scholarly journals Encephalopathy Related to Ivermectin Treatment of Onchocerciasis in Loa loa Endemic Areas: Operational Considerations

10.5772/28829 ◽  
2012 ◽  
Author(s):  
Takougang Innocent ◽  
Muteba Daniel
Keyword(s):  
Ivermectin Treatment ◽  
Loa Loa ◽  
Endemic Areas

scholarly journals Feasibility of onchocerciasis elimination using a “test-and-not-treat” strategy in Loa loa co-endemic areas

2020 ◽  
Author(s):  
David J Blok ◽  
Joseph Kamgno ◽  
Sebastien D Pion ◽  
Hugues C Nana-Djeunga ◽  
Yannick Niamsi-Emalio ◽  
...  
Keyword(s):  
Adverse Events ◽  
Drug Administration ◽  
Mass Drug Administration ◽  
Treatment Duration ◽  
Loa Loa ◽  
Serious Adverse Events ◽  
Endemic Areas ◽  
The Individual ◽  
The Impact ◽  
Main Strategy

Abstract Background Mass drug administration (MDA) with ivermectin is the main strategy for onchocerciasis elimination. Ivermectin is generally safe but associated with serious adverse events in individuals with high Loa loa microfilarial densities (MFD). Therefore, ivermectin MDA is not recommended in areas where onchocerciasis is hypo-endemic and L. loa is co-endemic. To eliminate onchocerciasis in those areas, a test-and-not-treat (TaNT) strategy has been proposed. We investigated whether onchocerciasis elimination can be achieved using TaNT and the required duration. Methods We used the individual-based model ONCHOSIM to predict the impact of TaNT on onchocerciasis microfilarial (mf) prevalence. We simulated pre-control mf prevalence levels from 2-40%. The impact of TaNT was simulated under varying levels of participation, systematic non-participation and exclusion from ivermectin due to high L. loa MFD. For each scenario, we assessed the time to elimination, defined as bringing onchocerciasis mf prevalence below 1.4%. Results In areas with 30-40% pre-control mf prevalence, the model predicted that it would take between 14 and 16 years to bring the mf prevalence below 1.4% using conventional MDA, assuming 65% participation. TaNT would increase the time to elimination by up to 1.5 years, depending on the level of systematic non-participation and the exclusion rate. At lower exclusion rates (≤2.5%), the delay would be less than six months. Conclusions Our model predicts that onchocerciasis can be eliminated using TaNT in L. loa co-endemic areas. The required treatment duration using TaNT would be only slightly longer than in areas with conventional MDA, provided that participation is good.

scholarly journals Loa loa Microfilariae in Skin Snips: Consequences for Onchocerciasis Monitoring and Evaluation in L. loa–Endemic Areas

2019 ◽  
Vol 69 (9) ◽  
pp. 1628-1630 ◽  
Author(s):  
Hugues C Nana-Djeunga ◽  
Floribert Fossuo-Thotchum ◽  
Sébastien D Pion ◽  
Cédric B Chesnais ◽  
Joseph Kubofcik ◽  
...  
Keyword(s):  
Diagnostic Testing ◽  
Monitoring And Evaluation ◽  
Molecular Methods ◽  
Onchocerca Volvulus ◽  
Loa Loa ◽  
Endemic Areas ◽  
Skin Snips

Abstract The specificity of skin snips for onchocerciasis diagnoses is considered to be almost 100%. Our molecular methods revealed that microfilariae emerging from skin snips collected from highly microfilaremic Loa loa–infected individuals were largely misidentified as Onchocerca volvulus. This has important implications for onchocerciasis diagnostic testing in Loa-endemic areas.

Three probable cases of Loa loa encephalopathy following ivermectin treatment for onchocerciasis.

