National Lymphatic Filariasis Elimination Programme Research Articles

Elimination of lymphatic filariasis as a public health problem in Malawi.

Lymphatic filariasis (LF) is a parasitic disease transmitted by mosquitoes, causing severe pain, disfiguring, and disabling clinical conditions such as lymphoedema and hydrocoele. LF is a global public health problem affecting 72 countries, primarily in Africa and Asia. Since 2000, the World Health Organization (WHO) has led the Global Programme to Eliminate Lymphatic Filariasis (GPELF) to support all endemic regions. This paper focuses on the achievements of the Malawi LF Elimination Programme between 2000 and 2020 to eliminate LF as a public health problem, making it the second sub-Saharan country to receive validation from the WHO. The Malawi LF Programme addressed the widespread prevalence of LF infection and disease across the country, using the recommended WHO GPELF strategies and operational research initiatives in collaboration with key national and international partners. First, to stop the spread of infection (i.e., interrupt transmission) and reduce the circulating filarial antigen prevalence from as high as 74.4% to below the critical threshold of 1-2% prevalence, mass drug administration (MDA) using a two-drug regime was implemented at high coverage rates (>65%) of the total population, with supplementary interventions from other programmes (e.g., malaria vector control). The decline in prevalence was monitored and confirmed over time using several impact assessment and post-treatment surveillance tools including the standard sentinel site, spot check, and transmission assessment surveys and alternative integrated, hotspot, and easy-access group surveys. Second, to alleviate suffering of the affected populations (i.e., control morbidity) the morbidity management and disability prevention (MMDP) package of care was implemented. Specifically, clinical case estimates were obtained via house-to-house patient searching activities; health personnel and patients were trained in self-care protocols for lymphoedema and/or referrals to hospitals for hydrocoele surgery; and the readiness and quality of treatment and services were assessed with new survey tools. Malawi's elimination of LF will ensure that future generations are not infected and suffer from the disfiguring and disabling disease. However, it will be critical that the Malawi LF Elimination programme remains vigilant, focussing on post-elimination surveillance and MMDP implementation and integration into routine health systems to support long-term sustainability and ongoing success. Lymphatic filariasis, also known as elephantiasis, is a disabling, disfiguring, and painful disease caused by a parasite that infected mosquitoes transmit to millions of people worldwide. Since 2000, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) has supported endemic countries such as Malawi in south-eastern Africa, to eliminate the disease as a public health problem. The Malawi National LF Elimination Programme has worked tirelessly over the past two decades to implement the GPELF recommended strategies to interrupt the transmission with a two-drug regime, and to alleviate suffering in patients with lymphoedema and/or hydrocoele through morbidity management and disability prevention. Additionally, the LF Programme has collaborated with national and international stakeholders to implement a range of supplementary operational research projects to address outstanding knowledge gaps and programmatic barriers. In 2020, the World Health Organisation validated that Malawi had successfully eliminated LF as a public health problem, making it the second country in sub-Saharan Africa to achieve this, which is remarkable given that Malawi previously had very high infection rates. The LF Programme now remains vigilant, putting its efforts towards post-elimination surveillance and the continued implementation of care for patients with chronic conditions. Malawi's elimination of LF will ensure that future generations are not affected by this devastating disease.

Status of Lymphatic Filariasis in Security Challenged Areas of Borno State, Nigeria

