scholarly journals Field Evaluation of Deltamethrin and Ivermectin Applications to Cattle on Culicoides Host-Alighting, Blood-Feeding, and Emergence

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 731
Author(s):  
Archie K. Murchie ◽  
Geoff M. Thompson ◽  
Sam Clawson ◽  
Andrew Brown ◽  
Alan W. Gordon ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Lethal Dose ◽  
Field Evaluation ◽  
Blood Feeding ◽  
Ivermectin Treatment ◽  
Sticky Traps ◽  
Obsoletus Group ◽  
The Impact ◽  
Topical Applications ◽  
Spray Applications

The impact of topical applications of deltamethrin and ivermectin to cattle on Culicoides spp. landing and blood-feeding was studied in this work using sticky traps mounted on Friesian heifers’ backs. There was no effect of the insecticides on total numbers of Culicoides trapped or the proportion engorged. Deltamethrin and ivermectin treatment did not prevent blood-feeding on these animals. Deltamethrin did result in significant Culicoides mortality as evidenced by the numbers of dead midges combed from heifers’ upper flanks. The proximity of engorged midges on traps to dead midges in the hair suggests that blood-feeding took place despite midges receiving an ultimately lethal dose of deltamethrin. Ivermectin application resulted in a smaller proportion of nulliparous than parous females caught. There was no significant effect of ivermectin on the numbers of Culicoides that emerged from dung samples (but p was small at 0.095 for the Obsoletus group Culicoides). In cases of suspect animal imports, pour-on or spray applications of deltamethrin could reduce the risk of onward transmission of bluetongue virus.

scholarly journals Onchocerciasis control in Ghana (1974–2016)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nana-Kwadwo Biritwum ◽  
Dziedzom K. de Souza ◽  
Odame Asiedu ◽  
Benjamin Marfo ◽  
Uche Veronica Amazigo ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Vector Control ◽  
Control Strategy ◽  
Financial Support ◽  
Control Programme ◽  
Ivermectin Treatment ◽  
Mobile Community ◽  
The Mean ◽  
The Impact ◽  
Onchocerciasis Control

Abstract Background The control of onchocerciasis in Ghana started in 1974 under the auspices of the Onchocerciasis Control Programme (OCP). Between 1974 and 2002, a combination of approaches including vector control, mobile community ivermectin treatment, and community-directed treatment with ivermectin (CDTI) were employed. From 1997, CDTI became the main control strategy employed by the Ghana OCP (GOCP). This review was undertaken to assess the impact of the control interventions on onchocerciasis in Ghana between 1974 and 2016, since which time the focus has changed from control to elimination. Methods In this paper, we review programme data from 1974 to 2016 to assess the impact of control activities on prevalence indicators of onchocerciasis. This review includes an evaluation of CDTI implementation, microfilaria (Mf) prevalence assessments and rapid epidemiological mapping of onchocerciasis results. Results This review indicates that the control of onchocerciasis in Ghana has been very successful, with a significant decrease in the prevalence of infection from 69.13% [95% confidence interval) CI 60.24–78.01] in 1975 to 0.72% (95% CI 0.19–1.26) in 2015. Similarly, the mean community Mf load decreased from 14.48 MF/skin snip in 1975 to 0.07 MF/skin snip (95% CI 0.00–0.19) in 2015. Between 1997 and 2016, the therapeutic coverage increased from 58.50 to 83.80%, with nearly 100 million ivermectin tablets distributed. Conclusions Despite the significant reduction in the prevalence of onchocerciasis in Ghana, there are still communities with MF prevalence above 1%. As the focus of the GOCP has changed from the control of onchocerciasis to its elimination, both guidance and financial support are required to ensure that the latter goal is met.

scholarly journals Infection of highly insecticide-resistant malaria vector Anopheles coluzzii with entomopathogenic bacteria Chromobacterium violaceum reduces its survival, blood feeding propensity and fecundity

