Predicting lymphatic filariasis elimination in data-limited settings: A reconstructive computational framework for combining data generation and model discovery.

Although there is increasing importance placed on the use of mathematical models for the effective design and management of long-term parasite elimination, it is becoming clear that transmission models are most useful when they reflect the processes pertaining to local infection dynamics as opposed to generalized dynamics. Such localized models must also be developed even when the data required for characterizing local transmission processes are limited or incomplete, as is often the case for neglected tropical diseases, including the disease system studied in this work, viz. lymphatic filariasis (LF). Here, we draw on progress made in the field of computational knowledge discovery to present a reconstructive simulation framework that addresses these challenges by facilitating the discovery of both data and models concurrently in areas where we have insufficient observational data. Using available data from eight sites from Nigeria and elsewhere, we demonstrate that our data-model discovery system is able to estimate local transmission models and missing pre-control infection information using generalized knowledge of filarial transmission dynamics, monitoring survey data, and details of historical interventions. Forecasts of the impacts of interventions carried out in each site made by the models estimated using the reconstructed baseline data matched temporal infection observations and provided useful information regarding when transmission interruption is likely to have occurred. Assessments of elimination and resurgence probabilities based on the models also suggest a protective effect of vector control against the reemergence of LF transmission after stopping drug treatments. The reconstructive computational framework for model and data discovery developed here highlights how coupling models with available data can generate new knowledge about complex, data-limited systems, and support the effective management of disease programs in the face of critical data gaps.

Upon entering an age of global ivermectin-based integrated mass drug administration for neglected tropical diseases and malaria.

Ivermectin mass drug administration (MDA) in humans to reduce malaria vectors is yet another use for this remarkable medicine whose discoverers shared the 2015 Nobel Prize in Medicine with the discoverer of artemisinin. The malaria community should join those who have long used ivermectin MDA in an integrated battle to break transmission of three vector-borne parasitic diseases.

Malaria prevalence, anemia and baseline intervention coverage prior to mass net distributions in Abia and Plateau States, Nigeria.

BACKGROUND: Nigeria suffers the world's largest malaria burden, with approximately 51 million cases and 207,000 deaths annually. As part of the country's aim to reduce by 50% malaria-related morbidity and mortality by 2013, it embarked on mass distribution of free long-lasting insecticidal nets (LLINs). METHODS: Prior to net distribution campaigns in Abia and Plateau States, Nigeria, a modified malaria indicator survey was conducted in September 2010 to determine baseline state-level estimates of Plasmodium prevalence, childhood anemia, indoor residual spraying (IRS) coverage and bednet ownership and utilization. RESULTS: Overall age-adjusted prevalence of Plasmodium infection by microscopy was similar between Abia (36.1%, 95% CI: 32.3%-40.1%; n = 2,936) and Plateau (36.6%, 95% CI: 31.3%-42.3%; n = 4,209), with prevalence highest among children 5-9 years. P. malariae accounted for 32.0% of infections in Abia, but only 1.4% of infections in Plateau. More than half of children ≤10 years were anemic, with anemia significantly higher in Abia (76.9%, 95% CI: 72.1%-81.0%) versus Plateau (57.1%, 95% CI: 50.6%-63.4%). Less than 1% of households in Abia (n = 1,305) or Plateau (n = 1,335) received IRS in the 12 months prior to survey. Household ownership of at least one bednet of any type was 10.1% (95% CI: 7.5%-13.4%) in Abia and 35.1% (95% CI: 29.2%-41.5%) in Plateau. Ownership of two or more bednets was 2.1% (95% CI: 1.2%-3.7%) in Abia and 14.5% (95% CI: 10.2%-20.3%) in Plateau. Overall reported net use the night before the survey among all individuals, children <5 years, and pregnant women was 3.4%, 6.0% and 5.7%, respectively in Abia and 14.7%, 19.1% and 21.0%, respectively in Plateau. Among households owning nets, 34.4% of children <5 years and 31.6% of pregnant women in Abia used a net, compared to 52.6% of children and 62.7% of pregnant women in Plateau. CONCLUSIONS: These results reveal high Plasmodium prevalence and childhood anemia in both states, low baseline coverage of IRS and LLINs, and sub-optimal net use-especially among age groups with highest observed malaria burden.