National lymphatic filariasis elimination programme (NLFEP) of Federal Ministry of Health sets to provide status of LF in the country before 2020. Borno State, situated in the North East political zone of Nigeria with an estimated population of 4.1million had been enmeshed in insurgency for over a decade. Following an initial mapping between 2008 and 2016 in 16 LGAs out of 27 LGAs, it became imperative that the status of LF in the remaining 11 LGAs of Borno State be ascertained in order to have complete data for planning and policy. Using stratified sampling method, eleven communities were selected from the 11 LGAs namely: Abadam, Ngala, Guzamala, Ngazai, Gubio, Mafa, Jere, Biu, Bayo, Askirin/Uba, and Kwayar Kusar. Blood samples were obtained from consented 990 participants and filarial test strip (FTS) were employed to determine their LF status between November 2017 and February 2018. Of the 990 consented participants only 15 (1.5%) were positive for lymphatic filariasis. Ten cases of hydrocele in men were observed in 4 communities namely Bunari (3), Peta (3), Zaramiramga (2) and Uba (2). Considering the number of positive cases by FTS and hydrocele, result showed that hydrocele accounted for 66.7% of the total positive cases within the positive communities. It is advised that the State health workers should continue to properly educate communities on health programmes including LF preventive measures. Also both Federal Ministry of Health and State Ministry of Health sensitize health partners to start LF treatment and morbidity management in all positive communities to fast track elimination of LF.

Lymphatic filariasis elimination efforts in Rufiji, southeastern Tanzania: decline in circulating filarial antigen prevalence in young school children after twelve rounds of mass drug administration and utilization of long-lasting insecticide-treated nets

Lymphatic filariasis (LF) is a parasitic infection transmitted by mosquito vectors, and in Sub-Saharan Africa it is caused by the nematode Wuchereria bancrofti. The disease has been targeted for global elimination with the annual mass drug administration (MDA) strategy. Vector control is known to play an important complementary role to MDA in reducing the transmission of LF. The effects of an MDA and insecticide-treated net intervention implemented in an endemic area of southeastern Tanzania are reported here. A cross-sectional study assessing W. bancrofti circulating filarial antigen (CFA) was conducted in five primary schools in five different villages. Standard one pupils aged 6-9 years were screened for CFA using immunochromatographic test cards (ICT), with a total of 413 screened in 2012 and 659 in 2015. Just after CFA testing, the children were interviewed on their participation in the MDA campaign. Moreover, 246 heads of households in 2012 and 868 in 2015 were interviewed on their participation in MDA and utilization of long-lasting insecticide-treated nets (LLINs). The prevalence of CFA for the 413 children tested in 2012 was 14.3%, while it was 0.0% for the 659 children tested in 2015. The Tanzanian National Lymphatic Filariasis Elimination Programme reported annual treatment coverage for Rufiji District ranging from 54.3% to 94.0% during the years 2002-2014. The surveyed treatment was 51.6% in 2011 and 57.4% in 2014. With regard to LLINs, possession and utilization increased from 63.4% and 59.2%, respectively, in 2012, to 92.5% and 75.4%, respectively, in 2015. The findings suggest that 12 rounds of MDA complemented with vector control through the use of insecticide-treated nets resulted in a marked reduction in W. bancrofti CFA in young school children.

Evidence of continued transmission of Wuchereria bancrofti and associated factors despite nine rounds of ivermectin and albendazole mass drug administration in Rufiji district, Tanzania

Background: In most sub-Saharan Africa, the National Lymphatic Filariasis Elimination Programme (NLFEP) is based on annual mass drug administration (MDA) with ivermectin and albendazole. In order to interrupt transmission, 4–6 rounds of MDA are required with at least 60–70% minimum effective coverage. Children born since the introduction of the MDA programme are recommended for assessing the interruption of transmission. The objective of this study was lymphatic filariasis transmission status after nine rounds of MDA in Rufiji district, Tanzania. Methods : This cross sectional survey involved 270 heads of household. Parents or guardians were interviewed on behalf of the schoolchildren about their participation in MDA programme. Status of LF prevalence was assessed by measuring Wuchereria bancrofti circulating filarial antigens (CFA) in blood samples from standard one school children (6 – 9 years) using immunochromatographic test cards. Results: A total of 413 standard one schoolchildren were tested for CFA; 59 (14.3%) had CFA. Two thirds (66.8%) of the children did not participate in 2011 MDA round. Prevalence of CFA was significantly lower in younger (6.4%) than older children (40.4%) (p<0.05). Participation in the last (2011) MDA did not significantly change the prevalence W. bancrofti CFA (χ 2 = 0.723, p=0.4). The recorded MDA coverage for 5 years including 2011 was above the 60–70 % minimum effective coverage. The community reported coverage was 40.4% for last MDA (2011), for previous MDAs was 53.0%; being far below the minimum effective coverage. Though the large majority (97.0%) of households had heard of LF, only about half (57.0%) knew it was transmitted by mosquitoes. Less than a half (43.6%) of households were aware of the adverse effects of LF, therefore motivated to participate in MDA. Conclusion: The findings indicate that LF transmission has continued in Rufiji district despite nine rounds of MDA. Low compliance to MDAs due to community and programmatic factors were responsible for the continued LF transmission. Detailed entomological studies are required to establish LF transmission dynamics and the programmatic factors associated with MDA implementation in the area.

