1.8 Lethal and sublethal effects of several formulations of azadirachtin on IPM Impact R&D colonies of the bumblebee Bombus terrestris (Hymenoptera: Apidae)

The effects of different dose rates of the most important commercially available formulations of azadirachtin and technical powder of azadirachtin were tested on Bombus terrestris, using a new laboratory method on full standardised IPM Impact R&D colonies, starting with a mother queen and 20 callows. The maximum field recommended concentration (MFRC) was applied in the first series of tests through topical, oral pollen and oral sugar water treatment. A sequential dilution testing scheme was used, by decreasing the dose rate each time with 1/10 of the concentration of the previous trial, if triggered, until no significant effects were recorded any more. The survival of the mother queen and initial workers, the total number of formed workers/drones at the end of the test and the number of new born gynes and queen brood were determined as the most important end points. For the evaluation of the results the data were calculated and categorized in the IOBC side-effect classes, used for laboratory trials.This study confirms the practical experience and the previous laboratory trials that no negative toxic or sublethal effects may occur in practice with legally registered formulations of azadirachtin on Bombus terrestris while spraying this botanical insecticide at the recommended and authorised dose rates.Furthermore, during this research study it was found that an illegal formulation of azadirachtin, based on a naphta petroleum which has been withdrawn several years before the study was carried out, was used in the study of Barbosa, W.F., De Meyer, L., Guedes, R.N.C. and Smagghe, G. (2015). Analysis of two samples of this applied formulation, in EU and USA laboratories, proved that only a limited amount of azadirachtin -about half of the indicated amount- was contained, while a chlorpyrifos contamination was traced in the formulation.The effects of different dose rates of the most important commercially available formulations of azadirachtin and technical powder of azadirachtin were tested on Bombus terrestris, using a new laboratory method on full standardised IPM Impact R&D colonies, starting with a mother queen and 20 callows. The maximum field recommended concentration (MFRC) was applied in the first series of tests through topical, oral pollen and oral sugar water treatment. A sequential dilution testing scheme was used, by decreasing the dose rate each time with 1/10 of the concentration of the previous trial, if triggered, until no significant effects were recorded any more. The survival of the mother queen and initial workers, the total number of formed workers/drones at the end of the test and the number of new born gynes and queen brood were determined as the most important end points. For the evaluation of the results the data were calculated and categorized in the IOBC side-effect classes, used for laboratory trials.This study confirms the practical experience and the previous laboratory trials that no negative toxic or sublethal effects may occur in practice with legally registered formulations of azadirachtin on Bombus terrestris while spraying this botanical insecticide at the recommended and authorised dose rates.Furthermore, during this research study it was found that an illegal formulation of azadirachtin, based on a naphta petroleum which has been withdrawn several years before the study was carried out, was used in the study of Barbosa, W.F., De Meyer, L., Guedes, R.N.C. and Smagghe, G. (2015). Analysis of two samples of this applied formulation, in EU and USA laboratories, proved that only a limited amount of azadirachtin -about half of the indicated amount- was contained, while a chlorpyrifos contamination was traced in the formulation

Implementation and evaluation of the Presto combined qualitative real-time assay for <i>Chlamydia trachomatis</i> and <i>Neisseria gonorrhoeae</i> in Rwanda.

BackgroundThe Presto combined qualitative real-time assay for Chlamydia trachomatis and Neisseria gonorrhoeae (Presto CT/NG PCR assay) is appealing for developing countries, because it can be used with multiple DNA extraction methods and polymerase chain reaction (PCR) platforms.ObjectivesThe objective of the study was to implement and evaluate the Presto CT/NG PCR assay at the National Reference Laboratory (NRL) in Kigali, Rwanda, where no real-time PCR assays for the detection of C. trachomatis or N. gonorrhoeae were available.MethodsThe Presto CT/NG PCR assay was first evaluated at the Institute of Tropical Medicine (ITM) in Antwerp, Belgium. Next, NRL laboratory technicians were trained to use the assay on their ABI PRISM 7500 real-time PCR instrument and their competencies were assessed prior to trial initiation. During the trial, endocervical swabs were tested at the NRL, with bi-monthly external quality control testing monitored by the ITM. The final NRL results were evaluated against extended gold standard testing at the ITM, consisting of the Abbott m2000 RealTime System with confirmation of positive results by an in-house real-time PCR assay for C. trachomatis or N. gonorrhoeae.ResultsOf the 192 samples analysed using the Presto assay at the NRL, 16 samples tested positive for C. trachomatis and 17 tested positive for N. gonorrhoeae; four of these were infected with both. The sensitivity and specificity of the Presto assay were 93.3% (95% confidence interval [CI]: 68.1% - 99.8%) and 99.4% (95% CI: 96.8% - 100%) for C. trachomatis and 100% (95% CI: 76.8% - 100%) and 98.8% (95% CI: 95.8% - 99.9%) for N. gonorrhoeae.ConclusionC. trachomatis and N. gonorrhoeae testing with the Presto assay was feasible in Kigali, Rwanda, and good performance was achieved.KeywordsqPCR; Chlamydia trachomatis; Neisseria gonorrhoeae

