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Wambabya–Rwamarongo onchocerciasis focus is one of the eight foci Uganda verified using the WHO verification guidelines. The approach for elimination was twice yearly treatment with ivermectin for every round, treating at least 90% of all the eligible population. This was in combination with vector elimination using Abate® (BASF SE, Limburgerhof, Germany) since elimination nationwide policy was launched. From 2008 to 2013, the program distributed ivermectin with a mean treatment coverage of the ultimate treatment goal (UTG) or eligible population of 91.2%, with a range of 85–96%. In 2009, vector elimination based on ground larviciding had a dramatic impact on the Simulium vectors, as the last fly was observed in October 2009. No more Simulium vectors were observed during a period of at least 7 years, including the 3-year posttreatment surveillance (PTS) until the focus was reclassified as eliminated in August 2017. During the PTS period, none of the 10,578 trapped crabs were found infested with the aquatic stages of the vector. The last infested crab was observed in March 2010, and for at least 7 years, no infested crabs were observed. Serological surveys showed that of 2,978 young children examined in 2013, only one was OV16 positive (0.0%; 95% CI: 0–0.21). In 2017, after the PTS period, all 3,079 young children examined were negative for OV16 (95% CI: 0–0.16). Therefore, entomological and serological results provided evidence that resulted in the reclassification of Wambabya–Rwamarongo focus from “transmission interrupted” to “transmission eliminated” with no possibility of recrudescence.

The purpose of this research is to design, deploy and validate artificial intelligence (AI) algorithms operating on drone videos to enable a real time methodology for optimizing predictive mapping unknown, geographic locations (henceforth, geolocation) of potential, seasonal, Anopheles (gambiae, and funestus) larval habitats in an agro-village, epi-entomological, intervention site (Akonyibedo village) in Gulu District, Northern Uganda. Formulae are developed for classifying the drone swath, capture point, land cover in Akonyibedo agro-village. An AI algorithm is designed for constructing a smartphone application (app) in order to enable automatic detection of potential larval habitats from drone videos. The aim of this work is to enable scaling up to larger intervention sites (e.g., district level, sub-county) and then throughout entire Uganda. We demonstrate how capture point, stratifiable, drone swath coverage in Akonyibedo village can be accomplished employing temporal series of re-centered, real time, imaged, Anopheline, larval habitat, seasonal, map projections. We also define a remote methodology for detecting unknown, georeferenceable, capture point geolocations of potential, seasonal, breeding sites employing multispectral, wavelength, signature, reflux emissivities in a drone spectral library. Our results show that high-resolution drone imagery when processed employing state of the art AI algorithms can discriminate a profile of water bodies where Anopheles mosquitoes are most likely to breed (overall ground truth accuracy of 100%). Live, high definition, Anopheline larval habitat signature maps can be generated in real-time drone AI app on a smartphone or Apple device while the image is being captured or larvicidal application is taking place. Key words: Anopheles, larval habitat, drones, artificial intelligence (AI), malaria, Uganda.

Mass drug administration (MDA) with ivermectin must reach a high treatment coverage (90% of the eligible population) if onchocerciasis is to be eliminated. Questions have been raised as to whether reported treatment figures reaching such high coverage are reliable. Sample surveys are proposed as the method of choice for “validating” reported coverage figures. The purpose of this study was to compare the district-level MDA coverage reported by programs with contemporaneous surveys of randomly selected respondents living in those same districts. Over an 8-year period, 19,219 households were selected using multistage random sampling; 38,433 adult male and female heads of those households were asked about their recent ivermectin MDA treatment experience. District coverage reports were considered “accurate” if they fell within the 95% CIs determined by the corresponding district’s survey. Ninety-eight treatment rounds were evaluated over an 8-year period. Overall, the reported coverage of 96.5% (range: 68–100%) was significantly higher than the 92.5% surveyed coverage (range: 62.1–99.6%, 95% CI: 91.9–93.2%). However, only 20% of districts reported significantly higher coverage than surveys, 68% of district program reports were judged as accurate, and 12% of districts reported significantly lower coverage figures than their corresponding surveys. Eighty-eight percent of districts reported coverage ≥ 90% threshold for success, compared with 97% of surveys that included 90% in their 95% CIs. We conclude that when analyzed statistically at the district level, most surveys verified the reported coverage.

