The analysis of the relationship between domestic and silvatic populations of Rhodnius prolixus/robustus (Hemiptera: Reduviidae) in Venezuela by geometric morphometric and molecular methods

Despite four decades of control of Chagas disease in Venezuela, domestic infestations still persist and transmission of Trypanosoma cruzi may be increasing. This is in contrast to the Southern cone region where control has successfully eliminated domestic populations of the main vector Triatoma infestans over large areas. However unlike T. infestans, the main vector in Venezuela, Rhodnius prolixus, has a widespread silvatic distribution occurring primarily in palm trees, which are a ubiquitous feature of the Venezuelan landscape. The palm tree is an important part of campensino life and is maintained for fruit, shade and for use in house construction. Control failures may be due to reinvasion of houses by these prevalent silvatic populations. However, debate exists as to whether the silvatic populations are in fact Rhodnius robustus, a related species of minor epidemiological importance, and therefore no threat to control. With an estimated 800,000 people infected with T. cruzi in Venezuela and a further 3 million at risk of infection, an effective control programme is required, which necessitates that this relationship between silvatic and domestic populations is resolved. This study was undertaken in order to (1) confirm the identity of silvatic populations of Rhodnius in Venezuela and (2) determine if domestic and silvatic populations are isolated, thus to clarify the role of silvatic populations in maintaining house infestations. To achieve these aims field collected silvatic and domestic populations of Rhodnius from 5 States were analysed by genetic methods, direct sequencing (cytochrome b, D2) and microsatellites, and by geometric morphometric analysis. A total of 551 specimens from 31 localities in six Venezuelan states were analysed by direct sequencing of cytochrome b (cytb). Results confirmed the presence of R. prolixus in both silvatic and domestic ecotopes, dispelling the belief that all silvatic populations are R.robustus. Rhodnius robustus does however occur and was found in this study in the Andean State Trujillo. Here it was limited to the silvatic environment. This project found that silvatic and domestic populations of R. prolixus are not isolated, sharing 6 haplotypes, including four silvatic haplotypes also detected in domestic nymphs, indicating that silvatic specimens are capable of domestic colonisation. This was also confirmed from the analysis of adjacent domestic and silvatic populations in Portuguesa and Barinas State where population homogeneity was detected. Additionally cytb analysis identified an introgression event between Amazonian R. robustus and R prolixus, confirmed by incongruence of cytb and D2 nuclear characterisation. Phylogenetic analysis of specimens was also undertaken. To investigate further fine scale population heterogeneity a panel of microsatellite markers, hitherto unavailable, was developed for R prolixus, using an enrichment technique. A panel of 10 loci was available for analysis following PCR screening and linkage analysis. A total of 555 specimens were analysed from 33 populations . Microsatellite analysis also detected population homogeneity between ecotopes, including adjacent populations, indicating that silvatic populations are not isolated. Population heterogeneity was greater among localities in Portuguesa than Barinas, may be due to landscape variation. Differences between control programmes may also play a role. Geometric morphometries identified shape similarity between populations across all States. However, shape convergence by ecotope was detected and results indicated that morphometries might be of limited use for the analysis of populations of R prolixus, with the exception of post-control reinvasion\recrudescent studies. The three methods did not always concur precisely. However comparison was difficult due to detected introgression and shape convergence distorting, respectively, mitochondrial and morphometric analysis. Results indicated that a combined use of microsatellites and morphometries would be beneficial in the analysis of adjacent domestic and silvatic populations. A similar pattern of a lack of isolation between silvatic and domestic ecotopes was detected by both genetic methods, with limited morphometries overlap detected; broadly all three methods showed that populations from differing ecotopes are not isolated. This is also supported by a parallel project on risk-factor analysis. From this study it is clear that silvatic populations of R prolixus present an unquestionable threat to the successful control of Chagas disease in some endemic regions of Venezuela and, unlike the Southern cone, elimination of domestic infestations may not be possible in areas where silvatic R prolixus occur. A restructuring of the control programme in Venezuela is required to deal with this silvatic threat. This may include increased vigilance and methodical respraying and the incorporation of novel approaches to deal with silvatic invasion such as use of insecticide treated curtains; ultimately more investment in the improvement of the rural rancho is required.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Leishmania donovani populations in Eastern Sudan: temporal structuring and a link between human and canine transmission.