Do Residents Believe that Onchocerciasis Transmission Was Eliminated? Results of A Post-Treatment Surveillance Knowledge, Attitude, and Practices Survey in Three Foci of Uganda.

In Uganda, 15 of 17 foci have interrupted transmission of onchocerciasis (river blindness) and stopped mass drug administration (MDA) of ivermectin. This 2016 study describes the results of a knowledge, attitude, and practices survey regarding river blindness among participants (N = 1,577) 3-5 years after ivermectin MDA was halted in three foci: Imaramagambo halted in 2012, Kashoya-Kitomi in 2013, and Mt. Elgon in 2011. The study showed high levels of composite knowledge (focus-specific range: 66.8-81.2%) related to river blindness transmission, signs, symptoms, and treatment. However, 38.1% of respondents did not know that blackflies transmitted river blindness. Notably, 72.2% claimed they had not been informed why MDA was stopped, 56.3% did not believe river blindness had been eliminated, and 83.1% wanted ivermectin MDA to resume. During the 3-5 year post-treatment surveillance period, only 27.7% (438 of 1,577) reported being informed of what to do once treatments stopped, with the most knowledgeable hailing from the Mt. Elgon focus (47.9%). This study reinforces the need for programs to intensify health education and information dissemination when MDA is stopped. Programs must remind residents that although biting insects may persist, they no longer transmit river blindness. Incorporating messages about the elimination of river blindness into community health education campaigns can help improve the community's perceptions related to the disease's absence and the ending of a long-standing MDA intervention.

Evaluation of the International Task Force for Disease Eradication: A Review of Past Deliberations.

The International Task Force for Disease Eradication (ITFDE) was formed at The Carter Center in 1988. Its primary purpose is to review activities and provide recommendations related to programs focused on eradication. The ITFDE also considers opportunities for disease elimination and improved control. Over the last two decades, the ITFDE has held 33 meetings, discussed 22 diseases, and made 244 recommendations. This report aims to analyze the patterns in recommendations made by the ITFDE between 2001 and 2022 and assess the ITFDE's role, impacts, and successes in advancing elimination and eradication efforts for selected diseases. Using a thematic analysis, recommendation categories were crafted, followed by a scoping review to determine evidence of implementation for each recommendation. Categories of recommendations included research (24%), leadership (20%), medical (17%), advocacy (11%), collaboration (13%), development (8%), and financial (8%). We determined that 123 (50.4%) ITFDE recommendations were implemented in some form. Notably, the ITFDE has helped raise the profile of neglected tropical diseases. Four salient outcomes include 1) the identification of the potential eradicability of lymphatic filariasis (1993), 2) the recognition of the critical need for improved treatments of human African trypanosomiasis (2002), 3) a recommendation for the elimination of lymphatic filariasis and malaria from Hispaniola (2006), and 4) recommendations for effective and safe ways to avoid disruption of elimination and eradication programs during the COVID-19 pandemic (2020). This review of the ITFDE will help to devise new approaches to monitor its impact in the future.

Progress Toward Onchocerciasis Elimination in Brazil.

The single onchocerciasis-endemic focus in the remote Amazon rainforest is shared by Brazil and Venezuela and affects primarily the indigenous Yanomami people. Regional elimination of onchocerciasis is challenged by the magnitude and inaccessibility of this area. In Brazil, 272 onchocerciasis-endemic communities are operationally organized through 21 health centers ("polos bases"). Mass drug administration of ivermectin began in 1995, with 36 effective biannual rounds (≥85% coverage of the eligible population) through 2022. The national on chocerciasis program maintains community-level monitoring to prioritize treatment activities and epidemiological surveys. The Onchocerciasis Elimination Program for the Americas and the WHO onchocerciasis elimination guidelines have helped Brazil move toward its goal of stopping ivermectin treatment by 2025 and verifying transmission elimination by 2030. Additional challenges to the Brazilian onchocerciasis program include cross-border movements and insecurity due to illegal mining and inter-community conflicts. The new government in Brazil offers hope given its commitment to the equity of indigenous people and preservation of the Amazon environment.

Scorecard Approach to Eliminate Onchocerciasis in Venezuela.

