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Stica C, Jeffries CL, Irish SR, Barry Y, Camara D, Yansane I, Kristan M, Walker T, Messenger LA. Characterizing the molecular and metabolic mechanisms of insecticide resistance in Anopheles gambiae in Faranah, Guinea. Malar J 2019; 18:244. [PMID: 31315630 PMCID: PMC6637595 DOI: 10.1186/s12936-019-2875-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 07/08/2019] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND In recent years, the scale-up of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) has greatly reduced malaria transmission. However, malaria remains a global public health concern with the majority of the disease burden in sub-Saharan Africa. Insecticide resistance is a growing problem among Anopheles vector populations, with potential implications for the continued effectiveness of available control interventions. Improved understanding of current resistance levels and underlying mechanisms is essential to design appropriate management strategies and to mitigate future selection for resistance. METHODS Anopheles gambiae sensu lato mosquitoes were collected from three villages in Faranah Prefecture, Guinea and their levels of susceptibility to seven insecticides were measured using CDC resistance intensity bioassays. Synergist assays with piperonyl butoxide (PBO) were also undertaken to assess the role of elevated mixed-function oxidases in resistance. Five hundred and sixty-three mosquitoes underwent molecular characterization of vector species, presence of target site mutations (L1014F kdr, N1575Y and G119S Ace-1), Plasmodium falciparum infection, and relative expression of three metabolic genes (CYP6M2, CYP6P3 and GSTD3). RESULTS In Faranah, resistance to permethrin and deltamethrin was observed, as well as possible resistance to bendiocarb. All assayed vector populations were fully susceptible to alpha-cypermethrin, pirimiphos-methyl, clothianidin and chlorfenapyr. Plasmodium falciparum infection was detected in 7.3% (37/508) of mosquitoes tested. The L1014F kdr mutation was found in 100% of a sub-sample of 60 mosquitoes, supporting its fixation in the region. The N1575Y mutation was identified in 20% (113/561) of individuals, with ongoing selection evidenced by significant deviations from Hardy-Weinberg equilibrium. The G119S Ace-1 mutation was detected in 62.1% (18/29) of mosquitoes tested and was highly predictive of bendiocarb bioassay survival. The metabolic resistance genes, CYP6M2, CYP6P3 and GSTD3, were found to be overexpressed in wild resistant and susceptible An. gambiae sensu stricto populations, compared to a susceptible G3 colony. Furthermore, CYP6P3 was significantly overexpressed in bendiocarb survivors, implicating its potential role in carbamate resistance in Faranah. CONCLUSIONS Identification of intense resistance to permethrin and deltamethrin in Faranah, is of concern, as the Guinea National Malaria Control Programme (NMCP) relies exclusively on the distribution of pyrethroid-treated LLINs for vector control. Study findings will be used to guide current and future control strategies in the region.
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Collins E, Vaselli NM, Sylla M, Beavogui AH, Orsborne J, Lawrence G, Wiegand RE, Irish SR, Walker T, Messenger LA. The relationship between insecticide resistance, mosquito age and malaria prevalence in Anopheles gambiae s.l. from Guinea. Sci Rep 2019; 9:8846. [PMID: 31222175 PMCID: PMC6586859 DOI: 10.1038/s41598-019-45261-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 05/30/2019] [Indexed: 11/15/2022] Open
Abstract
Insecticide resistance across sub-Saharan Africa may impact the continued effectiveness of malaria vector control. We investigated the association between carbamate and pyrethroid resistance with Anopheles gambiae s.l. parity, Plasmodium falciparum infection, and molecular insecticide resistance mechanisms in Guinea. Pyrethroid resistance was intense, with field populations surviving ten times the insecticidal concentration required to kill susceptible individuals. The L1014F kdr-N1575Y haplotype and I1527T mutation were significantly associated with mosquito survival following permethrin exposure (Prevalence Ratio; PR = 1.92, CI = 1.09–3.37 and PR = 2.80, CI = 1.03–7.64, respectively). Partial restoration of pyrethroid susceptibility following synergist pre-exposure suggests a role for mixed-function oxidases. Carbamate resistance was lower and significantly associated with the G119S Ace-1 mutation. Oocyst rates were 6.8% and 4.2% among resistant and susceptible mosquitoes, respectively; survivors of bendiocarb exposure were significantly more likely to be infected. Pyrethroid resistant mosquitoes had significantly lower parity rates than their susceptible counterparts (PR = 1.15, CI = 1.10–1.21). Our findings emphasize the need for additional studies directly assessing the influence of insecticide resistance on mosquito fitness.