COMMUNITY MEMBERS' PERCEPTIONS OF MASS DRUG ADMINISTRATION FOR CONTROL OF LYMPHATIC FILARIASIS IN RURAL AND URBAN TANZANIA.

Lymphatic filariasis is one of several neglected tropical diseases with severely disabling and stigmatizing manifestations that are referred to as 'neglected diseases of poverty'. It is a mosquito-borne disease found endemically and exclusively in low-income contexts where, concomitantly, general public health care is often deeply troubled and fails to meet the basic health needs of impoverished populations. This presents particular challenges for the implementation of mass drug administration (MDA), which currently is the principal means of control and eventual elimination. Several MDA programmes face the dilemma that they are unable to attain and maintain the required drug coverage across target groups. In recognition of this, a qualitative study was conducted in the Morogoro and Lindi regions of Tanzania to gain an understanding of community experiences with, and perceptions of, the MDA campaign implemented in 2011 by the National Lymphatic Filariasis Elimination Programme. The study revealed a wide variation of perceptions and experiences regarding the aim, rationale and justification of MDA. There were positive sentiments about the usefulness of the drugs, but many study participants were sceptical about the manner in which MDA is implemented. People were particularly disappointed with the limited attempts by implementers to share information and mobilize residents. In addition, negative sentiments towards MDA for lymphatic filariasis reflected a general feeling of desertion and marginalization by the health care system and political authorities. However, the results suggest that if the communities are brought on board with genuine respect for their integrity and informed self-determination, there is scope for major improvements in community support for MDA-based control activities.

Lymphatic filariasis baseline survey in two sentinel sites of Ogun state, Nigeria

IntroductionIn preparation for Mass Drug Administration by National Lymphatic Filariasis Elimination Programme, a baseline epidemiological investigation on lymphatic filariasis (LF) was conducted in two sentinel sites of Ogun State, Nigeria. The study was carried out in Ado-Odo Ota and Abeokuta South Local Government Areas (LGAs) to determine LF prevalence, microfilarial density and the abundance of Wucheraria bancrofti in the mosquito vectors.MethodsMicroscopic examination of thick blood smears of 299 and 288 participants from Ado-Odo Ota and Abeokuta South LGAs was conducted. Visual observations of clinical manifestations of chronic infection and questionnaire administration were also conducted. Indoor resting mosquitoes were collected using the pyrethrum spray technique and CDC light traps and mosquitoes were dissected for filarial larvae.ResultsMicrofilaria prevalences were 4.0% and 2.4% in Ado-odo Ota and Abeokuta South LGAs. The microflarial density (mfd) was 30.6mf/ml and 23.9 mf/ml in the same areas. No clinical manifestations of the infection were found at both sites. Knowledge of LF by inhabitants was very low in the two areas. Anopheles gambiae s.l and Culex species mosquitoes were collected but none was found positive for stage L3 infective larvae.ConclusionMass awareness campaigns on the goal of mass drug administration, cause of LF, mode of transmission, the relationship between infection and clinical signs/symptoms is advocated so as to increase acceptance and support of the control programme by the community.

