species in the genus Mansonella. Despite accumulating evidence of a high prevalence in endemic areas, there is currently no filariasis control programme targeting mansonellosis. The health-related impact on people living with these filariae remains unknown, and evidences regarding treatment strategies are scarce. Like other neglected diseases, it mainly affects poor populations living in tropical and subtropical climates. Mansonellosis can be considered one of the most neglected tropical infectious diseases. The objective of this literature review was to draw attention to the gap of knowledge regarding Mansonella spp. taxonomy, the transmission of these arthropod-borne filariasis and the health outcomes of people living with mansonellosis.

Factors Associated with Wuchereria bancrofti Microfilaremia in an Endemic Area of Mali.

Although Wuchereria bancrofti (Wb), the causative agent of lymphatic filariasis, is endemic throughout Mali, the prevalence of Wb microfilaremia (Mf) can vary widely between villages despite similar prevalence of infection as assessed by circulating antigen. To examine this variation, cross-sectional data obtained during screening prior to an interventional study in two neighboring villages in Mali were analyzed. The overall prevalence of Wb, as assessed by Wb CAg (circulating antigen), was 50.3% among 373 participants, aged 14-65. Wuchereria bancrofti Mf-positive and negative individuals appeared randomly distributed across the two villages (Moran's I spatial statistic = -0.01, Z score =0.1, P>0.05). Among the 187 subjects positive for Wb CAg, 117 (62.5%) had detectable Mansonella perstans microfilaremia (Mp Mf) and 64 (34.2%) had detectable Wb microfilaremia. The prevalence of Mp microfilaremia was 73.4% in the Wb Mf-positive group (as compared to 56.9% in the Wb Mf-negative group; p=0.01), and median Wb Mf load was increased in co-infected subjects (267Mf/ml vs 100 Mf/ml; p<0.001). In multivariate analysis, village of residence, Mp Mf positivity and gender were significantly associated with Wb Mf positivity. After controlling for age, gender, and village of residence, the odds of being Wb Mf positive was 2.67 times higher in Mp positive individuals (95% confidence interval [1.42-5.01]). Given the geographical overlap between Mp and Wb in Africa, a better understanding of the distribution and prevalence of Mp could assist national lymphatic filariasis control programs in predicting areas of high Wb Mf prevalence that may require closer surveillance.

Impact of the Lymphatic Filariasis Control Program towards elimination of filariasis in Vanuatu, 1997\u20132006

BackgroundLymphatic filariasis (LF) occurs when filarial parasites are transmitted to humans through mosquitoes. The filarial worms affect the lymphatic system which leads to abnormal enlargement of body parts, chronic pain, disability, and social discrimination. In 1999, a commitment was made to eliminate LF from the Pacific Region by 2010. The Pacific Program to Eliminate LF began, with Vanuatu being one of the 16 endemic countries included in this program.MethodsIn 1997/1998 a LF prevalence baseline survey was conducted to determine the need for mass drug administration (MDA) in Vanuatu. In 1999, the Vanuatu Lymphatic Filariasis Control Program was established, and nationwide MDA was implemented from 2000 to 2004. LF prevalence was collected during the MDA through sentinel site and spot check surveys, and after 5 years of MDA. MDA implementation methods included health worker training, social mobilization, and culturally appropriate health promotion strategies.ResultsLF prevalence at baseline was 4.79%; after MDA this declined to 0.16% in 2005/2006. Average MDA coverage ranged from 75.5–81.5% across 5 years. All three evaluation units surveyed in 2005/2006 were below the 1% threshold required to stop MDA.ConclusionsThe LF Control Program between 1997 and 2006 was successful in reducing LF prevalence to <1%. High MDA coverage was a critical component of this success. This period of the Vanuatu LF Control Program played an important role in helping to eliminate LF in Vanuatu.

Colorimetric tests for diagnosis of filarial infection and vector surveillance using non-instrumented nucleic acid loop-mediated isothermal amplification (NINA-LAMP).