Public health emergencies stemming from infectious disease outbreaks is creating a serious threat to global health security. For example, climate change and extreme weather events threaten to alter and affect geographic areas pertaining to disease vulnerability, such as greater risks of mosquito-borne diseases (dengue, malaria, yellow fever and Zika). The emergence of these disease outbreaks and their influence globally has sparked a renewed attention on global health security and the application of location intelligence. Persistent outbreaks characterize a ‘new normal’ that points to major deficiencies in preparedness, response and recovery initiatives. Malaria mosquito An. gambiae s.l., arabiensis s.s. and funestus s.s represent the main malaria mosquito vectors in sub-Saharan Africa. As reported in WHO (Jacob et al. in Open Remote Sensing 17:11–24, [1]), Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. It is preventable and curable. In 2019, there were an estimated 229 million cases of malaria worldwide. The estimated number of malaria deaths stood at 409,000 in 2019. Children aged under 5 years are the most vulnerable group affected by malaria; in 2019, they accounted for 67% (274,000) of all malaria deaths worldwide. The WHO African Region carries a disproportionately high share of the global malaria burden. In 2019, the region was home to 94% of malaria cases and deaths. Sensemaking lies at the heart of location intelligence. Location intelligence is defined as the collection and analysis of geospatial data that are transformed into strategic insights to support operations. Weick (Krizhevsky et al. in Advances in Neural Information Processing Systems, pp 1097–1105, [2]) refers to sensemaking in terms of ‘…how we structure the unknown so as to be able to act in it. Sensemaking involves coming up with a plausible understanding—a map—of a shifting world; testing this map with others through data collection, action, and conversation; and then refining, or abandoning, the map depending on how credible it is’ (Lin et al. in Proceedings of the IEEE International Conference on Computer Vision 2017, pp. 2980–2988, [3]). The application of machine learning algorithms are emerging as key public health intelligence approaches to support tactical, operational and strategic sensemaking. Recent advances that identify the reflective signatures of active mosquito breeding sites, and their temporal evolution, have made predictive algorithms possible to search and identify previously unidentified larval habitats from a Unmanned Aerial Vehicle (UAV), and monitor their activity in real time. Spectral signature is the variation of reflectance of a material (i.e., emittance as a function of wavelength) (www.esri.com). These real time aerial surveys can provide spatiotemporal data for targeting interventions to eliminate vectors before they become adult airborne biting mosquitoes, to reduce malaria transmission. Reference capture point habitats for Anopheles gambiae s.l., An. arabiensis s.s. and An. funestus s.s, the main malaria mosquito vectors in sub- Saharan Africa [www.who.int], may also be separately identified with this methodology. This chapter points to the application of predictive algorithms coupled with drone surveillance to support sensemaking in support of spatiotemporal data for targeting interventions to eliminate vectors before they become adult airborne biting mosquitoes, to reduce malaria transmission. The sensemaking applies not only to the targeted interventions to eliminate vectors, but also strategic sensemaking that contextualizes this intervention as part of a more holistic/systemic and strategic intervention encompassing a myriad of coordinated interventions across the disaster management spectrum (mitigation, preparedness, response, recovery).

Onchocerciasis, caused by infection with Onchocerca volvulus, has been targeted for elimination by 2030. Currently, onchocerciasis elimination programs rely primarily on mass distribution of ivermectin. However, ivermectin alone may not be sufficient to achieve elimination in some circumstances, and additional tools may be needed. Vector control has been used as a tool to control onchocerciasis, but vector control using insecticides is expensive and ecologically detrimental. Community-directed removal of the trailing vegetation black fly larval attachment sites (slash and clear) has been shown to dramatically reduce vector biting densities. Here, we report studies to optimize the slash and clear process. Conducting slash and clear interventions at Simulium damnosum sensu stricto breeding sites located within 2 km of afflicted communities resulted in a 95% reduction in vector biting. Extending slash and clear further than 2 km resulted in no further decrease. A single intervention conducted at the first half of the rainy season resulted in a 97% reduction in biting rate, whereas an intervention conducted at the end of the rainy season resulted in a 94% reduction. Vector numbers in any of the intervention villages did not fully recover by the start of the following rainy season. These results suggest that slash and clear may offer an inexpensive and effective way to augment ivermectin distribution in the effort to eliminate onchocerciasis in Africa.

Uganda has verified elimination of seven onchocerciasis foci since 2007 when the nationwide onchocerciasis elimination policy was launched. However, the Victoria Nile focus (which was eliminated in the early 1970s) had not been verified. The objective of this study was to verify this focus to the WHO verification guidelines and bring it in line with recently eliminated foci. Vector control with dichlorodiphenyltrichloroethane was the main intervention used at the Victoria Nile from the 1950s to the 1970s. Historical fly collection sites along River Nile were identified for recent fly collection. Relevant health workers near the sites were trained to supervise fly collection activity. With support from communities, fly collectors were identified, trained, and equipped to collect Simulium flies for at least a year. A total of 854 Simulium flies were collected and analyzed by polymerase chain reaction to detect Onchocerca volvulus DNA. The communities and their leaders provided consent for the collection of dry blood spots (DBS) from children younger than 10 years for investigation of recent exposure to the disease. A total of 2,953 DBS were collected and analyzed by OV16 ELISA to detect the presence of IgG(4) antibodies recognizing the OV16 antigen. The results showed that none of the flies carried O. volvulus DNA. Similarly, all the children were OV16 negative, showing no exposure to onchocerciasis. All the flies collected were identified as Simulium adersi, which is not a known vector for O. volvulus. The results confirmed that onchocerciasis and its vector Simulium damnosum had been eliminated in the Victoria Nile focus.

Concern is emerging regarding the challenges posed by spatial complexity for modelling and managing the area-wide elimination of parasitic infections. While this has led to calls for applying heterogeneity-based approaches for addressing this complexity, questions related to spatial scale, the discovery of locally-relevant models, and its interaction with options for interrupting parasite transmission remain to be resolved. We used a data-driven modelling framework applied to infection data gathered from different monitoring sites to investigate these questions in the context of understanding the transmission dynamics and efforts to eliminate Simulium neavei- transmitted onchocerciasis, a macroparasitic disease that causes river blindness in Western Uganda and other regions of Africa. We demonstrate that our Bayesian-based data-model assimilation technique is able to discover onchocerciasis models that reflect local transmission conditions reliably. Key management variables such as infection breakpoints and required durations of drug interventions for achieving elimination varied spatially due to site-specific parameter constraining; however, this spatial effect was found to operate at the larger focus level, although intriguingly including vector control overcame this variability. These results show that data-driven modelling based on spatial datasets and model-data fusing methodologies will be critical to identifying both the scale-dependent models and heterogeneity-based options required for supporting the successful elimination of S. neavei-borne onchocerciasis.

