Lymphatic filariasis control in Tanzania: infection, disease perceptions and drug uptake patterns in an endemic community after multiple rounds of mass drug administration

Assessment of microfilaremia in 'hotspots' of four lymphatic filariasis endemic districts of Nepal during post-MDA surveillance

BACKGROUND

The lymphatic filariasis (LF) elimination program in all sixty-three endemic districts of Nepal was based on annual mass drug administration (MDA) using a combination of diethylcarbamazine (DEC) and albendazole for at least 5 years. The MDA program was started in the Parsa district of the Terai region and at least six rounds of MDA were completed between 2003 and 2017 in all filariasis endemic districts of Central Nepal. Transmission Assessment Survey (TAS) report indicated that circulating filarial antigen (CFA) prevalence was below the critical value i.e., ≤ 2% in selected LF endemic districts of Central Nepal. Based on the TAS report, antigen-positive cases were found clustered in the foci of those districts which were considered as "hotspots". Hence the present study was designed to assess microfilaremia in hotspots of four endemic districts of Central Nepal after the MDA program.

METHODOLOGY AND PRINCIPAL FINDINGS

The present study assessed microfilaremia in hotspots of four endemic districts i.e. Lalitpur and Dhading from the hilly region and Bara and Mahottari from the Terai region of Central Nepal. Night blood samples (n = 1722) were collected by finger prick method from the eligible sample population irrespective of age and sex. Community people's participation in the MDA program was ensured using a structured questionnaire and chronic clinical manifestation of LF was assessed using standard case definition. Two districts one each from the hilly region (Lalitpur district) and Terai region (Bara district) showed improved microfilaria (MF) prevalence i.e. below the critical level (<1%) while the other two districts are still over the critical level. There was a significantly high prevalence of MF in male (p = <0.05) and ≥41 years of age group (p = <0.05) community people in the hotspots of four endemic districts. People who participated in the previous rounds of the MDA program have significantly low MF prevalence. The upper confidence limit of MF prevalence in all hotspots of four districts was above the critical level (>1%). Chronic clinical manifestation of LF showed significant association with the older age group (≥41 years) but not with sex.

CONCLUSIONS

The study revealed LF transmission improved in hotspots of two districts while continued in others but the risk of LF resurgence cannot be ignored since the upper confidence level of MF prevalence is over 1% in all the hotspots studied districts. High MF prevalence is well correlated with the number of MDA rounds but not with the MDA coverage. Community people involved in MDA drug uptake in any previous and last rounds have significantly less MF infection. Hence it is recommended that before deciding to stop the MDA rounds it is essential to conduct the MF survey at the hotspots of the sentinel sites.

Sensitivity analysis and parameters estimation for the transmission of lymphatic filariasis

Lymphatic filariasis is a neglected tropical disease which poses public health concern and socio-economic challenges in developing and low-income countries. In this paper, we formulate a deterministic mathematical model for transmission dynamics of lymphatic filariasis to generate data by white noise and use least square method to estimate parameter values. The validity of estimated parameter values is tested by Gaussian distribution method. The residuals of model outputs are normally distributed and hence can be used to study the dynamics of Lymphatic filariasis. After deriving the basic reproduction number, R 0 by the next generation matrix approach, the Partial Rank Correlation Coefficient is employed to explore which parameters significantly affect and most influential to the model outputs. The analysis for equilibrium states shows that the Lymphatic free equilibrium is globally asymptotically stable when the basic reproduction number is less a unity and endemic equilibrium is globally asymptotically stable when R 0 ≥ 1 . The findings reveal that rate of human infection, recruitment rate of mosquitoes increase the average new infections for Lymphatic filariasis. Moreover, asymptomatic individuals contribute significantly in the transmission of Lymphatic filariasis.

Knowledge and participation in mass drug administration against lymphatic filariasis and soil-transmitted helminth infections among the community members in Dar es Salaam, Tanzania

BACKGROUND

Although the WHO has made an effort to ensure optimal participation of the community in mass drug administration (MDA) against lymphatic filariasis (LF) and soil-transmitted helminth infections (STHIs), studies are still reporting suboptimal coverage. This study assessed the knowledge and participation of the community in MDA against LF and SHTIs in Tanzania to provide updates on its acceptability.

METHODS

A cross-sectional study was conducted in Dar es Salaam from December 2021 to February 2022 among market vendors. The information regarding demographic characteristics, knowledge and participation in MDA was collected using a questionnaire. Statistical Package for Social science version 26 was used for data analysis.

RESULTS

More than half of the participants demonstrated an adequate level of knowledge of LF and STHI, 212 (50.8%) and 267 (64%), respectively. Only 286 (68.5%) reported having heard about MDA against LF and STHIs, out of which 119 (42%) had taken the medication. Of those who disagreed to participate in MDA, 20 (50%) claimed to fear the side effects of the medication.