In the Americas, onchocerciasis has been eliminated in 11 of 13 endemic foci by mass administration of ivermectin. The remaining at-risk population resides in a contiguous cross-border transmission zone located in the Amazon jungle in northwest Brazil and southern Venezuela, known as the Yanomami Focus Area. Here, we describe the development and implementation of a data-driven tool, called the Scorecard Approach (SCA), for the 393 communities that comprise the Venezuela South Focus. The SCA was first applied in 2018 and is reassessed on an annual basis. This operational strategy seeks to prioritize communities with low ivermectin coverage while taking into account the nature and variation of other epidemiological and logistical variables. Numeric scores are assigned for each factor and added together to yield a composite score for each community that is categorized as high, medium, or low priority. In this way, the SCA serves as a valuable and comprehensive strategy for planning, monitoring, and maximizing programmatic efficiency. In addition, it has allowed the country to face the main challenges of this endemic area: its remoteness, its large areas of territory to cover, the semi-nomadic nature of the Yanomami people, and their continuous cross-border movements. For 2022, the SCA categorized 54 (13.7%), 108 (27.5%), and 231 (58.8%) communities as high, medium, and low priority, respectively. The results presented here show that prioritizing communities at risk and with greatest needs increases the feasibility of interrupting the transmission of onchocerciasis by 2025 in the last endemic focus in the Americas.

The Interruption of Transmission of Onchocerciasis in Abia, Anambra, Enugu, and Imo States, Nigeria: The Largest Global Onchocerciasis Stop-Treatment Decision to Date.

Onchocerciasis causes severe morbidity in sub-Saharan Africa. Abia, Anambra, Enugu, and Imo states of Nigeria were historically classified meso- or hyperendemic and eligible for ivermectin mass drug administration (MDA). After ≥25 years of annual and biannual MDA, serological and entomological assessments were conducted to determine if Onchocerca volvulus transmission was interrupted. Dried blood spots collected in October 2020 from ≥3167 children 5-9 years old in each state were screened for O. volvulus-specific Ov16 antibody by enzyme-linked immunosorbent assay. Additionally, 52,187 Simulium damnosum heads (≥8845 per state) collected over 12 months between 2021 and 2022 were tested by pooled polymerase chain reaction (PCR) for O-150 DNA. Among seven seropositive children, four were found for follow-up skin snip PCR to confirm active infection. Three were negative and the fourth was excluded as he was visiting from an endemic state. The final seroprevalence estimates of each state had 95% upper confidence limits (UCL) < 0.1%. All fly pools were negative by O-150 PCR, giving a 95% UCL infective fly prevalence < 0.05% in each state. Each state therefore met the World Health Organization epidemiological and entomological criteria for stopping MDA effective January 2023. With 18.9 million residents eligible for MDA, this marked the largest global onchocerciasis stop-treatment decision to date.

Physical durability of PermaNet 2.0 long-lasting insecticidal nets over three to 32 months of use in Ethiopia.

BACKGROUND: Ethiopia scaled up net distribution markedly starting in 2006. Information on expected net life under field conditions (physical durability and persistence of insecticidal activity) is needed to improve planning for net replacement. Standardization of physical durability assessment methods is lacking. METHODS: Permanet®2.0 long-lasting insecticidal bed nets (LLINs), available for distribution in early 2007, were collected from households at three time intervals. The number, size and location of holes were recorded for 189 nets used for three to six months from nine sites (2007) and 220 nets used for 14 to 20 months from 11 sites (2008). In 2009, a "finger/fist" sizing method classified holes in 200 nets used for 26 to 32 months from ten sites into small (<2 cm), medium (> = 2 to < =10 cm) and large (>10 cm) sizes. A proportionate hole index based on both hole number and area was derived from these size classifications. RESULTS: After three to six months, 54.5% (95% CI 47.1-61.7%) of 189 LLINs had at least one hole 0.5 cm (in the longest axis) or larger; mean holes per net was 4.4 (SD 8.4), median was 1.0 (Inter Quartile Range [IQR] 0-5) and median size was 1 cm (IQR 1-2). At 14 to 20 months, 85.5% (95% CI 80.1-89.8%) of 220 nets had at least one hole with mean 29.1 (SD 50.1) and median 12 (IQR 3-36.5) holes per net, and median size of 1 cm (IQR 1-2). At 26 to 32 months, 92.5% of 200 nets had at least one hole with a mean of 62.2 (SD 205.4) and median of 23 (IQR 6-55.5) holes per net. The mean hole index was 24.3, 169.1 and 352.8 at the three time periods respectively. Repairs were rarely observed. The majority of holes were in the lower half of the net walls. The proportion of nets in 'poor' condition (hole index >300) increased from 0% at three to six months to 30% at 26 to 32 months. CONCLUSIONS: Net damage began quickly: more than half the nets had holes by three to six months of use, with 40% of holes being larger than 2 cm. Holes continued to accumulate until 92.5% of nets had holes by 26 to 32 months of use. An almost complete lack of repairs shows the need for promoting proper use of nets and repairs, to increase LLIN longevity. Using the hole index, almost one third of the nets were classed as unusable and ineffective after two and a half years of potential use.