2020 ◽  
Author(s):  
Edounou Jacques Gnambani ◽  
Etienne Bilgo ◽  
Adama Sanou ◽  
Roch K. Dabire ◽  
Abdoulaye Diabate
Keyword(s):  
Burkina Faso ◽  
Post Infection ◽  
Blood Feeding ◽  
Egg Laying ◽  
Chromobacterium Violaceum ◽  
Hatching Rate ◽  
Anopheles Coluzzii ◽  
Potential Candidate ◽  
Mosquito Survival ◽  
The Impact

Abstract Background This is now a concern that malaria eradication will not be achieved without the introduction of novel control tools. Microbiological control might be able to make a greater contribution to vector control in the future. The interactions between bacteria and mosquito make mosquito microbiota really promising from a disease control perspective. Here, we studied the impact of Chromobacterium violaceum infections isolated from both larvae and adult of wild caught Anopheles gambiae s.l. mosquitoes in Burkina Faso on mosquito survival, blood feeding and fecundity propensy. Methods To assess entomopathogenic effects of C. violaceum infection on mosquitoes, three different types of bioassays were performed in laboratory. These bioassays aimed to evaluate the impact of C.violaceum infection on mosquito survival, blood feeding and fecundity, respectively. During bioassays mosquitoes were infected through the well-established system of cotton ball soaked with 6% glucose containing C.violaceum . Results C. violaceum kills pyrethroid resistant mosquitoes An. coluzzii (LT80 of 8.78 days ± 0.18 at 10 8 bacteria cell/ml of sugar meal). Interestingly, this bacterium had other negative effects on mosquito lifespan by significantly reducing (~59%, P<0.001) the mosquito feeding willingness from day 4-post infection (~81% would seek a host to blood feed) to 9- day post infection (22 ± 4.62% would seek a host to blood feed). Moreover, C. violaceum considerably jeopardized the egg laying (~16 eggs laid /mosquitoes with C. violaceum infected mosquitoes vs ~129 eggs laid / mosquitoes with control mosquitoes) and hatching of mosquitoes (A reduction of ~22 % of hatching rate with C. violaceum infected mosquitoes). Compared to the bacterial uninfected mosquitoes, mosquitoes infected with C. violaceum showed indeed significantly higher retention rates of immature eggs and follicles. Conclusion These data showed important properties of Burkina Faso C. violaceum strains , which are highly virulent against insecticide resistant Anopheles coluzzii , and reduce both mosquito blood feeding and fecundity propensities. However, additional studies as the sequencing of C. violaceum genome and the potential toxins secreted will certainly provide useful information render it a potential candidate for the biological control strategies of malaria and other disease vectors.

The National Shipbuilding Research Program Welding Fume Study

2001 ◽  
Vol 17 (01) ◽  
pp. 35-39
Author(s):  
Daniel O. Chute ◽  
Bradley W. Christ
Keyword(s):  
Field Evaluation ◽  
Control Measures ◽  
Welding Fume ◽  
Control Methods ◽  
Exposure Control ◽  
Exposure Limits ◽  
Shipbuilding Industry ◽  
Worker Exposure ◽  
The Cost ◽  
The Impact

This paper presents the results of a study evaluating the impact of anticipated reductions in OSHA worker exposure limits for airborne contaminants, nickel (Ni), manganese (Mn), and hexavalent chromium (Cr6) on the shipbuilding industry. As part of the study field evaluation, air monitoring and data analysis were conducted to measure the effectiveness of a series of exposure control methods including fume extractor guns, ixed fume extraction systems, portable fume extraction systems, low fume welding wires, downdraft/backdraft tables, and fume iltration devices. Six shipyards participated in this study. The study concluded that the cost of compliance increases greatly with lower exposure limits. It was recommended that the shipbuilding industry continue to develop and evaluate feasible control measures in anticipation of revised standards.

