African Programme For Onchocerciasis Control Research Articles

The burden of skin disease and eye disease due to onchocerciasis in countries formerly under the African Programme for Onchocerciasis Control mandate for 1990, 2020, and 2030.

Onchocerciasis ("river blindness") can cause severe morbidity, including vision loss and various skin manifestations, and is targeted for elimination using ivermectin mass drug administration (MDA). We calculated the number of people with Onchocerca volvulus infection and onchocercal skin and eye disease as well as disability-adjusted life years (DALYs) lost from 1990 through to 2030 in areas formerly covered by the African Programme for Onchocerciasis Control. Per MDA implementation unit, we collated data on the pre-control distribution of microfilariae (mf) prevalence and the history of control. Next, we predicted trends in infection and morbidity over time using the ONCHOSIM simulation model. DALY estimates were calculated using disability weights from the Global Burden of Disease Study. In 1990, prior to MDA implementation, the total population at risk was 79.8 million with 26.0 million (32.5%) mf-positive individuals, of whom 17.5 million (21.9%) had some form of onchocercal skin or eye disease (2.5 million DALYs lost). By 2030, the total population was predicted to increase to 236.1 million, while the number of mf-positive cases (about 6.8 million, 2.9%), people with skin or eye morbidity (4.2 million, 1.8%), and DALYs lost (0.7 million) were predicted to decline. MDA has had a remarkable impact on the onchocerciasis burden in countries previously under the APOC mandate. In the few countries where we predict continued transmission between now and 2030, intensified MDA could be combined with local vector control efforts, or the introduction of new drugs for mopping up residual cases of infection and morbidity.

Mapping the burden of onchocercal skin disease.

Onchocerciasis is a neglected tropical disease caused by a nematode parasite, Onchocerca volvulus, and transmitted by bites of Simulium blackflies which breed near fast-flowing rivers. In humans, thousands of microfilariae (immature worms) migrate to the skin and eyes where they cause pathology. Historically, much research was devoted to the serious effect of blindness, from which the disease earns its alternative name of 'river blindness'. Mapping the burden of onchocercal skin disease (OSD) was expedited by the development of a clinical classification and grading system that facilitated comparison of data from different countries. After successful field testing in Nigeria, the classification scheme was used in a multicountry study in seven endemic sites, to estimate the true burden of OSD across Africa. High levels of OSD were found, affecting 28% of the population. A new control programme, the African Programme for Onchocerciasis Control (APOC) was launched in 20 countries using annual doses of ivermectin, donated by Merck & Co., Inc. The multicountry study also found a close correlation between the levels of itching and OSD with the level of endemicity, as determined by the prevalence of onchocercal nodules. This enabled APOC to use Rapid Epidemiological Mapping of Onchocerciasis, which entailed identifying likely vector breeding sites near rivers, then sampling 50 adult males in nearby villages to determine the prevalence of nodules and delineate which villages required treatment. Onchocerciasis is now targeted for elimination in Africa, and the challenge is to complete Onchocerciasis Elimination Mapping of hypoendemic areas using serology.

Situation analysis of onchocerciasis in Cameroon: a protocol for systematic review of epidemiological studies and impact of disease control interventions

BackgroundMany control methods have been implemented to tackle onchocerciasis and great successes have been achieved, leading to a paradigm shift from control of morbidity to interruption of transmission and ultimately elimination. The mandate of the African Programme for Onchocerciasis Control (APOC) ended in 2015, and endemic countries are to plan and conduct elimination activities by themselves, with technical assistance by the Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN). To this end, an elimination expert committee was set up in Cameroon in 2018. This committee identified the need to update the data on the current situation of onchocerciasis. The present study aims to systematically review and report all available epidemiological data, including prevalence, intensity and transmission of onchocerciasis to provide pertinent information that will be useful to design optimal strategies to achieve onchocerciasis elimination in Cameroon.MethodsPubMed/MEDLINE, EMBASE and Web of Science will be searched from inception onwards. Grey literature will be identified through Google Scholar searches, dissertation databases and other relevant documents such as government reports. Eligible studies will be mostly observational, including cohort and cross-sectional surveys. No limitations will be imposed on publication status and study period. The primary outcomes will be (1) the prevalence and intensity of Onchocerca volvulus infection in humans, (2) transmission intensity and (3) impact of interventions on prevalence, intensity and transmission of onchocerciasis. Secondary outcomes will be environmental and socio-demographic factors supporting the primary outcomes. Two reviewers will independently screen all citations, full-text articles and abstract data. Potential conflicts will be resolved through discussion. Methodological quality including bias will be appraised using appropriate approaches. A narrative synthesis will describe quality and content of the epidemiological evidence. Prevalence and intensity of infection estimates will be stratified according to gender, age, geographical location and year of publication.DiscussionThis study will provide the health authorities as well as the scientific community with up-to-date information about the epidemiological situation of onchocerciasis in Cameroon. Understanding the spatiotemporal dynamics of the infection will help to define alternative and complementary strategies to accelerate onchocerciasis elimination in the country. Results of this review will also be used to update existing epidemiological models for onchocerciasis in order to fine-tune predictions of elimination timeframes in the country.Systematic review registrationThis protocol is under registration review in PROSPERO.