Integrated Prevalence Assessment of Wuchereria bancrofti and Onchocerca volvulus in Three Co-Endemic Districts of Gambella Region, Ethiopia.

Lymphatic filariasis (LF) and onchocerciasis (OV) are among the neglected tropical diseases (NTD) targeted for elimination in Ethiopia. We used a transmission assessment survey (TAS-1) to evaluate the serological status of OV in three co-endemic districts in Gambella simultaneously. During May and June 2019, blood samples were collected from 6- to 7-year-old children who were randomly selected through standard community-based TAS methodology. Children were tested for both circulating filarial antigen (CFA) for LF via filariasis test strip and for Onchocerca volvulus 16 (Ov16) antibody for OV via laboratory-based ELISA. A total of 3,377 children from 150 villages in the three districts were tested; 1,823 (54.0%) were male. All three districts had CFA results below the critical threshold for stopping LF mass drug administration (MDA). In contrast, 40 children (1.2%) were positive for Ov16 antibody, well above the WHO's OV stop MDA threshold of 0.1%. The integrated assessment indicated two programmatic decisions: stop MDA for LF and continue MDA for OV. Accordingly, albendazole MDA was discontinued in the districts but ivermectin MDA continued. This integrated assessment showed that a random sample for TAS can give important information about OV transmission status in co-endemic areas.

Two Nigerian States (Plateau and Nasarawa) Have Eliminated Transmission of Human Onchocerciasis-A Report of Post-Ivermectin Mass Drug Administration Surveillance.

Transmission of Onchocerca volvulus (causing "river blindness") was interrupted in two states of Nigeria (Plateau and Nasarawa) in 2017 in accordance with 2016 WHO guidelines. Ivermectin mass drug administration was halted in January 2018, and posttreatment surveillance activities were conducted over a 3-year period. Vector Simulium damnosum s.l. flies were collected during the 2019 (39 sites) and 2020 (42 sites) transmission seasons. Head pools were tested by polymerase chain reaction for the presence of third-stage O. volvulus larvae; 15,585 flies were all negative, demonstrating an infective rate of < 1/2,000 with 95% confidence. In 2021, the Nigerian Federal Ministry of Health declared the two-state area as having eliminated transmission. Plateau and Nasarawa states are the first of 30 endemic states in Nigeria to have met the WHO criteria for onchocerciasis elimination. Post-elimination surveillance will need to continue given the risk of reintroduction of transmission from neighboring states.

Analysis of malaria surveillance data in Ethiopia: what can be learned from the Integrated Disease Surveillance and Response System?

