scholarly journals Laboratory evaluation of molecular xenomonitoring using mosquito and tsetse fly excreta/feces to amplify Plasmodium, Brugia, and Trypanosoma DNA

2020 ◽  
Vol 3 ◽  
pp. 1734
Author(s):  
Nils Pilotte ◽  
Darren A.N. Cook ◽  
Joseph Pryce ◽  
Michael F. Zulch ◽  
Corrado Minetti ◽  
...  
Keyword(s):  
Large Scale ◽  
Pathogen Detection ◽  
Mosquito Species ◽  
Digital Pcr ◽  
Tsetse Fly ◽  
Laboratory Evaluation ◽  
Tsetse Flies ◽  
Successful Implementation ◽  
Pilot Studies ◽  
Molecular Xenomonitoring

Background:  Results from an increasing number of studies suggest that mosquito excreta/feces (E/F) testing has considerable potential to serve as a supplement for traditional molecular xenomonitoring techniques. However, as the catalogue of possible use-cases for this methodology expands, and the list of amenable pathogens grows, a number of fundamental methods-based questions remain. Answering these questions is critical to maximizing the utility of this approach and to facilitating its successful implementation as an effective tool for molecular xenomonitoring. Methods:  Utilizing E/F produced by mosquitoes or tsetse flies experimentally exposed to Brugia malayi, Plasmodium falciparum, or Trypanosoma brucei brucei, factors such as limits of detection, throughput of testing, adaptability to use with competent and incompetent vector species, and effects of additional blood feedings post parasite-exposure were evaluated.  Two platforms for the detection of pathogen signal (quantitative real-time PCR and digital PCR (dPCR)) were also compared, with strengths and weaknesses examined for each.       Results:  Experimental results indicated that high throughput testing is possible when evaluating mosquito E/F for the presence of either B. malayi or P. falciparum from both competent and incompetent vector mosquito species.  Furthermore, following exposure to pathogen, providing mosquitoes with a second, uninfected bloodmeal did not expand the temporal window for E/F collection during which pathogen detection was possible.  However, this collection window did appear longer in E/F collected from tsetse flies following exposure to T. b. brucei.  Testing also suggested that dPCR may facilitate detection through its increased sensitivity.  Unfortunately, logistical obstacles will likely make the large-scale use of dPCR impractical for this purpose. Conclusions:  By examining many E/F testing variables, expansion of this technology to a field-ready platform has become increasingly feasible.  However, translation of this methodology from the lab to the field will first require field-based pilot studies aimed at assessing the efficacy of E/F screening.

scholarly journals Laboratory evaluation of molecular xenomonitoring using mosquito excreta/feces to amplify Plasmodium, Brugia, and Trypanosoma DNA

2019 ◽  
Vol 3 ◽  
pp. 1734 ◽  
Author(s):  
Nils Pilotte ◽  
Darren A.N. Cook ◽  
Joseph Pryce ◽  
Michael F. Zulch ◽  
Corrado Minetti ◽  
...  
Keyword(s):  
Large Scale ◽  
Pathogen Detection ◽  
Mosquito Species ◽  
Digital Pcr ◽  
Laboratory Evaluation ◽  
Tsetse Flies ◽  
Successful Implementation ◽  
Pilot Studies ◽  
Increased Sensitivity ◽  
Molecular Xenomonitoring