BACKGROUND: Visceral leishmaniasis (VL), caused by the members of the Leishmania donovani complex, has been responsible for devastating VL epidemics in the Sudan. Multilocus microsatellite and sequence typing studies can provide valuable insights into the molecular epidemiology of leishmaniasis, when applied at local scales. Here we present population genetic data for a large panel of strains and clones collected in endemic Sudan between 1993 and 2001. METHODS: Genetic diversity was evaluated at fourteen microsatellite markers and eleven nuclear sequence loci across 124 strains and clones. RESULTS: Microsatellite data defined six genetic subpopulations with which the nuclear sequence data were broadly congruent. Pairwise estimates of FST (microsatellite) and KST (sequence) indicated small but significant shifts among the allelic repertoires of circulating strains year on year. Furthermore, we noted the co-occurrence of human and canine L. donovani strains in three of the six clusters defined. Finally, we identified widespread deficit in heterozygosity in all four years tested but strong deviation from inter-locus linkage equilibrium in two years. CONCLUSIONS: Significant genetic diversity is present among L. donovani in Sudan, and minor population structuring between years is characteristic of entrenched, endemic disease transmission. Seasonality in vector abundance and transmission may, to an extent, explain the shallow temporal clines in allelic frequency that we observed. Genetically similar canine and human strains highlight the role of dogs as important local reservoirs of visceral leishmaniasis

Intermittent attendance at breast cancer screening

Background. To determine why women skip rounds and factors influencing return of previous non attenders (PNAs) to breast screening. Design and methods. Retrospective, quantitative, structured questionnaire posted to 2500 women. First PNAs did not attend their first screening appointment in 2007/2008 but then attended in 2010; First Controls first attended in 2010 without missed previous appointments. Women who attended screening in 2006 or earlier then skipped a round but returned in 2010 were Subsequent PNAs; Subsequent Controls attended all appointments.Results. More First Controls than First PNAs had family history of cancer (72.7% vs 63.2%; P=0.003); breast cancer (31.3% vs 24.8%; P=0.04). More PNAs lived rurally; more First PNAs had 3rd level education (33.2% vs 23.6%; P=0.002) and fewer had private insurance than First Controls (57.7% vs 64.8%; P=0.04). Excellent/good health was reported in First PNAs and First Controls (82.9% vs 83.2%), but fewer Subsequent PNAs than Subsequent Controls (72.7% vs 84.9%; P=0.000). Common considerations at time of missed appointment were had mammogram elsewhere (33% First PNA) and postponed to next round (16% First PNA, 18.8% Subsequent PNA). Considerations when returning to screening were similar for First PNAs and Subsequent PNAs: I am older (35.4%, 29.6%), I made sure I remembered (29%, 23.6%), could reschedule (17.6%, 20.6%), illness of more concern (16.5%, 19%). More First PNAs stated my family/friends advised (22.3% vs 15.2%) or my GP (12.6% vs 4.6%) advised me to attend, heard good things about BreastCheck (28.8% vs 13.6%).Conclusions. Intermittent attenders do not fit socio-demographic patterns of non-attenders; GP recommendation and word of mouth were important in women’s return to screening. Fear and anxiety seem to act as a screening facilitator rather than an inhibitor

Effects of negative energy balance on liver gene and protein expression during the early postpartum period and its impacts on dairy cow fertility

End of project reportNegative energy balance (NEB) is a severe metabolic affecting high yielding dairy cows early post partum with both concurrent and latent negative effects on cow fertility as well as on milk production and cow health. The seasonal nature of Irish dairy production necessitates high cow fertility and a compact spring calving pattern in order to maximise grass utilisation. Poor dairy cow reproductive performance currently costs the Irish cattle industry in excess of €400 million annually. High milk yields have been associated with lower reproductive efficiency, and it has been suggested that this effect is probably mediated through its effects on the energy balance of the cow during lactation. The modern high genetic merit dairy cow prioritises nutrient supply towards milk production in early lactation and this demand takes precedence over the provision of optimal conditions for reproduction. In this study we used the bovine Affymetrix 23,000 gene microarray, which contains the most comprehensive set of bovine genes to be assembled and provides a means of investigating the modifying influences of energy balance on liver gene expression. Cows in severe negative energy balance (SNEB) in early lactation showed altered hepatic gene expression in metabolic processes as well as a down regulation of the insulin-like growth factor (IGF) system, where insulin like growth factor-1 (IGF-1), growth hormone receptor variant 1A (GHR1A) and insulin-like growth factor binding protein-acid labile subunit (IGFBP-ALS) were down regulated compared to the cows in the moderate negative energy balance MNEB group, consistent with a five-fold reduction in systemic concentrations of IGF1 in the SNEB group.Cows in SNEB showed elevated expression of key genes involved in the inflammatory response such as interleukin-8 (IL-8). There was a down regulation of genes involved in cellular growth in SNEB cows and moreover a negative regulator of cellular proliferation (HGFIN) was up regulated in SNEB cows, which is likely to compromise adaptation and recovery from NEB. The puma method of analysis revealed that 417 genes were differentially regulated by EB (P<0.05), of these genes 190 were up-regulated while 227 were down-regulated, with 405 genes having known biological functions. From Ingenuity Pathway Analysis (IPA), lipid catabolism was found to be the process most affected by differences in EB status