BACKGROUND: Routine malaria surveillance data is useful for assessing incidence and trends over time, and in stratification for targeting of malaria control. The reporting completeness and potential bias of such data needs assessment. METHODS: Data on 17 malaria indicators were extracted from the Integrated Disease Surveillance and Response System database for July 2004 to June 2009 (Ethiopian calendar reporting years 1997 to 2001). Reporting units were standardized over time with 2007 census populations. The data were analysed to show reporting completeness, variation in risk by reporting unit, and incidence trends for malaria indicators. RESULTS: Reporting completeness, estimated as product of unit-month and health facility reporting, was over 80% until 2009, when it fell to 56% during a period of reorganization in the Ministry of Health. Nationally the average estimated annual incidence of reported total malaria for the calendar years 2005 to 2008 was 23.4 per 1000 persons, and of confirmed malaria was 7.6 per 1,000, with no clear decline in out-patient cases over the time period. Reported malaria in-patient admissions and deaths (averaging 6.4 per 10,000 and 2.3 per 100,000 per year respectively) declined threefold between 2005 and 2009, as did admissions and deaths reported as malaria with severe anaemia. Only 8 of 86 reporting units had average annual estimated incidence of confirmed malaria above 20 per 1,000 persons, while 26 units were consistently below five reported cases per 1,000 persons per year. CONCLUSION: The Integrated Disease Surveillance and Response System functioned well over the time period mid 2004 to the end of 2008. The data suggest that the scale up of interventions has had considerable impact on malaria in-patient cases and mortality, as reported from health centres and hospitals. These trends must be regarded as relative (over space and time) rather than absolute. The data can be used to stratify areas for improved targeting of control efforts to steadily reduce incidence. They also provide a baseline of incidence estimates against which to gauge future progress towards elimination. Inclusion of climate information over this time period and extension of the dataset to more years is needed to clarify the impact of control measures compared to natural cycles on malaria.

Impact of Three to Five Rounds of Mass Drug Administration on Schistosomiasis and Soil-Transmitted Helminths in School-Aged Children in North-Central Nigeria.

Nasarawa and Plateau states of north-central Nigeria have implemented programs to control schistosomiasis (SCH) and soil-transmitted helminths (STH) in children since the 1990s. Statewide mapping surveys were conducted in 2013, when 11,332 school-aged children were sampled from 226 schools. The local government areas (LGAs) then received varying combinations of mass drug administration (MDA) for the next 5 years. We revisited 196 (87%) schools in 2018 plus an additional six (202 schools in total), sampling 9,660 children. We calculated overall prevalence and intensity of infection and evaluated associations with gender; age; behaviors; water, sanitation, and hygiene (WASH); and treatment regimen. Urine heme detection dipsticks were used for Schistosoma hematobium in both surveys, with egg counts added in 2018. Stool samples were examined by Kato-Katz for Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni, and hookworm. Schistosomiasis prevalence among sampled students dropped from 12.9% (95% confidence interval [CI]: 11.1-14.9%) to 9.0% (95% CI: 7.5-10.9%), a statistically significant change (P < 0.05). In 2018, eight LGAs still had > 1% of children with heavy-intensity schistosome infections. Prevalence of STH infection did not significantly change, with 10.8% (95% CI: 9.36-12.5%) of children positive in 2013 and 9.4% (95% CI: 8.0-10.9%) in 2018 (P = 0.182). Heavy-intensity STH infections were found in < 1% of children with hookworm, and none in children with A. lumbricoides or T. trichiura in either study. The WASH data were collected in 2018, indicating 43.6% of schools had a latrine and 14.4% had handwashing facilities. Although progress is evident, SCH remains a public health problem in Nasarawa and Plateau states.

Which nets are being used: factors associated with mosquito net use in Amhara, Oromia and Southern Nations, Nationalities and Peoples' Regions of Ethiopia.

BACKGROUND: There has been recent large scale-up of malaria control interventions in Ethiopia where transmission is unstable. While household ownership of long-lasting insecticidal nets (LLIN) has increased greatly, there are concerns about inadequate net use. This study aimed to investigate factors associated with net use at two time points, before and after mass distribution of nets. METHODS: Two cross sectional surveys were carried out in 2006 and 2007 in Amhara, Oromia and SNNP regions. The latter was a sub-sample of the national Malaria Indicator Survey (MIS 3R). Each survey wave used multi-stage cluster random sampling with 25 households per cluster (224 clusters with 5,730 households in Baseline 2006 and 245 clusters with 5,910 households in MIS 3R 2007). Net ownership was assessed by visual inspection while net utilization was reported as use of the net the previous night. This net level analysis was restricted to households owning at least one net of any type. Logistic regression models of association between net use and explanatory variables including net type, age, condition, cost and other household characteristics were undertaken using generalized linear latent and mixed models (GLLAMM). RESULTS: A total of 3,784 nets in 2,430 households were included in the baseline 2006 analysis while the MIS 3R 2007 analysis comprised 5,413 nets in 3,328 households. The proportion of nets used the previous night decreased from 85.1% to 56.0% between baseline 2006 and MIS 3R 2007, respectively. Factors independently associated with increased proportion of nets used were: LLIN net type (at baseline 2006); indoor residual spraying (at MIS 3R 2007); and increasing wealth index at both surveys. At both baseline 2006 and MIS 3R 2007, reduced proportion of nets used was independently associated with increasing net age, increasing damage of nets, increasing household net density, and increasing altitude (>2,000 m). CONCLUSION: This study identified modifiable factors affecting use of nets that were consistent across both surveys. While net replacement remains important, the findings suggest that: more education about use and care of nets; making nets more resistant to damage; and encouraging net mending are likely to maximize the huge investment in scale up of net ownership by ensuring they are used. Without this step, the widespread benefits of LLIN cannot be realized.