Attention is increasingly focusing on how best to accelerate progress toward meeting the WHO’s 2030 goals for neglected tropical diseases (NTDs). For river blindness, a major NTD targeted for elimination, there is a long history of using vector control to suppress transmission, but traditional larvicide-based approaches are limited in their utility. One innovative and sustainable approach, “slash and clear”, involves clearing vegetation from breeding areas, and recent field trials indicate that this technique very effectively reduces the biting density of Simulium damnosum s.s. In this study, we use a Bayesian data-driven mathematical modeling approach to investigate the potential impact of this intervention on human onchocerciasis infection. We developed a novel “slash and clear” model describing the effect of the intervention on seasonal black fly biting rates and coupled this with our population dynamics model of Onchocerca volvulus transmission. Our results indicate that supplementing annual drug treatments with “slash and clear” can significantly accelerate the achievement of onchocerciasis elimination. The efficacy of the intervention is not very sensitive to the timing of implementation, and the impact is meaningful even if vegetation is cleared only once per year. As such, this community-driven technique will represent an important option for achieving and sustaining O. volvulus elimination.

Background Onchocerciasis, or river blindness, has historically been an important cause of blindness, skin disease and economic disruption in Africa and the Americas. It is caused by the filarial parasite Onchocerca volvulus, which is transmitted by black flies in the genus Simulium. Over the past decade, several international programs have been formed to control, or more recently eliminate onchocerciasis, using mass drug administration (MDA) of ivermectin. However, in many areas of Africa (particularly those which are endemic for the eyeworm, Loa loa, or where vector densities are very high) ivermectin MDA alone will not be sufficient to achieve elimination. In these situations, additional interventions may be necessary. Methodology/Principal findings The Esperanza Window trap (EWT), a simple trap originally developed to replace human landing collections for entomological surveillance of O. volvulus transmission was optimized, resulting in a 17-fold improvement in trap performance. The optimized trap was tested in trials in schools and in agricultural fields to determine if it could reduce vector biting locally. The traps resulted in a 90% reduction in biting in the school setting. In the field setting, results varied. In one location, the traps reduced biting by roughly 50%, while in a separate trial, the traps did not significantly reduce the biting rate. Examination of the two settings suggested that trap placement may be critical to their success. Conclusions/Significance These results suggest that the optimized EWT might be capable of reducing local vector black fly biting in areas commonly frequented by residents. Together with other recently developed methods of community directed vector control, the traps may augment ivermectin MDA, bringing the goal of onchocerciasis elimination within reach in much of Africa., Author summary Onchocerciasis or river blindness is historically one of the most important causes of blindness and skin disease in the developing world. It is caused by infection with the filarial parasite Onchocerca volvulus. The finding that ivermectin was an effective and safe treatment for onchocerciasis and the decision by its manufacturer to donate it to treat this infection spawned the development of programs to eliminate river blindness through mass drug administration of ivermectin to the afflicted populations. This has dramatically reduced the prevalence of onchocerciasis worldwide and has resulted in its near elimination in the Americas. But ivermectin alone will not eliminate river blindness in much of Africa; additional interventions are necessary. Here we report the optimization of a simple trap for the black fly vector of O. volvulus and show that these traps can dramatically reduce vector biting in some settings. Together with other recently developed community directed methods of vector control, these traps may augment the effect of the ivermectin distribution programs, bringing the goal of elimination within reach in much of Africa.

It was not until early 1990s that, when the Imaramagambo focus of southwest Uganda was mapped, mass treatment with a single annual dose of ivermectin for onchocerciaisis control commenced. However, comprehensive investigations on its transmission were launched after a nationwide policy for onchocerciasis elimination in 2007. Entomological surveys throughout the focus from 2007 to 2015 have yielded few or no freshwater crabs (Potamonautes aloysiisabaudiae), which serve as the obligate phoretic host of the larvae and pupae of the vector Simulium neavei. No S. neavei flies have been observed or collected since 2007. Skin snips (microscopy) from 294 individuals in 2008 were negative for skin microfilariae, and of the 462 persons analyzed by polymerase chain reaction skin snip poolscreen in 2009, only five (1.08%) persons were indicated as infected with onchocerciasis. All five of the positive persons were at least 40 years old. Serosurvey results showed negative exposure among 3,332 children in 2012 and 3,108 children in 2015. Both were within the upper bound of the 95% confidence interval of the prevalence estimate of 0.06%, which confirmed the elimination of onchocerciasis. Treatment coverage in Imaramagambo was generally poor, and transmission interruption of onchocerciasis could not be attributed solely to annual mass treatment with ivermectin. There was sufficient evidence to believe that the possible disappearance of the S. neavei flies, presumed to have been the main vector, may have hastened the demise of onchocerciasis in this focus.

Previous studies have demonstrated that the presence of larvae of other filarial species in Simulium damnosum sensu lato can distort estimates of transmission potential for Onchocerca volvulus in West Africa. However, studies conducted in foci of onchocerciasis in West Central Uganda indicated that larvae other than O. volvulus were not common in vectors collected there. Recent data collected in Northern Uganda revealed a striking discordance between estimates of the prevalence of flies carrying O. volvulus infective larvae obtained from molecular pool screening and dissection methods. To resolve this discrepancy, sequences from three mitochondrially encoded genes were analyzed from the larvae collected by dissection. All larvae analyzed were Onchocerca ochengi v. Siisa, a parasite of cattle, or Onchocerca ramachandrini, a parasite of warthogs. These results suggest that nonhuman parasite larvae are common in vectors in Northern Uganda, underscoring the necessity for molecular identification methods to accurately estimate O. volvulus transmission.