Onchocerciasis: status and progress towards elimination

Abstract Craw craw was first described almost 150 years ago. Since then considerable progress has been made in understanding the Onchocerca volvulus life cycle, its effects on the host (blindness, skin disease and epilepsy) and potential control measures. Early attempts were aimed at controlling the black fly ( Simulium ) that transmits the disease. This included the early use of DDT in some isolated foci in East Africa. This was followed in the 1970s by the Onchocerciasis Control Programme (OCP) of West Africa using other safer insecticides. In 1987, MSD (known as Merck & Co Inc. in the USA and Canada) announced the donation of Mectizan ® (ivermectin MSD) as long as was necessary for onchocerciasis control. This began a new chapter in the control of the disease including the creation of the African Programme for Onchocerciasis Control (APOC) and the Onchocerciasis Elimination Programme for the Americas (OEPA). In the Americas, four countries have now been verified free of transmission of the disease by the World Health Organisation. In Africa where foci are considerably larger, APOC with its partners has succeeded in developing a control programme covering virtually all areas where the prevalence of the disease can cause serious effects. In some disease foci in Africa, elimination of transmission has been achieved. Following surveys on the Mali Senegal border, there was a move in 2009 to change the paradigm from control to elimination. Development has been slow but by 2030, there is hope that most countries will have stopped treatment and others will have completed post-treatment surveillance surveys although some foci in conflict areas will remain.

Review of the National Program for Onchocerciasis Control in the Democratic Republic of the Congo.

Here, we review all data available at the Ministry of Public Health in order to describe the history of the National Program for Onchocerciasis Control (NPOC) in the Democratic Republic of the Congo (DRC). Discovered in 1903, the disease is endemic in all provinces. Ivermectin was introduced in 1987 as clinical treatment, then as mass treatment in 1989. Created in 1996, the NPOC is based on community-directed treatment with ivermectin (CDTI). In 1999, rapid epidemiological mapping for onchocerciasis surveys were launched to determine the mass treatment areas called “CDTI Projects”. CDTI started in 2001 and certain projects were stopped in 2005 following the occurrence of serious adverse events. Surveys coupled with rapid assessment procedures for loiasis and onchocerciasis rapid epidemiological assessment were launched to identify the areas of treatment for onchocerciasis and loiasis. In 2006, CDTI began again until closure of the activities of African Program for Onchocerciasis Control (APOC) in 2015. In 2016, the National Program for Neglected Tropical Diseases Control using Preventive Chemotherapy (PNMTN-CP) was launched to replace NPOC. Onchocerciasis and CDTI are little known by the population. The objective of eliminating onchocerciasis by 2025 will not be achieved due to the poor results of the NPOC. The reform of strategies for eliminating this disease is strongly recommended.

Untreated villages and factors associated with the absence of Community-Directed Treatment with Ivermectin (CDTI) in DRC.

The African Programme for Onchocerciasis Control (APOC), the main objective of which was the Community-Directed Treatment with Ivermectin (CDTI), was closed by the end of 2015. The purpose of this study was to describe untreated villages in DRC and to assess the factors associated with the absence of CDTI in endemic villages, between 2001 and 2014. This retrospective study was descriptive. Several annual technical reports of the National Onchocerciasis Task Force (NOTF) and national technical reports of CDTI projects were analysed; 21 projects implemented to control the disease were considered, representing the coverage of 42,778 endemic villages. Data were collected over a 3 month-period, between October and December 2016. Only 15,700 endemic villages were not treated through an annual CDT with Mectizan, i.e. 36.7%. The population at risk totalled 29,712,381 individuals and 7,681,995 of them were not treated, i.e. 25.9%. Eight projects recorded high proportions of untreated villages, i.e. 7,100 endemic entities (16.6%). Factors independently associated with non-treatment were the fear of serious side effects (adjusted OR: 10.6; 95% CI: 4.5-27.7), supply impaired by insecurity (adjusted OR: 15.9; 95% CI: 6.7-41.4) and geographical inaccessibility (adjusted OR: 19; 95% CI: 6.9-63.9). After 15 CDTI-cycles in DRC, the mean geographical coverage and therapeutic coverage rates reached 63.3% and 74.1%, respectively. The 2025 target of onchocerciasis eradication, as advocated by APOC, will not be reached. Untreated areas are partly responsible for such results. Many weaknesses persist in the National Program for Onchocerciasis Control (NPOC) and new strategies of disease control should be investigated.