scholarly journals ANTI-MYCOBACTERIAL ACTIVITY OF CAPPARIS SPINOSA L. EXTRACT AGAINST CLINICAL ISOLATES OF MYCOBACTERIUM TUBERCULOSIS

2017 ◽  
Vol 10 (8) ◽  
pp. 181 ◽  
Author(s):  
Azadeh Ehsanifar ◽  
Nadia Kazemipoor ◽  
Bahman Fouladi
Keyword(s):  
Methanol Extract ◽  
Lethal Dose ◽  
Reference Sample ◽  
Inhibitory Effect ◽  
Maximum Efficiency ◽  
Clinical Samples ◽  
Health Issues ◽  
Capparis Spinosa ◽  
The Impact ◽  
Microbial Effects

  Objective: Tuberculosis (TB) has been one of the biggest global health issues for decades. Emerging forms of the disease; however, after many years since the discovery of the last effective treatment for this disease, the emerging forms of it have made scientists worried about the disease. Most herbs have anti-microbial properties; however, there was no research on the impact of fruit Capparis spinosa on TB. This study was conducted to evaluate the anti-microbial effects of bacterial C. spinosa.Methods: In this study, methanolic extract at maximum efficiency to maintain existing substances was prepared by the freeze dryer device and to determine the minimum inhibitory concentration of bacteria’s growth. The proportional method was used on 7 clinical samples and one reference sample H37RV with its six concentrations (80-50-25-10-1-0/2 mg/ml). In addition, to determine the effects of plant extracts in combination with rifampin, all samples were tested by the supplement combination or cover combination of these two materials. All tests were performed twice. The methanol extract of the plant at the concentration of 25 mg/mL in all samples has inhibitory effect on the growth.Results: In study, clinical samples with a lethal dose of RIFAMPIN, it was shown that none of the samples have drug resistance. The results have revealed that the methanol extract has an anti-mycobacterial effect.Conclusion: The results of this study indicate that Capparis spinosa possess considerable anti-mycobacterial properties in the laboratory. These results can be used as a background for further future studies on this species.

scholarly journals Field Evaluation of the Dust Impacts from Construction Sites on Surrounding Areas: A City Case Study in China

2019 ◽  
Vol 11 (7) ◽  
pp. 1906 ◽  
Author(s):  
Hui Yan ◽  
Guoliang Ding ◽  
Hongyang Li ◽  
Yousong Wang ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Meteorological Data ◽  
Large Diameter ◽  
Field Evaluation ◽  
Building Construction ◽  
Major Constituent ◽  
Construction Sites ◽  
Pm10 And Pm2.5 ◽  
Surrounding Areas ◽  
The Impact

Construction activities generate a large amount of dust and cause significant impacts on air quality of surrounding areas. Thus, revealing the characteristics of construction dust is crucial for finding the way of reducing its effects. To fully uncover the characteristics of construction dust affecting surrounding areas, this study selected seven representative construction sites in Qingyuan city, China as empirical cases for field evaluation. In the experiment, the up-downwind method was adopted to monitor and collect TSP (total suspended particulate), PM10 and PM2.5 (particulate matter ≤10 µm and 2.5 µm in aerodynamic diameter, respectively) concentrations, meteorological data and construction activities of each site for 2 to 3 days and 18 h in a day. The results show that the average daily construction site makes the surrounding areas’ concentration of TSP, PM10 and PM2.5 increase by 42.24%, 19.76% and 16.27%, respectively. The proportion of TSP, PM10 and PM2.5 in building construction dust is 1, 0.239 and 0.116, respectively. The large diameter particulate matter was the major constituent and the distance of its influence was limited. In addition, construction vehicles were one of the main influencing factors for building construction dust. However, building construction dust was not significantly correlated with any single meteorological factor when it did not change too much. Findings of this research can provide a valuable basis for reducing the impact of building construction dust on surrounding areas.