A recent article “Is onchocerciasis elimination in Africa feasible by 2025: a perspective based on lessons learnt from the African control programmes” in Infectious Diseases of Poverty claimed that undue influence on African programs by concepts developed by the Onchocerciasis Elimination Program of the Americas (OEPA) is detrimental to stopping mass drug administration (MDA) in Africa. This claim is made despite a record year for MDA stoppage in four African countries of > 3.5 million treatments in 2018, far exceeding any past OEPA or African Program for Onchocerciasis Control (APOC) stop MDA success. Electronic supplementary material The online version of this article (10.1186/s40249-019-0558-0) contains supplementary material, which is available to authorized users.

Stopping interventions is a critical decision for parasite elimination programmes. Quantifying the probability that elimination has occurred due to interventions can be facilitated by combining infection status information from parasitological surveys with extinction thresholds predicted by parasite transmission models. Here we demonstrate how the integrated use of these two pieces of information derived from infection monitoring data can be used to develop an analytic framework for guiding the making of defensible decisions to stop interventions. We present a computational tool to perform these probability calculations and demonstrate its practical utility for supporting intervention cessation decisions by applying the framework to infection data from programmes aiming to eliminate onchocerciasis and lymphatic filariasis in Uganda and Nigeria, respectively. We highlight a possible method for validating the results in the field, and discuss further refinements and extensions required to deploy this predictive tool for guiding decision making by programme managers., The decision when to stop an intervention is a critical component of parasite elimination programmes, but reliance on surveillance data alone can be inaccurate. Here, Michael et al. combine parasite transmission model predictions with disease survey data to more reliably determine when interventions can be stopped.

Onchocerciasis is a neglected tropical disease targeted for elimination. The World Health Organization (WHO) has developed guidelines for the verification of onchocerciasis elimination that include entomological and epidemiological criteria. The latter require demonstrating with statistical confidence that the infection prevalence in children is less than 0.1%, necessitating an assay with a high degree of specificity. We present an analysis of the performance of the Onchocerciasis Elimination Program for the Americas (OEPA) version of the Ov16 enzyme-linked immunosorbant assay (ELISA) when used under operational conditions. In Africa and Latin America, the assay demonstrated 99.98% specificity in 69,888 children in 20 foci where transmission was believed to be interrupted. The assay produced a prevalence estimate equal to that of skin snip microscopy when applied in putatively hypo-endemic zones of Ethiopia. The OEPA Ov16 ELISA demonstrated the specificity required to be effectively deployed to verify transmission elimination under the WHO guidelines, while exhibiting a sensitivity equivalent to skin snip microscopy to identify hypo-endemic areas.

Background The community-directed intervention (CDI) approach has improved treatment coverage in onchocerciasis-affected communities. However, there is still a lot to learn. This study assessed its performance and highlighted the lessons learnt so far. Methods Representative samples of households were selected from Cameroon and Uganda program areas through multi-stage random sampling. An adult male and female from every selected household were interviewed separately on their involvement in CDI activities every year between 2004 and 2010. Community health workers (CHWs) were interviewed and treatment records reviewed to determine whether 90% treatment coverage was attained within 2 weeks. Records related to training of CHWs and their supervisors were analyzed. Results Decision making decreased for community leaders and health workers, while it increased for community members. The proportion of CHWs attaining 90% treatment coverage within 2 weeks improved as their demand for monetary incentives, and number of persons they served, reduced. The number of CHWs supervised by a community supervisor remained low, but increased for the health workers. The cost of training a CHW and a community supervisor reduced to about US$1 and US$4.8, respectively. Conclusions The CDI approach was effective, culturally appropriate and probably less costly in delivering health services in low-resource communities.

Previous studies have demonstrated that the presence of larvae of other filarial species in Simulium damnosum sensu lato can distort estimates of transmission potential for Onchocerca volvulus in West Africa. However, studies conducted in foci of onchocerciasis in West Central Uganda indicated that larvae other than O. volvulus were not common in vectors collected there. Recent data collected in Northern Uganda revealed a striking discordance between estimates of the prevalence of flies carrying O. volvulus infective larvae obtained from molecular pool screening and dissection methods. To resolve this discrepancy, sequences from three mitochondrially encoded genes were analyzed from the larvae collected by dissection. All larvae analyzed were Onchocerca ochengi v. Siisa, a parasite of cattle, or Onchocerca ramachandrini, a parasite of warthogs. These results suggest that nonhuman parasite larvae are common in vectors in Northern Uganda, underscoring the necessity for molecular identification methods to accurately estimate O. volvulus transmission.