Valuing the Unpaid Contribution of Community Health Volunteers to Mass Drug Administration Programs.

Community health volunteers (CHVs) are being used within a growing number of healthcare interventions, and they have become a cornerstone for the delivery of mass drug administration within many neglected tropical disease control programs. However, a greater understanding of the methods used to value the unpaid time CHVs contribute to healthcare programs is needed. We outline the two main approaches used to value CHVs’ unpaid time (the opportunity cost and the replacement cost approaches). We found that for mass drug administration programs the estimates of the economic costs relating to the CHVs’ unpaid time can be significant, with the averages of the different studies varying between US$0.05 and $0.16 per treatment. We estimated that the time donated by CHVs’ to the African Programme for Onchocerciasis Control alone would be valued between US$60 and $90 million. There is a need for greater transparency and consistency in the methods used to value CHVs’ unpaid time.

Evaluation of onchocerciasis control in the Upper Denkyira East municipal in the forest area of Ghana: Responses of participants and distributors to the CDTI programme

The African Programme for Onchocerciasis Control (APOC), which focused on annual mass treatment with ivermectin, was launched in 1995 and was replaced by the Expanded Special Project for Neglected Tropical Diseases (ESPEN) by the end of 2015. In Ghana, the Community Directed Treatment with Ivermectin (CDTI) was introduced in 1999. After a decade, biannual reinforcement was introduced during which the Ghana Health Service (GHS) recorded coverage rates through routine data collection. Transmission studies conducted in the Upper Denkyira East Municipal (UDEM) of the forest zone of Ghana in 2002 and 2006 had shown that annual treatments with ivermectin had hardly any effect on the transmission of Onchocerca volvulus by the vector Simulium sanctipauli. In order to establish whether or not this was due to an insufficient compliance to the CDTI programme, an additional questionnaire survey was carried out in 2013 following those conducted in 2002 and 2006. The repeat transmission survey conducted in 2013 in the same area revealed that the vector S. sanctipauli had apparently disappeared from the rivers Ofin and Pra due to gold mining activities. In 2006 and 2013, we conducted surveys using structured questionnaires to address issues related to compliance and to compare results on the effectiveness of CDTI. A total of 692 individuals from 7 villages and 447 individuals from 9 villages were interviewed in 2006 and 2013 respectively. Questions asked included whether or not they had taken the ivermectin and reasons for not doing so when that was the case. Results were compared with the previous investigations conducted in 2002. Whereas official reported coverage rates ranged from 59 to 85% in 2006 and from 88 to 97% in 2013, compliance rates decreased from 36% in 2006 to 21% in 2013. Factors affecting compliance included fear of unpleasant side effects (pruritus and oedema), which decreased from 36% to 21% for the same period. Lack of awareness of CDTI sharply increased from 12% to 46% for the same period. Participants believed that treatments were no longer necessary due to the absence of vectors observed in 2013. There seems to be a considerable difference between coverage and compliance rates in the study communities. The difference can be attributed to the performance of the Community-Directed Distributors (CDDs) and the absence of the vector population observed in 2013. Discussions with CDDs suggested that factors that led to non-compliance were mostly side effects, unawareness of the disease by immigrants and lack of financial motivation for the CDDs. Also included was the fact that they needed to complete distribution of the drugs in the entire village, covering all households within just one week irrespective of the size of the catchment area. This, they thought was too much work for a short period of time. We propose to intensify the training of CDDs by the national Neglected Tropical Diseases Programme (NTDP) and to include the Community-based Health and Planning Services (CHPS) concept into onchocerciasis control efforts for awareness creation while the vector population and the transmission should be further monitored. The population should be made aware that the side effects they experienced from previous treatments or had heard about had reduced significantly. They also should be in the known that vector flies may return and so the risk of transmission remains.

