Influence of Nesting Material Composition on Tick Tube Use by Peromyscus leucopus

Host-targeted acaricides are a valuable tool for the reduction of ticks and tick-borne disease. Tick tubes (also known as tick control tubes) are commercially available products containing permethrin-treated nesting materials. Through superficial acaricide application to Peromyscus mice, tick tubes reduce populations of the blacklegged tick, Ixodes scapularis Say. Results of prior field trials have varied, suggesting that mouse behavior as well as the scale of the intervention and the composition of the local host community are important determinants of efficacy. Here we evaluated behaviors related to nest material collection by P. leucopus. Two forms of nest materials used in commercial tick tube products (cotton batting and balls) were assessed through side-by-side comparisons over a four-week period. We quantified cotton uptake by monitoring weekly changes in material weight and used video surveillance to categorize and assess mouse behaviors. The odds of cotton batting being taken from tubes was 2.14 times greater than cotton balls but the process was less efficient; mice removed 0.35 g less cotton batting for each removal event and required 2.17 times longer to complete the removal. While cotton balls were readily carried in the jaws of mice, batting required separating smaller fragments from the mass before placement in the oral cavity. Video surveillance suggested that a small number of mice were super users and responsible for 22% of the 119 visits in which material was removed. Combined, material weight loss and video-captured removal events improve our understanding of host usage of nest materials but also raise questions about dissemination of the material in nests of the local mouse community.

Neutrophil Depletion Enhanced the Clostridium novyi-NT Therapy in Mouse and Rabbit Tumor Models

Background Hypoxia is a prominent feature of solid tumors and can function as fertile environment for oncolytic anaerobic bacteria such as Clostridium novyi-NT (C. novyi-NT) where it can induce tumor destruction in mice and patients. However, two major obstacles have limited its use, namely the host inflammatory response and the incomplete clearance of normoxic tumor areas. Methods In this study, we first used a subcutaneous tumor model of a glioblastoma (GBM) cell line in immunocompetent mice to investigate the local distribution of tumor hypoxia, kinetics of C.novyi-NT germination and spread, and the local host immune response. We subsequently applied the acquired knowledge to develop a C.novyi-NT therapy in an orthotopic rabbit brain tumor model. Results We found that local accumulation of granular leukocytes, mainly neutrophils, could impede the spread of bacteria through the tumor and prevented complete oncolysis. Depletion of neutrophils via anti-Ly6G antibody or bone marrow suppression using hydroxyurea significantly improved tumor clearance. We then applied this approach to rabbits implanted with an aggressive intracranial brain tumor and achieved long term survival in majority of the animals without apparent toxicity. Conclusion These results indicated that depleting neutrophils can greatly enhance the safety and efficacy of C.novyi-NT cancer therapy for brain tumors.

Heritage Stone 8. Formation of Pinolitic Magnesite at Quartz Creek, British Columbia, Canada: Inferences from Preliminary Petrographic, Geochemical and Geochronological Studies

Rocks in the Late Proterozoic Horsethief Creek Group at Quartz Creek in British Columbia display rare ‘pinolitic’ textures resembling those described in some sparry magnesite deposits elsewhere in the world. Elongated white magnesite crystals up to 30 cm long occur in a contrasting, dark, fine-grained matrix of dolomite, chlorite, organic material, clay minerals and pyrite. The rocks are aesthetically appealing for use in sculpture and as dimension stone. The term ‘pinolite’ is derived from the superficial similarities between these unusual textures and pinecones. Petrographic examination indicates that these textures formed when metasomatic fluids replaced primary sedimentary dolomite with magnesite. Fluids moved along fractures and bedding planes with repeated fracturing yielding magnesite crystals oriented in opposite directions on either side of annealed fractures, and broken magnesite crystals adjacent to later fractures. Magnesite contains dolomite microinclusions and has elevated Ca contents that are consistent with its formation by replacement of dolomite. Low concentrations of Cr, Ni, Co, Ti, Sr, and Ba in magnesite also imply formation in a metasomatic rather than a sedimentary environment. The rare earth element (REE) concentrations in the Quartz Creek magnesite are higher than those in most evaporitic magnesite and REE patterns lack the Ce and Eu anomalies that characterize carbonate rocks from sedimentary environments. Enrichment in light REE relative to heavy REE, and the similarities between dolomite, chlorite, and magnesite REE profiles, imply that metasomatic fluids modified the original sedimentary geochemical signature of the dolostones during formation of the pinolite rocks. A Late Ordovician to Early Silurian U–Pb age (433 ± 12 Ma), for titanite in the black matrix surrounding the sparry magnesite is younger than the local host rocks, and also younger than the Mesoproterozoic to Middle Cambrian stratigraphic ages of the host rocks for nearby magnesite deposits. The ca. 433 Ma titanite overlaps the ages for numerous fault-associated diatremes and volcaniclastic deposits in the area. Possibly the igneous activity furnished heat for, and/or was the source for, metasomatic fluids that produced the pinolite deposits.