Background:  Results from an increasing number of studies suggest that mosquito excreta/feces (E/F) testing has considerable potential to serve as a supplement for traditional molecular xenomonitoring techniques. However, as the catalogue of possible use-cases for this methodology expands, and the list of amenable pathogens grows, a number of fundamental methods-based questions remain. Answering these questions is critical to maximizing the utility of this approach and to facilitating its successful implementation as an effective tool for molecular xenomonitoring. Methods:  Utilizing E/F produced by mosquitoes or tsetse flies experimentally exposed to Brugia malayi, Plasmodium falciparum, or Trypanosoma brucei brucei, factors such as limits of detection, throughput of testing, adaptability to use with competent- and incompetent-vector species, and effects of additional blood feedings post parasite-exposure were evaluated.  Two platforms for the detection of pathogen signal (quantitative real-time PCR and digital PCR [dPCR]) were also compared, with strengths and weaknesses examined for each.       Results:  Experimental results indicated that high throughput testing is possible when evaluating mosquito E/F for the presence of either B. malayi or P. falciparum from both competent- and incompetent-vector mosquito species.  Furthermore, following exposure to pathogen, providing mosquitoes with a second, uninfected bloodmeal did not expand the temporal window for E/F collection during which pathogen detection was possible.  However, this collection window did appear longer in E/F collected from tsetse flies following exposure to T. b. brucei.  Testing also suggested that dPCR may facilitate detection through its increased sensitivity.  Unfortunately, logistical obstacles will likely make the large-scale use of dPCR impractical for this purpose. Conclusions:  By examining many E/F testing variables, expansion of this technology to a field-ready platform has become increasingly feasible.  However, translation of this methodology from the lab to the field will first require the completion of field-based pilot studies aimed at assessing the efficacy of E/F screening.

scholarly journals Apparent density, trypanosome infection rates and host preference of tsetse flies in the sleeping sickness endemic focus of Northwestern Uganda

2020 ◽  
Author(s):  
Robert Opiro ◽  
Robert Opoke ◽  
Harriet Angwech ◽  
Esther Nakafu ◽  
Francis A. Oloya ◽  
...  
Keyword(s):  
Infection Rate ◽  
Apparent Density ◽  
Blood Meal ◽  
Nested Pcr ◽  
Large Scale ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Trypanosome Species ◽  
Infection Rates ◽  
Monitor Lizard

Abstract Background: African trypanosomiasis, caused by protozoa of the genus Trypanosoma and transmitted by the tsetse fly, is a serious parasitic disease of humans and animals. Reliable data on the vector distribution, feeding preference and the trypanosome species they carry is pertinent to planning sustainable control strategies.Methodology: We deployed 109 biconical traps in 10 villages in two districts of northwestern Uganda to obtain information on the apparent density, infection rates and blood meal sources of tsetse flies. A subset (272) of the collected samples was analyzed for detection of trypanosomes species and sub-species using a nested PCR protocol based on primers amplifying the Internal Transcribed Spacer (ITS) region of ribosomal DNA. 34 blood-engorged adult tsetse midguts were analyzed for blood meal sources by sequencing of the mitochondrial cytochrome c oxidase 1 (COI) and cytochrome b (cytb) genes. Results: Out of the 109 traps deployed, we captured 622 Glossina fuscipes fuscipes tsetse flies (269 males and 353 females). Apparent density (AD) ranged from 0.6 to 3.7 flies/trap/day in the two districts. 29 (10.7%) of the flies were infected with one or more trypanosome species. Infection rate was not significantly associated with neither age group (χ2 = 5.001, df=2, 0.082), sex of the fly (χ2 = 0.099, df = 1, p = 0.753), district of origin (χ2= 0.629, df = 1, p = 0.428) nor village (χ2= 9.252, df = 9, p = 0.414). Nested PCR revealed several species of trypanosomes: T. vivax (6.62%), T. congolense (2.57%), and T. brucei and T. simiae each at 0.73%. Blood meal analyses revealed five principal vertebrate hosts, namely, cattle (Bos taurus), humans (Homo sapiens), Nile monitor lizard (Varanus niloticus), African mud turtle (Pelusio schapini) and the African Savanna elephant (Loxodonta africana).Conclusion: We found a moderately high infection rate of 10.78%, with all infections attributed to trypanosome species that are causative agents for the animal disease only. However, more validation using large-scale passive and active screening of human and tsetse samples should be done. Cattle and humans appear to be the most important tsetse hosts in the region and should be considered in the design of interventions.

scholarly journals Apparent density, trypanosome infection rates and host preference of tsetse flies in the sleeping sickness endemic focus of northwestern Uganda

