Bayesian coalescent analysis reveals a high rate of molecular evolution in GB virus C

GB virus C/hepatitis G (GBV-C) is an RNA virus of the family Flaviviridae. Despite replicating with an RNA-dependent RNA polymerase, some previous estimates of rates of evolutionary change in GBV-C suggest that it fixes mutations at the anomalously low rate of similar to 100(-7) nucleotide substitution per site, per year. However, these estimates were largely based on the assumption that GBV-C and its close relative GBV-A (New World monkey GB viruses) codiverged with their primate hosts over millions of years. Herein, we estimated the substitution rate of GBV-C using the largest set of dated GBV-C isolates compiled to date and a Bayesian coalescent approach that utilizes the year of sampling and so is independent of the assumption of codivergence. This revealed a rate of evolutionary change approximately four orders of magnitude higher than that estimated previously, in the range of 10(-2) to 10(-3) sub/site/year, and hence in line with those previously determined for RNA viruses in general and the Flaviviridae in particular. In addition, we tested the assumption of host-virus codivergence in GBV-A by performing a reconciliation analysis of host and virus phylogenies. Strikingly, we found no statistical evidence for host-virus codivergence in GBV-A, indicating that substitution rates in the GB viruses should not be estimated from host divergence times.

Development of molecular assays for the identification of the 11 Eimeria species of the domestic rabbit (Oryctolagus cuniculus)

Coccidiosis are the major parasitic diseases in poultry and other domestic animals including the domestic rabbit (Oryctolagus cuniculus). Eleven distinct Eimeria species have been identified in this host, but no PCR-based method has been developed so far for unequivocal species differentiation. In this work, we describe the development of molecular diagnostic assays that allow for the detection and discrimination of the 11 Eimeria species that infect rabbits. We determined the nucleotide sequences of the ITS1 ribosomal DNAs and designed species-specific primers for each species. We performed specificity tests of the assays using heterologous sets of primers and DNA samples, and no cross-specific bands were observed. We obtained a detection limit varying from 500 fg to 1 pg, which corresponds approximately to 0.8-1.7 sporulated oocysts, respectively. The test reported here showed good reproducibility and presented a consistent sensitivity with three different brands of amplification enzymes. These novel diagnostic assays will permit population surveys to be performed with high sensitivity and specificity, thus contributing to a better understanding of the epidemiology of this important group of coccidian parasites. (C) 2010 Elsevier B.V. All rights reserved.

Viral RNA silencing suppressors (RSS) : novel strategy of viruses to ablate the host RNA interference (RNAi) defense system

Pathogenic viruses have developed a molecular defense arsenal for their survival by counteracting the host anti-viral system known as RNA interference (RNAi). Cellular RNAi, in addition to regulating gene expression through microRNAs, also serves as a barrier against invasive foreign nucleic acids. RNAi is conserved across the biological species, including plants, animals and invertebrates. Viruses in turn, have evolved mechanisms that can counteract this anti-viral defense of the host. Recent studies of mammalian viruses exhibiting RNA silencing suppressor (RSS) activity have further advanced our understanding of RNAi in terms of host–virus interactions. Viral proteins and non-coding viral RNAs can inhibit the RNAi (miRNA/siRNA) pathway through different mechanisms. Mammalian viruses having dsRNA-binding regions and GW/WG motifs appear to have a high chance of conferring RSS activity. Although, RSSs of plant and invertebrate viruses have been well characterized, mammalian viral RSSs still need in-depth investigations to present the concrete evidences supporting their RNAi ablation characteristics. The information presented in this review together with any perspective research should help to predict and identify the RSS activity-endowed new viral proteins that could be the potential targets for designing novel anti-viral therapeutics.

Identifying crucial gaps in our knowledge of the life-history of avian influenza viruses - An Australian perspective

We review our current knowledge of the epidemiology and ecology of avian influenza viruses (AIVs) in Australia in relation to the ecology of their hosts. Understanding the transmission and maintenance of low-pathogenic avian influenza (LPAI) viruses deserves scientific scrutiny because some of these may evolve to a high-pathogenic AIV (HPAI) phenotype. That the HPAI H5N1 has not been detected in Australia is thought to be a result of the low level of migratory connectivity between Asia and Australia. Some AIV strains are endemic to Australia, with Australian birds acting as a reservoir for these viruses. However, given the phylogenetic relationships between Australian and Eurasian strains, both avian migrants and resident birds within the continent must play a role in the ecology and epidemiology of AIVs in Australia. The extent to which individual variation in susceptibility to infection, previous infections, and behavioural changes in response to infection determine AIV epidemiology is little understood. Prevalence of AIVs among Australian avifauna is apparently low but, given their specific ecology and Australian conditions, prevalence may be higher in little-researched species and under specific environmental conditions.