CONCLUSIONS

This study found that the community has average knowledge and poor participation in MDA against LF and STHIs. Community sensitization is recommended to increase the participation of the community.

Step towards elimination of Wuchereria bancrofti in Southwest Tanzania 10 years after mass drug administration with Albendazole and Ivermectin

Background

Lymphatic filariasis is a mosquito transmitted parasitic infection in tropical regions. Annual mass treatment with ivermectin and albendazole is used for transmission control of Wuchereria bancrofti, the infective agent of lymphatic filariasis in many African countries, including Tanzania.

Methodology

In a general population study in Southwest Tanzania, individuals were tested for circulating filarial antigen, an indicator of W. bancrofti adult worm burden in 2009 before mass drug administration commenced in that area. Seven annual rounds with ivermectin and albendazole were given between 2009 and 2015 with a population coverage of over 70%. Participants of the previous study took part in a follow-up activity in 2019 to measure the effect of this governmental activity.

Findings

One thousand two hundred and ninety nine inhabitants of Kyela district in Southwest Tanzania aged 14 to 65 years who had participated in the study activities in 2009 were revisited in 2010/11 and 2019. Among this group, the prevalence of lymphatic filariasis of the 14–65 years olds in 2009 was 35.1%. A follow-up evaluation in 2010/11 had shown a reduction to 27.7%. In 2019, after 7 years of annual treatment and an additional three years of surveillance, the prevalence had dropped to 1.7%, demonstrating successful treatment by the national control programme. Risk factors for W. bancrofti-infection were the occupation as farmer, male sex, and older age. Most infected individuals in the 2019 follow-up study already had a positive test for filarial antigen in 2009 and/or 2010/11.

Conclusions

This data supports the findings of the Tanzanian Neglected Tropical Disease Control Programme (NTDCP), who conducted Transmission Assessment Surveys and found an impressive reduction in the prevalence of LF in children. Our results complement this data by showing a similar decrease in prevalence of LF in the adult population in the same area. The elimination of LF seems achievable in the near future.

The viability of utilising phone-based text messages in data capture and reporting morbidities due to lymphatic Filariasis by community health workers: a qualitative study in Kilwa district, Tanzania

Background

Globally, there is recognition of the value of using mobile phones among health providers in improving health systems performance. However, in many Low- and Middle-income countries where there is shortage of health providers, Community Health Workers have assumed some responsibilities especially relating to identifying and reporting on health problems within their communities. Despite the known benefits of using mobile phone technology to deliver health services, there is limited information on the extent to which Community Health Workers are able to effectively use the technology in data collection and reporting. The aim of this study was to determine the feasibility of utilizing phone-based text messages on Lymphatic Filariasis morbidity surveillance by Community Health Workers.

Methods

This was a cross sectional study whose data was collected through key informant interviews and focused group discussions among community health workers, health providers and staff of neglected tropical diseases control program. Collected transcripts were analysed through Thematic content analysis as it allowed for the identification of data codes through inductive reasoning.

Results

The use of mobile phone-based text messages in data collection and reporting lymphatic filariasis morbidity cases by Community Health Workers was perceived by study participants to be a relevant tool and feasible due to the ease of use of the technology. The tool was reported by end-users to significantly increase their performance and efficiency was gained in terms of reduced paper work, increased the number of patients accessing health care services and the ability to report in real-time. All respondents were confident that Community Health Workers were the right persons to interact with communities in tracking and reporting morbidity cases using mobile technology.

Conclusion

Mobile phone-based text messages have proven to be effective in routine workflows such as, data collection and reporting on Lymphatic Filariasis morbidity cases, patient to provider communication, decision making and supportive supervision. Mobile phones have also improved efficiency and general performance of end users in terms of increased number of cases identified and efficiency gained in terms of reduced paper work and the ability to collect and report in real-time.

Prevalence and management of filarial lymphoedema and its associated factors in Lindi district, Tanzania: A community-based cross-sectional study

OBJECTIVE

To determine the burden and management of filarial lymphoedema and its associated factors in Lindi district, Tanzania.

METHODS

Cross-sectional study involving 954 community members who were screened for filarial lymphoedema by using a checklist. Moreover, lymphoedema patients were examined for the presence of entry lesions, staging of disease, and interviewed on acute dermatolymphangioadenitis (ADLA) attacks, and their current practices on lymphoedema management. Descriptive statistics and logistic regression analyses were performed. A p < 0.05 was considered statistically significant.