1998 ◽  
Vol 58 (4) ◽  
pp. 461-469 ◽  
Author(s):  
M Boussinesq ◽  
P Ngoumou ◽  
J Gardon ◽  
J Kamgno ◽  
N Gardon-Wendel ◽  
...  
Keyword(s):  
Ivermectin Treatment ◽  
Loa Loa

scholarly journals An Integrated District Mapping Strategy for Loiasis to Enable Safe Mass Treatment for Onchocerciasis in Gabon

2021 ◽  
Author(s):  
Sylvie Ntsame Ella ◽  
Kisito Ogoussan ◽  
Katherine Gass ◽  
Lee Hundley ◽  
Peter J. Diggle ◽  
...  
Keyword(s):  
Risk Prediction ◽  
Rapid Test ◽  
Treatment Decisions ◽  
Ivermectin Treatment ◽  
Mass Treatment ◽  
Modeling Tools ◽  
Prediction Tools ◽  
Mapping Strategy ◽  
Mapping Approach ◽  
Endemic Areas

The lack of a WHO-recommended strategy for onchocerciasis treatment with ivermectin in hypo-endemic areas co-endemic with loiasis is an impediment to global onchocerciasis elimination. New loiasis diagnostics (LoaScope; Loa antibody rapid test) and risk prediction tools may enable safe mass treatment decisions in co-endemic areas. In 2017–2018, an integrated mapping strategy for onchocerciasis, lymphatic filariasis (LF), and loiasis, aimed at enabling safe ivermectin treatment decisions, was piloted in Gabon. Three ivermectin-naïve departments suspected to be hypo-endemic were selected and up to 100 adults per village across 30 villages in each of the three departments underwent testing for indicators of onchocerciasis, LF, and loiasis. An additional 67 communities in five adjoining departments were tested for loiasis to extend the prevalence and intensity predictions and possibly expand the boundaries of areas deemed safe for ivermectin treatment. Integrated testing in the three departments revealed within-department heterogeneity for all the three diseases, highlighting the value of a mapping approach that relies on cluster-based sampling rather than sentinel sites. These results suggest that safe mass treatment of onchocerciasis may be possible at the subdepartment level, even in departments where loiasis is present. Beyond valuable epidemiologic data, the study generated insight into the performance of various diagnostics and the feasibility of an integrated mapping approach utilizing new diagnostic and modeling tools. Further research should explore how programs can combine these diagnostic and risk prediction tools into a feasible programmatic strategy to enable safe treatment decisions where loiasis and onchocerciasis are co-endemic.

scholarly journals Assessing Hypoendemic Onchocerciasis in Loa loa Endemic Areas of Southeast Nigeria

2020 ◽  
Vol 103 (6) ◽  
pp. 2328-2335
Author(s):  
Lindsay J. Rakers ◽  
Emmanuel Emukah ◽  
Barminas Kahansim ◽  
Bertram E. B. Nwoke ◽  
Emmanuel S. Miri ◽  
...  
Keyword(s):  
Loa Loa ◽  
Endemic Areas

scholarly journals Projected Number of People With Onchocerciasis–Loiasis Coinfection in Africa, 1995 to 2025

2019 ◽  
Vol 70 (11) ◽  
pp. 2281-2289 ◽  
Author(s):  
Natalie V S Vinkeles Melchers ◽  
Luc E Coffeng ◽  
Michel Boussinesq ◽  
Belén Pedrique ◽  
Sébastien D S Pion ◽  
...  
Keyword(s):  
At Risk ◽  
Adverse Events ◽  
Control Strategies ◽  
Central Africa ◽  
Ivermectin Treatment ◽  
Loa Loa ◽  
Serious Adverse Events ◽  
West And Central Africa ◽  
And Control ◽  
The Impact

Abstract Background Onchocerciasis elimination through mass drug administration (MDA) is hampered by coendemicity of Loa loa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and loiasis prevalence and estimated the number of coinfected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. Methods Focusing on regions with suspected loiasis transmission in 14 countries, we overlaid precontrol maps of loiasis and onchocerciasis prevalence to calculate precontrol prevalence of coinfection by 5 km2 × 5 km2 pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted prevalence of both infections and coinfection for 2015 and 2025, accounting for the impact of MDA with ivermectin. Results The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137 000 people were estimated to also have L. loa hypermicrofilaremia (≥20 000 L. loa mf/mL) in 1995, declining to 31 000 in 2025. In 2025, 92.8% of coinfected cases with loiasis hypermicrofilaremia are predicted to live in hypoendemic areas currently not targeted for MDA. Conclusions Loiasis coinfection is a major concern for onchocerciasis elimination in Africa. We predict that under current strategies, at least 31 000 coinfected people still require treatment for onchocerciasis in 2025 while being at risk of SAEs, justifying continued efforts in research and development for safer drugs and control strategies.