Migratory birds reinforce local circulation of avian influenza viruses

Migratory and resident hosts have been hypothesized to fulfil distinct roles in infectious disease dynamics. However, the contribution of resident and migratory hosts to wildlife infectious disease epidemiology, including that of low pathogenic avian influenza virus (LPAIV) in wild birds, has largely remained unstudied. During an autumn H3 LPAIV epizootic in free-living mallards (Anas platyrhynchos) - a partially migratory species - we identified resident and migratory host populations using stable hydrogen isotope analysis of flight feathers. We investigated the role of migratory and resident hosts separately in the introduction and maintenance of H3 LPAIV during the epizootic. To test this we analysed (i) H3 virus kinship, (ii) temporal patterns in H3 virus prevalence and shedding and (iii) H3-specific antibody prevalence in relation to host migratory strategy. We demonstrate that the H3 LPAIV strain causing the epizootic most likely originated from a single introduction, followed by local clonal expansion. The H3 LPAIV strain was genetically unrelated to H3 LPAIV detected both before and after the epizootic at the study site. During the LPAIV epizootic, migratory mallards were more often infected with H3 LPAIV than residents. Low titres of H3-specific antibodies were detected in only a few residents and migrants. Our results suggest that in this LPAIV epizootic, a single H3 virus was present in resident mallards prior to arrival of migratory mallards followed by a period of virus amplification, importantly associated with the influx of migratory mallards. Thus migrants are suggested to act as local amplifiers rather than the often suggested role as vectors importing novel strains from afar. Our study exemplifies that a multifaceted interdisciplinary approach offers promising opportunities to elucidate the role of migratory and resident hosts in infectious disease dynamics in wildlife.

Epidemiology of early Rapid Response Team activation after emergency department admission

BACKGROUND: Rapid Response Team (RRT) calls can often occur within 24h of hospital admission to a general ward. We seek to determine whether it is possible to identify these patients before there is a significant clinical deterioration. METHODS: Retrospective case-controlled study comparing patient characteristics, vital signs, and hospital outcomes in patients triggering RRT activation within 24h of ED admission (cases) with matched ED admissions not receiving a RRT call (controls). RESULTS: Over 12 months, there were 154 early RRT calls. Compared with controls, cases had a higher heart rate (HR) at triage (92 vs. 84beats/min; p=0.008); after 3h in the ED (91 vs. 80beats/min; p=0.0007); and at ED discharge (91 vs. 81beats/min; p=0.0005). Respiratory rate (RR) was also higher at triage (21.2 vs. 19.2breaths/min; p=0.001). On multiple variable analysis, RR at triage and HR before ward transfer predicted early RRT activation: OR 1.07 [95% CI 1.02-1.12] for each 1breath/min increase in RR; and 1.02 [95% CI 1.002-1.030] for each beat/minute increase in HR, respectively. Study patients required transfer to the intensive care in approximately 20% of cases and also had a greater mortality: (21% vs. 6%; OR 4.65 [95% CI 1.86-11.65]; p=0.0003) compared with controls. CONCLUSIONS: Patients that trigger RRT calls within 24h of admission have a fourfold increase in risk of in-hospital mortality. Such patients may be identified by greater tachycardia and tachypnoea in the ED.

Molecular targets in arthritis and recent trends in nanotherapy

Due to its severity and increasing epidemiology, arthritis needs no description. There are various forms of arthritis most of which are disabling, very painful, and common. In spite of breakthroughs in the field of drug discovery, there is no cure for arthritis that can eliminate the disease permanently and ease the pain. The present review focuses on some of the most successful drugs in arthritis therapy and their side effects. Potential new targets in arthritis therapy such as interleukin-1β, interleukin-17A, tumor necrosis factor alpha, osteopontin, and several others have been discussed here, which can lead to refinement of current therapeutic modalities. Mechanisms for different forms of arthritis have been discussed along with the molecules that act as potential biomarkers for arthritis. Due to the difficulty in monitoring the disease progression to detect the advanced manifestations of the diseases, drug-induced cytotoxicity, and problems with drug delivery; nanoparticle therapy has gained the attention of the researchers. The unique properties of nanoparticles make them highly attractive for the design of novel therapeutics or diagnostic agents for arthritis. The review also focuses on the recent trends in nanoformulation development used for arthritis therapy. This review is, therefore, important because it describes the relevance and need for more arthritis research, it brings forth a critical discussion of successful drugs in arthritis and analyses the key molecular targets. The review also identifies several knowledge gaps in the published research so far along with the proposal of new ideas and future directions in arthritis therapy.

The epidemiology of sepsis during rapid response team reviews in a teaching hospital

In a three-month retrospective study, we assessed the proportion of rapid response team (RRT) calls associated with systemic inflammatory response syndrome (SIRS) and sepsis. We also documented the site of infection (whether it was community- or hospital-acquired), antibiotic modifications after the call and in-hospital outcomes. Amongst 358 RRT calls, two or more SIRS criteria were present in 277 (77.4%). Amongst the 277 RRT calls with SIRS criteria, 159 (57.4%) fulfilled sepsis criteria in the 24 hours before and 12 hours after the call. There were 118 of 277 (42.6%) calls with SIRS criteria but no evidence of sepsis and 62 of 277 (22.3%) calls associated with both criteria for sepsis as well as an alternative cause for SIRS. Hence, 159 (44.4%) of all 358 RRT calls over the three-month study period fulfilled criteria for sepsis and in 97 (159-62) (27.1%) of the 358 calls, there were criteria for sepsis without other causes for SIRS criteria. The most common sites of infection were respiratory tract (86), abdominal cavity (38), urinary tract (26) and bloodstream (26). Infection was hospital-acquired in 91 (57.2%) and community-acquired in 67 (42.1%) cases, respectively. Patients were on antibiotics in 127 of 159 (79.9%) cases before the RRT call and antibiotics were added or modified in 76 of 159 (47.8%) cases after RRT review. The hospital length-of-stay of patients who received an RRT call associated with sepsis was longer than those who did not (16.0 [8.0 to 28.5] versus 10 days [6.0 to 18.0]; P=0.002).