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Ramesh A, Jeffries CL, Castanha P, Oliveira PAS, Alexander N, Cameron M, Braga C, Walker T. No evidence of Zika, dengue, or chikungunya virus infection in field-caught mosquitoes from the Recife Metropolitan Region, Brazil, 2015. Wellcome Open Res 2019; 4:93. [PMID: 31363498 PMCID: PMC6644828 DOI: 10.12688/wellcomeopenres.15295.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2019] [Indexed: 02/02/2023] Open
Abstract
Background: The Recife Metropolitan Region (RMR), north-eastern Brazil, was the epicentre of the 2015 Zika virus (ZIKV) epidemic, which was followed by a 2016 chikungunya virus (CHIKV) epidemic. It historically has amongst the highest incidence of dengue virus (DENV) infections and is the only remaining focus of lymphatic filariasis (LF) in Brazil. In early 2015, a molecular xenomonitoring surveillance project focused on Culex (Cx.) quinquefasciatus commenced to inform LF elimination activities. Aedes (Ae.) aegypti mosquitoes were also collected, concurrent with the first microcephaly cases detected in the RMR. In terms of the 2015 ZIKV epidemic, these are the earliest known field-collected mosquitoes, preserved for potential RNA virus detection, when ZIKV was known to be circulating locally. Methods: Adult mosquitoes were collected in two sites (0.4 km 2) of Sítio Novo, Olinda, RMR, from July 22 to August 21, 2015. Mosquitoes were morphologically identified, sorted by physiological status, and pooled (up to 10 mosquitoes per house per day or week). RNA was extracted, reverse transcribed and the cDNA tested by real-time PCR. Results: A total of 10,139 adult female Cx. quinquefasciatus and 939 adult female Ae. aegypti were captured. All female Ae. aegypti specimens were included within 156 pools and screened for ZIKV, DENV and CHIKV. In addition, a sub-set of 1,556 Cx. quinquefasciatus adult females in 182 pools were screened for ZIKV. No evidence of infection with any of the three arboviruses was found. Conclusions: The absence of arbovirus detection may have been expected given the extremely restricted geographic area and collection of mosquitoes during a very short time period of peak mosquito abundance (July-September), but low arbovirus circulation (November-March). However, this study demonstrates the potential to retrospectively screen for additional unexpected pathogens in situations of rapid emergence, such as occurred during the outbreak of ZIKV in the RMR.
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Stewart P, Stewart J, Walker T, Gullapudi VRL, Selby NM, Taal MW. SP541MEASURING PRESSURE WAVES IN DIALYSIS LINES TO DERIVE CONTINUOUS ARTERIAL BLOOD PRESSURE: PILOT WORK IN AN IN VITRO AND IN SILICO MODEL. Nephrol Dial Transplant 2019. [DOI: 10.1093/ndt/gfz103.sp541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Stewart P, Stewart J, Walker T, Gullapudi VRL, Taal MW, Selby NM. FP630DEVELOPMENT OF AN IN VITRO SIMULATION MODEL TO INVESTIGATE HAEMODYNAMIC RESPONSES DURING HAEMODIALYSIS. Nephrol Dial Transplant 2019. [DOI: 10.1093/ndt/gfz106.fp630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Gullapudi VRL, Stewart J, Stewart P, Walker T, Eldehni TE, Taal MW, Selby NM. FP638FREQUENCY ANALYSIS REVEALS UNIQUE HAEMODYNAMIC RESPONSES TO HAEMODIALYSIS: BASELINE RESULTS FROM THE ITREND STUDY. Nephrol Dial Transplant 2019. [DOI: 10.1093/ndt/gfz106.fp638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Walker T, Kelly R, Frezzini C, Cereceda-Monteoliva N, Clark R, Cobb A, Ayliffe P. The rose trellis mucoperiosteal scoring technique improves flap stretch for alveolar cleft and oro antral fistula repair. Int J Oral Maxillofac Surg 2019. [DOI: 10.1016/j.ijom.2019.03.947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Walker T, Frezzini C, Wu E, Haria N, Sahjir G, Cobb A. Cleft LIP & palate and photosharing social media platforms (instagram). Int J Oral Maxillofac Surg 2019. [DOI: 10.1016/j.ijom.2019.03.943] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Walker T, Clark R, Deacon S, Revington P. Factors affecting success in the management of the alveolar cleft - a review of 304 tibial bone grafts in a single institution. Int J Oral Maxillofac Surg 2019. [DOI: 10.1016/j.ijom.2019.03.948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Orsborne J, Furuya-Kanamori L, Jeffries CL, Kristan M, Mohammed AR, Afrane YA, O'Reilly K, Massad E, Drakeley C, Walker T, Yakob L. Investigating the blood-host plasticity and dispersal of Anopheles coluzzii using a novel field-based methodology. Parasit Vectors 2019; 12:143. [PMID: 30909960 PMCID: PMC6434891 DOI: 10.1186/s13071-019-3401-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 03/15/2019] [Indexed: 11/10/2022] Open
Abstract