Onchocerciasis prevalence, human migration and risks for onchocerciasis elimination in the Upper Mouhoun, Nakambé and Nazinon river basins in Burkina Faso

Historically, the whole of Burkina Faso was considered to be endemic for onchocerciasis (except a small area in the far north of the country) with prevalence rates 60–80%, but all endemic areas were included in the World Health Organisation Onchocerciasis Control Programme, which operated a system of vector control by larviciding beginning in 1974. In Burkina Faso larviciding had been phased out by 1989 when it was considered that onchocerciasis had been reduced to levels below the transmission breakpoint (and any residual infections would disappear without further intervention). There was never any mass drug administration against onchocerciasis in Burkina Faso, except in the Bougouriba and Comoé river basins (from 1996 and 2011 to present respectively) because in each of these two areas there was a resurgence of infection, and in parts of the Nakambé River basin and Sissili River basin from 1992 to 1998. However, mass drug administration with ivermectin was also phased in across the whole country starting in 2000 using ivermectin against lymphatic filariasis and is currently being phased out (depending upon the epidemiological parameters). In this publication we report a new epidemiological survey for onchocerciasis which was carried out in 2014 in the Upper Mouhoun, Nakambé and Nazinon river basins in Burkina Faso to evaluate the prevalence and intensity of infection of onchocerciasis. A total of 11,195 people from 61 villages were examined across these three river basins, and onchocerciasis prevalence by skin-snip was below 5% in all villages, below 1% in 57 villages (93% of 61 villages) and zero in 47. In the 14 villages with positive skin snips, prevalence figures ranged from 0.31% to 3.50%. During the survey 31 infected individuals were found. All of them were Burkinabé, of whom 30 had a recent history of residence in Côte d’Ivoire (with a range of 0.5 to 73 microfilariae per skin-snip from two snips per person) and only one had no history of migration and presumably had an autochthonous infection (mean of 0.5 microfilariae per skin snip from two snips). According to parasitological indicators listed by the World Health Organization African Programme for Onchocerciasis Control in 2010, the situation for onchocerciasis was considered to be satisfactory in all three river basins and probably below the transmission threshold, in which case the disease should disappear naturally without the need for further intervention in the absence of continuing immigration. However, the results clearly indicate that infected persons coming from endemic zones of Côte d’Ivoire are settling in small communities which are otherwise nearly free from onchocerciasis in Burkina Faso. They are thus a source of continuing re-introduction of the parasite into the basins and could be a risk for the achievement of onchocerciasis elimination in all three basins. This would justify the continuation of periodic epidemiological surveys to monitor the possible recrudescence of the disease, and entomological (vector) surveys should be undertaken to assess and monitor the residual transmission.

Onchocerciasis in the Democratic Republic of Congo: Survey of knowledge, attitude and perception in Bandundu province.

A community-directed treatment with ivermectin (CDTI) for fighting onchocerciasis was started in 2003 in the hyperendemic province of Bandundu, Democratic Republic of Congo (DRC); such initiative was supported by the African Programme for Onchocerciasis Control (APOC). As the APOC stopped at the end of 2015, there was an urgent need to assess the sustainability of an ivermectin treatment. A cross-sectional survey of knowledge, attitude and perception was conducted to determine the awareness level of local population regarding the disease. A multi-stage random sampling technique allowed the selection of 450 heads of households. Most respondents (96.9%) knew about onchocerciasis as a disease. The black-fly was viewed as the causing agent of onchocerciasis by 49.9% of respondents. The most commonly cited clinical manifestations were nodules (34.4%) and pruritus (31.1%), while blindness was the most frequently reported complication (90.7%). Approximately 55.1% of respondents had a good knowledge of onchocerciasis and CDTI. Overall, only 37% of participants had a favourable attitude and 46% a positive perception. Good knowledge was associated with school attendance (adjusted OR=1.9, 95%CI: 1.3-2.8, p=0.001), while education and continuation of treatment were related with good attitude (adjusted OR=9.7, 95%CI:4.8-19.5 and adjusted OR=19.8, 95%CI: 9.7-40.6, respectively, both with p<0.001). Good perception was associated with being at least 46 years old, non-Catholic and continuing the treatment (adjusted OR=3.2, 95%CI:1.2-9.1; adjusted OR=29.6, 95%CI:14.1-62.2 and adjusted OR=5.1, 95%CI:1.6-16.0 respectively, all with p<0.001). A good level of knowledge, attitude and perception is needed for a massive adherence of population to onchocerciasis control programmes. In the area of study (Moanza, DRC), good attitude and perception motivated the continuation of treatment in the population. In the future, different plans should focus on educational strategies to maintain a massive adherence and reduce onchocerciasis prevalence.