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Robert Opiro ◽  
Robert Opoke ◽  
Harriet Angwech ◽  
Esther Nakafu ◽  
Francis A. Oloya ◽  
...  
Keyword(s):  
Infection Rate ◽  
Apparent Density ◽  
Blood Meal ◽  
Nested Pcr ◽  
Large Scale ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Trypanosome Species ◽  
Trypanosome Infection ◽  
Monitor Lizard

Abstract Background African trypanosomiasis, caused by protozoa of the genus Trypanosoma and transmitted by the tsetse fly, is a serious parasitic disease of humans and animals. Reliable data on the vector distribution, feeding preference and the trypanosome species they carry is pertinent to planning sustainable control strategies. Methodology We deployed 109 biconical traps in 10 villages in two districts of northwestern Uganda to obtain information on the apparent density, trypanosome infection status and blood meal sources of tsetse flies. A subset (272) of the collected samples was analyzed for detection of trypanosomes species and sub-species using a nested PCR protocol based on primers amplifying the Internal Transcribed Spacer (ITS) region of ribosomal DNA. 34 blood-engorged adult tsetse midguts were analyzed for blood meal sources by sequencing of the mitochondrial cytochrome c oxidase 1 (COI) and cytochrome b (cytb) genes. Results We captured a total of 622 Glossina fuscipes fuscipes tsetse flies (269 males and 353 females) in the two districts with apparent density (AD) ranging from 0.6 to 3.7 flies/trap/day (FTD). 10.7% (29/272) of the flies were infected with one or more trypanosome species. Infection rate was not significantly associated with district of origin (Generalized linear model (GLM), χ2 = 0.018, P = 0.895, df = 1, n = 272) and sex of the fly (χ2 = 1.723, P = 0.189, df = 1, n = 272). However, trypanosome infection was highly significantly associated with the fly’s age based on wing fray category (χ2 = 22.374, P < 0.001, df = 1, n = 272), being higher among the very old than the young tsetse. Nested PCR revealed several species of trypanosomes: T. vivax (6.62%), T. congolense (2.57%), T. brucei and T. simiae each at 0.73%. Blood meal analyses revealed five principal vertebrate hosts, namely, cattle (Bos taurus), humans (Homo sapiens), Nile monitor lizard (Varanus niloticus), African mud turtle (Pelusios chapini) and the African Savanna elephant (Loxodonta africana). Conclusion We found an infection rate of 10.8% in the tsetse sampled, with all infections attributed to trypanosome species that are causative agents for AAT. However, more verification of this finding using large-scale passive and active screening of human and tsetse samples should be done. Cattle and humans appear to be the most important tsetse hosts in the region and should be considered in the design of control interventions.

Some applications of electron beam microanalysis techniques in VLSI process evaluation

1983 ◽  
Vol 41 ◽  
pp. 160-161
Author(s):  
Simon Thomas
Keyword(s):  
Integrated Circuits ◽  
Process Evaluation ◽  
Large Scale ◽  
Technology Development ◽  
Analytical Techniques ◽  
Successful Implementation ◽  
Analysis Of Failures ◽  
Characterization Of Materials ◽  
Circuits Vlsi

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.

scholarly journals Comparative performance of traps in catching tsetse flies (Diptera: Glossinidae) in Tanzania

2016 ◽  
Vol 83 (1) ◽  
Author(s):  
Imna I. Malele ◽  
Johnson O. Ouma ◽  
Hamisi S. Nyingilili ◽  
Winston A. Kitwika ◽  
Deusdedit J. Malulu ◽  
...  
Keyword(s):  
Glossina Pallidipes ◽  
Abundant Species ◽  
Tsetse Fly ◽  
Tsetse Flies ◽  
Comparative Performance ◽  
Control Programmes ◽  
Fly Control ◽  
Tsetse Fly Control ◽  
Species Being ◽  
Biconical Traps