Background The biting behaviour and dispersal of insect vectors in the field underlies the transmission of many diseases. Here, a novel collection methodology coupled with the molecular analysis of blood-meal sources and digestion rates is introduced with the aim of aiding the understanding of two critical and relatively understudied mosquito behaviours: plasticity in blood-host choice and vector dispersal. Results A collection strategy utilising a transect of mosquito traps placed at 50 m intervals allowed the collection of blood-fed Anopheles coluzzii from a malaria-endemic village of southern Ghana where human host availability ranged from zero (a cattle pen), increasing until humans were the dominant host choice (the middle of the village). Blood-meal analysis using PCR showed statistically significant variation in blood-meal origins for mosquitoes collected across the 250 m transect: with decreasing trend in Bovine Blood Index (OR = 0.60 95% CI: 0.49–0.73, P < 0.01) and correspondingly, an increasing trend in Human Blood Index (OR = 1.50 95% CI: 1.05–2.16, P = 0.028) as the transect approached the village. Using qPCR, the host DNA remaining in the blood meal was quantified for field-caught mosquitoes and calibrated according to timed blood digestion in colony mosquitoes. Time since blood meal was consumed and the corresponding distance the vector was caught from its blood-host allowed the estimation of An. coluzzii dispersal rates. Within 7 hours of feeding, mosquitoes typically remained within 50 m of their blood-host but at 60 hours they had dispersed up to 250 m. Conclusions Using this methodology the remarkably small spatial scale at which An. coluzzii blood-host choice can change was demonstrated. In addition, conducting qPCR on host blood from field-caught mosquitoes and calibrating with timed experiments with colonised mosquitoes presents a novel methodology for investigating the dispersal behaviour of vectors. Future adaptations to this novel method to make it broadly applicable to other types of setting are also discussed.
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Walker T, Spencer J, Dancer S, Craft J. Comparative analysis of the composition and change of the microbiome of diabetic foot ulcers from patients on different therapies. Access Microbiol 2019. [DOI: 10.1099/acmi.ac2019.po0141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Mulchandani R, Massebo F, Bocho F, Jeffries CL, Walker T, Messenger LA. A community-level investigation following a yellow fever virus outbreak in South Omo Zone, South-West Ethiopia. PeerJ 2019; 7:e6466. [PMID: 30809451 PMCID: PMC6387579 DOI: 10.7717/peerj.6466] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/17/2019] [Indexed: 01/08/2023] Open
Abstract
Background Despite the availability of a highly effective vaccine, yellow fever virus (YFV) remains an important public health problem across Africa and South America due to its high case-fatality rate. This study investigated the historical epidemiology and contemporary entomological and social determinants of a YFV outbreak in South Omo Zone (SOZ), Ethiopia. Methods A YFV outbreak occurred in SOZ, Ethiopia in 2012–2014. Historical epidemiological data were retrieved from the SOZ Health Department and analyzed. Entomological sampling was undertaken in 2017, including mosquito species identification and molecular screening for arboviruses to understand mosquito habitat distribution, and finally current knowledge, attitudes and preventative practices within the affected communities were assessed. Results From October 2012 to March 2014, 165 suspected cases and 62 deaths were reported, principally in rural areas of South Ari region (83.6%). The majority of patients were 15–44 years old (75.8%) and most case deaths were males (76%). Between June and August 2017, 688 containers were sampled across 180 households to identify key breeding sites for Aedes mosquitoes. Ensete ventricosum (“false banana”) and clay pots outside the home were the most productive natural and artificial breeding sites, respectively. Entomological risk indices classified most sites as “high risk” for future outbreaks under current World Health Organization criteria. Adult mosquitoes in houses were identified as members of the Aedes simpsoni complex but no YFV or other arboviruses were detected by PCR. The majority of community members had heard of YFV, however few activities were undertaken to actively reduce mosquito breeding sites. Discussion Study results highlight the potential role vector control could play in mitigating local disease transmission and emphasize the urgent need to strengthen disease surveillance systems and in-country laboratory capacity to facilitate more rapid responses to future YFV outbreaks.
