Implementation Challenges of Community Directed Treatment with Ivermectin Program for Control of Onchocerciasis in Ulanga, Tanzania

Background: Community drug distributors (CDDs) have a crucial role in distributing ivermectin for onchocerciasis control and prevention. Their roles, experiences and challenges faced in the implementation of community-directed treatment with ivermectin (CDTI) programme could potentially affect coverage, consequently leading to persistent transmission. Therefore, this study aimed to explore the experience and the roles which CDDs plays in implementation of community directed treatment with ivermectin program for onchocerciasis control in Ulanga, Tanzania. Methods: A cross-sectional study design was used to collect qualitative data in 2018 in Ulanga district, Tanzania. Five community drug distributors were purposively selected for in-depth interviews. Thematic framework approach for qualitative data analysis was used to generate codes, categories and themes. Results: Out of the five community drug distributors interviewed, two had experience of 15 to 20 years on implementation of the community directed treatment with ivermectin programme while the remaining community drug distributors had experience of less than 10 years. The main challenges faced by CDDs in the implementation of the CDTI programme include; the geographical location of the hamlets (hard to reach hamlets), long distances between houses, low compliance of community members to medication due to fear of side effects experienced before and mistrust of methods of dose calculation, short time of drug distribution and absence of people from their households as the exercise was conducted when community members were involved in agricultural activities. Conclusions: The challenges faced in the implementation of the CDTI programme could negatively affect the distribution and coverage of ivermectin treatment in the Ulanga district. It’s now an opportune time to address the challenges that CDDs are facing in the implementation of the CDTI programme to ensure effective control of onchocerciasis in the district.

“Slash and Clear”, a Community-Based Vector Control Method to Reduce Onchocerciasis Transmission by Simulium sirbanum in Maridi, South Sudan: A Prospective Study

Background: High ongoing Onchocerca volvulus transmission was recently documented in Maridi County, South Sudan. To complement community-directed treatment with ivermectin (CDTI) as the main onchocerciasis control strategy, we initiated a community-based vector control method “slash and clear” at the Maridi dam, a Simulium damnosum s.l. breeding site, to reduce O. volvulus transmission. Methods: Simulium damnosum s.l. biting rates were collected before and during the twenty months following the “slash and clear” intervention using the human landing catches. Black flies were dissected to measure parity rates before and twelve months after the intervention. Larvae and pupae of S. damnosum s.l. were collected from the dam for morphological and chromosomal characterization to identify the cytospecies involved. Results: Biting rates of S. damnosum s.l. close to the Maridi dam spillway decreased by >90% post-“slash and clear” for more than six months. Twelve months after the “slash and clear” intervention, the reduction in biting rates was still at <50% (p = 0.0007). Parity rates reduced from 13% pre-“slash and clear” (November 2019) to 5.6% post-“slash and clear” (November 2020). Larvae collected from the dam were identified as Simulium sirbanum. Conclusion: The “slash and clear” method was found to be an effective and cheap community-based method to reduce black fly biting rates caused by S. sirbanum. When repeated at least annually together with a high CDTI coverage, this intervention has the potential to considerably accelerate onchocerciasis elimination.

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

Background 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. Methods 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. Results 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. Conclusions 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.

COVID-19: The African Enigma

To the editor Related article: https://colombiamedica.univalle.edu.co/...iew/4613 We read with interest the paper by Guerrero et al “COVID-19: The Ivermectin African Enigma” . In an ecological study they compared COVID-19 related mortality and infection rates between APOC (African Programme for Onchocerciasis Control) and non-APOC countries. After adjusting for Human Development Index (HDI) and number of performed test, COVID-19 mortality and infection rate were respectively 28% and 8% lower in non-APOC countries compared to APOC countries. The authors suggested that this difference may be related to the community directed treatment with ivermectin (CDTI) programs established in APOC countries. We agree that it remains to be explained why a lower COVID-19 mortality is observed in many APOC countries compared to other parts of the world. However, we do not believe that this is related to CDTI programs. Indeed, in APOC countries ivermectin is distributed only once (most countries) or twice a year 2. Moreover, April 1st 2020, because of the COVID-19 pandemic, CDTI programs were interrupted and were only recently restarted. Ivermectin has an in vitro anti-COVID-19 effect and also certain clinical trials suggested a beneficial effect of ivermectin on COVID-19 disease outcome. However, in a recent small double blind, randomized control trial in Colombia, five days of ivermectin, at a 10 times the recommended dose, did not reduce the duration of symptoms of mild COVID-19 disease compared to placebo. Given the half-life of ivermectin, approximately 18h, it is unlikely that CDTI, only one dose of ivermectin once or twice a year, may be able to reduce COVID-19 related mortality. Many factors could explain the lower COVID-19 mortality in APOC countries. One of them could be exposure to parasitic infections and the immune response induced by these infections. For example, for P. falciparum, a parasitic infection highly prevalent in APOC countries, it has been hypothesised that the immunological memory against P. falciparum merozoites primes SARS-CoV-2 infected cells for early phagocytosis and therefore may protect persons with a recent P. falciparum infection against severe COVID-19 disease. Helminth infections, such as onchocerciasis, may down regulate immune responses and potentially inactivate the inflammatory signalling pathways that may induce acute respiratory distress syndrome (ARDS), one of the causes of death in COVID-19 infected persons