Affective and perceptual responses during reduced-exertion high-intensity interval training (REHIT)

We have previously demonstrated that reduced-exertion high-intensity interval training (REHIT) is a genuinely time-efficient exercise strategy for improving cardiometabolic health. Here, we examined the affective and perceptual responses to REHIT. Eight young men and women (age 21 ± 1 y, BMI 24.9 ± 2.1 m/kg2, V̇O2max 39 ± 10 ml/kg/min) and 11 men with type 2 diabetes (T2D; age 52 ± 6 y, BMI 29.7 ± 3.1 m/kg2, V̇O2max 29 ± 5 ml/kg/min) took part in three-arm crossover trials with RPE and affective valence measured during, and enjoyment and exercise preferences measured following either: 1) REHIT (2 × 20-s sprints in a 10-min exercise session), 2) HIIT (10 × 1-min efforts) and 3) 30 min MICT. Furthermore, 19 young men and women (age 25 ± 6 y, BMI 24 ± 4 m/kg2, V̇O2max 34 ± 8 ml/kg/min) completed a 6-week REHIT intervention with affective valence during an acute REHIT session measured before and after training. Affect decreases (briefly) during REHIT, but recovers rapidly, and the decline is not significantly different when compared to MICT or HIIT in either healthy participants or T2D patients. Young sedentary participants reported similar levels of enjoyment for REHIT, MICT and HIIT, but 7 out of 8 had a preference for REHIT. Conversely, T2D patients tended to report lower levels of enjoyment with REHIT compared with MICT. The decrease in affective valence observed during an acute REHIT session was significantly attenuated following training. We conclude that affective and perceptual responses to REHIT are no more negative compared to those associated with MICT or HIIT, refuting claims that supramaximal sprint interval training protocols are associated with inherent negative responses

temporal structuring and a link between human and canine transmission

Background Visceral leishmaniasis (VL), caused by the members of the Leishmania donovani complex, has been responsible for devastating VL epidemics in the Sudan. Multilocus microsatellite and sequence typing studies can provide valuable insights into the molecular epidemiology of leishmaniasis, when applied at local scales. Here we present population genetic data for a large panel of strains and clones collected in endemic Sudan between 1993 and 2001. Methods Genetic diversity was evaluated at fourteen microsatellite markers and eleven nuclear sequence loci across 124 strains and clones. Results Microsatellite data defined six genetic subpopulations with which the nuclear sequence data were broadly congruent. Pairwise estimates of FST (microsatellite) and KST (sequence) indicated small but significant shifts among the allelic repertoires of circulating strains year on year. Furthermore, we noted the co-occurrence of human and canine L. donovani strains in three of the six clusters defined. Finally, we identified widespread deficit in heterozygosity in all four years tested but strong deviation from inter-locus linkage equilibrium in two years. Conclusions Significant genetic diversity is present among L. donovani in Sudan, and minor population structuring between years is characteristic of entrenched, endemic disease transmission. Seasonality in vector abundance and transmission may, to an extent, explain the shallow temporal clines in allelic frequency that we observed. Genetically similar canine and human strains highlight the role of dogs as important local reservoirs of visceral leishmaniasis

Anomalies in low-energy Gamma-Ray Burst spectra with the Fermi Gamma-Ray Burst Monitor