Knowledge, attitudes, and practices toward onchocerciasis among local population in Bioko Island, Equatorial Guinea

Introduction: Since 1998, the African program for onchocerciasis control has been working with ultimate goal of reducing the public health impact associated with onchocerciasis in Equatorial Guinea. Although dedicated community engagement is crucial for the success of this program, there is no information on the levels of community's knowledge, attitude, and practice (KAP) toward onchocerciasis in this country. Methods: A cross-sectional study was carried out in Bioko Island from mid-January to mid-February 2014. Sampling was carried out by multistage cluster survey. Sociodemographic characteristics, KAP, and stigma-related questions were collected through a pretested questionnaire. A bivariate analysis was performed and results were adjusted by sex and age using logistic regression. Results: A total of 140 housekeepers or head of households agreed to participate. Around 54% of the interviewees had heard about the disease, of which more than one-third identified the disease as filariasis (28/68, 41.2%). Overall, 19.3% respondents highlighted the bite of a blackfly as the main mode of transmission. From those who had a familiar affected by onchocerciasis in the past, 21 out of 32 (65.6%) pointed ivermectin as the preferred treatment and 43.8% pointed out the health center as the first choice place to seek for treatment. About 67.1% of individuals believed that having onchocerciasis would not cause any contact avoidance with other members in the community. Conclusions: People's practices toward onchocerciasis tend to be better than disease knowledge in Bioko Island. Increasing awareness through community-based campaigns and educational activities is encouraged in the current onchocerciasis preelimination stage at Bioko Island.

Evaluation of Lymphatic Filariasis and Onchocerciasis in Three Senegalese Districts Treated for Onchocerciasis with Ivermectin.

In Africa, onchocerciasis and lymphatic filariasis (LF) are co-endemic in many areas. Current efforts to eliminate both diseases are through ivermectin-based mass drug administration (MDA). Years of ivermectin distribution for onchocerciasis may have interrupted LF transmission in certain areas. The Kédougou region, Senegal, is co-endemic for LF and onchocerciasis. Though MDA for onchocerciasis started in 1988, in 2014 albendazole had not yet been added for LF. The objective of this study was to assess in an integrated manner the LF and onchocerciasis status in the three districts of the Kédougou region after ≥10 years of ivermectin-based MDA. The study employed an African Programme for Onchocerciasis Control (APOC) onchocerciasis-related methodology. In the three districts, 14 villages close to three rivers that have Simulium damnosum breeding sites were surveyed. Convenience sampling of residents ≥5 years old was performed. Assessment for LF antigenemia by immunochromatographic testing (ICT) was added to skin snip microscopy for onchocerciasis. Participants were also tested for antibodies against Wb123 (LF) and Ov16 (onchocerciasis) antigens. In two districts, no participants were ICT or skin snip positive. In the third district, 3.5% were ICT positive and 0.7% were skin snip positive. In all the three districts, Wb123 prevalence was 0.6%. Overall, Ov16 prevalence was 6.9%. Ov16 prevalence among children 5–9 years old in the study was 2.5%. LF antigenemia prevalence was still above treatment threshold in one district despite ≥10 years of ivermectin-based MDA. The presence of Ov16 positive children suggested recent transmission of Onchocerca volvulus. This study showed the feasibility of integrated evaluation of onchocerciasis and LF but development of integrated robust methods for assessing transmission of both LF and onchocerciasis are needed to determine where MDA can be stopped safely in co-endemic areas.

Progress towards onchocerciasis elimination in the participating countries of the African Programme for Onchocerciasis Control: epidemiological evaluation results.

BackgroundThe African Programme for Onchocerciasis Control (APOC) was created in 1995 to establish community-directed treatment with ivermectin (CDTi) in order to control onchocerciasis as a public health problem in 20 African countries that had 80 % of the global disease burden. When research showed that CDTi may ultimately eliminate onchocerciasis infection, APOC was given in 2008 the additional objective to determine when and where treatment can be safely stopped. We report the results of epidemiological evaluations undertaken from 2008 to 2014 to assess progress towards elimination in CDTi areas with ≥6 years treatment.MethodsSkin snip surveys were undertaken in samples of first-line villages to determine the prevalence of O. volvulus microfilariae. There were two evaluation phases. The decline in prevalence was evaluated in phase 1A. Observed and model-predicted prevalences were compared after correcting for endemicity level and treatment coverage. Bayesian statistics and Monte Carlo simulation were used to classify the decline in prevalence as faster than predicted, on track or delayed. Where the prevalence approached elimination levels, phase 1B was launched to determine if treatment could be safely stopped. Village sampling was extended to the whole CDTi area. Survey data were analysed within a Bayesian framework to determine if stopping criteria (overall prevalence <1.4 % and maximum stratum prevalence <5 %) were met.ResultsIn phase 1A 127 665 people from 639 villages in 54 areas were examined. The prevalence had fallen dramatically. The decline in prevalence was faster than predicted in 23 areas, on track in another 23 and delayed in eight areas. In phase 1B 108 636 people in 392 villages were examined in 22 areas of which 13 met the epidemiological criteria for stopping treatment. Overall, 32 areas (25.4 million people) had reached or were close to elimination, 18 areas (17.4 million) were on track but required more years treatment, and in eight areas (10.4 million) progress was unsatisfactory.ConclusionsOnchocerciasis has been largely controlled as a public health problem. Great progress has been made towards elimination which already appears to have been achieved for millions of people. For most APOC countries, nationwide onchocerciasis elimination is within reach.Electronic supplementary materialThe online version of this article (doi:10.1186/s40249-016-0160-7) contains supplementary material, which is available to authorized users.

