Differential susceptibility of Onchocerca volvulus microfilaria to ivermectin in two areas of contrasting history of mass drug administration in Cameroon: relevance of microscopy and molecular techniques for the monitoring of skin microfilarial repopulation within six months of direct observed treatment

Background Ivermectin is an excellent microfilaricide against Onchocerca volvulus. However, in some regions, long term use of ivermectin has resulted in sub-optimal responses to the treatment. More data to properly document the phenomenon in various contexts of ivermectin mass drug administration (IVM-MDA) is needed. Also, there is a need to accurately monitor a possible repopulation of skin by microfilariae following treatment. Skin snip microscopy is known to have a low sensitivity in individuals with light infections, which can be the case following treatment. This study was designed with two complementary objectives: (i) to assess the susceptibility of O. volvulus microfilariae to ivermectin in two areas undergoing IVM-MDA for different lengths of time, and (ii) to document the repopulation of skin by the O. volvulus microfilariae following treatment, using 3 independent diagnostic techniques. Method Identified microfilaridermic individuals were treated with ivermectin and re-examined after 1, 3, and 6 months using microscopy, actin real-time PCR (actin-qPCR) and O-150 LAMP assays. Susceptibility to ivermectin and trends in detecting reappearance of skin microfilariae were determined using three techniques. Microscopy was used as an imperfect gold standard to determine the performance of actin-qPCR and LAMP. Results In Bafia with over 20 years of IVM-MDA, 11/51 (21.6%) direct observe treated microfilaridemic participants were still positive for skin microfilariae after 1 month. In Melong, with 10 years of IVM-MDA, 2/29 (6.9%) treated participants were still positive. The microfilarial density reduction per skin biopsy within one month following treatment was significantly lower in participants from Bafia. In both study sites, the molecular techniques detected higher proportions of infected individuals than microscopy at all monitoring time points. LAMP demonstrated the highest levels of sensitivity and real-time PCR was found to have the highest specificity. Conclusion Patterns in skin mirofilariae clearance and repopulation were established. O. volvulus worms from Bafia with higher number of annual MDA displayed a lower clearance and higher repopulation rate after treatment with ivermectin. Molecular assays displayed higher sensitivity in monitoring O. volvulus microfilaridemia within six months following treatment

Correction to: Differential susceptibility of Onchocerca volvulus microfilaria to ivermectin in two areas of contrasting history of mass drug administration in Cameroon: relevance of microscopy and molecular techniques for the monitoring of skin microfilarial repopulation within six months of direct observed treatment

After publication of the original article [1], the authors identified an error in the author name of Manuel Ritter. The given name and family name were erroneously transposed. The original article has been corrected. (BMC Infectious Diseases, (2020), 20, 1, (726), 10.1186/s12879-020-05444-2

Using Postcolonial Perspectives to Consider Rehabilitation with Children with Disabilities: The Bamenda-Toronto Dialogue

This work is published and distributed by The Critical Institute.This article discusses tensions in children’s rehabilitation that came to light through a series of ‘postcolonial dialogues’ amongst Canadian and Cameroonian participants. We defined ‘tensions’ as conflicts, contrasting ways of seeing things, and/or taken-for-granted ideas that shape issues related to rehabilitation for children with disabilities. These tensions were identified, articulated, and deconstructed through an iterative, multi-phase dialogue among eight individuals who identify as people with disabilities, rehabilitation providers, and/or rehabilitation researchers in Cameroon and Canada. The tensions discussed in this article problematize conceptualizations of disability and of client-centred care, the role of pain as a reinforcement tool in rehabilitation, and assumptions about poverty and religion in the context of rehabilitation practice. We present this synthesis to achieve several aims: (1) to provide multiple ways for rehabilitation providers and others to better understand these particular substantive issues; (2) to model the use of a critical lens as an approach for thinking about rehabilitation that promotes reflective and deliberate practice and that can be applied across contexts; and, (3) to promote dialogue about postcolonial and other critical perspectives on rehabilitation with children and with other groups

Concordance between Ov16 rapid diagnostic test(RDT) and Ov16 enzyme-linked immunosorbent assay (ELISA) for the diagnosis of onchocerciasis in areas of contrasting endemicity in cameroon

The diagnosis of onchocerciasis in endemic areas has been demanding given the need to replace the invasive skin snip method with a more sensitive and specific rapid point-of-contact tool. Filarial antigen detection tests are better alternative methods in diagnosing Onchocercal infections, as they detect infections and could be used to monitor transmission in endemic areas following mass drug administration. With the shift in paradigme from control to elimination, a rapid point- of-contact tool is required to support elimination programs. This was a cross-sectional, community-based study conducted in 50 villages selected from six health districts using a systematic sampling technique. Individuals ≥17 years who had lived in the community for a duration of 5 years and above provided blood specimens for IgG4 antibodies testing against O. volvulus antigens. Data were analyzed using SPSS v.20 and expectation maximization to classify optical densities for positive and negative samples from ELISA results. The kappa statistics was used to measure the level of agreement between the two tests. In a total of 5001 participants which were recruited for the study, 4416 (88.3%) participant samples passed the plate quality control criteria and were considered for the test comparison analysis. Out of the 4416 participants, 292 (6.6%) tested positive with Ov16 RDT and 310 (7.0%) with Ov16 ELISA. All those who tested positive with the rapid test agreed positive with ELISA. The overall percentage agreement was 99.2%, the Kappa score of 0.936. The results obtained indicate an excellent agreement between ELISA and RDT as measured by kappa (0.936) which was statistically significant (P < 0.001). Our experience with the Ov16 ELISA biplex rapid test was favorable. However, the Ov16 RDT test may be more appropriate to use in remote areas for the point diagnosis of onchocerciasis in view towards achieving elimination in Africa