This study was conducted to determine the efficiency of different tsetse traps in 28 sites across Tanzania. The traps used were biconical, H, NGU, NZI, pyramidal, S3, mobile, and sticky panels. Stationary traps were deployed at a distance of 200 m apart and examined 72 h after deployment. The results showed that 117 (52.2%) out of the 224 traps deployed captured at least one Glossina species. A total of five Glossina species were captured, namely Glossina brevipalpis, Glossina pallidipes, Glossina swynnertoni, Glossina morsitans, and Glossina fuscipes martinii. Biconical traps caught tsetse flies in 27 sites, pyramidal in 26, sticky panel in 20, mobile in 19, S3 in 15, NGU in 7, H in 2 and NZI in 1. A total of 21 107 tsetse flies were trapped, with the most abundant species being G. swynnertoni (55.9%), followed by G. pallidipes (31.1%), G. fuscipes martinii (6.9%) and G. morsitans (6.0%). The least caught was G. brevipalpis (0.2%). The highest number of flies were caught by NGU traps (32.5%), followed by sticky panel (16%), mobile (15.4%), pyramidal (13.0%), biconical (11.3%) and S3 (10.2%). NZI traps managed to catch 0.9% of the total flies and H traps 0.7%. From this study, it can be concluded that the most efficient trap was NGU, followed by sticky panel and mobile, in that order. Therefore, for tsetse fly control programmes, NGU traps could be the better choice. Conversely, of the stationary traps, pyramidal and biconical traps captured tsetse flies in the majority of sites, covering all three ecosystems better than any other traps; therefore, they would be suitable for scouting for tsetse infestation in any given area, thus sparing the costs of making traps for each specific Glossina species.Keywords: tseste; traps; densties; Glossina; mobile; stationary; Tanzania

A Synthesis of Knowns, Unknowns, and Policy Recommendations from the Sea Lamprey International Symposium

1980 ◽  
Vol 37 (11) ◽  
pp. 2202-2208 ◽  
Author(s):  
Carl J. Walters ◽  
George Spangler ◽  
W. J. Christie ◽  
Patrick J. Manion ◽  
James F. Kitchell
Keyword(s):  
International Symposium ◽  
Large Scale ◽  
Fishery Management ◽  
Field Experiments ◽  
Lake Trout ◽  
Sea Lamprey ◽  
Future Research ◽  
Fish Stock ◽  
Total Production ◽  
Pilot Studies

The Sea Lamprey International Symposium (SLIS) has provided a broad spectrum of facts and speculations for consideration in future research and management programs. Many aspects of the laboratory biology and field life history of the sea lamprey (Petromyzon marinus) are now well understood. There is little question that it can now be controlled by chemical larvicides, and perhaps in the future by more efficient integrated control programs. There is correlative evidence (wounds, scars, catch curves) that lamprey caused major mortalities in some fish species, and that control in conjunction with stocking has lead to remarkable recoveries of salmonid stocks in the Great Lakes. However, there are great gaps in understanding about just what the lamprey does under field conditions, and it is not yet possible to reject several hypotheses that assign lamprey a minimum or transient role in fish stock changes. Further studies on details of lamprey biology are, in themselves, unlikely to fill the gaps; one alternative is to conduct a large-scale field experiment involving cessation of lamprey control while holding other factors (fishing, stocking) as steady as possible. If it is decided to proceed with management on the assumption that lamprey are important, without the major field experiments to confirm it, then at least the following steps should be taken: (1) the chemical treatment program should be reviewed in detail, with a view to finding treatment schedules that will minimize frequency and dose rates for lampricide applications; (2) pilot studies on alternative control schemes (sterile male, attractants, barriers) should only be funded if they are statistically well designed (several replicate and control streams), and involve quantitative monitoring of lamprey spawning success and subsequent total production of transforming larvae; (3) the lake trout (Salvelinus namaycush) stocking program should be maintained at its present level, and should involve diverse genotypes rather than a few hatchery strains; (4) growth in the sport fisheries for lake trout should be curtailed, and commercial fisheries should not yet be permitted; (5) a multispecies harvesting policy should be designed that takes into account the buffering effect of each species on lamprey mortality suffered by others (i.e. should some species not be harvested at all, and viewed instead as buffers for more valuable species?); and (6) a program should be developed for restoring, by culture if necessary, native forage species in case the introduced smelt and alewife should collapse under pressure from fishing and prédation by the growing salmonid community.Key words: sea lamprey, proposed research, fishery management, mathematical models, population dynamics

scholarly journals Easier Said Than Done: Keys to Successful Implementation of the Distress Assessment and Response Tool (DART) Program