Modelling Neglected Tropical Diseases diagnostics: the sensitivity of skin snips for Onchocerca volvulus in near elimination and surveillance settings.

BackgroundThe African Programme for Onchocerciasis Control has proposed provisional thresholds for the prevalence of microfilariae in humans and of L3 larvae in blackflies, below which mass drug administration (MDA) with ivermectin can be stopped and surveillance started. Skin snips are currently the gold standard test for detecting patent Onchocerca volvulus infection, and the World Health Organization recommends their use to monitor progress of treatment programmes (but not to verify elimination). However, if they are used (in transition and in parallel to Ov-16 serology), sampling protocols should be designed to demonstrate that programmatic goals have been reached. The sensitivity of skin snips is key to the design of such protocols.MethodsWe develop a mathematical model for the number of microfilariae in a skin snip and parameterise it using data from Guatemala, Venezuela, Ghana and Cameroon collected before the start of ivermectin treatment programmes. We use the model to estimate sensitivity as a function of time since last treatment, number of snips taken, microfilarial aggregation and female worm fertility after exposure to 10 annual rounds of ivermectin treatment.ResultsThe sensitivity of the skin snip method increases with time after treatment, with most of the increase occurring between 0 and 5 years. One year after the last treatment, the sensitivity of two skin snips taken from an individual infected with a single fertile female worm is 31 % if there is no permanent effect of multiple ivermectin treatments on fertility; 18 % if there is a 7 % reduction per treatment, and 0.6 % if there is a 35 % reduction. At 5 years, the corresponding sensitivities are 76 %, 62 % and 4.7 %. The sensitivity improves significantly if 4 skin snips are taken: in the absence of a permanent effect of ivermectin, the sensitivity of 4 skin snips is 53 % 1 year and 94 % 5 years after the last treatment.ConclusionsOur model supports the timelines proposed by APOC for post-MDA follow-up and surveillance surveys every 3–5 years. Two skin snips from the iliac region have reasonable sensitivity to detect residual infection, but the sensitivity can be significantly improved by taking 4 snips. The costs and benefits of using four versus two snips should be evaluated.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1605-3) contains supplementary material, which is available to authorized users.

Knowledge, attitude and practice of community drug distributors' about onchocerciasis and community directed treatment with ivermectin in Quara district, North Western Ethiopia.

BackgroundOnchocerciasis is one of the most important public health problems over large areas of tropical Africa countries including Ethiopia. The African Program for Onchocerciasis Control (APOC) has been working with ultimate goal of reducing the public health and socio-economic problems of onchocerciasis through administration of the tablet for continuous 12–15 years using the strategy of yearly community-directed treatment with ivermectin (CDTI) in endemic areas of Africa to kill the microfilariae that invade the eyes and are present in the skin to be transported to another victim by the black fly. The objective of this study was to assess knowledge, attitude and practice of community drug distributors (CDDs) towards onchocerciasis and CDTI in Quara district.ResultOf all the study participating CDD 11.4 % (9/79) said that they knew about the etiology of the disease, 35.4 % (28/79) had good level of knowledge, 19 (24.1 %) had good level of positive attitude and 18 (22.8 %) had good level of positive practice about onchocerciasis. Similarly, 45.6 % (36/79), 81.0 % (64/79) and 29.1 % (23/79) had good level of knowledge, attitude and practice about CDTIP, respectively. Being a female CDD (adjusted OR 7.246, P = 0.035, 95 % CI 1.147, 45.455) and being older than 35 years (adjusted OR 8.435, P = 0.001, 95 % CI 4.53, 9.003) were significantly associated with the likelihood of having good level of knowledge about the disease.ConclusionAlthough onchocerciasis is endemic in Quara district, large proportion of the CDDs had misconceptions about its causation, transmission and prevention. Therefore, CDTIP for onchocerciasis control need to be supported by proper and continuous training, and health education about different aspects of the disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-016-2010-x) contains supplementary material, which is available to authorized users.

