Short report: Semi-quantitative scoring of an immunochromatographic test for circulating filarial antigen

The value of a semi-quantitative scoring of the filarial antigen test (Binax Now Filariasis card test, ICT) results was evaluated during a field survey in. the Republic of Congo. One hundred and thirty-four (134) of 774 tests (17.3%) were clearly positive and were scored 1, 2, or 3; and 11 (1.4%) had questionable results. Wuchereria bancrofti microfilariae (mf) were detected in 41 of those 133 individuals with an ICT test score 1 who also had a night blood smear; none of the 11 individuals with questionable ICT results harbored night mf. Cuzick's test showed a significant trend for higher microfilarial densities in groups with higher ICT scores (P < 0.001). The ICT scores were also significantly correlated with blood mf counts. Because filarial antigen levels provide an indication of adult worm infection intensity, our results suggest that semi-quantitative reading of the ICT may be useful for grading the intensity of filarial infections in individuals and populations

THREE-DIMENSIONAL VISUALIZATION OF THE INTERNAL ARRANGEMENT OF ONCHOCERCAL (ONCHOCERCA VOLVULUS) NODULES USING HIGH-RESOLUTION MAGNETIC RESONANCE IMAGING

International audienceTHREE-DIMENSIONAL VISUALIZATION OF THE INTERNAL ARRANGEMENT OF ONCHOCERCAL (ONCHOCERCA VOLVULUS) NODULES USING HIGH-RESOLUTION MAGNETIC RESONANCE IMAGIN

THREE-DIMENSIONAL VISUALIZATION OF THE INTERNAL ARRANGEMENT OF ONCHOCERCAL (ONCHOCERCA VOLVULUS) NODULES USING HIGH-RESOLUTION MAGNETIC RESONANCE IMAGING

International audienceTHREE-DIMENSIONAL VISUALIZATION OF THE INTERNAL ARRANGEMENT OF ONCHOCERCAL (ONCHOCERCA VOLVULUS) NODULES USING HIGH-RESOLUTION MAGNETIC RESONANCE IMAGIN

Effect of a single standard dose (150-200 mu g/kg) of ivermectin on Loa loa microfilaremia : systematic review and meta-analysis

Background. In central Africa, millions of individuals infected with Loa loa have received the anthelminthic drug ivermectin (IVM) as part of mass drug administration (MDA) campaigns targeting onchocerciasis control or elimination. Nonetheless, the parasitological surveys that are occasionally conducted to evaluate the impact of IVM treatments on Onchocerca volvulus do not include an assessment of the extra benefits of those MDA campaigns on L. loa. Methods. We conducted a systematic review of trials on the effect of a single standard (150-200 mu g/kg) dose of IVM on L. loa microfilarial density (MFD). The dynamics of MFD over 365 days of treatment were described using multilevel regression and latent class modeling. Results. IVM brings about a rapid, dramatic, and sustained decrease, with reduction rates of 60%, 75%, 85%, and 90% on day 1 (D1), D2, D7, and D365, respectively. At D365, no participants (0/238) with an initial MFD of = 20 000 mf/mL presented with an MFD above this value. The main predictor of post-treatment MFD was the pretreatment value, but this post-treatment value varied little between D8 and D365 regardless of the pretreatment level. Conclusions. A single dose of IVM is very effective at substantially reducing L. loa MFD for at least a year, irrespective of the initial level of parasitemia. Individuals treated with IVM are probably not any more at risk of severe adverse events when retreated 1 year later

Loa loa Microfilariae in skin snips : consequences for onchocerciasis monitoring and evaluation in L. loa-endemic areas

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

Loa loa microfilariae in skin snips: consequences for onchocerciasis monitoring and evaluation in L. loa endemic areas

International audienceThe 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

Implications for annual retesting after a test-and-not-treat strategy for onchocerciasis elimination in areas co-endemic with Loa loa infection : an observational cohort study

Background A test-and-not-treat (TaNT) strategy has been developed to prevent people with high concentrations of circulating Loa boa microfilariae (>20 000 microfilariae per mL) developing serious adverse events after ivermectin treatment during mass drug administration to eliminate onchocerciasis. An important question related to cost and programmatic issues is whether annual retesting is required for everyone. We therefore aimed to investigate changes in L boa microfilarial densities during TaNT campaigns run 18 months apart. Methods In this observational cohort study, we assessed the participants of two TaNT campaigns for onchocerciasis. These campaigns, which were run by a research team, together with personnel from the Ministry of Health and community health workers, were done in six health areas (in 89 communities) in Okola health district (Cameroon); the first campaign was run between Aug 10, and Oct 29, 2015, and the second was run between March 7, and May 26, 2017. All individuals aged 5 years and older were invited to be screened for Loa boa microfilaraemia before being offered ivermectin (unless contraindicated). L boa microfilarial density was measured at the point of care using the LoaScope. All those with a L. boa microfilarial density of 20 000 microfilariae per mL or less were offered treatment; in the first 2 weeks of the 2015 campaign, a higher exclusion threshold of 26 000 microfilariae per mL or less was used. At both rounds of the intervention, participants were registered with a paper form, in which personal information were collected. In 2017, we also recorded whether each individual reported participation in the 2015 campaign. The primary outcome, assessed in all participants, was whether L boa microfilarial density was above or below the exclusion threshold (ie, the criteria that guided the decision to treat). Findings In the 2015 TaNT campaign, 26 415 people were censused versus 29 587 people in the 2017 TaNT campaign. All individuals aged 5 years and older without other contraindications to treatment (22842 people in 2015 and 25 421 people in 2017) were invited to be screened for L boa microfilaraemia before being offered ivermectin. In 2015, 16 182 individuals were examined with the LoaScope, versus 18 697 individuals in the same communities in 2017. 344 (2.1%) individuals were excluded from ivermectin treatment because of a high L boa microfilarial density in 2015, versus 283 (1.5%) individuals in 2017 (p99.9%) of 6983 individuals treated with ivermectin in 2015 had L boa microfilariae density below the level associated with neurological serious adverse events. Interpretation Individuals treated with ivermectin do not need to be retested for L boa microfilaraemia before the next treatment, provided that they can be re-identified. This adjusted approach will enable substantial cost savings and facilitate reaching programmatic goals for elimination of onchocerciasis in areas that are co-endemic for loiasis