Loiasis — a neglected and under-estimated affliction: endemicity, morbidity and perceptions in eastern Cameroon

Takougang, Innocent; Meli, Jean; Lamlenn, Samson B.; Tatah, Peter; Ntep, M.

doi:10.1179/136485907x154511

Cited by 38 publications

(26 citation statements)

References 16 publications

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“…The RAPLOA method is based on the history of clinical manifestations and largely depends on the appreciation of the eye worm phenomenon by the members of a community. The results of our validation study confirmed previous observations that the experience of eye worm migration is well known by members of endemic communities irrespective of their cultures and dialects [10,23,24] and that they have descriptive local names for the phenomenon. The subconjunctival migration of adult L. loa is a spectacular phenomenon in endemic communities, which are often located far from any health facility.…”

Section: Discussionsupporting

confidence: 88%

Validation of the rapid assessment procedure for loiasis (RAPLOA) in the democratic republic of Congo

et al. 2012

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BackgroundA simple method called RAPLOA, to rapidly assess what proportion of people in a community are infected with L. loa and hence which communities are at high risk of severe adverse reactions following ivermectin treatment, was developed in Cameroon and Nigeria. The method needed further validation in other geographical and cultural contexts before its application in all endemic countries. The present study was designed to validate RAPLOA in two regions in the North East and South West of the Democratic Republic of Congo.MethodsIn each study region, villages were selected from different bio-ecological zones in order to cover a wide range of loiasis endemicity. In each selected community, 80 people above the age of 15 years were interviewed for a history of eye worm (migration of adult L. loa under the conjunctiva of the eye) and parasitologically examined for the presence and intensity of L. loa infection. In total, 8100 individuals from 99 villages were enrolled into the study.ResultsThe results confirmed the findings of the original RAPLOA study: i) the eye worm phenomenon was well-known in all endemic areas, ii) there was a clear relationship between the prevalence of eye worm history and the prevalence and intensity of L. loa microfilaraemia, and iii) using a threshold of 40%, the prevalence of eye worm history was a sensitive and specific indicator of high-risk communities.ConclusionFollowing this successful validation, RAPLOA was recommended for the assessment of loiasis endemicity in areas targeted for ivermectin treatment by lymphatic filariasis and onchocerciasis control programmes.

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Section: Discussionsupporting

confidence: 88%

Validation of the rapid assessment procedure for loiasis (RAPLOA) in the democratic republic of Congo

et al. 2012

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“…This is consistent with a previous report from endemic areas. 15 Although Calabar swellings typically appear on extremities, 3,13 some patients experienced swellings on other parts of the body: swellings on the eyelid were seen more frequently than that on the upper arms in this series.…”

Section: Discussionmentioning

confidence: 57%

Clinical Features of Imported Loiasis: A Case Series from the Hospital for Tropical Diseases, London

Saito

Armstrong

Boadi

et al. 2015

The American Society of Tropical Medicine and Hygiene

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Abstract. We retrospectively analyzed the background, clinical features, and treatment response of 50 cases of imported loiasis who presented between 2000 and 2014 to the Hospital for Tropical Diseases (HTD), London, United Kingdom. Of them, 29 were migrants from, and 21 were visitors to, countries where the disease is endemic. Clinical features differed between these groups. Migrants experienced fewer Calabar swellings (odds ratio [OR] = 0.12), more eye worm (OR = 3.4), more microfilaremia (OR = 3.5), lower filarial antibody levels, and lower eosinophil counts (P < 0.05 for all tests). Among 46 patients who were started on treatment at HTD, 33 (72%) received diethylcarbamazine (DEC) monotherapy as first-line treatment, and among 26 patients who were followed up after treatment, seven (27%) needed a second course of treatment. There were 46 courses of treatment with DEC, and 20 (43%) of them had reactions. All patients with microfilaremia > 3,000 microfilariae/mL and all those with an elevated C-reactive protein (CRP) (≥ 5 mg/L) before treatment had reactions (P = 0.10 and P = 0.01, respectively). These data suggest that monotherapy with DEC may not be the optimal treatment for patients with loiasis, particularly for those with a high microfilarial load.

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“…Although the overwhelming majority of L. loainfected individuals are clinically asymptomatic, Calabar swelling (transient, localized angioedema), and the subconjunctival migration of an adult worm ("eyeworm") are the most common clinical manifestations (3)(4)(5). Rarely, nephropathy, cardiomyopathy, retinopathy, neuropsychiatric complications, and encephalopathy (6)(7)(8)(9)(10)(11)(12) can occur as a consequence of chronic infection.…”

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confidence: 99%

Loop-Mediated Isothermal Amplification for Rapid and Semiquantitative Detection of Loa loa Infection

et al. 2014

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cRapid and accurate tests are currently needed to identify individuals with high levels of Loa loa microfilaria (mf), so that these individuals may be excluded from mass ivermectin administration campaigns against onchocerciasis and lymphatic filariasis being conducted in areas where Onchocerca volvulus, Wuchereria bancrofti, and L. loa are coendemic. To address this need, colorimetric loop-mediated isothermal amplification (LAMP) assays targeting the L. loa-specific gene sequences LLMF72 and LLMF342 were developed for the detection and quantification of L. loa microfilaremia. Both LAMP assays were highly specific (100%) for L. loa infection compared to the absence of infection or infection with related filarial pathogens. The LLMF72-based LAMP assay showed greater analytic sensitivity (limit of detection, 0.1 pg/ml of genomic DNA [gDNA] and/or 5 mf/ml) than the LLMF342-based LAMP assay (10 pg/ml of gDNA and/or 50 mf/ml), and its analytic sensitivity was similar to that of LLMF72-based quantitative PCR (qPCR). A high level of correlation was observed between microfilaria counts as determined by LLMF72-based qPCR and time to positivity by the LAMP assay, and performance measures of sensitivity, specificity, and positive and negative predictive values were similar for both assays when applied to field-collected clinical samples. By simply varying the run time, the LAMP assay was able to accurately distinguish individuals at risk for serious adverse events (SAEs) after exposure to ivermectin, using thresholds of >5,000 mf/ml and >30,000 mf/ml as indicators of increasing levels of risk. In summary, LLMF72 LAMP represents a new molecular diagnostic tool that is readily applicable as a point-of-care method for L. loa microfilarial detection and quantification in resource-limited countries where L. loa infection is endemic.

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Loiasis — a neglected and under-estimated affliction: endemicity, morbidity and perceptions in eastern Cameroon

Cited by 38 publications

References 16 publications

Validation of the rapid assessment procedure for loiasis (RAPLOA) in the democratic republic of Congo

Validation of the rapid assessment procedure for loiasis (RAPLOA) in the democratic republic of Congo

Clinical Features of Imported Loiasis: A Case Series from the Hospital for Tropical Diseases, London

Loop-Mediated Isothermal Amplification for Rapid and Semiquantitative Detection of Loa loa Infection

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