RESULTS

The prevalence of filarial lymphoedema was 7.8%, with the majority in the early stage of lymphoedema (78.4%). The large majority (98.6%) of the patients had lower limb lymphoedema and 46% of lymphoedema patients had entry lesions. More than a half (60.8%) of those lymphoedema patients had experienced ADLA attacks; close to two-thirds (64.8%) had one or two attacks in the past 6 months. Generally, patients had inappropriate hygiene care practices for filarial lymphoedema management. Inappropriate hygiene care practice for lymphoedema management was associated with an increased risk for the development of advance stage of lymphoedema (adjusted odds ratio = 7.379, 95%, confidence interval: 3.535-16.018, p = 0.04).

CONCLUSION

Though lymphatic filariasis transmission has drastically declined, chronic manifestations of lymphoedema persist in Lindi district. The recommended disease management practices are deficient, which calls for a programmatic approach for mapping the burden of lymphoedema and implementing its management.

Community views on mass drug administration for filariasis: a qualitative evidence synthesis

BACKGROUND

The World Health Organization (WHO) recommends mass drug administration (MDA), giving a drug at regular intervals to a whole population, as part of the strategy for several disease control programmes in low- and middle-income countries. MDA is currently WHO policy for areas endemic with lymphatic filariasis, which is a parasitic disease that can result in swollen limbs and disability. The success depends on communities adhering to the drugs given, and this will be influenced by the perception of the drug, the programme, and those delivering it.  OBJECTIVES: To synthesize qualitative research evidence about community experience with, and understanding and perception of, MDA programmes for lymphatic filariasis. To explore whether programme design and delivery influence the community experience identified in the analysis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and seven other databases up to 8 April 2021, together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

This review synthesized qualitative research and mixed-methods studies when it was possible to extract qualitative data. Eligible studies explored community experiences, perceptions, or attitudes towards MDA programmes for lymphatic filariasis in any country, conducted between 2000 and 2019.  DATA COLLECTION AND ANALYSIS: We extracted data on study design including: authors, aims, participants, methods, and qualitative data collection methods. We also described programme delivery factors including: country, urban or rural setting, endemicity, drug regimen, rounds of MDA received at the time of the study, who delivered the drugs, how the drugs were delivered, use of health education, and sensitization and adherence monitoring. We conducted a thematic analysis and developed codes inductively using ATLAS.ti software. We examined codes for underlying ideas, connections, and interpretations and, from this, generated analytical themes. We assessed the confidence in the findings using the GRADE-CERQual approach, and produced a conceptual model to display our findings.  MAIN RESULTS: From 902 results identified in the search, 29 studies met our inclusion criteria. The studies covered a broad range of countries in Africa, South-East Asia, and South America, and explored the views and experiences of community members and community drug distributors in low-income countries endemic for lymphatic filariasis. Four themes emerged. People weigh up benefits and harms before participating. People understand the potential benefits in terms of relief of suffering, stigma, and avoiding costs (high confidence); however, these theoretical benefits do not always mesh with their experiences (high confidence). In particular, adverse effects are frightening and unwelcome (high confidence); and these effects are amplified through rumour and social media (moderate confidence). Many people are suspicious of MDA programmes. When people lack a scientific explanation for the programme and their experiences of it, they often develop social explanations instead. These are largely shaped on the historical backdrop and level of trust people have in relevant authority figures (high confidence), although some have unwavering faith in their government and, by extension, the programme (moderate confidence). Programmes expect compliance, and this can become coercive and blaming. Health workers and community members stigmatize non-compliance, which can become coercive (moderate confidence), so communities may appear to comply publicly, but privately reject treatment (moderate confidence). Community distributors are often not respected or valued. They have little authority (moderate confidence), and the behaviour of some distributors damages the MDA programme's reputation (high confidence). Communities want information about programmes to help make decisions about participation, but drug distributors are not sufficiently informed, or skilled in this communication (high confidence). We intended to assess whether programme designs influenced communities' perceptions of the programme and decision to adhere but were unable to do so as few studies adequately reported the design and implementation of the local programme. We have moderate to high confidence in the evidence contributing to the review themes and subthemes.

AUTHORS' CONCLUSIONS

Adherence with MDA for filariasis is influenced by individual direct experience of benefit and harm; social influences in the community; political influences and their relationship to government; and historical influences. Fear of adverse effects was frequently described and this appears to be particularly important for communities. When views were negative, we were surprised by the strength of feeling expressed. Enthusiasm for these schemes as a strategy in global policy needs debate in the light of these findings.