Evaluation of Convalescent Plasma for Ebola Virus Disease in Guinea

: In the wake of the recent outbreak of Ebola virus disease (EVD) in several African countries, the World Health Organization prioritized the evaluation of treatment with convalescent plasma derived from patients who have recovered from the disease. We evaluated the safety and efficacy of convalescent plasma for the treatment of EVD in Guinea. : In this nonrandomized, comparative study, 99 patients of various ages (including pregnant women) with confirmed EVD received two consecutive transfusions of 200 to 250 ml of ABO-compatible convalescent plasma, with each unit of plasma obtained from a separate convalescent donor. The transfusions were initiated on the day of diagnosis or up to 2 days later. The level of neutralizing antibodies against Ebola virus in the plasma was unknown at the time of administration. The control group was 418 patients who had been treated at the same center during the previous 5 months. The primary outcome was the risk of death during the period from 3 to 16 days after diagnosis with adjustments for age and the baseline cycle-threshold value on polymerase-chain-reaction assay; patients who had died before day 3 were excluded. The clinically important difference was defined as an absolute reduction in mortality of 20 percentage points in the convalescent-plasma group as compared with the control group. : A total of 84 patients who were treated with plasma were included in the primary analysis. At baseline, the convalescent-plasma group had slightly higher cycle-threshold values and a shorter duration of symptoms than did the control group, along with a higher frequency of eye redness and difficulty in swallowing. From day 3 to day 16 after diagnosis, the risk of death was 31% in the convalescent-plasma group and 38% in the control group (risk difference, -7 percentage points; 95% confidence interval [CI], -18 to 4). The difference was reduced after adjustment for age and cycle-threshold value (adjusted risk difference, -3 percentage points; 95% CI, -13 to 8). No serious adverse reactions associated with the use of convalescent plasma were observed. : The transfusion of up to 500 ml of convalescent plasma with unknown levels of neutralizing antibodies in 84 patients with confirmed EVD was not associated with a significant improvement in survival. (Funded by the European Union's Horizon 2020 Research and Innovation Program and others; ClinicalTrials.gov number, NCT02342171.).<br/

Prevalence and incidence estimation of HSV-2 by two IgG ELISA methods among South African women at high risk of HIV.

Previous comparison studies of the Kalon and HerpeSelect 2 ELISA IgG assays on sub-Saharan samples have found differences in the sensitivity and specificity of these assays. Using longitudinal samples from an HIV prevention study, we compared both assays and determined the HSV-2 prevalence and incidence in a South African young female population at elevated risk of acquiring HIV.Samples at baseline were tested in both assays using the manufacturers' guidelines (cut-off > 1.10). When non-reactive in one assay, the final visit samples were tested to determine the incidence rate. Using correlation and regression analyses, the intra- and inter-assay variabilities were assessed.The prevalence rate was 41.1% and 44.9% for Kalon and HerpeSelect using the manufacturer guidelines, respectively. Agreement between the two tests were high (kappa = 0.92). The original optical density values of both assays were highly correlated (R = 0.94), but the calibrator and correspondingly cut-off index values differed between the assays. Lowering the index value cut-off for the Kalon assay by 40% (to 0.66) resulted in a HSV-2 prevalence of 43.2%, and increased agreement between the assays (to kappa = 0.96). The incidence rate was 16.3/100 Person Years using the lower cut-off for the Kalon assay.In this longitudinal study, we showed that the performance of the two assays was very similar. After lowering the cut-off for the Kalon assay to 0.66 early infections were detected without impairing its specificity. The prevalence and incidence rates are in line with previously described rates for sub-Saharan African cohorts

Sexually Transmitted Infections and Associated Risk Factors Among Male Clients of Sex Workers:A Cross-Sectional Pilot Project in Antwerp, Belgium

Introduction: Prevalence of sexually transmitted infections (STIs) is increasing in Belgium in recent years. Clients of sex workers form a key population for acquisition of STIs, due to their sexual relations, with or without a condom, with sex workers. STI testing uptake is low among clients of sex workers, and prevalence of STIs remains to be investigated in Belgium. Therefore, we offered STI-testing to clients of sex workers during outreach sessions in Antwerp. Methods: Time location sampling (TLS) was used to improve representativeness of the sample during ten test sessions in the red light district, Antwerp in May and September 2019 by using a passive approach. Individuals that were interested to get tested for STIs could enter the study. Participants completed an online survey and samples for STI testing were collected. Testing included HIV, syphilis, Chlamydia trachomatis (Ct) and Neisseria gonorrhoeae (Ng). Test results were communicated via a cell phone message (for negative test results) or by phone (for positive test results). Results: In total, 154 male clients of sex workers with a median age of 38 participated. A total of eight Ct and one Ng infections were detected. TLS analysis revealed a Ct/Ng prevalence of 8.2%. No new HIV nor syphilis infections were detected. Using univariate analysis, testing positive for STI was associated with younger age and anorectal sex with a sex worker. Using multivariate analysis, an STI-positive test result was associated with being younger, having non-Belgian nationality, and being in a relationship. Conclusion: Our study found a substantial prevalence of Ct/Ng which highlights the need for sensitization and facilitation of STI testing among clients of sex workers. It is difficult to compare results due to the lack of reference material. Moreover, our relatively small convenience sample limits generalizability of results. However, phone counseling (for positive test results) was accepted, linkage to care was provided, and partner notification was facilitated.</p