Ocular findings after ivermectin treatment of patients with high Loa loa microfilaremia

2000 ◽  
Vol 7 (1) ◽  
pp. 27-39 ◽  
Author(s):  
Grace Fobi ◽  
Jacques Gardon ◽  
Michel Santiago ◽  
Demanga Ngangue ◽  
Nathalie Gardon-Wendel ◽  
...  
Keyword(s):  
Ivermectin Treatment ◽  
Loa Loa ◽  
Ocular Findings

scholarly journals Strongyloidiasis Outside Endemic Areas: Long-term Parasitological and Clinical Follow-up After Ivermectin Treatment

2018 ◽  
Vol 66 (10) ◽  
pp. 1558-1565 ◽  
Author(s):  
Silvia A Repetto ◽  
Paula Ruybal ◽  
Estela Batalla ◽  
Carlota López ◽  
Vanesa Fridman ◽  
...  
Keyword(s):  
Ivermectin Treatment ◽  
Endemic Areas

Encephalopathy after Ivermectin Treatment in a Patient Infected with Loa Loa and Plasmodium spp.

2008 ◽  
Vol 78 (4) ◽  
pp. 546-551 ◽  
Author(s):  
Joseph Kamgno ◽  
Michel Boussinesq ◽  
Charles D. Mackenzie ◽  
Björn I. Thylefors ◽  
Blaise Nkegoum ◽  
...  
Keyword(s):  
Ivermectin Treatment ◽  
Loa Loa

scholarly journals Unusual localization of blood-borne Loa loa microfilariae in the skin depends on microfilarial density in the blood: Implications for onchocerciasis diagnosis in co-endemic areas

2021 ◽  
Author(s):  
Yannick Niamsi-Emalio ◽  
Hugues C Nana-Djeunga ◽  
Cédric B Chesnais ◽  
Sébastien D S Pion ◽  
Jules B Tchatchueng-Mbougua ◽  
...  
Keyword(s):  
Regression Tree ◽  
Classification And Regression Tree ◽  
Loa Loa ◽  
Immunoglobulin G4 ◽  
East Region ◽  
Antibody Positivity ◽  
Endemic Areas ◽  
Cart Model ◽  
The Relationship

Abstract Background The diagnostic gold standard for onchocerciasis relies on identification and enumeration of (skin-dwelling) Onchocerca volvulus microfilariae (mf) using the skin snip technique (SST). In a recent study, blood-borne Loa loa mf were found by SST in individuals heavily infected with L. loa, and microscopically misidentified as O. volvulus due to their superficially similar morphology. This study investigates the relationship between L. loa microfilarial density (Loa MFD) and the probability of testing SST positive. Methods A total of 1053 participants from the (onchocerciasis and loiasis co-endemic) East Region in Cameroon were tested for: i) Loa MFD in blood samples; ii) O. volvulus presence by SST, and iii) Ig[immunoglobulin]G4 antibody positivity to Ov16 by rapid diagnostic test (RDT). A Classification and Regression Tree (CART) model was used to perform a supervised classification of SST status and identify a Loa MFD threshold above which it is highly likely to find L. loa mf in skin snips. Results Of 1011 Ov16-negative individuals, 28 (2.8%) tested SST positive and 150 (14.8%) were L. loa positive. The range of Loa MFD was 0–85200mf/mL. The CART model subdivided the sample into two Loa MFD classes with a discrimination threshold of 4080 (95% CI: 2180–12240) mf/mL. The probability of being SST positive exceeded 27% when Loa MFD was >4080mf/mL. Conclusions The probability of finding L. loa mf by SST increases significantly with Loa MFD. Skin-snip polymerase chain reaction (PCR) would be useful when monitoring onchocerciasis prevalence by SST in onchocerciasis–loiasis co-endemic areas.

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