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Walker T, Rutkowski L, Innmann M, Panzram B, Herre J, Gotterbarm T, Aldinger PR, Merle C. Unicondylar knee arthroplasty using cobalt-chromium implants in patients with self-reported cutaneous metal hypersensitivity. Bone Joint J 2019; 101-B:227-232. [DOI: 10.1302/0301-620x.101b2.bjj-2018-0778.r1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Aims The treatment of patients with allergies to metal in total joint arthroplasty is an ongoing debate. Possibilities include the use of hypoallergenic prostheses, as well as the use of standard cobalt-chromium (CoCr) alloy. This non-designer study was performed to evaluate the clinical outcome and survival rates of unicondylar knee arthroplasty (UKA) using a standard CoCr alloy in patients reporting signs of a hypersensitivity to metal. Patients and Methods A consecutive series of patients suitable for UKA were screened for symptoms of metal hypersensitivity by use of a questionnaire. A total of 82 patients out of 1737 patients suitable for medial UKA reporting cutaneous metal hypersensitivity to cobalt, chromium, or nickel were included into this study and prospectively evaluated to determine the functional outcome, possible signs of hypersensitivity, and short-term survivorship at a minimum follow-up of 1.5 years. Results At a mean follow-up of three years (1.5 to 5.7), no local or systemic symptoms of hypersensitivity to metal were observed. One patient underwent revision surgery to a bicondylar prosthesis due to a tibial periprosthetic fracture resulting in a survival rate of 98.8% (95% confidence interval (CI) 91.7 to 99.8; number at risk, 28) at three years with the endpoint of revision for any reason and a survival rate of 97.6% (95% CI 90.6 to 99.3; number at risk, 29) for the endpoint of all reoperations. Clinical outcome was good to excellent with a mean Oxford Knee Score of 42.5 (sd 2.5; 37 to 48). Conclusion This study is the first demonstrating clinical results and survival analysis of UKA using a CoCr alloy in patients with a history of metal hypersensitivity. Functional outcome and survivorship are on a high-level equivalent to those reported for UKA in patients without a history of metal hypersensitivity. No serious local or systemic symptoms of metal hypersensitivity could be detected, and no revision surgery was performed due to an adverse reaction to metal ions.
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Jamil K, Walker T, Onikul E, Munns CF, Little DG. A comparison of subtraction MRI with the standard contrast-enhanced imaging in Perthes' disease. J Child Orthop 2019; 13:82-88. [PMID: 30838080 PMCID: PMC6376440 DOI: 10.1302/1863-2548.13.180136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 12/19/2018] [Indexed: 02/03/2023] Open
Abstract
PURPOSE Perthes' disease (PD) results from loss of blood supply to the hip and can progress to femoral head deformity. MRI in the early course of the disease can provide data on the initial extent of infarct. Vascularity of the femoral head is assessed by gadolinium-enhanced MRI (contrast MRI), which may be improved by the digital subtraction technique (subtraction MRI). We hypothesized that gadolinium-enhanced MRI without subtraction was comparable with subtraction MRI in depicting the femoral head perfusion. METHODS In all, 34 patients (34 hips) with unilateral PD had gadolinium-enhanced MRI as part of a prospectively randomized study. Nine patients had three MRIs, 15 had two and ten had a single MRI. Measurement of perfusion of the femoral head (MRI perfusion index) was obtained using digital image analysis on all the MRIs, including both before and after subtraction. A paired sample t-test was performed to compare the measurements. RESULTS The mean age of the patients was 8.9 years (sd 1.6). At the time of diagnosis, the subtraction MRI did not elicit a statistically significant difference in MRI perfusion index measurements when compared with the contrast MRI (p = 0.19). The same findings were found when including all patients at various stages of the disease (p = 0.30). Qualitatively, although some subtraction MRI images showed superior delineation of epiphysis, there are no significant differences throughout the whole series. CONCLUSION Although the current literature supports the increasing role of the subtraction MRI for PD management, our study proposed that the contrast MRI without subtraction technique appears adequate in assessing femoral head perfusion. LEVEL OF EVIDENCE Level I - Diagnostic study.