Accurate detection of filarial parasites in humans is essential for the implementation and evaluation of mass drug administration programs to control onchocerciasis and lymphatic filariasis. Determining the infection levels in vector populations is also important for assessing transmission, deciding when drug treatments may be terminated and for monitoring recrudescence. Immunological methods to detect infection in humans are available, however, cross-reactivity issues have been reported. Nucleic acid-based molecular assays offer high levels of specificity and sensitivity, and can be used to detect infection in both humans and vectors. In this study we developed loop-mediated isothermal amplification (LAMP) tests to detect three different filarial DNAs in human and insect samples using pH sensitive dyes for enhanced visual detection of amplification. Furthermore, reactions were performed in a portable, non-instrumented nucleic acid amplification (NINA) device that provides a stable heat source for LAMP. The efficacy of several strand displacing DNA polymerases were evaluated in combination with neutral red or phenol red dyes. Colorimetric NINA-LAMP assays targeting Brugia Hha I repeat, Onchocerca volvulus GST1a and Wuchereria bancrofti LDR each exhibit species-specificity and are also highly sensitive, detecting DNA equivalent to 1/10-1/5000th of one microfilaria. Reaction times varied depending on whether a single copy gene (70 minutes, O. volvulus) or repetitive DNA (40 min, B. malayi and W. bancrofti) was employed as a biomarker. The NINA heater can be used to detect multiple infections simultaneously. The accuracy, simplicity and versatility of the technology suggests that colorimetric NINA-LAMP assays are ideally suited for monitoring the success of filariasis control programs.

THE EFFICACY OF ALBENDAZOLE AGAINST SOIL-TRANSMITTED HELMINTHS AND THE IMPACT OF MASS DRUG ADMINISTRATION OF ALBENDAZOLE AND IVERMECTIN ON HEALTH STATUS

BackgroundThe lymphatic filariasis (LF) control programme has been on-going in Ghana since 2000 with mass drug administration (MDA) of ivermectin (IVM) and albendazole (ALB). Soil-transmitted helminth (STH) infections control is...

Review on current and future molecular diagnostic tests for bancroftian filariasis

In a public health perspective, filariasis is still a problem in tropical countries, which warrants an appropriate diagnosis and drug-based prophylaxis in the endemic areas to reduce the number of diseased individuals. Among the four species causing filariasis,Wuchereria bancroftiis reported to cause 90% of infections globally. Difficulty in accurate diagnosis of filarial infections remains a problem in filariasis control programs. Improved simple methods are needed for monitoringW. bancroftiinfection and thereby to accomplish success in elimination programs. Conventional methods available are tedious and time consuming with low sensitivity and specificity. Recently designed filarial molecular diagnostic assays are highly sensitive and specific for clinical use. These molecular assays have vast advantage over the conventional techniques wherein only a small quantity of samples is required for diagnosis without expert training in parasitological techniques. Molecular diagnostic methods alleviate surveillance activities, help in monitoring and evaluating newer drugs and vaccines. With the anticipated success in filariasis elimination, DNA-based methods gain more importance in the population diagnostic surveillance. Furthermore, molecular techniques are more sensitive enabling species identification and greatly facilitate the collection of epidemiological data. Proper research on filariasis may help to bridge the host–parasite interface by coordinating research and social outcomes that is vitally important for human public health.

Impact of vectorborne parasitic neglected tropical diseases on child health

Chagas disease, leishmaniasis, onchocerciasis and lymphatic filariasis are all vectorborne neglected tropical diseases (NTDs) that are responsible for significant disease burden in impoverished children and adults worldwide. As vectorborne parasitic...

Deleting the 'neglect' from two neglected tropical diseases in India

Deleting the 'neglect' from two neglected tropical diseases in India

Pharmacokinetic comparison of different flubendazole formulations in pigs: A further contribution to its development as a macrofilaricide molecule