Colonization and local host response following intramammary Staphylococcus chromogenes challenge in dry cows

Although extensive research has been performed on bovine non-aureus staphylococci (NAS), several aspects such as bacteria-host interaction remain largely unstudied. Moreover, only a few mastitis pathogen challenge studies in cows have been conducted in the dry period, an important period that allows intramammary infection (IMI) to cure and new IMI to occur. We challenged 16 quarters of 4 Holstein Friesian cows at dry off with 100; 100 000 or 10 000 000 CFU of the udder-adapted S. chromogenes IM strain. Four quarters from one cow served as negative controls. Internally sealed quarters remained untouched, whereas non-sealed quarters were sampled 3 times during the dry period. After parturition, colostrum and daily milk samples were taken during the first week of lactation of all quarters. In total, 8 quarters appeared to be colonized, since S. chromogenes IM was recovered at least once during the experiment, as substantiated using Multilocus Sequence Typing. S. chromogenes IM shedding was highest in dry quarters inoculated with 10 000 000 CFU. Colonized quarters had the highest quarter somatic cell count (qSCC) in early lactation. Inoculated quarters (both colonized and non-colonized) had lower IL-6 and IL-10 concentrations in the dry period, whilst IFN-γ levels tended to be higher in colonized quarters compared to non-inoculated quarters. Also, IgG2 levels were higher in inoculated compared to non-inoculated quarters and the IgG2/IgG1 ratio was on average above 1. To conclude, we showed that dry quarters can be colonized with S. chromogenes IM, resulting in a shift towards a Th1 response in late gestation and early lactation characterised by an increased IgG2 concentration. However, further research is needed to confirm our findings.

Viral etiology of acute gastroenteritis among Forcibly Displaced Myanmar Nationals and adjacent host population in Bangladesh

Background Since August 2017 Myanmar nationals from Rakhine state have crossed the border into Bangladesh and settled in Cox’s Bazar, the World's largest refugee camp. Due to overcrowding, poor sanitation, and hygienic practices they have been under significant health risks including diarrheal diseases. Objective To determine the viral etiology of acute gastroenteritis (AGE) among forcibly displaced Myanmar nationals (FDMN) and adjacent Bangladeshi local host population (AHP). Methods From April 2018 to April 2019, we collected stool specimens from 764 FDMN and 1159 AHP of all ages. We tested 100 randomly selected specimens from each group for the most common acute gastroenteritis viruses. Results Among 200 diarrhea patients, 55% and 64% of FDMN and AHP patients respectively had viral infections; the most common viruses were rotavirus (29% vs 44%), adenovirus (24% vs 31%) and norovirus (14% vs 10%). In both populations, viral infections were significantly higher in children less than five years; compared to bacterial infections which were higher in patients older than five years of age (p=<0.05). Conclusion Disparities in viral and bacterial prevalence among various age groups warrant careful antibiotic usage, especially in children less than five years.

Short- and long-range cis interactions between integrated HPV genomes and cellular chromatin dysregulate host gene expression in early cervical carcinogenesis

Development of cervical cancer is directly associated with integration of human papillomavirus (HPV) genomes into host chromosomes and subsequent modulation of HPV oncogene expression, which correlates with multi-layered epigenetic changes at the integrated HPV genomes. However, the process of integration itself and dysregulation of host gene expression at sites of integration in our model of HPV16 integrant clone natural selection has remained enigmatic. We now show, using a state-of-the-art ‘HPV integrated site capture’ (HISC) technique, that integration likely occurs through microhomology-mediated repair (MHMR) mechanisms via either a direct process, resulting in host sequence deletion (in our case, partially homozygously) or via a ‘looping’ mechanism by which flanking host regions become amplified. Furthermore, using our ‘HPV16-specific Region Capture Hi-C’ technique, we have determined that chromatin interactions between the integrated virus genome and host chromosomes, both at short- (<500 kbp) and long-range (>500 kbp), appear to drive local host gene dysregulation through the disruption of host:host interactions within (but not exceeding) host structures known as topologically associating domains (TADs). This mechanism of HPV-induced host gene expression modulation indicates that integration of virus genomes near to or within a ‘cancer-causing gene’ is not essential to influence their expression and that these modifications to genome interactions could have a major role in selection of HPV integrants at the early stage of cervical neoplastic progression.