Factors associated with mosquito net use by individuals in households owning nets in Ethiopia.

BACKGROUND: Ownership of insecticidal mosquito nets has dramatically increased in Ethiopia since 2006, but the proportion of persons with access to such nets who use them has declined. It is important to understand individual level net use factors in the context of the home to modify programmes so as to maximize net use. METHODS: Generalized linear latent and mixed models (GLLAMM) were used to investigate net use using individual level data from people living in net-owning households from two surveys in Ethiopia: baseline 2006 included 12,678 individuals from 2,468 households and a sub-sample of the Malaria Indicator Survey (MIS) in 2007 included 14,663 individuals from 3,353 households. Individual factors (age, sex, pregnancy); net factors (condition, age, net density); household factors (number of rooms [2006] or sleeping spaces [2007], IRS, women's knowledge and school attendance [2007 only], wealth, altitude); and cluster level factors (rural or urban) were investigated in univariate and multi-variable models for each survey. RESULTS: In 2006, increased net use was associated with: age 25-49 years (adjusted (a) OR = 1.4, 95% confidence interval (CI) 1.2-1.7) compared to children U5; female gender (aOR = 1.4; 95% CI 1.2-1.5); fewer nets with holes (Ptrend = 0.002); and increasing net density (Ptrend < 0.001). Reduced net use was associated with: age 5-24 years (aOR = 0.2; 95% CI 0.2-0.3). In 2007, increased net use was associated with: female gender (aOR = 1.3; 95% CI 1.1-1.6); fewer nets with holes (aOR [all nets in HH good] = 1.6; 95% CI 1.2-2.1); increasing net density (Ptrend < 0.001); increased women's malaria knowledge (Ptrend < 0.001); and urban clusters (aOR = 2.5; 95% CI 1.5-4.1). Reduced net use was associated with: age 5-24 years (aOR = 0.3; 95% CI 0.2-0.4); number of sleeping spaces (aOR [per additional space] = 0.6, 95% CI 0.5-0.7); more old nets (aOR [all nets in HH older than 12 months] = 0.5; 95% CI 0.3-0.7); and increasing household altitude (Ptrend < 0.001). CONCLUSION: In both surveys, net use was more likely by women, if nets had fewer holes and were at higher net per person density within households. School-age children and young adults were much less likely to use a net. Increasing availability of nets within households (i.e. increasing net density), and improving net condition while focusing on education and promotion of net use, especially in school-age children and young adults in rural areas, are crucial areas for intervention to ensure maximum net use and consequent reduction of malaria transmission.

Simulating a Transmission Assessment Survey: An evaluation of current methods used in determining the elimination of the neglected tropical disease, Lymphatic Filariasis.