2016 ◽  
Vol 12 (5) ◽  
pp. e513-e526 ◽  
Author(s):  
Madeline Li ◽  
Alyssa Macedo ◽  
Sean Crawford ◽  
Sabira Bagha ◽  
Yvonne W. Leung ◽  
...  
Keyword(s):  
Cancer Care ◽  
Large Scale ◽  
Performance Indicator ◽  
Evaluation Framework ◽  
Comprehensive Cancer Center ◽  
Cancer Center ◽  
Successful Implementation ◽  
Psychosocial Needs ◽  
Electronic Screening ◽  
Screening For Distress

Purpose: Systematic screening for distress in oncology clinics has gained increasing acceptance as a means to improve cancer care, but its implementation poses enormous challenges. We describe the development and implementation of the Distress Assessment and Response Tool (DART) program in a large urban comprehensive cancer center. Method: DART is an electronic screening tool used to detect physical and emotional distress and practical concerns and is linked to triaged interprofessional collaborative care pathways. The implementation of DART depended on clinician education, technological innovation, transparent communication, and an evaluation framework based on principles of change management and quality improvement. Results: There have been 364,378 DART surveys completed since 2010, with a sustained screening rate of > 70% for the past 3 years. High staff satisfaction, increased perception of teamwork, greater clinical attention to the psychosocial needs of patients, patient-clinician communication, and patient satisfaction with care were demonstrated without a resultant increase in referrals to specialized psychosocial services. DART is now a standard of care for all patients attending the cancer center and a quality performance indicator for the organization. Conclusion: Key factors in the success of DART implementation were the adoption of a programmatic approach, strong institutional commitment, and a primary focus on clinic-based response. We have demonstrated that large-scale routine screening for distress in a cancer center is achievable and has the potential to enhance the cancer care experience for both patients and staff.

PHENYLKETONURIA, AND GUTHRIE INHIBITION ASSAY SCREENING PROCEDURE

PEDIATRICS ◽  
1963 ◽  
Vol 32 (3) ◽  
pp. 344-346
Keyword(s):  
Public Health ◽  
Large Scale ◽  
Human Genetics ◽  
Screening Program ◽  
Genetic Diseases ◽  
State Department ◽  
The State ◽  
Detection Methods ◽  
Inhibition Assay ◽  
Pilot Studies

Recommendations were made in view of the following facts: (1) the need for further information on the mechanisms involved in the phenotypic expressions of phenylketonuria; (2) the present lack of adequate data on the effectiveness of the Guthrie Inhibition Assay, in terms of number of cases which may be missed, factors making for positive determinations and providing other information on which to evaluate the appropriateness of the large-scale screening program proposed; (3) the undesirability of deploying inordinate resources in the evaluation of the Guthrie Inhibition Assay to the detriment of the needs of other areas of child health including phenylketonuria; (4) the indications that a multi-faceted approach to phenylketonuria would be productive, not only in resolving the problems involving this disorder but also as a model for the investigation of and application to the treatment of other genetic diseases; (5) the possibility that the Guthrie Inhibition Assay could be a useful tool in the early detection, treatment and investigation of phenylketonuria; and (6) the fact that other state health departments are participating in the Guthrie Field Trials, indicating that the California State Department of Public Health should apply its resources to a more intensive study of PKU and detection methods. The consultants made the following recommendations, through resolution, to the California State Department of Public Health. It was resolved that: 1. The State of California not be responsible at this time for initiating or recommending that the Guthrie procedure be accomplished on a state-wide basis in all newborn nurseries (one dissent). 2. The State of California initiate and coordinate the development of pilot studies in selected hospitals and medical centers throughout the State in the investigation of phenylketonuria, utilizing the Guthrie Inhibition Assay or other tests. 3. A scientific committee be appointed immediately as an advisory committee to the State Department of Public Health to develop recommendations for carrying out the suggested investigations. 4. A registry for phenylketonuria and other diseases (as listed in the recommendations by the Subcommittee on Human Genetics) be established within the framework of the State organization.