Neglected tropical diseases in Africa: a new paradigm.

Programmes to control onchocerciasis have been ongoing for over 40 years. What was once a devastating blinding and disabling disease, particularly in West Africa, has largely been eliminated at least as a public health problem. Efforts continue to eliminate the transmission of the disease. However, as the elimination agenda has developed so have efforts to control/eliminate other neglected tropical diseases (NTDs). The African Programme for Onchocerciasis Control will close at the end of 2015. There has been considerable discussion as to what should replace it and the World Health Organization Africa Region has been consulting widely during the first part of 2015 and has established a new project framework that will be presented to a wider group of stakeholders to mobilise support with the aim of the coordination of NTD activities in the region. This will be called the Expanded Special Project for Elimination of Neglected Tropical Diseases (ESPEN). This will put the countries in the driving seat but offer technical advice, capacity building and financial support, where needed, to enable countries to implement their NTD Master Plans, and also to implement recommendations of the Regional Programme Review Group. An NTD forum will be held periodically to consult with stakeholders.

River Blindness: Mathematical Models for Control and Elimination.

Human onchocerciasis (river blindness) is one of the few neglected tropical diseases (NTDs) whose control strategies have been informed by mathematical modelling. With the change in focus from elimination of the disease burden to elimination of Onchocerca volvulus, much remains to be done to refine, calibrate and validate existing models. Under the impetus of the NTD Modelling Consortium, the teams that developed EPIONCHO and ONCHOSIM have joined forces to compare and improve these frameworks to better assist ongoing elimination efforts. We review their current versions and describe how they are being used to address two key questions: (1) where can onchocerciasis be eliminated with current intervention strategies by 2020/2025? and (2) what alternative/complementary strategies could help to accelerate elimination where (1) cannot be achieved? The control and elimination of onchocerciasis from the African continent is at a crucial crossroad. The African Programme for Onchocerciasis Control closed at the end of 2015, and although a new platform for support and integration of NTD control has been launched, the diseasewill have to compete with a myriad of other national health priorities at a pivotal time in the road to elimination. However, never before had onchocerciasis control a better arsenal of intervention strategies as well as diagnostics. It is, therefore, timely to present two models of different geneses and modelling traditions as they come together to produce robust decision-support tools. We start by describing the structural and parametric assumptions of EPIONCHO and ONCHOSIM; we continue by summarizing the modelling of current treatment strategies with annual (or biannual) mass ivermectin distribution and introduce a number of alternative strategies, including other microfilaricidal therapies (such as moxidectin), macrofilaricidal (anti-wolbachial) treatments, focal vector control and the possibility of an onchocerciasis vaccine. We conclude by discussing challenges, opportunities and future directions.

African Program for Onchocerciasis Control 1995-2010: Impact of Annual Ivermectin Mass Treatment on Off-Target Infectious Diseases.

Since its initiation in 1995, the African Program for Onchocerciasis Control (APOC) has had a substantial impact on the prevalence and burden of onchocerciasis through annual ivermectin mass treatment. Ivermectin is a broad-spectrum anti-parasitic agent that also has an impact on other co-endemic parasitic infections. In this study, we roughly assessed the additional impact of APOC activities on the burden of the most important off-target infections: soil-transmitted helminthiases (STH; ascariasis, trichuriasis, hookworm, and strongyloidiasis), lymphatic filariasis (LF), and scabies. Based on a literature review, we formulated assumptions about the impact of ivermectin treatment on the disease burden of these off-target infections. Using data on the number of ivermectin treatments in APOC regions and the latest estimates of the burden of disease, we then calculated the impact of APOC activities on off-target infections in terms of disability-adjusted life years (DALYs) averted. We conservatively estimated that between 1995 and 2010, annual ivermectin mass treatment has cumulatively averted about 500 thousand DALYs from co-endemic STH infections, LF, and scabies. This impact comprised approximately an additional 5.5% relative to the total burden averted from onchocerciasis (8.9 million DALYs) and indicates that the overall cost-effectiveness of APOC is even higher than previously reported.

