Competition between two virulent Marek's disease virus strains in vivo

Previous studies have demonstrated the presence of multiple strains of Marek's disease virus simultaneously circulating within poultry flocks, leading to the assumption that individual birds are repeatedly exposed to a variety of virus strains in their lifetime. Virus competition within individual birds may be an important factor that influences the outcome of co-infection under field conditions, including the potential outcome of emergence or evolution of more virulent strains. A series of experiments was designed to evaluate virus competition within chickens following simultaneous challenge with two virulent serotype 1 Marek's disease virus strains, using either pathogenically similar (rMd5 and rMd5/pp38CVI) or dissimilar (JM/102W and rMd5/pp38CVI) virus pairs. Bursa of Fabricius, feather follicle epithelium, spleen, and tumour samples were collected at multiple time points to determine the frequency and distribution of each virus present using pyrosequencing, immunohistochemistry and virus isolation. In the similar pair, rMd5 appeared to have a competitive advantage over rMd5/pp38CVI, which in turn had a competitive advantage over the less virulent JM/102W in the dissimilar virus pair. Dominance of one strain over the other was not absolute for either virus pair, as the subordinate virus was rarely eliminated. Interestingly, competition between two viruses with either pair rarely ended in a draw. Further work is needed to identify factors that influence virus-specific dominance to better understand what characteristics favour emergence of one strain in chicken populations at the expense of other strains.     

Development of a Conceptual Framework for Understanding Shared Decision making Among African-American LGBT Patients and their Clinicians

BACKGROUND

Enhancing patient-centered care and shared decision making (SDM) has become a national priority as a means of engaging patients in their care, improving treatment adherence, and enhancing health outcomes. Relatively little is known about the healthcare experiences or shared decision making among racial/ethnic minorities who also identify as being LGBT. The purpose of this paper is to understand how race, sexual orientation and gender identity can simultaneously influence SDM among African-American LGBT persons, and to propose a model of SDM between such patients and their healthcare providers.

METHODS

We reviewed key constructs necessary for understanding SDM among African-American LGBT persons, which guided our systematic literature review. Eligible studies for the review included English-language studies of adults (≥ 19 y/o) in North America, with a focus on LGBT persons who were African-American/black (i.e., > 50 % of the study population) or included sub-analyses by sexual orientation/gender identity and race. We searched PubMed, CINAHL, ProQuest Dissertations & Theses, PsycINFO, and Scopus databases using MESH terms and keywords related to shared decision making, communication quality (e.g., trust, bias), African-Americans, and LGBT persons. Additional references were identified by manual reviews of peer-reviewed journals’ tables of contents and key papers’ references.

RESULTS

We identified 2298 abstracts, three of which met the inclusion criteria. Of the included studies, one was cross-sectional and two were qualitative; one study involved transgender women (91 % minorities, 65 % of whom were African-Americans), and two involved African-American men who have sex with men (MSM). All of the studies focused on HIV infection. Sexual orientation and gender identity were patient-reported factors that negatively impacted patient/provider relationships and SDM. Engaging in SDM helped some patients overcome normative beliefs about clinical encounters. In this paper, we present a conceptual model for understanding SDM in African-American LGBT persons, wherein multiple systems of social stratification (e.g., race, gender, sexual orientation) influence patient and provider perceptions, behaviors, and shared decision making.

DISCUSSION

Few studies exist that explore SDM among African-American LGBT persons, and no interventions were identified in our systematic review. Thus, we are unable to draw conclusions about the effect size of SDM among this population on health outcomes. Qualitative work suggests that race, sexual orientation and gender work collectively to enhance perceptions of discrimination and decrease SDM among African-American LGBT persons. More research is needed to obtain a comprehensive understanding of shared decision making and subsequent health outcomes among African-Americans along the entire spectrum of gender and sexual orientation.

     

Identifying potential germline variants from sequencing hematopoietic malignancies

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Dengue and dengue hemorrhagic fever among adults: clinical outcomes related to viremia, serotypes, and antibody response

BACKGROUND: Clinical manifestations of dengue vary in different areas of endemicity and between specific age groups, whereas predictors of outcome have remained controversial. In Brazil, the disease burden predominantly affects adults, with an increasing trend toward progression to dengue hemorrhagic fever (DHF) noted. METHODS: A cohort of adults with confirmed cases of dengue was recruited in central Brazil in 2005. Patients were classified according to the severity of their disease. Associations of antibody responses, viremia levels (as determined by real-time polymerase chain reaction [PCR]), and serotypes (as determined by multiplex PCR) with disease severity were evaluated. RESULTS: Of the 185 symptomatic patients >14 years of age who had a confirmed case of dengue, 26.5% and 23.2% were classified as having intermediate dengue fever (DF)/DHF (defined as internal hemorrhage, plasma leakage, manifested signs of shock, and/or thrombocytopenia [platelet count, < or =50,000 platelets/mm3]) and DHF, respectively. The onset of intermediate DF/DHF and DHF occurred at a late stage of disease, around the period of defervescence. Patients with DHF had abnormal liver enzyme levels, with a >3-fold increase in aspartate aminotransferase level, compared with the range of values considered to be normal. Overall, 65% of patients presented with secondary infections with dengue virus, with such infection occurring in similar proportions of patients in each of the 3 disease category groups. Dengue virus serotype 3 (DV3) was the predominant serotype, and viremia was detected during and after defervescence among patients with DHF or intermediate DF/DHF. CONCLUSIONS: Viremia was detected after defervescence in adult patients classified as having DHF or intermediate DF/DHF. Secondary infection was not a predictor of severe clinical manifestation in adults with infected with the DV3 serotype.     

Malaria-associated cytokine changes in the placenta of women with pre-term deliveries in Yaounde, Cameroon

The prevalence of pre-term deliveries (PTDs) is increased in women who become infected with Plasmodium falciparum during pregnancy. Because prematurity is a risk factor for newborns, it is important to identify conditions that contribute to malaria-associated PTDs. Plasmodium falciparum-infected erythrocytes sequester in the placenta and attract activated mononuclear cells that secrete pro-inflammatory cytokines. Increased inflammatory cytokine levels in other microbial infections are associated with PTDs. To determine if such is the case in women with placental malaria, concentrations of interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-4 (IL-4), and IL-10 were measured in placental plasma of 391 malaria-infected and -uninfected Cameroonian women with premature and full-term deliveries. Risk factors for malaria-associated PTDs included peripheral and placental parasitemias greater than 1%, maternal anemia, elevated IL-10 levels, and low TNF-alpha:IL-10 ratios due to over-expression of IL-10. Alterations in cytokine levels may contribute to PTDs through the induction of anemia and/or altering cellular immune responses required for eliminating placental parasites.