Respiratory metabolism of Camponotus rufipes ants: Brood and adults

The respiratory metabolism of immature forms (eggs, larvae, prepupae and pupae) of Camponotus rufipes (Hymenoptera: Formicidae) was studied at 25 degrees C, using a Warburg respirometer. Mean respiratory rates (mu l O gamma mg(-1) live weight.hr(-1)) for eggs, first instars, second instars, third instars, fourth instars, prepupae, and pupae were respectively: 2.53, 5.07, 1.23, 0.32, 0.22, 0.19 and 0.13. Adult workers with body mass between 20 and 30 mg had a mean respiratory rate of 0.43. The high respiratory rate in first instars probably reflects, besides the size influence, the metabolic costs of differentiation that occurs in this phase. (C) 1998 Published by Elsevier B.V.

Molecular characterisation of Bartonella species in cats from Sao Luis, state of Maranhao, north-eastern Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Molecular typing and antifungal susceptibility of clinical sequential isolates of Cryptococcus neoformans from São Paulo State, Brazil

The antifungal susceptibility profiles and the genetic variability of 83 sequential clinical isolates of Cryptococcus neoformans, including four Cryptococcus gattii isolates, obtained from 38 São Paulo AIDS patients with cryptococcal meningitis were assessed by electrophoretic karyotyping and random amplified polymorphic DNA (RAPD) analysis. The majority of the Cryptococcus neoformans isolates were highly susceptible to amphotericin B and fluconazole. Twenty percent of the minimum inhibitory concentration values for amphotericin B varied from 0.5 to 1 mu g mL(-1). For fluconazole, 22% occurred in the range 8-16 mu g mL(-1). Sequential isolates from nine patients showed a trend towards lower susceptibility to fluconazole, flucytosine, itraconazole and amphotericin B. The results of molecular typing by electrophoretic karyotyping and RAPD analysis showed the presence of 22 electrophoretic karyotypes (EK) and 15 RAPD profiles that were highly correlated. Our results provided evidence for the occurrence of genetic changes in some strains associated with microevolution during the course of infection. We also observed both microevolution and simultaneous coinfection with two distinct Cryptococcus neoformans strains in one patient. In some patients, we found changed EK- and RAPD patterns in association with increased MIC values.

Classic and molecular study of Giardia duodenalis in children from a daycare center in the region of Presidente Prudente, São Paulo, Brazil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização genética e evolução dos vírus dengue no Estado do Rio Grande do Norte

Dengue is considered as the most important arthropod-borne viral disease throughout the world due to the high number of people at risk to be infected, mainly in tropical and subtropical regions of the planet. The etiologic agent is Dengue Virus (DENV), it is a single positive-stranded RNA virus of the family Flavivirus, genus Flaviviridae. Four serotypes are known, DENV-1, DENV-2, DENV-3 and DENV-4. One of the most important characteristic of these viruses is the genetic variability, which demands phylogenetic and evolutionary studies to understand key aspects like: epidemiology, virulence, migration patterns and antigenic characteristics. The objective of this study is the genetic characterization of dengue viruses circulating in the state of Rio Grande does Norte from January 2010 to December 2012. The complete E gene (1485 pb) of DENV1, 2 e 4 from Brazilian (Rio Grande do Norte) patients was sequenced. Phylogenetic analysis was performed using MEGA 5.2 software, Tamura-Nei model and Neighbor-Joining trees were inferred for the datasets. In Brazil, there is just one DENV-1 genotype (genotype V), one DENV-2 genotype (Asian/American) and two DENV-4 genotypes (genotypes I and II). Brazilian strains of DENV-1 are subdivided in two different lineages (BR-I and BR-II), the Brazilian strains of DENV-2 are subdivided in four lineages (BRI-IV) and genotype II of DENV-4 is subdivided in three Brazilian lineages (BRI-III). The viruses isolated in RN belong to lineage BR-II (DENV-1), BR-IV (DENV-2) and BR-III (DENV-4).The Caribbean and near Latin American countries are the main source of these viruses to Brazil. Amino acids substitutions were detected in three domains of E protein, this makes clear the necessity of studies that associate epidemiological and molecular data to better understand the effects of these mutations. This is the first study about genetic characterization and evolution of Dengue viruses in Rio Grande do Norte, Brazil

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA): molecular background, virulence, and relevance for public health

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Epidemiology of leptospirosis at Sorocaba Zoo, São Paulo state, Southeastern Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)