Intervention Few studies have documented the interruption of onchocerciasis and Lymphatic Filariasis (LF) by integrated chemotherapy in Uganda. The study describes the interruption of transmission of the two diseases co-endemic in Obongi focus, north western Uganda. Base line data for Onchocerciasis and LF were collected in 1994 and 2006, respectively. Annual mass drug administration for onchocerciasis (Ivermectin) and Lymphatic Filariasis (Ivermectin + albendazole) was conducted for 20 and 6 years, respectively. Thereafter, assessments by skin snip, larval searches in rivers and human landing catches were performed. Children 65% was achieved in the six treatment rounds. Household ownership of ITN’s and utilization was 96% and 72.4%., respectively. Impact Parasitological examinations conducted for onchocerciasis among 807 adults and children, revealed a reduction in mf prevalence from 58% in 1994 to 0% in 2012. Entomological monitoring conducted at the two sites had no single Simulium damnosum fly caught. Serological analysis using Ov16 ELISA for onchocerciasis revealed that out of the 3,308 children

Entomological measures of transmission are important metrics specified by the World Health Organization to document the suppression and interruption of transmission of Onchocerca volvulus, the causative agent of onchocerciasis. These metrics require testing of large numbers of vector black flies. Black fly collection has relied on human landing collections, which are inefficient and potentially hazardous. As the focus of the international community has shifted from onchocerciasis control to elimination, replacement of human landing collections has become a priority. The Esperanza window trap (EWT) has shown promise as an alternative method for collection of Simulium damnosum s.l., the primary vector of O. volvulus in Africa. Here, we report the results of a community-based trial of the EWT in northern Uganda. Traps operated by residents were compared with human landing collections in two communities over 5 months. Three traps, when operated by a single village resident, collected over four times as many S. damnosum as did the two-men collection team. No significant differences were noted among the bait formulations. The results suggest that EWTs may be effectively operated by community residents and that the trap represents a viable alternative to human landing collections for entomological surveillance of O. volvulus transmission.

Onchocerciasis causes severe itching, serious skin disease and ocular damage leading to visual impairment or permanent blindness. It is associated with hanging groin, epilepsy, Nakalanga dwarfism and, most recently, nodding disease. This disease affected communities in 17 transmission foci in 37 districts of Uganda, where about 6.7 million people are once at risk. The efforts against onchocerciasis in Uganda commenced in the late 1940s, when vector control was launched using dichlorodiphenyltrichloroethane; by 1973, Simulium damnosum had been eliminated in the Victoria focus. Success outside of the Victoria focus was short-lived due to changes in government priorities and the political upheavals of the 1970s and 1980s. With the return of political stability, annual treatment with ivermectin through mass drug administration was launched in the early 1990s. Control of the disease has been successful, but there has been failure in interrupting transmission after more than 15 years. In 2007 Uganda launched a nationwide transmission elimination policy based on twice-per-year treatment and vector control/elimination, with a goal of eliminating river blindness nationwide by 2020. By 2017, 1 157 303 people from six foci had been freed from river blindness. This is the largest population ever declared free under World Health Organization elimination guidelines, providing evidence that elimination of river blindness in Africa is possible.

National onchocerciasis elimination committees (NOECs) serve to help ministries of health complete the pathway to successful verification of elimination of onchocerciasis (river blindness), as outlined in the 2016 World Health Organization guidelines. These guidelines, however, only take effect when the country believes it has reached a point that elimination can be demonstrated, and do not address the preceding milestones. Therefore, NOECs can be of great help with guiding and tailoring earlier planning, programming and assessments to empower national programs to aggressively move toward their countries' elimination goals. In this article, we provide suggestions for organizing NOECs and examples of four such committees that have successfully operated in Africa and the Americas.

The objective of the study was to determine whether annual ivermectin treatment in the Nyagak-Bondo onchocerciasis focus could safely be withdrawn. Baseline skin snip microfilariae (mf) and nodule prevalence data from six communities were compared with data collected in the 2011 follow-up in seven communities. Follow-up mf data in 607 adults and 145 children were compared with baseline (300 adults and 58 children). Flies collected in 2011were dissected, and poolscreen analysis was applied to ascertain transmission. Nodule prevalence in adults dropped from 81.7% to 11.0% (P < 0.0001), and mf prevalence dropped from 97.0% to 23.2% (P < 0.0001). In children, mf prevalence decreased from 79.3% to 14.1% (P < 0.0001). Parous and infection rates of 401 flies that were dissected were 52.9% and 1.5%, respectively, whereas the infective rate on flies examination by polymerase chain reaction (PCR) was 1.92% and annual transmission potential was 26.9. Stopping ivermectin treatment may result in onchocerciasis recrudescence.

To evaluate the effectiveness of 10 years' annual single dose ivermectin treatment on onchocerciasis transmission in hyperendemic areas of Cameroon and Uganda.Baseline nodule and microfilaria ('skin snip') prevalence data were available from 10 hyperendemic sentinel communities in Cameroon (from 1996) and hyperendemic 20 sentinel communities in Uganda (from 1993). We returned to these villages in 2005, 10 months after the last annual ivermectin distribution, to repeat the cross-sectional surveys. Each sentinel community reported a mean interval treatment coverage of eligible persons of88% (range 37-100%). Data were analyzed for more than 6200 person examinations. In Cameroon, 719 peopleor=10 years were examined at the baseline survey in 1996 and 838 at the follow-up survey in 2005. In Uganda, 1590 peopleor=10 years were examined at the baseline survey in 1993 and 2122 people at the follow-up survey in 2005. We also examined children under 10 in Cameroon (1996, n = 185; 2005, n = 448) and Uganda (1993, n = 177; 2005, n = 130). In Uganda, the vitality of worms was judged using standard histological criteria in 80 nodules excised in 2005.The prevalence of microfilaria carriers among older children and adults (or=10 years) in Cameroon sentinel communities dropped from 70.1% to 7.04% (P0.0001) over the 10-year treatment period; that of nodule carriers from 58% to 9.55% (P0.0001). Similarly, in Uganda, the prevalence of microfilaria carriers fell from 71.9% to 7.49% (P0.0001) over the 13-year treatment period, and that of nodule carriers from 53.21% to 9.66% (P0.0001). The number of microfilaria carriers among children10 years in Cameroon decreased from 29.73% to 3.8% (P0.0001), and in Uganda from 33.89% to 3.1% (P0.0001). In 2005, worms excised from nodules in Uganda, 81.4% of males remained alive, and 64% of females, with 24% of them inseminated.A decade or more of annual single dose ivermectin treatment in hyperendemic areas has reduced onchocerciasis to 'hypoendemicity', but onchocerciasis transmission persists. For now, annual treatment with ivermectin should be continued in formerly mesoendemic and hyperendemic zones.