scholarly journals An Experimental Hut Evaluation of PBO-Based and Pyrethroid-Only Nets against the Malaria Vector Anopheles funestus Reveals a Loss of Bed Nets Efficacy Associated with GSTe2 Metabolic Resistance

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 143 ◽  
Author(s):  
Benjamin D. Menze ◽  
Mersimine F. Kouamo ◽  
Murielle J. Wondji ◽  
Williams Tchapga ◽  
Micareme Tchoupo ◽  
...  
Keyword(s):  
Anopheles Funestus ◽  
Blood Feeding ◽  
Malaria Vectors ◽  
Bed Nets ◽  
Glutathione S Transferase ◽  
Metabolic Resistance ◽  
Experimental Hut ◽  
The Impact ◽  
Long Lasting Insecticidal Nets ◽  
Permanet 3.0

Growing insecticide resistance in malaria vectors is threatening the effectiveness of insecticide-based interventions, including Long Lasting Insecticidal Nets (LLINs). However, the impact of metabolic resistance on the effectiveness of these tools remains poorly characterized. Using experimental hut trials and genotyping of a glutathione S-transferase resistance marker (L119F-GSTe2), we established that GST-mediated resistance is reducing the efficacy of LLINs against Anopheles funestus. Hut trials performed in Cameroon revealed that Piperonyl butoxide (PBO)-based nets induced a significantly higher mortality against pyrethroid resistant An. funestus than pyrethroid-only nets. Blood feeding rate and deterrence were significantly higher in all LLINs than control. Genotyping the L119F-GSTe2 mutation revealed that, for permethrin-based nets, 119F-GSTe2 resistant mosquitoes have a greater ability to blood feed than susceptible while the opposite effect is observed for deltamethrin-based nets. For Olyset Plus, a significant association with exophily was observed in resistant mosquitoes (OR = 11.7; p < 0.01). Furthermore, GSTe2-resistant mosquitoes (cone assays) significantly survived with PermaNet 2.0 (OR = 2.1; p < 0.01) and PermaNet 3.0 (side) (OR = 30.1; p < 0.001) but not for Olyset Plus. This study shows that the efficacy of PBO-based nets (e.g., blood feeding inhibition) against pyrethroid resistant malaria vectors could be impacted by other mechanisms including GST-mediated metabolic resistance not affected by the synergistic action of PBO. Mosaic LLINs incorporating a GST inhibitor (diethyl maleate) could help improve their efficacy in areas of GST-mediated resistance.

scholarly journals Use of kinase inhibitors against schistosomes to improve and broaden praziquantel efficacy

Parasitology ◽  
2020 ◽  
Vol 147 (13) ◽  
pp. 1488-1498
Author(s):  
Sujeevi S. K. Nawaratna ◽  
Donald P. McManus ◽  
Robin B. Gasser ◽  
Paul J. Brindley ◽  
Glen M. Boyle ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Kinase Inhibitors ◽  
Lethal Dose ◽  
Alternative Therapies ◽  
Potential Drug ◽  
Dependent Protein Kinase ◽  
Drug Of Choice ◽  
Dependent Protein ◽  
The Impact

AbstractPraziquantel (PZQ) is the drug of choice for schistosomiasis. The potential drug resistance necessitates the search for adjunct or alternative therapies to PZQ. Previous functional genomics has shown that RNAi inhibition of Ca2+/calmodulin-dependent protein kinase II (CaMKII) gene in Schistosoma adult worms significantly improved the effectiveness of PZQ. Here we tested the in vitro efficacy of 15 selective and non-selective CaMK inhibitors against Schistosoma mansoni and showed that PZQ efficacy was improved against refractory juvenile parasites when combined with these CaMK inhibitors. By measuring CaMK activity and the mobility of adult S. mansoni, we identified two non-selective CaMK inhibitors, Staurosporine (STSP) and 1Naphthyl PP1 (1NAPP1), as promising candidates for further study. The impact of STSP and 1NAPP1 was investigated in mice infected with S. mansoni in the presence or absence of a sub-lethal dose of PZQ against 2- and 7-day-old schistosomula and adults. Treatment with STSP/PZQ induced a significant (47–68%) liver egg burden reduction compared with mice treated with PZQ alone. The findings indicate that the combination of STSP and PZQ dosages significantly improved anti-schistosomal activity compared to PZQ alone, demonstrating the potential of selective and non-selective CaMK/kinase inhibitors as a combination therapy with PZQ in treating schistosomiasis.

