An isothermal DNA amplification method for detection of Onchocerca volvulus infection in skin biopsies

Lagatie, Ole; Merino, Michelle; Debrah, Linda Batsa; Debrah, Alexander Yaw; Stuyver, Lieven

doi:10.1186/s13071-016-1913-7

Cited by 31 publications

(41 citation statements)

References 48 publications

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“…Evidence showed that more than 120 million people were at risk of onchocerciasis infection in Africa region, of whom 26 million people were infected and over 265,000 people were blind. People who live in fertile land, extensive agricultural farming area, and people who live and settle near to river banks were more vulnerable for onchocerciasis infection [6].…”

Section: Introductionmentioning

confidence: 99%

Prevalence of Onchocerciasis and Associated Factors among Adults Aged ≥ 15 Years in Semen Bench District, Bench Maji Zone, Southwest Ethiopia: Community Based Cross-Sectional Study

Kifle¹,

Woldemichael

Nigatu

2019

Advances in Public Health

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Background. Though onchocerciasis control and elimination through community directed treatment with ivermectin were conducted for the last fifteen years, prevalence of onchocerciasis and factors associated with it in the study area are yet not known. The aim of the current study is to assess prevalence of onchocerciasis and associated factors among adults aged greater than or equal to fifteen years in Semen Bench district, Bench Maji zone, southwest Ethiopia: community based cross-sectional study 2018. Methods. Community based cross-sectional study was conducted on 553 study participants selected by multistage sampling in April 2018. Data were collected using a pretested interviewer-administered questionnaire. Data were entered using EpiData version 3.1 and exported to SPSS version 20 for statistical analysis. Descriptive statistics were done to summarize dependent and independent variables. Bivariate logistic regression was done to select candidate variables. Multivariable logistic regression was performed to identify independent predictors of onchocerciasis infection. Adjusted odds ratios with 95% CI were calculated to assess association and statistical significance, respectively. Confidence interval was used to declare statistical significance. Result. The overall prevalence of onchocerciasis infection in the study area was 6.32%. Age category of 35-44 years (AOR: 13.48, 95%CI: 3.51, 51.76), age of 45 years and above (AOR: 9.41, 95% CI: 2.26, 39.06), male sex (AOR 4.568, 95% C.I: 1.622, 12.861), not being compliant with ivermectin treatment (AOR: 3.804, 95%CI: 1.524, 9.49), and residing at less than 2Km from the river (AOR: 9.15, 95%CI: 3.9, 21.49) were significantly associated with onchocerciasis infection. Conclusion and Recommendation. After more than a decade of treatment with ivermectin, onchocerciasis in the study area is still hypoendemic. Zonal health department and other stakeholders should evaluate therapeutic coverage and community directed treatment with ivermectin in the study area. Zonal health department with other stokeholds should give community based information education communication, giving due attention to older ages, male residents, and those living near the rivers. Further community based study should also be done to identify factors hindering the community compliance with the treatment.

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Section: Introductionmentioning

confidence: 99%

Prevalence of Onchocerciasis and Associated Factors among Adults Aged ≥ 15 Years in Semen Bench District, Bench Maji Zone, Southwest Ethiopia: Community Based Cross-Sectional Study

Kifle¹,

Woldemichael

Nigatu

2019

Advances in Public Health

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“…In endemic localities of RB, communities' hesitation to inhabit and dwell around fertile riverside (bank) is linked with black fly infestation [37][38][39]. Likewise, in this study, living around river basin was an independent determinant for CLTI adherence.…”

Section: Discussionmentioning

confidence: 48%

Determinants of community-led ivermectin treatment adherence for onchocerciasis control in Western Ethiopia: a case-control study

et al. 2020

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Background: Onchocerciasis is an infection of a filarial worm which is endemic in Sub-Saharan Africa, including Ethiopia. Annual mass treatment with high coverage over for a long period of time should lead to a complete interruption of transmission and the ultimate elimination of the parasite. However, in Ethiopia, the required coverage levels were not achieved. Thus, the aim of this study was to identify the possible determinants of onchocerciasis treatment adherence in Assossa District. Methods: A case-control study was conducted among 528 respondents (176 cases and 352 controls). Cases were respondents who took all five doses of treatments, and controls were those who took at most four does of ivermectin treatments (missed at least one or more doses). Structured questionnaire was used for data collection. Each possible factor for treatment adherence, with a P value < 0.2 obtained in the bi-variable logistic regression was entered into the multivariable logistic regression models to control the confounding factors. p value < 0.05 was used as cutoff point for a variable to become a significant determinant of treatment adherence in multivariable logistic regression. Results: Participation in selecting drug distributers [AOR = 2.7, 95%CI (1.7-4.1)], measuring height for dose determination [AOR = 3.6, 95%CI (1.9-6.7)], perceived risk of getting onchocerciasis [AOR = 2.1, 95%CI (1.6-2.7)], living near running water [AOR = 1.7, 95%CI (1.1-2.8)], and perceived needs of support for intake of ivermectin [AOR = 3.2, 95%CI(2.1-4.9)] were independent predictors for t treatment adherence. Conclusions: Treatment adherence was influenced by participation in selecting drug distributers, measuring height for dose determination, perceived risk of getting onchocerciasis, living near running water and perceived needs of support for intake of ivermectin. To improve intake of the drug and its adherence, the community should be empowered to make decisions, and counseling family members and sensitizing those living far from river sides is commendable. Health information about onchocerciasis should be strengthening to increase risk perception.

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“…As shown on gures 4 and 5, as well as tables 5 and 6, the LAMP assay was the most sensitive of the three techniques in the detection of micro laria in all the skin biopsies and at all monitoring time points in both study sites. This therefore implies that in terms of sensitivity, LAMP assay with its reported advantages over actin-qPCR in terms of cost, robustness and simplicity [55][56][57][58][59] could be the most appropriate diagnostic tool to detect the presence of O volvulus infection in humans [22,23,36] as well as monitor the clearance and reappearance of skin Mf following treatment with a micro laricidal compound as observed in this study. However, we also observed that the speci city of LAMP is lower than the actin-qPCR and a very high speci city (≥99%) of a diagnostic technique is usually required for programme evaluation.…”

Section: Discussionmentioning

confidence: 99%

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

Abong

Amambo

Ndongmo

et al. 2020

Preprint

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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.

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An isothermal DNA amplification method for detection of Onchocerca volvulus infection in skin biopsies

Cited by 31 publications

References 48 publications

Prevalence of Onchocerciasis and Associated Factors among Adults Aged ≥ 15 Years in Semen Bench District, Bench Maji Zone, Southwest Ethiopia: Community Based Cross-Sectional Study

Prevalence of Onchocerciasis and Associated Factors among Adults Aged ≥ 15 Years in Semen Bench District, Bench Maji Zone, Southwest Ethiopia: Community Based Cross-Sectional Study

Determinants of community-led ivermectin treatment adherence for onchocerciasis control in Western Ethiopia: a case-control study

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