The molecular epidemiology of trypanosoma cruzi infection in wild and domestic transmission cycles with special emphasis on multilocus microsatellite analysis

Trypanosoma cruzi is a zoonotic vector-bome unicellular parasite, with a highly complex silvatic ecology, and native to the Americas. Substantial genetic diversity has been identified in T. cruzi populations, with six phylogenetic groups or Discrete Typing Groups (DTUs) commonly recognised: TCI, TCIIa, TCIIb, TCIIc, TCIId, and TCIIe. The silvatic affinities of these groups are poorly defined, although broad associations between some lineages and distinct ecological niches are recognised. Additionally, a number of studies have demonstrated a degree of within-DTU diversity, and the current classification may be a poor reflection of the total diversity present. In this PhD thesis the genetic diversity of silvatic T. cruzi is examined, in conjunction with a limited number of domestic strains, to investigate the underlying ecological and epidemiological phenomena that dictate the population genetic structure of this parasite. >200 new T. cruzi and Trypanosoma rangeli isolates, including those from silvatic mammals, domestic and peridomestic triatomine bugs, were collected during fieldwork in Venezuela and Bolivia. Where possible, these isolates were genotyped to a DTU level, and the epidemiological significance of these data discussed. Original silvatic genotype data from this study were then compiled with >1000, historical records (1981-2007) for both mammals and triatomines. This dataset was subjected to basic statistical analysis, and strong support found for an association between parasite genotype, silvatic niche, and triatomine vector. Within-DTU genetic diversity was established for ~200 isolates from two widespread silvatic genotypes, TCI and TCIIc, using a genome-wide panel of 49 microsatellite markers, in tandem with sequence analysis. Substantial genetic diversity was identified in both lineages, coincident with weak spatial structuring. The possibility a population bottleneck was investigated within TCI derived from Andean rodent populations. Moreover, the possibility of a bottleneck was also examined in geographically dispersed human TCI isolates taken from lowland Venezuela. Associated epidemiological implications are discussed. Genetic diversity in TCI was additionally examined at a within-host level. A total of 211 clones were taken from eight mammals, and analysed using a subset of microsatellite markers. Again substantial genetic diversity was evident, with stable infection of the same mammal by a number of different stains. Limited evidence of genetic exchange was also observed, but could not be confirmed, and the implications of this are also discussed

Strong Double Higgs Production at the LHC

The hierarchy problem and the electroweak data, together, provide a plausible motivation for considering a light Higgs emerging as a pseudo-Goldstone boson from a strongly-coupled sector. In that scenario, the rates for Higgs production and decay differ significantly from those in the Standard Model. However, one genuine strong coupling signature is the growth with energy of the scattering amplitudes among the Goldstone bosons, the longitudinally polarized vector bosons as well as the Higgs boson itself. The rate for double Higgs production in vector boson fusion is thus enhanced with respect to its negligible rate in the SM. We study that reaction in pp collisions, where the production of two Higgs bosons at high pT is associated with the emission of two forward jets. We concentrate on the decay mode hh -> WW^(*)WW^(*) and study the semi-leptonic decay chains of the W's with 2, 3 or 4 leptons in the final states. While the 3 lepton final states are the most relevant and can lead to a 3 sigma signal significance with 300 fb^{-1} collected at a 14 TeV LHC, the two same-sign lepton final states provide complementary information. We also comment on the prospects for improving the detectability of double Higgs production at the foreseen LHC energy and luminosity upgrades.Comment: 54 pages, 26 figures. v2: typos corrected, a few comments and one table added. Version published in JHE

The pharmaceutical use of permethrin: Sources and behavior during municipal sewage treatment

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2010 Springer Science+Business Media, LLC.Permethrin entered use in the 1970s as an insecticide in a wide range of applications, including agriculture, horticultural, and forestry, and has since been restricted. In the 21st century, the presence of permethrin in the aquatic environment has been attributed to its use as a human and veterinary pharmaceutical, in particular as a pedeculicide, in addition to other uses, such as a moth-proofing agent. However, as a consequence of its toxicity to fish, sources of permethrin and its fate and behavior during wastewater treatment are topics of concern. This study has established that high overall removal of permethrin (approximately 90%) was achieved during wastewater treatment and that this was strongly dependent on the extent of biological degradation in secondary treatment, with more limited subsequent removal in tertiary treatment processes. Sources of permethrin in the catchment matched well with measured values in crude sewage and indicated that domestic use accounted for more than half of the load to the treatment works. However, removal may not be consistent enough to achieve the environmental quality standards now being derived in many countries even where tertiary treatment processes are applied.United Utilities PL