Investing in Onchocerciasis Control: Financial Management of the African Programme for Onchocerciasis Control (APOC)

The African Programme for Onchocerciasis Control (APOC) has been described as one of the most successful public-private partnerships for health in Africa [1]. The Programme helps the governments of 20 onchocerciasis-endemic countries to develop sustainable delivery of ivermectin treatment in order to control and eliminate river blindness [2]. APOC is one of a very few programs that the WHO implements directly, in this case through the Regional Office for Africa (AFRO) and the APOC Secretariat established in Ouagadougou, Burkina Faso. As the Executing Agency of APOC, WHO is responsible for the development of procedures for implementing community-directed treatment with ivermectin (CDTi), approving funding to countries, maintaining surveillance, and ensuring monitoring and evaluation [3]. The Executing Agency supports governments directly in this role, aided by a group of 15 Non-Governmental Development Organizations (NGDOs), operating nationally, regionally, and globally [4]. The 15 NGDOs include Charitable Society for Social Welfare, Christoffel-Blindenmission (CBM), Helen Keller International (HKI), Light the World, Mectizan Donation Program (MDP), Mission to Save the Helpless (MITOSATH), Organisation pour la Prevention de la Cecite (OPC), Sightsavers International, United Front Against Riverblindness (UFAR), Interchurch Medical Assistance (IMA) World Health, Lions Clubs International Foundation, Malaria Consortium, Schistosomiasis Control Initiative, The Carter Center, and The United States Fund for UNICEF. The funding for national onchocerciasis control comes from the countries and civil society, with additional funding from APOC through contributions from more than 30 development partners to a Trust Fund that the World Bank manages in its role as Fiscal Agent. Scheduled to close in 2015, the main governing body of APOC decided to set up a new programme for a ten-year period from 2016, actively seeking to eliminate river blindness from most of Africa by 2025 and, by strengthening the same health system that successfully delivered treatment for river blindness, seeking to also eliminate lymphatic filariasis and co-implement treatments for the five other major preventable neglected tropical diseases (NTDs) that can be addressed through mass drug administration. Plans are underway to transform APOC beyond 2015 and transition from a single-disease entity to an expanded regional NTD initiative [5]. This article is one of a series developed by the partnership of agencies, institutions, and individuals that make up APOC. This article is written from the perspective of the Fiscal Agent (the APOC Team at the World Bank) and should be read in conjunction with the corresponding articles in this series that examine the depth and diversity of the river blindness partnership, which includes the Executing Agency (World Health Organization) [3], civil society [4], and the Mectizan Donation Program [6].

Situation analysis of parasitological and entomological indices of onchocerciasis transmission in three drainage basins of the rain forest of South West Cameroon after a decade of ivermectin treatment.

BackgroundCommunity-Directed Treatment with Ivermectin (CDTI) is the main strategy adopted by the African Programme for Onchocerciasis control (APOC). Recent reports from onchocerciasis endemic areas of savannah zones have demonstrated the feasibility of disease elimination through CDTI. Such information is lacking in rain forest zones. In this study, we investigated the parasitological and entomological indices of onchocerciasis transmission in three drainage basins in the rain forest area of Cameroon [after over a decade of CDTI]. River basins differed in terms of river number and their flow rates; and were characterized by high pre-control prevalence rates (60-98%).MethodsNodule palpation and skin snipping were carried out in the study communities to determine the nodule rates, microfilarial prevalences and intensity. Simulium flies were caught at capture points and dissected to determine the biting, parous, infection and infective rates and the transmission potential.ResultsThe highest mean microfilaria (mf) prevalence was recorded in the Meme (52.7%), followed by Mungo (41.0%) and Manyu drainage basin (33.0%). The same trend was seen with nodule prevalence between the drainage basins. Twenty-three (23/39) communities (among which 13 in the Meme) still had mf prevalence above 40%. All the communities surveyed had community microfilarial loads (CMFL) below 10 mf/skin snip (ss). The infection was more intense in the Mungo and Meme. The intensity of infection was still high in younger individuals and children less than 10 years of age. Transmission potentials as high as 1211.7 infective larvae/person/month were found in some of the study communities. Entomological indices followed the same trend as the parasitological indices in the three river basins with the Meme having the highest values.ConclusionWhen compared with pre-control data, results of the present study show that after over a decade of CDTI, the burden of onchocerciasis has reduced. However, transmission is still going on in this study site where loiasis and onchocerciasis are co-endemic and where ecological factors strongly favour the onchocerciasis transmission. The possible reasons for this persistent and differential transmission despite over a decade of control efforts using ivermectin are discussed.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-0817-2) contains supplementary material, which is available to authorized users.