Onchocerciasis control in Ghana (1974–2016)

Background The control of onchocerciasis in Ghana started in 1974 under the auspices of the Onchocerciasis Control Programme (OCP). Between 1974 and 2002, a combination of approaches including vector control, mobile community ivermectin treatment, and community-directed treatment with ivermectin (CDTI) were employed. From 1997, CDTI became the main control strategy employed by the Ghana OCP (GOCP). This review was undertaken to assess the impact of the control interventions on onchocerciasis in Ghana between 1974 and 2016, since which time the focus has changed from control to elimination. Methods In this paper, we review programme data from 1974 to 2016 to assess the impact of control activities on prevalence indicators of onchocerciasis. This review includes an evaluation of CDTI implementation, microfilaria (Mf) prevalence assessments and rapid epidemiological mapping of onchocerciasis results. Results This review indicates that the control of onchocerciasis in Ghana has been very successful, with a significant decrease in the prevalence of infection from 69.13% [95% confidence interval) CI 60.24–78.01] in 1975 to 0.72% (95% CI 0.19–1.26) in 2015. Similarly, the mean community Mf load decreased from 14.48 MF/skin snip in 1975 to 0.07 MF/skin snip (95% CI 0.00–0.19) in 2015. Between 1997 and 2016, the therapeutic coverage increased from 58.50 to 83.80%, with nearly 100 million ivermectin tablets distributed. Conclusions Despite the significant reduction in the prevalence of onchocerciasis in Ghana, there are still communities with MF prevalence above 1%. As the focus of the GOCP has changed from the control of onchocerciasis to its elimination, both guidance and financial support are required to ensure that the latter goal is met.

The big three versus NTDs - finding common purpose.

Even so, no country in sub-Saharan Africa before 2000 had national control programs for any of the seven programs, with the exception of cervical cancer. Onchocerciasis is the target of the Africa Program for Onchocerciasis Control (APOC) with the help of many NGOs organisation using the drug mectizan (ivermectin). The use of drug financing at APOC is revolutionary. They had, for the first time, established as a viable concept with leprosy control programs, and now, with APOC, demonstrated that pharmaceutical companies can and will reuse a drug and treat it as part of a humanitarian response. This book chapter focused on repurposing drugs against schistosomiasis.

COVID-19: The Ivermectin African Enigma

Introduction: The low frequency of cases and deaths from the SARS-CoV-2 COVID-19 virus in some countries of Africa has called our attention to the unusual behavior of this disease. Aims: Describe SARS-CoV2 infection and death rates in African countries that participated in an intensive Ivermectin mass campaign carried out to control onchocerciasis and compare them with those of countries that did not participate. Methods: Data from 19 countries that participated in the WHO sponsored African Programme for Onchocerciasis Control (APOC), from 1995 until 2015, intended to treat over 90 million people annually and protect an at-risk population of 115 million, were compared with thirty-five (Non-APOC), countries that were not included. Information was obtained from https://www.worldometers.info/coronavirus/ database. Results After controlling for different factors including the Human Development Index, APOC countries, show statistically significant 28% lower mortality (0.72 IC 95% 0,67-0,78) and 8% lower rate of infection (0.92 IC95% 0,91-0,93) due to COVID-19. Conclusions: The incidence in mortality rates and the number of cases is significantly lower among the APOC countries compared to non-APOC countries. That a mass public health preventive campaign against COVID-19 may have taken place, inadvertently, in some African countries with massive community ivermectin use is an attractive hypothesis. Additional studies are needed to confirm it.

What does the COVID-19 pandemic mean for the next decade of onchocerciasis control and elimination?

BackgroundMass drug administration (MDA) of ivermectin for onchocerciasis has been disrupted by the SARS-CoV-2 (COVID-19) pandemic. Mathematical modelling can help predict how missed/delayed MDA will affect short-term epidemiological trends and elimination prospects by 2030.MethodsTwo onchocerciasis transmission models (EPIONCHO-IBM and ONCHOSIM) are used to simulate microfilarial prevalence trends, elimination probabilities, and age-profiles of Onchocerca volvulus microfilarial prevalence and intensity, for different treatment histories and transmission settings, assuming no interruption, a 1-year (2020) or 2-year (2020–2021) interruption. Biannual MDA or increased coverage upon MDA resumption are investigated as remedial strategies.ResultsProgrammes with shorter MDA histories and settings with high pre-intervention endemicity will be the most affected. Biannual MDA is more effective than increasing coverage for mitigating COVID-19’s impact on MDA. Programmes which had already switched to biannual MDA should be minimally affected. In high transmission settings with short treatment history, a 2-year interruption could lead to increased microfilarial load in children (EPIONCHO-IBM) or adults (ONCHOSIM).ConclusionsProgrammes with shorter (annual MDA) treatment histories should be prioritised for remedial biannual MDA. Increases in microfilarial load could have short- and long-term morbidity and mortality repercussions. These results can guide decision-making to mitigate the impact of COVID-19 on onchocerciasis elimination.