scholarly journals Differential virulence and tsetse fly transmissibility of Trypanosoma congolense and Trypanosoma brucei strains

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Purity K. Gitonga ◽  
Kariuki Ndung’u ◽  
Grace A. Murilla ◽  
Paul C. Thande ◽  
Florence N. Wamwiri ◽  
...  
Keyword(s):  
Survival Time ◽  
Trypanosoma Brucei ◽  
Acute Infection ◽  
Glossina Pallidipes ◽  
Trypanosoma Congolense ◽  
Tsetse Fly ◽  
Economic Losses ◽  
Entire Group ◽  
Tsetse Flies ◽  
African Countries

African animal trypanosomiasis causes significant economic losses in sub-Saharan African countries because of livestock mortalities and reduced productivity. Trypanosomes, the causative agents, are transmitted by tsetse flies (Glossina spp.). In the current study, we compared and contrasted the virulence characteristics of five Trypanosoma congolense and Trypanosoma brucei isolates using groups of Swiss white mice (n = 6). We further determined the vectorial capacity of Glossina pallidipes, for each of the trypanosome isolates. Results showed that the overall pre-patent (PP) periods were 8.4 ± 0.9 (range, 4–11) and 4.5 ± 0.2 (range, 4–6) for T. congolense and T. brucei isolates, respectively (p < 0.01). Despite the longer mean PP, T. congolense–infected mice exhibited a significantly (p < 0.05) shorter survival time than T. brucei–infected mice, indicating greater virulence. Differences were also noted among the individual isolates with T. congolense KETRI 2909 causing the most acute infection of the entire group with a mean ± standard error survival time of 9 ± 2.1 days. Survival time of infected tsetse flies and the proportion with mature infections at 30 days post-exposure to the infective blood meals varied among isolates, with subacute infection–causing T. congolense EATRO 1829 and chronic infection–causing T. brucei EATRO 2267 isolates showing the highest mature infection rates of 38.5% and 23.1%, respectively. Therefore, our study provides further evidence of occurrence of differences in virulence and transmissibility of eastern African trypanosome strains and has identified two, T. congolense EATRO 1829 and T. brucei EATRO 2267, as suitable for tsetse infectivity and transmissibility experiments.

Supporting our supervisors: a Summary and Discussion of the Special Issue on CBT supervision

2016 ◽  
Vol 9 ◽  
Author(s):  
Cory F. Newman ◽  
Robert P. Reiser ◽  
Derek L. Milne
Keyword(s):  
Large Scale ◽  
Political Support ◽  
Successful Implementation ◽  
Special Issue ◽  
Cultural Adaptations ◽  
Cognitive Behavioural ◽  
Cognitive Behaviour ◽  
Feedback Strategies ◽  
Technical Innovations ◽  
Procedural Guidance

AbstractContributors to this Special Issue of the Cognitive Behaviour Therapist have considered the kind of infrastructure that should be in place to best support and guide CBT supervisors, providing practical advice and extensive procedural guidance. Here we briefly summarize and discuss in turn the 10 papers within this Special Issue, including suggestions for further enhancements. The first paper, by Milne and Reiser, conceptualized this infrastructure in terms of an ‘SOS’ (supporting our supervisors) framework, from identifying supervision competencies, to training, evaluation and feedback strategies. The next nine papers illustrate this framework with specific technical innovations, educational enhancements and procedural issues, or through comprehensive quality improvement systems, all designed to support supervisors. These papers suggest an assortment of workable infrastructure developments: two large-scale and comprehensive initiatives, some promising proposals and technologies, and a series of local, exploratory work. Collectively, they provide us with models for further developing evidence-based cognitive-behavioural supervision, and offer practical suggestions for giving supervisors the tools and support to maximize their supervisees’ learning, and to improve the associated client outcomes. Much research and development work remains to be done, and successful implementation will require institutional and political support, as well as cross-cultural adaptations. We conclude with an optimistic assessment of progress toward addressing some of the infrastructure improvements required to adequately support supervisors.

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