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Miyazaki K, Sekiya T, Fu D, Bowman KW, Kulawik SS, Sudo K, Walker T, Kanaya Y, Takigawa M, Ogochi K, Eskes H, Boersma KF, Thompson AM, Gaubert B, Barre J, Emmons LK. Balance of Emission and Dynamical Controls on Ozone During the Korea-United States Air Quality Campaign From Multiconstituent Satellite Data Assimilation. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:387-413. [PMID: 31007989 PMCID: PMC6472638 DOI: 10.1029/2018jd028912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 10/29/2018] [Accepted: 11/06/2018] [Indexed: 05/05/2023]
Abstract
Global multiconstituent concentration and emission fields obtained from the assimilation of the satellite retrievals of ozone, CO, NO2, HNO3, and SO2 from the Ozone Monitoring Instrument (OMI), Global Ozone Monitoring Experiment 2, Measurements of Pollution in the Troposphere, Microwave Limb Sounder, and Atmospheric Infrared Sounder (AIRS)/OMI are used to understand the processes controlling air pollution during the Korea-United States Air Quality (KORUS-AQ) campaign. Estimated emissions in South Korea were 0.42 Tg N for NO x and 1.1 Tg CO for CO, which were 40% and 83% higher, respectively, than the a priori bottom-up inventories, and increased mean ozone concentration by up to 7.5 ± 1.6 ppbv. The observed boundary layer ozone exceeded 90 ppbv over Seoul under stagnant phases, whereas it was approximately 60 ppbv during dynamical conditions given equivalent emissions. Chemical reanalysis showed that mean ozone concentration was persistently higher over Seoul (75.10 ± 7.6 ppbv) than the broader KORUS-AQ domain (70.5 ± 9.2 ppbv) at 700 hPa. Large bias reductions (>75%) in the free tropospheric OH show that multiple-species assimilation is critical for balanced tropospheric chemistry analysis and emissions. The assimilation performance was dependent on the particular phase. While the evaluation of data assimilation fields shows an improved agreement with aircraft measurements in ozone (to less than 5 ppbv biases), CO, NO2, SO2, PAN, and OH profiles, lower tropospheric ozone analysis error was largest at stagnant conditions, whereas the model errors were mostly removed by data assimilation under dynamic weather conditions. Assimilation of new AIRS/OMI ozone profiles allowed for additional error reductions, especially under dynamic weather conditions. Our results show the important balance of dynamics and emissions both on pollution and the chemical assimilation system performance.
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Orsborne J, Furuya-Kanamori L, Jeffries CL, Kristan M, Mohammed AR, Afrane YA, O'Reilly K, Massad E, Drakeley C, Walker T, Yakob L. Using the human blood index to investigate host biting plasticity: a systematic review and meta-regression of the three major African malaria vectors. Malar J 2018; 17:479. [PMID: 30563533 PMCID: PMC6299493 DOI: 10.1186/s12936-018-2632-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/14/2018] [Indexed: 12/17/2022] Open
Abstract
Background The proportion of mosquito blood-meals that are of human origin, referred to as the ‘human blood index’ or HBI, is a key determinant of malaria transmission. Methods A systematic review was conducted followed by meta-regression of the HBI for the major African malaria vectors. Results Evidence is presented for higher HBI among Anopheles gambiae (M/S forms and Anopheles coluzzii/An. gambiae sensu stricto are not distinguished for most studies and, therefore, combined) as well as Anopheles funestus when compared with Anopheles arabiensis (prevalence odds ratio adjusted for collection location [i.e. indoor or outdoor]: 1.62; 95% CI 1.09–2.42; 1.84; 95% CI 1.35–2.52, respectively). This finding is in keeping with the entomological literature which describes An. arabiensis to be more zoophagic than the other major African vectors. However, analysis also revealed that HBI was more associated with location of mosquito captures (R2 = 0.29) than with mosquito (sibling) species (R2 = 0.11). Conclusions These findings call into question the appropriateness of current methods of assessing host preferences among disease vectors and have important implications for strategizing vector control. Electronic supplementary material The online version of this article (10.1186/s12936-018-2632-7) contains supplementary material, which is available to authorized users.