INTRODUCTION: The World Health Organization (WHO) recommends Transmission Assessment Surveys (TAS) to determine when an evaluation unit (EU) (a designated population survey area) has achieved elimination of transmission of the vector-borne macroparasitic disease Lymphatic Filariasis (LF). These determinations are based on combining data from multiple survey units within an EU; it is unclear how underlying cluster-level variation influences the outcome of the TAS at EU level. We simulate LF infection distribution in an EU and compare three methods for assessing whether LF elimination has occurred based on currently recommended decision thresholds and sampling methods. METHODS: We simulate an EU divided into clusters of varying size and disease prevalence. We produce 1000 samples according to LF TAS examples and WHO guidelines and compare three decision-making approaches: lot quality assurance sampling (LQAS) (recommended by WHO), one-sided interval estimate (CI), and nth order statistic (MAX). Summary statistics demonstrating the "pass" rate for the EU under different disease transmission conditions are generated using a versatile SAS® macro. RESULTS: As the prevalence of LF decreases, the LQAS and CI approaches produce increased likelihood of a pass outcome for an EU while some cluster units may still have a high likelihood of transmission. The MAX provides an alternative that increases the likelihood of determining a pass only once the whole area has a low likelihood of transmission. LQAS and CI approaches designed to estimate the LF prevalence in the EU miss hotspots that will continue to transmit infection while the MAX approach focuses on identifying clusters with high risk of transmission. CONCLUSIONS: The current TAS methodology has a flaw that may result in false predictions of LF transmission interruption throughout an EU. Modifying the TAS methodology to address results from extreme clusters rather than being based on mean prevalence over an EU will result in greater success for global elimination of LF.

Does onchocerciasis transmission take place in hypoendemic areas? a study from the North Region of Cameroon.

OBJECTIVE: Community-directed treatment with ivermectin (CDTI) for onchocerciasis control is targeted to meso and hyperendemic areas in Africa. Below the threshold, communities are considered hypoendemic and, mass treatment is not recommended. As policy begins to shift from control to elimination, the role of hypoendemic areas in maintaining Onchocerca volvulus needs to be re-examined. The study determined whether independent transmission occurs in a hypoendemic area in the North region of Cameroon. METHODS: Ten 'high risk' communities along the River Mayo Douka system in Ngong Health District, at least 20 km from the nearest CDTI program were studied. Six hundred and forty-nine adults (over 20 years of age) and 561 children (under 10 years) were examined for nodules and microfilaria. A subsample of 334 adults was examined for onchocercal ocular morbidity. Simulium flies from 4 collection points were captured over 3 months annually for 2 years and dissected for larval stages of O. volvulus. RESULTS: Nodule and microfilariae (mf) prevalence among adults was 12.20% and 2.91%, and 9.2% and 0.48% among children, respectively. Blindness because of onchocerciasis was insignificant, although low rates of chronic onchocercal ocular disease (<2%) were observed. Four (0.16 percent) of 255 flies collected in 2008 were infected with L3 larval stage, and 1 black fly of 39 collected in 2009 had two L2 larval stage morphologically consistent with O. volvulus. CONCLUSION: Ngong is a 'hypoendemic' focus with likely low grade indigenous transmission in isolation from meso/hyperendemic areas. Consequently, transmission from hypoendemic areas could contribute to rapid disease recrudescence in the post-treatment phase of adjacent former meso and hyperendemic areas.

The role of non-governmental development organizations in the implementation of lymphatic filariasis programmes.

The Lymphatic Filariasis (LF) Non-governmental Development Organization (NGDO) Network was established to engage in supporting both international and national LF elimination agendas covering areas such as assisting ministries of health as an on-the-ground link between communities and programmes, which additionally gives the Network members an important voice from the field at international meetings; playing key roles in programme evolution (especially helping to both scale up and scale down mass drug administration [MDA] as elimination thresholds are met); having a role in operational research and developing new programme delivery models that can be taken to scale (such as linkages with other disease programmes and approaches to morbidity management and disability prevention); developing advocacy and policy approaches with other partners; convening other important stakeholders (academic, technical, programmatic and funding); mobilizing financial and technical resources to support programmes; supporting national human resource capacity building to catalyse national ownership of LF programmes; providing leadership in LF governance structures and working in areas of conflict to ensure that everybody in LF-endemic areas enjoys treatment services. Three case studies will illustrate the roles identified for NGDOs in LF programmes covering development of operational research, policy and advocacy linkage between LF and malaria programmes; launching LF morbidity management projects and NGDO's ability to work and deliver LF services in areas of conflict. In addition, the case studies will show the role of NGDOs in mobilising financial and technical resources that support national human resources, leading to national ownership of programmes. Conclusions will be drawn on the role of NGDOs in the Global Alliance for LF elimination and the need for continued partnerships to reach programme goals.