Composite Higgs Sketch

The coupling of a composite Higgs to the standard model fields can deviate substantially from the standard model values. In this case perturbative unitarity might break down before the scale of compositeness is reached, which would suggest that additional composites should lie well below this scale. In this paper we account for the presence of an additional spin 1 custodial triplet of rhos. We examine the implications of requiring perturbative unitarity up to the compositeness scale and find that one has to be close to saturating certain unitarity sum rules involving the Higgs and the rho couplings. Given these restrictions on the parameter space we investigate the main phenomenological consequences of the spin 1 triplet. We find that they can substantially enhance the Higgs di-photon rate at the LHC even with a reduced Higgs coupling to gauge bosons. The main existing LHC bounds arise from di-boson searches, especially in the experimentally clean channel where the charged rhos decay to a W-boson and a Z, which then decay leptonically. We find that a large range of interesting parameter space with 700 GeV < m(rho) < 2 TeV is currently experimentally viable.Comment: 37 pages, 12 figures; v4: sum rule corrected, conclusions unchange

Sex, Subdivision, and Domestic Dispersal of Trypanosoma cruzi Lineage I in Southern Ecuador

Trypanosoma cruzi is transmitted by blood sucking insects known as triatomines. This protozoan parasite commonly infects wild and domestic mammals in South and Central America. However, triatomines also transmit the parasite to people, and human infection with T. cruzi is known as Chagas disease, a major public health concern in Latin America. Understanding the complex dynamics of parasite spread between wild and domestic environments is essential to design effective control measures to prevent the spread of Chagas disease. Here we describe T. cruzi genetic diversity and population dynamics in southern Ecuador. Our findings indicate that the parasite circulates in two largely independent cycles: one corresponding to the sylvatic environment and one related to the domestic/peridomestic environment. Furthermore, our data indicate that human activity might promote parasite dispersal among communties. This information is the key for the design of control programmes in Southern Ecuador. Finally, we have encountered evidence of a sexual reproductive mode in the domestic T. cruzi population, which constitutes a new and intriguing finding with regards to the biology of this parasite

Illness cognitions in head and neck squamous cell carcinoma: predicting quality of life outcome

Goals of work: This paper presents an observational study of the longitudinal effects of cancer treatment on quality of life (QoL) in patients treated for head and neck squamous cell carcinoma (HNSCC), and evaluated the contribution of patients' baseline illness cognitions to the prediction of QoL 2 years after diagnosis. Patients and methods: One hundred seventy-seven patients eligible for primary treatment for HNSCC completed the Illness Perception Questionnaire-Revised at baseline and the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire-30 at baseline, at 1-year and 2-year follow-ups. Main results Compared to baseline, patients reported better emotional functioning at both follow-ups (p<0.001), worse social functioning at 12 months (p<0.05), and better global health

Chagas Cardiomyopathy Manifestations and Trypanosoma cruzi Genotypes Circulating in Chronic Chagasic Patients

Chagas disease caused by Trypanosoma cruzi is a complex disease that is endemic and an important problem in public health in Latin America. The T. cruzi parasite is classified into six discrete taxonomic units (DTUs) based on the recently proposed nomenclature (TcI, TcII, TcIII, TcIV, TcV and TcVI). The discovery of genetic variability within TcI showed the presence of five genotypes (Ia, Ib, Ic, Id and Ie) related to the transmission cycle of Chagas disease. In Colombia, TcI is more prevalent but TcII has also been reported, as has mixed infection by both TcI and TcII in the same Chagasic patient. The objectives of this study were to determine the T. cruzi DTUs that are circulating in Colombian chronic Chagasic patients and to obtain more information about the molecular epidemiology of Chagas disease in Colombia. We also assessed the presence of electrocardiographic, radiologic and echocardiographic abnormalities with the purpose of correlating T. cruzi genetic variability and cardiac disease. Molecular characterization was performed in Colombian adult chronic Chagasic patients based on the intergenic region of the mini-exon gene, the 24Sα and 18S regions of rDNA and the variable region of satellite DNA, whereby the presence of T.cruzi I, II, III and IV was detected. In our population, mixed infections also occurred, with TcI-TcII, TcI-TcIII and TcI-TcIV, as well as the existence of the TcI genotypes showing the presence of genotypes Ia and Id. Patients infected with TcI demonstrated a higher prevalence of cardiac alterations than those infected with TcII. These results corroborate the predominance of TcI in Colombia and show the first report of TcIII and TcIV in Colombian Chagasic patients. Findings also indicate that Chagas cardiomyopathy manifestations are more correlated with TcI than with TcII in Colombia

The relationship between appetite and food preferences in British and Australian children