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Jeffries CL, Tantely LM, Raharimalala FN, Hurn E, Boyer S, Walker T. Diverse novel resident Wolbachia strains in Culicine mosquitoes from Madagascar. Sci Rep 2018; 8:17456. [PMID: 30498246 PMCID: PMC6265278 DOI: 10.1038/s41598-018-35658-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022] Open
Abstract
Wolbachia endosymbiotic bacteria are widespread throughout insect species and Wolbachia transinfected in Aedes mosquito species has formed the basis for biocontrol programs as Wolbachia strains inhibit arboviral replication and can spread through populations. Resident strains in wild Culicine mosquito populations (the vectors of most arboviruses) requires further investigation given resident strains can also affect arboviral transmission. As Madagascar has a large diversity of both Culicine species and has had recent arboviral outbreaks, an entomology survey was undertaken, in five ecologically diverse sites, to determine the Wolbachia prevalence. We detected diverse novel resident Wolbachia strains within the Aedeomyia, Culex, Ficalbia, Mansonia and Uranotaenia genera. Wolbachia prevalence rates and strain characterisation through Sanger sequencing with multilocus sequence typing (MLST) and phylogenetic analysis revealed significant diversity and we detected co-infections with the environmentally acquired bacteria Asaia. Mosquitoes were screened for major arboviruses to investigate if any evidence could be provided for their potential role in transmission and we report the presence of Rift Valley fever virus in three Culex species: Culex tritaeniorhynchus, Culex antennatus and Culex decens. The implications of the presence of resident Wolbachia strains are discussed and how the discovery of novel strains can be utilized for applications in the development of biocontrol strategies.
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Jeffries CL, Lawrence GG, Golovko G, Kristan M, Orsborne J, Spence K, Hurn E, Bandibabone J, Tantely LM, Raharimalala FN, Keita K, Camara D, Barry Y, Wat'senga F, Manzambi EZ, Afrane YA, Mohammed AR, Abeku TA, Hedge S, Khanipov K, Pimenova M, Fofanov Y, Boyer S, Irish SR, Hughes GL, Walker T. Novel Wolbachia strains in Anopheles malaria vectors from Sub-Saharan Africa. Wellcome Open Res 2018; 3:113. [PMID: 30483601 PMCID: PMC6234743 DOI: 10.12688/wellcomeopenres.14765.2] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2018] [Indexed: 12/31/2022] Open
Abstract
Background: Wolbachia, a common insect endosymbiotic bacterium that can influence pathogen transmission and manipulate host reproduction, has historically been considered absent from the Anopheles (An.) genera, but has recently been found in An. gambiae s.l. populations in West Africa. As there are numerous Anopheles species that have the capacity to transmit malaria, we analysed a range of species across five malaria endemic countries to determine Wolbachia prevalence rates, characterise novel Wolbachia strains and determine any correlation between the presence of Plasmodium, Wolbachia and the competing bacterium Asaia. Methods: Anopheles adult mosquitoes were collected from five malaria-endemic countries: Guinea, Democratic Republic of the Congo (DRC), Ghana, Uganda and Madagascar, between 2013 and 2017. Molecular analysis was undertaken using quantitative PCR, Sanger sequencing, Wolbachia multilocus sequence typing (MLST) and high-throughput amplicon sequencing of the bacterial 16S rRNA gene. Results: Novel Wolbachia strains were discovered in five species: An. coluzzii, An. gambiae s.s., An. arabiensis, An. moucheti and An. species A, increasing the number of Anopheles species known to be naturally infected. Variable prevalence rates in different locations were observed and novel strains were phylogenetically diverse, clustering with Wolbachia supergroup B strains. We also provide evidence for resident strain variants within An. species A. Wolbachia is the dominant member of the microbiome in An. moucheti and An. species A but present at lower densities in An. coluzzii. Interestingly, no evidence of Wolbachia/Asaia co-infections was seen and Asaia infection densities were shown to be variable and location dependent. Conclusions: The important discovery of novel Wolbachia strains in Anopheles provides greater insight into the prevalence of resident Wolbachia strains in diverse malaria vectors. Novel Wolbachia strains (particularly high-density strains) are ideal candidate strains for transinfection to create stable infections in other Anopheles mosquito species, which could be used for population replacement or suppression control strategies.
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Felsenberg J, Jacob PF, Walker T, Barnstedt O, Edmondson-Stait AJ, Pleijzier MW, Otto N, Schlegel P, Sharifi N, Perisse E, Smith CS, Lauritzen JS, Costa M, Jefferis GSXE, Bock DD, Waddell S. Integration of Parallel Opposing Memories Underlies Memory Extinction. Cell 2018; 175:709-722.e15. [PMID: 30245010 PMCID: PMC6198041 DOI: 10.1016/j.cell.2018.08.021] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 08/07/2018] [Accepted: 08/13/2018] [Indexed: 11/16/2022]
Abstract
Accurately predicting an outcome requires that animals learn supporting and conflicting evidence from sequential experience. In mammals and invertebrates, learned fear responses can be suppressed by experiencing predictive cues without punishment, a process called memory extinction. Here, we show that extinction of aversive memories in Drosophila requires specific dopaminergic neurons, which indicate that omission of punishment is remembered as a positive experience. Functional imaging revealed co-existence of intracellular calcium traces in different places in the mushroom body output neuron network for both the original aversive memory and a new appetitive extinction memory. Light and ultrastructural anatomy are consistent with parallel competing memories being combined within mushroom body output neurons that direct avoidance. Indeed, extinction-evoked plasticity in a pair of these neurons neutralizes the potentiated odor response imposed in the network by aversive learning. Therefore, flies track the accuracy of learned expectations by accumulating and integrating memories of conflicting events.