A Band function has become the standard spectral function used to describe the prompt emission spectra of gamma-ray bursts (GRBs). However, deviations from this function have previously been observed in GRBs detected by BATSE and in individual GRBs from the \textit{Fermi} era. We present a systematic and rigorous search for spectral deviations from a Band function at low energies in a sample of the first two years of high fluence, long bursts detected by the \textit{Fermi} Gamma-Ray Burst Monitor (GBM). The sample contains 45 bursts with a fluence greater than 2$\times10^{-5}$ erg / cm$^{2}$ (10 - 1000 keV). An extrapolated fit method is used to search for low-energy spectral anomalies, whereby a Band function is fit above a variable low-energy threshold and then the best fit function is extrapolated to lower energy data. Deviations are quantified by examining residuals derived from the extrapolated function and the data and their significance is determined via comprehensive simulations which account for the instrument response. This method was employed for both time-integrated burst spectra and time-resolved bins defined by a signal to noise ratio of 25 $\sigma$ and 50 $\sigma$. Significant deviations are evident in 3 bursts (GRB\,081215A, GRB\,090424 and GRB\,090902B) in the time-integrated sample ($\sim$ 7%) and 5 bursts (GRB\,090323, GRB\,090424, GRB\,090820, GRB\,090902B and GRB\,090926A) in the time-resolved sample ($\sim$ 11%).} The advantage of the systematic, blind search analysis is that it can demonstrate the requirement for an additional spectral component without any prior knowledge of the nature of that extra component. Deviations are found in a large fraction of high fluence GRBs; fainter GRBs may not have sufficient statistics for deviations to be found using this method

PCR-ribotype distribution of Clostridium difficile in Irish pigs

Clostridium difficile is an important enteric pathogen in humans causing infections in the healthcare environment and the community. Carriage of C. difficile and C. difficile-related enterocolitis has been reported in piglets worldwide. The aim of this study was to investigate the rates of C. difficile isolation from pigs in Ireland. Faecal samples from piglet litters and sows were collected from six farms in 2015. The sows were non-diarrhoeal at the time of sampling. The diarrhoeal status of the piglets was unknown. C. difficile was isolated from 34/44 (77%) of piglet litter samples and from 33/156 (21%) of sow samples. The isolation rate in sows varied from 3 to 39% and in piglet litters from 72 to 86% depending on farm location. Toxin A and toxin B were present in 99% (66/67) of isolates; and binary toxin in 85% (57/67). Only PCR-ribotypes 078 (88%) and 193 (12%) were identified in piglets. Seven PCR-ribotypes were detected in sow C. difficile isolates: PCR-ribotypes 078 (67%), 050 (12%), 014/020 (6%), 015 (6%), 029 (3%), 035 (3%) and 193 (3%). This study shows that toxigenic C. difficile strains such as PCR-ribotype 078 can be commonly isolated from pigs at different geographical locations in Ireland. Since PCR-ribotype 078 is frequently found in humans in Ireland, this highlights the potential for interspecies transmission

Protecting older people living in care homes from COVID-19 : a protocol for a mixed-methods study to understand the challenges and solutions to implementing social distancing and isolation.

Older people living in residential and nursing care homes often have complex needs and are at high risk of poor health outcomes and mortality, especially if they contract COVID-19. Care homes use infection prevention and control measures such as social distancing and isolating residents to protect them from COVID-19. The care home sector has stated that implementing social distancing and isolation when caring for residents is a significant challenge. This paper presents the protocol of a mixed-methods study to explore and understand the real-life experiences of implementing social distancing and isolation of residents in care homes for older people from the perspective of residents, families/friends and staff working in and with care homes. The study aims to develop a toolkit of resources for health and care delivery now and for future outbreaks of infectious diseases. The study will be conducted in three phases. Phase 1 is a rapid review of evidence to collate knowledge on the mechanisms and measures used by care homes and long-term facilities to socially distance and isolate older people or control the spread of other infectious and contagious diseases. The review results will contribute to participant interviews in phase 2 and toolkit development in phase 3. Phase 2 will involve case studies with six care homes in England, involving the conduct of individual interviews with residents, families and friends, and staff, collection of care home policies and protocols related to social distancing and isolation for residents, and routinely collected care home data. A focus group with a purposive sample of external key informants will also be conducted. Phase 3, synthesising findings from phases 1 and 2, will inform the codesign of a toolkit of resources for residents, families/friends and care homes. The study has been approved by Coventry and Warwick Research Ethics Committee (20/WM/0318). To maximise impact, we will work closely with the Study Committees and the Patient and Public Involvement group to ensure the findings reach key stakeholders, including residents, families/friends, care homes, commissioners and organisations representing care home providers. We will disseminate the study outputs in peer-reviewed and professional journals, at professional conferences and via other knowledge transfer activities with the care home sector, and resident and carer organisations. The toolkit comprising evidence-informed guidance and resources and a mosaic film will be hosted on a project webpage. This project is funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research Programme (Project reference NIHR132541). The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. CRD42021226734. [Abstract copyright: © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.