Evaluation of an enzymatic Chlamydia trachomatis point-of-care rapid assay in Rwanda: the BioChekSwab Rapid Test

Objectives: We evaluated the performance of an enzymatic point-of-care rapid test for Chlamydia trachomatis (CT) (the BioChekSwab CT Rapid Test, EnZtek Diagnostics, Rio Vista, California, USA), which detects CT's Peptidase 123CBV enzyme and provides a result 15 min after specimen collection. Methods: Two endocervical swabs, including one BioChekSwab, per person were obtained from 137 women who participated in a reproductive health study in Rwanda. The BioChekSwab was processed according to the manufacturer's instructions. A substrate was squirted over the swab by the study physician immediately after collection, and another reagent was released over the swab tip at arrival in the laboratory. The test was considered positive if a blue colour developed within 2 min. The other regular flocked endocervical swab was processed at the Institute of Tropical Medicine (ITM), Belgium, using a testing algorithm: Abbott RealTime CT/Neisseria gonorrhoeae (NG) assay with the confirmation of positive results by an in-house real-time PCR assay. Results: Of the 137 women, nine were CT positive by the testing algorithm. All nine positive results were missed by the BioChekSwab assay and four false-positive results were obtained. The sensitivity was therefore 0% (95% CI 0% to 33.6%) and the specificity was 96.9% (95% CI 92.2% to 99.1%). Conclusions: The BioChekSwab Rapid Test, although ISO13485 certified and Conformitée Européenne (CE) labelled, lacked any sensitivity in our setting.</p

Evaluation of an enzymatic Chlamydia trachomatis point-of-care rapid assay in Rwanda: the BioChekSwab Rapid Test

Objectives: We evaluated the performance of an enzymatic point-of-care rapid test for Chlamydia trachomatis (CT) (the BioChekSwab CT Rapid Test, EnZtek Diagnostics, Rio Vista, California, USA), which detects CT's Peptidase 123CBV enzyme and provides a result 15 min after specimen collection. Methods: Two endocervical swabs, including one BioChekSwab, per person were obtained from 137 women who participated in a reproductive health study in Rwanda. The BioChekSwab was processed according to the manufacturer's instructions. A substrate was squirted over the swab by the study physician immediately after collection, and another reagent was released over the swab tip at arrival in the laboratory. The test was considered positive if a blue colour developed within 2 min. The other regular flocked endocervical swab was processed at the Institute of Tropical Medicine (ITM), Belgium, using a testing algorithm: Abbott RealTime CT/Neisseria gonorrhoeae (NG) assay with the confirmation of positive results by an in-house real-time PCR assay. Results: Of the 137 women, nine were CT positive by the testing algorithm. All nine positive results were missed by the BioChekSwab assay and four false-positive results were obtained. The sensitivity was therefore 0% (95% CI 0% to 33.6%) and the specificity was 96.9% (95% CI 92.2% to 99.1%). Conclusions: The BioChekSwab Rapid Test, although ISO13485 certified and Conformitée Européenne (CE) labelled, lacked any sensitivity in our setting.</p

Lymphogranuloma venereum is on the rise in Belgium among HIV negative men who have sex with men: surveillance data from 2011 until the end of June 2017

Abstract Background The number of cases of Lymphogranuloma venereum (LGV) is increasing in Europe. The described epidemic is mostly confined to HIV positive men who have sex with men (MSM). However, dissemination of LGV from HIV positive to HIV negative MSM could take place due to the implementation of pre-exposure prophylaxis (PrEP) and subsequent possible decrease in condom use. We describe here the LGV epidemiology in Belgium before the PrEP-era, starting from 2011 up to the end of the first half of 2017. Methods A descriptive analysis of the socio-demographic and clinical characteristics of all LGV cases was performed. Fisher’s exact test was used to compare symptomatic to asymptomatic patients. Logistic regression models were used to check for trends over time for: number of LGV cases, HIV status and symptoms. Results The number of LGV cases rose by a factor four, from 21 in 2011 to 88 in 2016, and regression models showed a positive trend estimate of 14% increase per half year (p < 0.001). LGV decreased among HIV positive cases (odds ratio (OR): 0.79, p < 0.001) and increased among HIV negative cases (OR: 1.27, p < 0.001). In addition, a rise in the number of asymptomatic LGV cases (6.7%) was observed (OR:1.39, p = 0.047). Asymptomatic cases were also less likely to be HIV (p = 0.046) or Hepatitis C positive (p = 0.027). Conclusions The rise of LGV in HIV negative MSM has now been documented. If we aim to halt the epidemic in HIV negative MSM, future public health strategies should include LGV testing of all Chlamydia trachomatis positive samples from MSM