Background: Appetitive traits and food preferences are key determinants of children’s eating patterns but it is unclear how these behaviours relate to one another. This study explores relationships between appetitive traits and preferences for fruits and vegetables, and energy dense, nutrient poor (noncore) foods in two distinct samples of Australian and British preschool children. Methods: This study reports secondary analyses of data from families participating in the British GEMINI cohort study (n = 1044) and the control arm of the Australian NOURISH RCT (n = 167). Food preferences were assessed by parent-completed questionnaire when children were aged 3–4 years and grouped into three categories; vegetables, fruits and noncore foods. Appetitive traits; enjoyment of food, food responsiveness, satiety responsiveness, slowness in eating, and food fussiness were measured using the Children’s Eating Behaviour Questionnaire when children were 16 months (GEMINI) or 3–4 years (NOURISH). Relationships between appetitive traits and food preferences were explored using adjusted linear regression analyses that controlled for demographic and anthropometric covariates. Results: Vegetable liking was positively associated with enjoyment of food (GEMINI; β = 0.20 ± 0.03, p < 0.001, NOURISH; β = 0.43 ± 0.07, p < 0.001) and negatively related to satiety responsiveness (GEMINI; β = -0.19 ± 0.03, p < 0.001, NOURISH; β = -0.34 ± 0.08, p < 0.001), slowness in eating (GEMINI; β = -0.10 ± 0.03, p = 0.002, NOURISH; β = -0.30 ± 0.08, p < 0.001) and food fussiness (GEMINI; β = −0.30 ± 0.03, p < 0.001, NOURISH; β = -0.60 ± 0.06, p < 0.001). Fruit liking was positively associated with enjoyment of food (GEMINI; β = 0.18 ± 0.03, p < 0.001, NOURISH; β = 0.36 ± 0.08, p < 0.001), and negatively associated with satiety responsiveness (GEMINI; β = −0.13 ± 0.03, p < 0.001, NOURISH; β = −0.24 ± 0.08, p = 0.003), food fussiness (GEMINI; β = -0.26 ± 0.03, p < 0.001, NOURISH; β = −0.51 ± 0.07, p < 0.001) and slowness in eating (GEMINI only; β = -0.09 ± 0.03, p = 0.005). Food responsiveness was unrelated to liking for fruits or vegetables in either sample but was positively associated with noncore food preference (GEMINI; β = 0.10 ± 0.03, p = 0.001, NOURISH; β = 0.21 ± 0.08, p = 0.010). Conclusion: Appetitive traits linked with lower obesity risk were related to lower liking for fruits and vegetables, while food responsiveness, a trait linked with greater risk of overweight, was uniquely associated with higher liking for noncore foods

Analyses of 32 Loci Clarify Phylogenetic Relationships among Trypanosoma cruzi Lineages and Support a Single Hybridization prior to Human Contact

Trypanosoma cruzi is the protozoan parasite that causes Chagas disease, a major health problem in Latin America. The genetic diversity of this parasite has been traditionally divided in two major groups: T. cruzi I and II, which can be further divided in six major genetic subdivisions (subgroups TcI-TcVI). T. cruzi I and II seem to differ in important biological characteristics, and are thought to represent a natural division relevant for epidemiological studies and development of prophylaxis. Having a correct reconstruction of the evolutionary history of T. cruzi is essential for understanding the potential connection between the genetic and phenotypic variability of T. cruzi with the different manifestations of Chagas disease. Here we present results from a comprehensive phylogenetic analysis of T. cruzi using more than 26 Kb of aligned sequence data. We show strong evidence that T. cruzi II (TcII-VI) is not a natural evolutionary group but a paraphyletic lineage and that all major lineages of T. cruzi evolved recently (<3 million years ago [mya]). Furthermore, the sequence data is consistent with one major hybridization event having occurred in this species recently (< 1 mya) but well before T. cruzi entered in contact with humans in South America

Body composition impacts appetite regulation in middle childhood. A prospective study of Norwegian community children

Background Research suggests a role for both fat mass and muscle mass in appetite regulation, but the longitudinal relationships between them have not yet been examined in children. The present study therefore aimed to explore the prospective relationships between fat mass, muscle mass and the appetitive traits food responsiveness and satiety responsiveness in middle childhood. Methods Food responsiveness and satiety responsiveness were measured using the parent-reported Children’s Eating Behavior Questionnaire in a representative sample of Norwegian 6 year olds, followed up at 8 and 10 years of age (n = 807). Body composition was measured by bioelectrical impedance. Results Applying a structural equation modeling framework we found that higher fat mass predicted greater increases in food responsiveness over time, whereas greater muscle mass predicted decreases in satiety responsiveness. This pattern was consistent both from ages 6 to 8 and from ages 8 to 10 years. Conclusions Our study is the first to reveal that fat mass and muscle mass predict distinct changes in different appetitive traits over time. Replication of findings in non-European populations are needed, as are studies of children in other age groups. Future studies should also aim to reveal the underlying mechanisms