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Jeffries CL, Lawrence GG, Golovko G, Kristan M, Orsborne J, Spence K, Hurn E, Bandibabone J, Tantely LM, Raharimalala FN, Keita K, Camara D, Barry Y, Wat’senga F, Manzambi EZ, Afrane YA, Mohammed AR, Abeku TA, Hedge S, Khanipov K, Pimenova M, Fofanov Y, Boyer S, Irish SR, Hughes GL, Walker T. Novel Wolbachia strains in Anopheles malaria vectors from Sub-Saharan Africa. Wellcome Open Res 2018; 3:113. [DOI: 10.12688/wellcomeopenres.14765.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2018] [Indexed: 01/09/2023] Open
Abstract
Background: Wolbachia, a common insect endosymbiotic bacterium that can influence pathogen transmission and manipulate host reproduction, has historically been considered absent from the Anopheles (An.) genera, but has recently been found in An. gambiae s.l. populations. As there are numerous Anopheles species that have the capacity to transmit malaria, we analysed a range of species to determine Wolbachia prevalence rates, characterise novel Wolbachia strains and determine any correlation between the presence of Plasmodium, Wolbachia and the competing endosymbiotic bacterium Asaia. Methods: Anopheles adult mosquitoes were collected from five malaria-endemic countries: Guinea, Democratic Republic of the Congo (DRC), Ghana, Uganda and Madagascar, between 2013 and 2017. Molecular analysis of samples was undertaken using quantitative PCR, Sanger sequencing, Wolbachia multilocus sequence typing (MLST) and high-throughput amplicon sequencing of the bacterial 16S rRNA gene. Results: Novel Wolbachia strains were discovered in five species: An. coluzzii, An. gambiae s.s., An. arabiensis, An. moucheti and An. species ‘A’, increasing the number of Anopheles species known to be naturally infected. Variable prevalence rates in different locations were observed and novel strains were phylogenetically diverse, clustering with Wolbachia supergroup B strains. We also provide evidence for resident strain variants within An. species ‘A’. Wolbachia is the dominant member of the microbiome in An. moucheti and An. species ‘A’, but present at lower densities in An. coluzzii. Interestingly, no evidence of Wolbachia/Asaia co-infections was seen and Asaia infection densities were also shown to be variable and location dependent. Conclusions: The important discovery of novel Wolbachia strains in Anopheles provides greater insight into the prevalence of resident Wolbachia strains in diverse malaria vectors. Novel Wolbachia strains (particularly high-density strains) are ideal candidate strains for transinfection to create stable infections in other Anopheles mosquito species, which could be used for population replacement or suppression control strategies.
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Patzelt J, Ulrich M, Magunia HF, Sauter R, Droppa M, Jorbenadze R, Becker AS, Walker T, Von Bardeleben RS, Grasshoff C, Rosenberger P, Gawaz M, Seizer P, Langer HF. P2575Comparison of deep sedation with general anesthesia in patients undergoing percutaneous mitral valve repair (PMVR). Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy565.p2575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Francis NK, Walker T, Carter F, Hübner M, Balfour A, Jakobsen DH, Burch J, Wasylak T, Demartines N, Lobo DN, Addor V, Ljungqvist O. Consensus on Training and Implementation of Enhanced Recovery After Surgery: A Delphi Study. World J Surg 2018; 42:1919-1928. [PMID: 29302724 DOI: 10.1007/s00268-017-4436-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Enhanced Recovery After Surgery (ERAS) is widely accepted in current surgical practice due to its positive impact on patient outcomes. The successful implementation of ERAS is challenging and compliance with protocols varies widely. Continual staff education is essential for successful ERAS programmes. Teaching modalities exist, but there remains no agreement regarding the optimal training curriculum or how its effectiveness is assessed. We aimed to draw consensus from an expert panel regarding the successful training and implementation of ERAS. METHODS A modified Delphi technique was used; three rounds of questionnaires were sent to 58 selected international experts from 11 countries across multiple ERAS specialities and multidisciplinary teams (MDT) between January 2016 and February 2017. We interrogated opinion regarding four topics: (1) the components of a training curriculum and the structure of training courses; (2) the optimal framework for successful implementation and audit of ERAS including a guide for data collection; (3) a framework to assess the effectiveness of training; (4) criteria to define ERAS training centres of excellence. RESULTS An ERAS training course must cover the evidence-based principles of ERAS with team-oriented training. Successful implementation requires strong leadership, an ERAS facilitator and an effective MDT. Effectiveness of training can be measured by improved compliance. A training centre of excellence should show a willingness to teach and demonstrable team working. CONCLUSIONS We propose an international expert consensus providing an ERAS training curriculum, a framework for successful implementation, methods for assessing effectiveness of training and a definition of ERAS training centres of excellence.