Factors influencing drug uptake during mass drug administration for control of lymphatic filariasis in rural and urban Tanzania.

BackgroundIn most countries of Sub-Saharan Africa, control of lymphatic filariasis (LF) is based on annual mass drug administration (MDA) with a combination of ivermectin and albendazole. Treatment coverages are however often suboptimal for programmes to reach the goal of transmission interruption within reasonable time. The present study aimed to identify predictors and barriers to individual drug uptake during MDA implementation by the National LF Elimination Programme in Tanzania.MethodsA questionnaire based cross sectional household survey was carried out in two rural and two urban districts in Lindi and Morogoro regions shortly after the 2011 MDA. 3279 adults (≥15 years) were interviewed about personal characteristics, socio-economic status, MDA drug uptake among themselves and their children, reasons for taking/not taking drugs, and participation in previous MDA activities for LF control.FindingsThe overall drug uptake rate was 55.1% (range of 44.5–75.6% between districts). There was no overall major difference between children (54.8%) and adults (55.2%) or between females (54.9%) and males (55.8%), but the role of these and other predictors varied to some extent between study sites. Major overall predictors of drug uptake among the interviewed adults were increasing age and history of previous drug uptake. Being absent from home during drug distribution was the main reason for not taking the drugs (50.2%) followed by clinical contraindications to treatment (10.8%), missing household visits of drug distributors (10.6%), and households not being informed about the distribution (9.0%).ConclusionDrug uptake relied more on easily modifiable provider-related factors than on individual perceptions and practices in the target population. Limited investments in appropriate timing, dissemination of accurate timing information to recipients and motivation of drug distributors to visit all households (repeatedly when residents are absent) are likely to have considerable potential for increasing drug uptake, in support of successful LF transmission elimination.

Lymphatic filariasis control in Tanzania: effect of six rounds of mass drug administration with ivermectin and albendazole on infection and transmission

BackgroundControl of lymphatic filariasis (LF) in most countries of sub-Saharan Africa is based on annual mass drug administration (MDA) with a combination of ivermectin and albendazole, in order to interrupt transmission. We present findings from a detailed study on the effect of six rounds of MDA with this drug combination as implemented by the National Lymphatic Filariasis Elimination Programme (NLFEP) in a highly endemic rural area of north-eastern Tanzania.MethodsThe effect of treatment on transmission and human infection was monitored in a community- and a school-based study during an 8-year period (one pre-intervention and 7 post-intervention years) from 2003 to 2011.ResultsBefore intervention, 24.5% of the community population had microfilariae (mf) in the blood, 53.3% had circulating filarial antigens (CFA) and 78.9% had specific antibodies to the recombinant filarial antigen Bm14. One year after the sixth MDA, these values had decreased considerably to 2.7%, 19.6% and 27.5%, respectively. During the same period, the CFA prevalence among new intakes of Standard 1 pupils in 10 primary schools decreased from 25.2% to 5.6%. In line with this, transmission by the three vectors (Anopheles gambiae, An. funestus and Culex quinquefasciatus) as determined by dissection declined sharply (overall vector infectivity rate by 99.3% and mean monthly transmission potential by 99.2% between pre-intervention and fifth post-intervention period). A major shift in vector species composition, from predominantly anopheline to almost exclusively culicine was observed over the years. This may be largely unrelated to the MDAs but may have important implications for the epidemiology of LF in the area.ConclusionsSix MDAs caused considerable decrease in all the measured indices for transmission and human infection. In spite of this, indices were still relatively high in the late period of the study, and it may take a long time to reach the recommended cut-off levels for interruption of transmission unless extra efforts are made. These should include increased engagement of the target population in the control activities, to ensure higher treatment coverage. It is expected that the recent initiative to distribute insecticide impregnated bed nets to every household in the area will also contribute towards reaching the goal of successful LF elimination.