Summary The community-directed interventions (CDI) strategy achieved a desired coverage of the ultimate treatment goal (UTG) of at least 90% with ivermectin distribution for onchocerciasis control, and filled the gap between the health care services and the communities. However, it was not clear how its primary actors ‐ the community-directed health workers (CDHW) and community-directed health supervisors (CDHS) ‐ would perform if they were given more responsibilities for other health and development activities within their communities. A total of 429 of 636 (67.5%) of the CDHWs who were involved in other health and development activities performed better than those who were involved only in ivermectin distribution, with a drop-out rate of 2.3%. A total of 467 of 864 (54.1%) of CDHSs who were involved in other health and development activities also maintained the desired level of performance. They facilitated updating of household registers (P < 0.05), trained and supervised CDHWs, and educated community members about onchocerciasis control (P < 0.001). Their drop-out rate was 2.6%. The study showed that the majority of those who dropped out had not been selected by their community members. Therefore, CDI strategy promoted integration of health and development activities with a high potential for sustainability.

We interpolated a geospectrally decomposed 5 meter (m) RapidEye™,Red Edge, Normalized Difference Vegetation Index (NDVI), unmixed, endmember, biosignature of a georeferenced, larval habitat of Similium damnosum s.l.,a black fly vector of onchocerciasis. We did so to identify unknown, unsampled, prolific, habitats in African riverine environments. The S. damnosum s.l.larval habitat was initially geosampled in a riverine village in Burkina Faso and overlaid onto the 5m resolution data. The Band Mathfunction of ENVI 4.8TM was employed to calculate the RedEdge NDVI. Before applying the spectral index to the imagery raw mixel (“mixed pixel”) values, digital numbers(DN)] were converted into physically meaningful units to differentiate absorption reflectance spectra and immature Similium productivity based on habitat size.Linear regression was used to equate and quantitate band data to DN and the reflectance values which in the geospectral,sub-mixel, risk analysis was equivalent to removing the solar irradiance and the atmospheric path radiance in the object-based classifier. A radiometric calibration tool then calibrated the spaceborne sensor data to radiance and top-of-atmosphere (ToA) reflectance.Additionally,Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes (FLAASH®)removed the effects of multiscattering in the scene.We calculated the internal relative reflectance which normalized the image to a scene average spectrum. ENVI’s Log Residuals Correction Tool removed the instrument gain, topographic effects, and albedo effects from the reflectance, transmittance, wavelength emissitivities. The instantaneous fraction of direct beam radiation intercepted by the habitat canopy was calculated and described as fPAR = 1 - exp (-k (leaf area index)/cosθs) where the extinction coefficient k was a function of leaf angle distribution.We employed a successive progressive algorithm, a two stream radiative atmospheric transfer analyses, a geometric-optical model and a bidirectional reflectance distribution function to unmix the S. damnosum s.l., larval habitat,canopied endmembers.The non-parametric, residual, explanatorial, decomposed, sub-mixel estimators derived from the RapidEye™data were then used to construct a Boolean model.Therefater,the imaged larval habitat and its geospatially, ecohydrological, within-canopy pigments (e.g., chorophyll, zeathinins) were defined and a Red Edge,NDVI, endmember biosignature was decomposed in ENVI. An autocorrelation uncertainty matrix was deconvolved into combinations of the unmixed canopied endmembers.Subsequently, the NDVI, endmember biosignature, decomposed, canopied endmembers with its multiple ToA noise-adjusted coefficients were kriged in Geospatial Analyst of ArcGIS 10.3®to identify unknown, unsampled, prolific, S. damnosum s.l., georeferencable, larval habitats along a northern Ugandan riverine ecosystem. Of the forecasted prolific, shaded, larval habitats by the canopy model, 72% were found to contain S. damnosum s.l. larvae when field verified. The sensitivity of the test was 78.26 while the specifity was 100.

The study determined that Simulium neavei-transmitted onchocerciasis in Mount Elgon onchocerciasis focus had been interrupted. Annual mass treatment with ivermectin changed to two times per year along with vector elimination in 2007. Then, baseline microfilaria (mf) prevalence data of 1994 in five sentinel communities were compared with follow-up data in 2005 and 2011. Blood spots from 3,051 children obtained in 2009 were analyzed for Onchocerca volvulus immunoglobulin G4 antibodies. Fresh water crab host captures and blackflies collected indicated their infestation with larval stages of S. neavei and presence or absence of the vector, respectively. Mf rates dropped from 62.2% to 0.5%, and 1 (0.03%) of 3,051 children was positive for O. volvulus antibodies. Crab infestation dropped from 41.9% in 2007 to 0%, and S. neavei biting reduced to zero. Both remained zero for the next 3 years, confirming interruption of onchocerciasis transmission, and interventions were halted.