Refined experimental design may increase the value of murine models for estimation of bluetongue virus virulence

2020 ◽  
pp. 002367722093005
Author(s):  
Maria Stokstad ◽  
Peter Coetzee ◽  
Mette Myrmel ◽  
Paidamwoyo Mutowembwa ◽  
Estelle H Venter ◽  
...  
Keyword(s):  
Experimental Design ◽  
Response Surface ◽  
Bluetongue Virus ◽  
Reverse Genetics ◽  
Lethal Dose ◽  
Murine Models ◽  
Negative Consequences ◽  
Infectious Dose

Bluetongue is a serious non-contagious vector-borne viral disease in ruminants, causing poor animal welfare and economic consequences globally. Concern has been raised about the development of novel bluetongue virus (BTV) strains and their possibly altered virulence through the process of viral reassortment. Virulence is traditionally estimated in lethal dose 50 (LD50) studies in murine models, but agreement with both in vitro and virulence in ruminants is questionable, and a refined experimental design is needed. Specific reassortants between wild-type and vaccine strains of BTV-1, -6 and -8 have previously been developed by reverse genetics. The aim of the present study was to rank the in vivo virulence of these parental and reassortant BTV strains by calculating LD50 in a murine model by using an experimental design that is new to virology: a between-patient optimised three-level response surface pathway design. The inoculation procedure was intracranial. Fifteen suckling mice were used to establish LD50 for each strain. Three parental and five reassortant virus strains were included. The LD50s varied from of 0.1 (95% confidence interval (CI) 0–0.20) to 3.3 (95% CI 2.96–3.72) tissue culture infectious dose 50/ml. The results support the hypothesis that reassortment in BTV may lead to increased virulence in mice with potential negative consequences for the natural ruminant host. The ranking showed low agreement with in vitro properties and virulence in ruminants according to existing literature. Refined design such as response surface pathway design was found suitable for use in virology, and it introduces significant ethical and scientific improvements.

Towards astrobiological experimental approaches to study planetary UV surface environments

2018 ◽  
Vol 14 (S345) ◽  
pp. 222-226
Author(s):  
Ximena C. Abrevaya ◽  
Martin Leitzinger ◽  
Oscar J. Oppezzo ◽  
Petra Odert ◽  
G. Juan M. Luna ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Laboratory Experiments ◽  
Lethal Dose ◽  
Action Spectrum ◽  
Interdisciplinary Approach ◽  
Accurate Estimation ◽  
Atmospheric Attenuation ◽  
Approaches To Study ◽  
Experimental Approaches ◽  
The Impact

AbstractThe stellar ultraviolet radiation (UVR) has been studied in the last decade and has been found to be an important factor to determine the habitability of planetary surfaces. It is known that UVR can be a constraint for life. However, most of the studies of UVR and habitability have missed some fundamental aspects: i) Accurate estimation of the planetary atmospheric attenuation, ii) The biological inferences used to represent the impact of the stellar UVR on life are theoretical and based on the action spectrum (for DNA or microorganisms) or considering parameters as the “lethal dose” obtained from non-astrobiological experiments. Therefore, the conclusions reached by previous studies about the UVR habitability of planetary bodies may be inaccurate. In this work, we propose how to address these studies in a more accurate way through an interdisciplinary approach that combines astrophysics, microbiology, and photobiology and by the use of specially designed laboratory experiments.

Sign in / Sign up

Export Citation Format

Share Document