Despite the well established ivermectin activity against microfilaria, the success of human filariasis control programmes requires the use of a macrofilaricide compound. Different in vivo trials suggest that flubendazole (FLBZ), an anthelmintic benzimidazole compound, is a highly efficacious and potent macrofilaricide. However, since serious injection site reactions were reported in humans after the subcutaneous FLBZ administration, the search for alternative pharmaceutical strategies to improve the systemic availability of FLBZ has acquired special relevance both in human and veterinary medicine. The goal of the current experimental work was to compare the pharmacokinetic plasma behavior of FLBZ, and its metabolites, formulated as either an aqueous hydroxypropyl- β -cyclodextrin-solution (HPBCD), an aqueous carboxymethyl cellulose-suspension (CMC) or a Tween 80-based formulation, in pigs. Animals were allocated into three groups and treated (2 mg/kg) with FLBZ formulated as either a HPBCD-solution (oral), CMC-suspension (oral) or Tween 80-based formulation (subcutaneous). Only trace amounts of FLBZ parent drug and its reduced metabolite were measured after administration of the different FLBZ formulations in pigs. The hydrolyzed FLBZ (H-FLBZ) metabolite was the main analyte recovered in the bloodstream in pigs treated with the three experimental FLBZ formulations. The oral administration of the HPBCD-solution accounted for significantly higher (P < 0.05) Cmax and AUC (23.1 ± 4.4 μg h/mL) values for the main metabolite (H-FLBZ), compared with those observed for the oral CMC-suspension (AUC = 3.5 ± 1.0 μg h/mL) and injectable Tween 80-based formulation (AUC: 7.5 ± 1.7 μg h/mL). The oral administration of the HPBCD-solution significantly improved the poor absorption pattern (indirectly assessed as the H-FLBZ plasma concentrations) observed after the oral administration of the FLBZ-CMC suspension or the subcutaneous injection of the Tween 80 FLBZ formulation to pigs. Overall, the work reported here indicates that FLBZ pharmacokinetic behavior can be markedly changed by the pharmaceutical formulation.

Modelling lymphatic filariasis transmission and control: modelling frameworks, lessons learned and future directions.

Mathematical modelling provides a useful tool for policy making and planning in lymphatic filariasis control programmes, by providing trend forecasts based on sound scientific knowledge and principles. This is now especially true, in view of the ambitious target to eliminate lymphatic filariasis as a public health problem globally by the year 2020 and the short remaining timeline to achieve this. To meet this target, elimination programmes need to be accelerated, requiring further optimization of strategies and tailoring to local circumstances. Insights from epidemiological transmission models provide a useful basis. Two general models of lymphatic filariasis transmission and control are nowadays in use to support decision-making, namely a population-based deterministic model (EPIFIL) and an individual-based stochastic model (LYMFASIM). Model predictions confirm that lymphatic filariasis transmission can be interrupted by annual mass drug administration (MDA), but this may need to be continued much longer than the initially suggested 4-6years in areas with high transmission intensity or poor treatment coverage. However, the models have not been validated against longitudinal data describing the impact of MDA programmes. Some critical issues remain to be incorporated in one or both of the models to make predictions on elimination more realistic, including the possible occurrence of systematic noncompliance, the risk of emerging parasite resistance to anthelmintic drugs, and spatial heterogeneities. Rapid advances are needed to maximize the utility of models in decision-making for the ongoing ambitious lymphatic filariasis elimination programmes.

Survey of Bancroftian filariasis infection in humans and Culex mosquitoes in the western Brazilian Amazon region: implications for transmission and control

The aim of this work was to identify possible lymphatic filariasis foci in the western Brazilian Amazonian that could be established from the reports of Rachou in the 1950s. The study was conducted in three cities of the western Brazilian Amazon region - Porto Velho and Guajará-Mirim (State of Rondônia) and Humaitá (State of Amazonas). For human infection evaluation thick blood smear stained with Giemsa was used to analyze samples collected from 10pm to 1am. Polymerase chain reaction (PCR) was used to examine mosquito vectors for the presence of Wuchereria bancrofti DNA. Humans were randomly sampled from night schools students and from inhabitants in neighborhoods lacking sanitation. Mosquitoes were collected from residences only. A total 2,709 night students enrolled in the Program for Education of Young Adults (EJA), and 935 people registered in the residences near the schools were examined, being 641 from Porto Velho, 214 from Guajará-Mirim and 80 from Humaitá. No individual examined was positive for the presence of microfilariae in the blood stream. A total of 7,860 female Culex quinquefasciatus specimens examined were negative by PCR. This survey including human and mosquito examinations indicates that the western Amazon region of Brazil is not a focus of Bancroftian filariasis infection or transmission. Therefore, there is no need to be included in the Brazilian lymphatic filariasis control program.