Uganda is the only African country whose onchocerciasis elimination program uses a two-pronged approach of vector control and mass drug distribution. The Ugandan program relies heavily upon the use of serosurveys of children to monitor progress toward elimination. The program has tested over 39,000 individuals from 11 foci for Onchocerca volvulus exposure, using the Ov16 ELISA test. The data show that the Ov16 ELISA is a useful operational tool to monitor onchocerciasis transmission interruption in Africa at the World Health Organization (WHO) recommended threshold of < 0.1% in children. The Ugandan experience has also resulted in a re-examination of the statistical methods used to estimate the boundary of the upper 95% confidence interval for the WHO prevalence threshold when all samples tested are negative. This has resulted in the development of Bayesian and hypergeometric statistical methods that reduce the number of individuals who must be tested to meet the WHO criterion.

The Itwara onchocerciasis focus is located around the Itwara forest reserve in western Uganda. In 1991, annual treatments with ivermectin started in the focus. They were supplemented in 1995 by the control of the vector Simulium neavei, which was subsequently eliminated from the focus. The impact of the two interventions on the disease was assessed in 2010 by nodule palpations, examinations of skin snips by microscopy and PCR, and Ov16 recombinant ELISA. There was no evidence of any microfilaria in 688 skin snips and only 2 (0.06%) of 3316 children examined for IgG4 were slightly above the arbitrary cut off of 40. A follow up of the same children 21 months later in 2012 confirmed that both were negative for diagnostic antigen Ov-16, skin snip microscopy and PCR. Based on the World Health Organization (WHO) elimination criteria of 2001 and the Uganda onchocerciasis certification guidelines, it was concluded that the disease has disappeared from the Itwara focus after 19 years of ivermectin treatments and the elimination of the vector around 2001. Ivermectin treatments were recommended to be halted.

Wadelai, an isolated focus for onchocerciasis in northwest Uganda, was selected for piloting an onchocerciasis elimination strategy that was ultimately the precursor for countrywide onchocerciasis elimination policy. The Wadelai focus strategy was to increase ivermectin treatments from annual to semiannual frequency and expand geographic area in order to include communities with nodule rate of less than 20%. These communities had not been covered by the previous policy that sought to control onchocerciasis only as a public health problem. From 2006 to 2010, Wadelai program successfully attained ultimate treatment goal (UTG), treatment coverage of ≥90%, despite expanding from 19 to 34 communities and from 5,600 annual treatments to over 29,000 semiannual treatments. Evaluations in 2009 showed no microfilaria in skin snips of over 500 persons examined, and only 1 of 3011 children was IgG4 antibody positive to the OV16 recombinant antigen. NoSimuliumvectors were found, and their disappearance could have sped up interruption of transmission. Although twice-per-year treatment had an unclear role in interruption of transmission, the experience demonstrated that twice-per-year treatment is feasible in the Ugandan setting. The monitoring data support the conclusion that onchocerciasis has been eliminated from the Wadelai focus of Uganda.

OBJECTIVES To assess and compare the effectiveness of ivermectin distributors in attaining 90% treatment coverage of the eligible population with each additional health activity they take up. METHODS Random sampling was applied every year to select distributors for interviews in community-directed treatment with ivermectin (CDTI) areas of Cameroon and Uganda. A total of 288 in 2004, 357 in 2005 and 348 in 2006 distributors were interviewed in Cameroon, and 706, 618 and 789 in Uganda, respectively. The questions included treatment coverage, involvement in additional activities, where and for how long these activities were provided, and whether they were supervised. RESULTS At least 70% of the distributors in Cameroon and Uganda during the study period were involved in CDTI and additional health activities. More of the distributors involved in CDTI alone attained 90% treatment coverage than those who had CDTI with additional health activities. The more the additional activities, the less likely the distributors were to attain 90% treatment coverage. In Uganda, distributors were more likely to attain 90% coverage (P < 0.001 if they worked within 1 km of their homesteads were selected by community members, worked among kindred, and were responsible for

The challenges of community-directed treatment with ivermectin (CDTI) for onchocerciasis control in Africa have been: maintaining a desired treatment coverage, demand for monetary incentives, high attrition of community distributors and low involvement of women. This study assessed how challenges could be minimised and performance improved using existing traditional kinship structures. In classic CDTI areas, community members decide upon selection criteria for community distributors, centers for health education and training, and methods of distributing ivermectin. In kinship enhanced CDTI, similar procedures were followed at the kinship level. We compared 14 randomly selected kinship enhanced CDTI communities with 25 classic CDTI communities through interviews of 447 and 750 household members and 127 and 64 community distributors respectively. Household respondents from kinship enhanced CDTI reported better performance (P