Behavioural Response in an Asilid Fly: Influence of Ecological and Environmental Factors on Spatial Density Dependence

Behavioural response of a parasitoid shows the effect on host parasitism patterns at a given host distribution resulting in an increase or decrease of parasitism intensity according to local host densities. This relationship could be proportional, positive, or negative, as a consequence of foraging of parasitoids searching for hosts. Mallophora ruficauda is a fly parasitoid of Cyclocephala signaticollis scarab beetle larvae and a predator of honeybees. Females search and place egg-clusters overground in open grasslands near beehives. Larvae actively searching for host underground following chemical cues arising from the host itself. The parasitism pattern is a result of this complex host-searching strategy which is shared between both stages of the fly. In this work we carried out a study at four spatial scales in apiaries located in the Pampas region of Argentina. We found that parasitism is inverse density-dependent at high female activity and direct density-dependent at low female activity at the larger spatial scale. We found a direct density dependent pattern associated to substrate height at intermediate spatial scale that is lost when the habitat has abundant oviposition substrates. Conversely, parasitism is inversely density-dependent at both smaller spatial scales, associated to oviposition substrate distance and saturation of healthy host by larvae attacking. Additionally, M. ruficauda does not select the oviposition substrates according to the abundance of Cyclocephala signaticollis inhabiting underground. This work shows the importance of a proper scale for analysis of factors that influence population dynamics and how environmental characteristics mould parasitism patterns in this dipteran parasitoid.

Examining prevalence and diversity of tick-borne pathogens in questing Ixodes pacificus ticks in California.

Tick-borne diseases in California include Lyme disease (caused by Borrelia burgdorferi), infections with Borrelia miyamotoi, and human granulocytic anaplasmosis (caused by Anaplasma phagocytophilum). We surveyed multiple sites and habitats (woodland, grassland, coastal chaparral) in California to describe spatial patterns of tick-borne pathogen prevalence in western black-legged ticks (Ixodes pacificus). We found that several species of Borrelia – B. burgdorferi, B. americana and B. bissettiae - were observed in habitats such as coastal chaparral that does not harbor obvious reservoir host candidates. Describing tick-borne pathogen prevalence is strongly influenced by the scale of surveillance: aggregating data from individual sites to match jurisdictional boundaries (e.g., county or state) can lower the reported infection prevalence. Considering multiple pathogen species in the same habitat allows a more cohesive interpretation of local pathogen occurrence. Importance Understanding the local host ecology and prevalence of zoonotic diseases is vital for public health. Using tick-borne diseases in California, we show that there is often a bias to our understanding and that studies tend to focus on particular habitats e.g., Lyme disease in oak woodlands. Other habitats may harbor a surprising diversity of tick-borne pathogens but have been neglected, e.g., coastal chaparral. Explaining pathogen prevalence requires descriptions of data at a local scale; otherwise, aggregating the data can misrepresent the local dynamics of tick-borne diseases.

Host-guest interaction: A retrospective analysis of the conflict between sons of second homeowners and local youth – The case of Vall de Lord (Catalonia)

While various aspects of host-guest conflict have been studied, there has been little published about the relationship between the local community and second homeowners, particularly the male youth population, who often expressed their concerns in a more direct and violent manner. This is a retrospective case study of Vall de Lord, in which one of the authors was a participant, depicted as reflective, ethnographic participant-observation. Combining personal reflection with conversations in the form of interviews and focus group discussions, it provides an opportunity to apply the results to the development of a theoretical model. The findings indicate that the most important factors affecting this relationship were external (environmental), and internal (intrinsic). Appling thematic analysis the study found that the attitudes and behaviour of the local community towards the sons of second home owners sit well with Ajzen’s Theory of Planned Behaviour. This study contributes to our understanding of the relationship between local host communities and second homeowners as a social phenomenon, and how this relationship is affected by the nature of the encounter and the contested identities, values and beliefs of each group when they coexist in the same time and space.

Socioeconomic Status Changes of the Host Communities after the Rohingya Refugee Influx in the Southern Coastal Area of Bangladesh

The refugee influx from Myanmar, known as Rohingya refugees, is a serious concern for global refugee issues. Bangladesh currently hosts one million Rohingya refugees in the coastal district of Cox’s Bazar. Considering the number of the refugees, in addition to the humanitarian concerns, they are also creating pressure on the local host communities. This study explored the socioeconomic changes of the host communities after the refugee influx. In order to fulfill this study’s objectives, 35 villages near the Rohingya refugee camps from the coastal district of Bangladesh were surveyed. In the villages, 10% of households were surveyed in 2016 and also in 2020, covering 1924 and 2265 households, respectively. A temporal comparison of the host community’s socioeconomic status between 2016 and 2020 was conducted in order to determine the changes after the recent refugee influx. This study found that the local community’s socioeconomic status degraded. The annual income decreased by 24%, which is unusual for a country with over 6% gross domestic product (GDP) growth in recent times. The income decreased from all livelihood options except farming, which could be related to the availability of cheap labor and the high demand for commodities. The villages were clustered using k-means, and 20 villages were found to be affected after the refugee influx with degraded socioeconomic status. The host community’s general perception was initially positive, but later turned negative toward the refugees. This study will be important for the government and donor agencies to develop strategies to properly manage the refugee camps and adjacent host communities.