Lymphatic filariasis among the Yakurr people of Cross River State, Nigeria

BackgroundIn order to initiate a disease elimination programme for lymphatic filariasis based on mass drug administration, a proper understanding of the geographical distribution and degree of risk is essential.MethodsAn investigation of lymphatic filariasis due to Wuchereria bancrofti was carried out among 785 people in four communities of Yakurr Local Government Area of Cross River State, Nigeria between March and August, 2009. Finger prick blood smear samples collected from the subjects were examined for W. bancrofti using standard parasitological protocol. The subjects were also screened for clinical manifestations of lymphatic filariasis.ResultsOf the 785 persons examined, 48 (6.1%) were positive for microfilariae in their thick blood smear. There was a significant difference in the prevalence of lymphatic filariasis among the various age groups (P < 0.01) although peak prevalence occurred between 41 – 60 years. There was no significant difference in prevalence and density with respect to sex (P > 0.05). The overall mean microfilarial density of the infected individuals was 5.6mf/50 μl. There was a significant variation (P < 0.01) in mean microfilarial density within the communities, ranging from 4.7 to 6.4 mf/50 μl. The only clinical sign found in the study area was lymphoedema of the leg recording 2 (0.3%) prevalence.ConclusionsThe National Lymphatic Filariasis Elimination Programme should intervene by expanding the distribution of albendazole and ivermectin to all endemic areas including Yakurr Local Government Area of Cross River State, Nigeria.

Monitoring lymphatic filariasis control in Tanzania: effect of repeated mass drug administration on circulating filarial antigen prevalence in young schoolchildren

In most countries of Sub-Saharan Africa the control of lymphatic filariasis (LF) is based on annual mass drug administration (MDA) with a combination of ivermectin and albendazole, in order to interrupt transmission. We monitored the effect of four repeated MDAs with this combination, as implemented by the Tanzanian National Lymphatic Filariasis Elimination Programme (NLFEP), on the circulating filarial antigen (CFA) status of young schoolchildren. A new batch of Standard 1 pupils from 10 rural primary schools in Tanga Municipality were examined for CFA each year in September/October (691-848 children per survey; mean age of 7.5-8.1 years), from immediately before the first MDA until eight months after the fourth MDA. The overall pre-MDA prevalence of CFA was 25.2%. Only minor and non-significant change in prevalence was seen after the first two MDAs. However, this was followed by substantial and statistically significant decreases in subsequent surveys, and eight months after the fourth MDA the prevalence was only 6.4%. Continuous entomological surveillance in a village accommodating one of the schools showed progressive decrease in transmission right from the first MDA. The usefulness of screening young schoolchildren for CFA as a tool for monitoring the impact of MDA on LF transmission is discussed.

Lymphatic Filariasis Control in Tanzania: Effect of Repeated Mass Drug Administration with Ivermectin and Albendazole on Infection and Transmission

BackgroundIn most countries of sub-Saharan Africa the control of lymphatic filariasis (LF) is based on annual mass drug administration (MDA) with a combination of ivermectin and albendazole, in order to interrupt transmission. Here we present the first detailed study on the effect of 3 repeated MDAs with this drug combination, as implemented by the Tanzanian National Lymphatic Filariasis Elimination Programme (NLFEP).Methodology/Principal FindingsInfection and transmission was monitored during a five-year period (one pre-intervention and four post-intervention years) in a highly endemic community (Kirare village) in north-eastern Tanzania. The vectors were Anopheles gambiae, An. funestus and Cx. quinquefasciatus. After start of intervention, human microfilaraemia initially decreased rapidly and statistically significant (prevalence by 21.2% and 40.4%, and mean intensity by 48.4% and 73.7%, compared to pre-treatment values after the first and second MDA, respectively), but thereafter the effect levelled off. The initial decrease in microfilaraemia led to significant decreases in vector infection and vector infectivity rates and thus to a considerable reduction in transmission (by 74.3% and 91.3% compared to pre-treatment level after first and second MDA, respectively). However, the decrease in infection and infectivity rates subsequently also levelled off, and low-level transmission was still noted after the third MDA. The MDAs had limited effect on circulating filarial antigens and antibody response to Bm14.Conclusion/SignificanceCritical issues that may potentially explain the observed waning effect of the MDAs in the later study period include the long intervals between MDAs and a lower than optimal treatment coverage. The findings highlight the importance of ongoing surveillance for monitoring the progress of LF control programmes, and it calls for more research into the long-term effect of repeated ivermectin/albendazole MDAs (including the significance of treatment intervals and compliance), in order to optimize efforts to control LF in sub-Saharan Africa.