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Walker T, Chang FY, Carter F, Curtis N, Dennison G, Francis N. Application of digital learning platforms within ERAS: A systematic review. Clin Nutr ESPEN 2018. [DOI: 10.1016/j.clnesp.2018.03.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Abi Hachem R, Goncalves S, Walker T, Angeli S. Middle ear irrigation using a hydrodebrider decreases biofilm surface area in an animal model of otitis media. Laryngoscope Investig Otolaryngol 2018; 3:231-237. [PMID: 30062140 PMCID: PMC6057225 DOI: 10.1002/lio2.164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 03/15/2018] [Accepted: 03/30/2018] [Indexed: 11/16/2022] Open
Abstract
Objective To compare the safety and efficacy of manual and powered irrigation of the middle ear using saline or 1% baby shampoo to treat biofilm‐forming bacterial middle ear infections. Background Biofilms play a major role in recalcitrant otitis media and are challenging to treat. Many therapeutic strategies have been attempted and the role of topical therapies is still being investigated. Topical irrigation using saline or 1% baby shampoo and the use of a hydrodebrider have been investigated in biofilms involved in chronic rhinosinusitis and their role within the middle ear is yet to be determined. Methods Twenty‐two adult chinchillas underwent bilateral trans‐bullar inoculation of non‐typable biofilm forming Haemophilus influenza followed by unilateral middle ear irrigation 5 days later using saline administered via a powered hydrodebrider or manual irrigation of saline or 1% baby shampoo. Contralateral inoculated ears served as control and were not irrigated. Two days following irrigation, the bullae were harvested and processed for scanning electron microscopy to assess biofilm surface area. Auditory brainstem responses were performed before bacterial inoculation and prior to euthanasia. Results Manual and powered irrigation were effective in reducing the surface area of biofilm when compared to the control group. The hydrodebrider demonstrated to be more effective at eradicating biofilm than manual irrigation, especially in areas of difficult access, such as the ventral portion of the chinchillas' bullae. There was no difference in manual irrigation of saline when compared to 1% baby shampoo. Irrigations either manually or using the hydrodebrider did not affect hearing, the vestibular system or facial function. Conclusion Middle ear biofilms can be treated safely and effectively with rinses using either normal saline or 1% baby shampoo administered manually or with a powered hydrodebrider. Level of Evidence NA.
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Walker T, Miyanishi K, Ikuta R, Takahashi H, Vartabi Kashanian S, Tsujimoto Y, Hayasaka K, Yamamoto T, Imoto N, Keller M. Long-Distance Single Photon Transmission from a Trapped Ion via Quantum Frequency Conversion. PHYSICAL REVIEW LETTERS 2018; 120:203601. [PMID: 29864312 DOI: 10.1103/physrevlett.120.203601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Indexed: 06/08/2023]
Abstract
Trapped atomic ions are ideal single photon emitters with long-lived internal states which can be entangled with emitted photons. Coupling the ion to an optical cavity enables the efficient emission of single photons into a single spatial mode and grants control over their temporal shape. These features are key for quantum information processing and quantum communication. However, the photons emitted by these systems are unsuitable for long-distance transmission due to their wavelengths. Here we report the transmission of single photons from a single ^{40}Ca^{+} ion coupled to an optical cavity over a 10 km optical fiber via frequency conversion from 866 nm to the telecom C band at 1530 nm. We observe nonclassical photon statistics of the direct cavity emission, the converted photons, and the 10 km transmitted photons, as well as the preservation of the photons' temporal shape throughout. This telecommunication-ready system can be a key component for long-distance quantum communication as well as future cloud quantum computation.
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