Barriers and Facilitators of Use of Hydroxyurea among Children with Sickle Cell Disease: Experiences of Stakeholders in Tanzania

Factors contributing to low use of HU among SCD patients exist in high-income countries. The latter leaves a drift of literature on factors for low utilization of HU in developing countries. This study aimed to explore the factors influencing the use of HU in the management of SCD in Tanzania. A qualitative study was employed to interview purposively selected participants for this study. The in-depth interviews were conducted with 11 parents of children with SCD, four medical doctors working at sickle cell clinics, and two representatives of the national health insurance fund (NHIF). Interviews were audio-recorded, transcribed, and thematically analysed. Barriers identified were misconception of parents on SCD, financial constraints, regulatory restrictions, worries and fears of medical doctors on the acceptability of HU, shortages of laboratory equipment and consumables, and limited availability of HU. Adequate knowledge of the parents and medical doctors on SCD and HU and opportunities for HU accessibility were the facilitators identified. The utilization of HU by the individual with SCD is affected by several factors, from individual to policy level. Nevertheless, parents of children with SCD and medical doctors working in sickle cell clinics demonstrated good knowledge of the diseases and HU.

Optimising the performance of frontline implementers engaged in the NTD programme in Nigeria: lessons for strengthening community health systems for universal health coverage

BACKGROUND

The control and elimination of Neglected Tropical Diseases (NTDs) is dependent on mass administration of medicines (MAM) in communities and schools by community drug distributers (CDDs) who are supported and supervised by health facility staff (FLHF) and teachers. Understanding how to motivate, retain and optimise their performance is essential to ensure communities accept medicines. This study aimed to capture and translate knowledge, problems and solutions, identified by implementers, to enhance NTD programme delivery at the community level in Nigeria.

METHODS

Qualitative data was collected through participatory stakeholder workshops organised around two themes: (i) identification of problems and (ii) finding solutions. Eighteen problem-focused workshops and 20 solution-focussed workshops were held with FLHF, CDDs and teachers in 12 purposively selected local government areas (LGA) across two states in Nigeria, Ogun and Kaduna States.

RESULT

The problems and solutions identified by frontline implementers were organised into three broad themes: technical support, social support and incentives. Areas identified for technical support included training, supervision, human resource management and workload, equipment and resources and timing of MAM implementation. Social support needs were for more equitable drug distributor selection processes, effective community sensitisation mechanisms and being associated with the health system. Incentives identified were both non-financial and financial including receiving positive community feedback and recognition and monetary remuneration. The results led to the development of the 'NTD frontline implementer's framework' which was adapted from the Community Health Worker (CHW) Generic Logic Model by Naimoli et al. (Hum Resour Health 12:56, 2014).

CONCLUSION

Maximising performance of frontline implementers is key to successful attainment of NTD goals and other health interventions. As NTDs are viewed as a 'litmus test' for universal health coverage, the lessons shared here could cut across programmes aiming to achieve equitable coverage. It is critical to strengthen the collaboration between health systems and communities so that together they can jointly provide the necessary support for frontline implementers to deliver health for all. This research presents additional evidence that involving frontline implementers in the planning and implementation of health interventions through regular feedback before, during and after implementation has the potential to strengthen health outcomes.

Lymphatic filariasis transmission in Rufiji District, southeastern Tanzania: infection status of the human population and mosquito vectors after twelve rounds of mass drug administration

Background

Control of lymphatic filariasis (LF) in most of the sub-Saharan African countries is based on annual mass drug administration (MDA) using a combination of ivermectin and albendazole. Monitoring the impact of this intervention is crucial for measuring the success of the LF elimination programmes. This study assessed the status of LF infection in Rufiji district, southeastern Tanzania after twelve rounds of MDA.

Methods

Community members aged between 10 and 79 years were examined for Wuchereria bancrofti circulating filarial antigens (CFA) using immunochromatographic test cards (ICTs) and antigen-positive individuals were screened for microfilaraemia. All study participants were examined for clinical manifestation of LF and interviewed for drug uptake during MDA rounds. Filarial mosquito vectors were collected indoor and outdoor and examined for infection with W. bancrofti using a microscope and quantitative real-time polymerase chain reaction (qPCR) techniques.

Results

Out of 854 participants tested, nine (1.1%) were positive for CFA and one (0.1%) was found to be microfilaraemic. The prevalence of hydrocele and elephantiasis was 4.8% and 2.9%, respectively. Surveyed drug uptake rates were high, with 70.5% of the respondents reporting having swallowed the drugs in the 2014 MDA round (about seven months before this study). Further, 82.7% of the respondents reported having swallowed the drugs at least once since the inception of MDA programme in 2000. Of the 1054 filarial vectors caught indoors and dissected to detect W. bancrofti infection none was found to be infected. Moreover, analysis by qPCR of 1092 pools of gravid Culex quinquefasciatus collected outdoors resulted in an estimated infection rate of 0.1%. None of the filarial vectors tested with qPCR were found to be infective.

Conclusion

Analysis of indices of LF infection in the human population and filarial mosquito vectors indicated a substantial decline in the prevalence of LF and other transmission indices, suggesting that local transmission was extremely low if occurring at all in the study areas. We, therefore, recommend a formal transmission assessment survey (TAS) to be conducted in the study areas to make an informed decision on whether Rufiji District satisfied WHO criteria for stopping MDA.