Marriage, Sex, and Hydrocele: An Ethnographic Study on the Effect of Filarial Hydrocele on Conjugal Life and Marriageability from Orissa, India

BackgroundLymphatic filariasis (LF), a leading cause of permanent and long-term disability, affects 120 million people globally. Hydrocele, one of the chronic manifestations of LF among 27 million people worldwide, causes economic and psychological burdens on patients and their families. The present study explores and describes the impact of hydrocele on sexual and marital life as well as on marriageability of hydrocele patients from rural areas of Orissa, an eastern state of India.Methodology/Principal FindingsThis paper is based on ethnographic data collected through focus group discussions and in-depth interviews with hydrocele patients, wives of hydrocele patients, and other participants from the community. The most worrisome effect of hydrocele for patients and their wives was the inability to have a satisfactory sexual life. The majority of patients (94%) expressed their incapacity during sexual intercourse, and some (87%) reported pain in the scrotum during intercourse. A majority of hydrocele patients' wives (94%) reported dissatisfaction in their sexual life. As a result of sexual dissatisfaction and physical/economic burden, communication has deteriorated between the couples and they are not living happily. This study also highlights the impact on marriageability. The wives of hydrocele patients said that a hydrocele patient is the “last choice” and that girls show reluctance to marry hydrocele patients. In some cases, the patients were persuaded by their wives to remove hydrocele by surgery (hydrocelectomy).Conclusions/SignificanceThe objective of the morbidity management arm of the Global Programme to Eliminate LF should be to increase access to hydrocelectomy, as hydrocelectomy is the recommended intervention. Though the study area is covered by the programme, like in other endemic areas, hydrocelectomy has not been emphasised by the national LF elimination programme. The policy makers and programme managers should be sensitised by utilising this type of research finding.

The geographical distribution of lymphatic filariasis infection in Malawi

Mapping distribution of lymphatic filariasis (LF) is a prerequisite for planning national elimination programmes. Results from a nation wide mapping survey for lymphatic filariasis (LF) in Malawi are presented. Thirty-five villages were sampled from 23 districts excluding three districts (Karonga, Chikwawa and Nsanje) that had already been mapped and Likoma, an Island, where access was not possible in the time frame of the survey. Antigenaemia prevalence [based on immunochromatographic card tests (ICT)] ranged from 0% to 35.9%. Villages from the western side of the country and distant from the lake tended to be of lower prevalence. The exception was a village in Mchinji district on the Malawi-Zambia border where a prevalence of 18.2% was found. In contrast villages from lake shore districts [Salima, Mangochi, Balaka and Ntcheu (Bwanje valley)] and Phalombe had prevalences of over 20%.A national map is developed which incorporates data from surveys in Karonga, Chikwawa and Nsanje districts, carried out in 2000. There is a marked decline in prevalence with increasing altitude. Further analysis revealed a strong negative correlation (R2 = 0.7 p < 0.001) between altitude and prevalence. These results suggest that the lake shore, Phalombe plain and the lower Shire valley will be priority areas for the Malawi LF elimination programme. Implications of these findings as regards implementing a national LF elimination programme in Malawi are discussed.