The national onchocerciasis-control programme in Uganda successfully eliminated Simulium neavei s.s. from the Itwara focus in 1997, by monthly ground spraying with larvicidal temophos (Abate). Since then, no vectors have been caught in the main Itwara focus or two secondary foci in the same area. After 4 years of intervention, S. neavei s.s. has also been nearly eliminated from the Mpamba-Nkusi focus, and the elimination of this vector from two more foci (West Nile and Wambabya-Rwamarongo) appears quite feasible. There are, however, four isolated foci in Uganda (Budongo, Kashoya-Kitomi, Mount Elgon and Kigezi-Bwindi) which are probably too large and inaccessible to make the elimination of S. neavei s.s. by ground spraying a realistic possibility. Encouragingly,70% of Ugandans have received an annual dose of ivermectin for at least 10 years, and the national programme of community-directed treatment with ivermectin (CDTI) is thought to be progressing towards sustainability. Despite the good treatment coverages, however, many potential vectors are still found infected with Onchocerca volvulus and many Ugandans have O. volvulus in their skin. There is now evidence that adult O. volvulus can be eliminated, within a period of about 6 years, through semiannual treatment with ivermectin. Together, the isolated foci where vector elimination is not considered feasible have a human population of about 700,000, most of whom (595,000) are eligible to receive ivermectin treatment. The estimated cost of each treatment, via the Ugandan CDTI, is U.S.$0.78 if the salaries of the government-employed personnel and the working time lost by the volunteers who act as community-directed drug distributors (CDD) are taken into account. If these 'expenses' are ignored, however, the cost falls to just U.S.$0.17/treatment, and the total costs for the four isolated foci where vector control is not likely to be successful become about U.S.$101,150/year for annual treatment (for an indefinite period of time) or approximately U.S.$202,300/year for semi-annual treatment (for the 6 years needed to eliminate adult O. volvulus), which would be the more cost-effective option. With the necessary financial support and the continued free supply of ivermectin from Merck, the national onchocerciasis-control programme could eliminate human onchocerciasis from Uganda, through a combination of semi-annual treatment with ivermectin in the isolated foci where S. neavei s.s. elimination is not feasible, and vector elimination in all the other foci.

The present study aimed: (1) to assess and improve the level of women's involvement in a strategy to control onchocerciasis by community-directed treatment with ivermectin (CDTI) in three parishes of Rukungiri District, Uganda; (2) to measure the performance of female community-directed health workers (CDHWs) in comparison with males; and (3) to identify culturally acceptable means of enhancing women's involvement in community-directed healthcare. Health education sessions were used to instruct community members to select female CDHWs in Masya Parish and to stress their potential importance in Karangara Parish; this subject was not raised in Mukono Parish. In all, 403 mature women who were randomly selected from the three parishes were interviewed as to their: (1) knowledge of the classes of people not eligible to take ivermectin; (2) knowledge and beliefs about the benefits of ivermectin; (3) participation in decision-making; and (4) attitudes on the performance of female CDHWs. For analysis, the respondees were divided into: (1) those who had or had not taken ivermectin treatment during the previous year; and (2) those who had or had not attended health education sessions. During the period when face-to-face interviews with women in randomly selected households were being carried out, participatory evaluation meetings (PEMs) were conducted in selected communities from the same parishes in order to reach a consensus on issues which could not easily be included in individual face-to-face interviews. Participant observations were also made regarding: how communities selected their CDHWs; how the CDHWs organised the distribution exercise and treated community members; and how the CDHWs kept records in order to understand issues which were deliberately hidden from the researchers during face-to-face interviews and PEMs. Significantly, the women who had been treated or health educated in Masya Parish were: (1) more knowledgeable on the groups which were not supposed to be treated; (2) aware of women's involvement in mobilisation of other community members; (3) involved in CDTI decision-making; and (4) had a better attitude towards female CDHWs' performance compared with males when compared with those from Karangara and Mukono parishes. There were no differences between the attitude of women in Karangara and Mukono parishes towards performance of female CDHWs. Face-to-face interviews and records from all parishes indicated that female CDHWs achieved as good a coverage as their male counterparts, and sometimes better, in about the same time. Health education increased the number of female CDHWs from nine to 52 in Masya Parish, from 7 to 22 in Karangara Parish and from 6 to 20 in Mukono Parish. Health education improved the attitude of women towards female CDHWs, but the actual experience of having and observing female CDHWs in action in Masya Parish had a more significant positive impact on the womenfolk, as well as on the rest of the community members, and created an impetus for more of them to become actively involved in actual ivermectin distribution. The present authors conclude that recruiting more female CDHWs and supervisors would reduce the current male domination of the health delivery services, greatly strengthening the activities of CDTI programmes.

Over the period 1997-2000, an evaluation was made, in 10 districts of Uganda, of the onchocerciasis-control programme based on community-directed treatment with ivermectin (CDTI). This programme is supported by the Ministry of Health, the African Progamme for Onchocerciasis Control (APOC) and The Carter Center Global 2000 River Blindness Programme. The data analysed came from: (1) monthly and annual reports; (2) annual interviews, in randomly-selected communities in selected districts, with heads of household, community leaders and ivermectin distributors; (3) participatory evaluation meetings (PEM); (4) participant observation studies; and (5) key informants. The percentage of treated communities in the 10 study districts achieving satisfactory treatment coverage [i.e. > or = 90% of the annual treatment objective (ATO)] rose from 46.0 in 1997 to 86.8 in 2000. This improvement was largely attributable to the adoption of collective CDTI decision-making by community members, avoidance of paving monetary incentives to the ivermectin distributors, and the satisfaction with the programme of those who had been treated. Coverage improved as the numbers of community members who were involved in choosing the method of distribution and in selecting their own community-directed health workers (CDHW) increased. Health education was also critical in improving individual members' involvement in decision-making, and in mobilizing other community members to take part in CDTI. Involvement of kinship groups, as well as educated community members as supervisors of CDHW, also helped to increase coverage. In a regression model, satisfaction with the programme was revealed as a significant predictor of the achievement of the target coverage (P