Bat Coronaviruses and Experimental Infection of Bats, the Philippines

Virus-infected fruit bats showed no signs of clinical infection

DIFFERENCES IN VISUAL ATTENTION BETWEEN NOVICE AND EXPERT NURSES PERFORMING ENDOTRACHEAL SUCTIONING (ES) : A SIMULATION STUDY

Background: Endotracheal suctioning was authorized to be performed by　individuals after attending a training course even though they do not possess a medical/nursing qualification in 2012 in Japan, though it is still considered as an evasive medical procedure. Objectives: This paper aims to discover experienced nurses’ proficiency of endotracheal suctioning in order to discuss future solution of nursing delegation. Methods: EMR-9○R (NAC Image technology Inc.) was used for eye tracking. EMR-dFactory○R version 2.7.0 was used for data analysis. ES was separated into six phases. Performance time, visual pathways, and movement speed of each participant were then analysed. Participants: Participants were recruited by snowball method and bulletin board. Inclusion criteria for nurses were experience of endotracheal suctioning in real work at any institution, and for students no experience of endotracheal suctioning in real settings. Results: Nurses' average time for ES was significantly shorter than students’; however, there was no significant correlation between years of 4 experience and the time (p= -0.006). Bimodality of eye movement velocity at 0-40 and 180-220 deg./s was also observed in the nurses’ group, in contrast to the unimodal distribution of the students’ velocity. Conclusion: Nurses achieved both time-efficiency and risk-avoidance by quickly gathering adequate visual information. Preparations before procedure to avoid task multiplicity are also important

Susceptibility to flavivirus-specific antiviral response of Oas1b affects the neurovirulence of the Far-Eastern subtype of tick-borne encephalitis virus

Tick-borne encephalitis virus (TBEV) is a zoonotic agent that causes fatal encephalitis in humans. 2'-5'-oligoadenylate synthetase 1b (Oas1b) has been identified as a flavivirus resistance gene, but most inbred laboratory mice do not possess a functional Oas1b gene. In this study, a congenic strain carrying a functional Oas1b gene, B6.MSM-Oas, was used to evaluate the pathogenicity of Far-Eastern TBEV. Although intracerebral infection of B6.MSM-Oas mice by Oshima 5-10 resulted in limited signs of illness, infection by Sofjin-HO resulted in death with severe neurologic signs. While Oshima 5-10 was cleared from the brain, Sofjin-HO was not cleared despite a similar level of expression of the intact Oas1b gene. Necrotic neurons with viral antigens and inflammatory reactions were observed in the brain infected with Sofjin-HO. These data indicate that the different susceptibility to the antiviral activity of Oas1b resulted in a difference in neurovirulence in the two TBEV strains

Puumala virus infection in Syrian hamsters (Mesocricetus auratus) resembling hantavirus infection in natural rodent hosts

The mechanism of hantavirus persistent infection in natural hosts is poorly understood due to a lack of laboratory animal models. Herein, we report that Syrian hamsters (Mesocricetus auratus) infected with Puumala virus (PUUV) at 4 weeks old show persistent infection without clinical symptoms for more than 2 months. IgG and IgM antibodies against the viral nucleocapsid protein and neutralizing antibody were first detectable at 14 days postinoculation (dpi) and maintained through 70 dpi. Viral RNA was first detected from 3 dpi in lungs and blood clots, and was detected in all tissues tested at 7 dpi. The viral RNA persisted for at least 70 days in the lungs, kidney, spleen, heart, and brain. The highest level of RNA copies was observed at 14 dpi in the lungs. Slight inflammatory reactions were observed in the lungs, adrenal glands, and brain. Immunohistochemical analysis revealed that PUUV antigen persisted until 56 dpi in the kidneys and adrenal glands. Infected hamsters showed no body weight loss or clinical signs. These results indicate that PUUV infection in hamsters is quite similar to the hantavirus infection of natural host rodents

Genetic and Biological Characterization of Tick-Borne Encephalitis Virus Isolated from Wild Rodents in Southern Hokkaido, Japan in 2008

Tick-borne encephalitis virus (TBEV) is a zoonotic agent causing severe encephalitis in humans. A recent epizootiological survey indicated that endemic foci of TBEV have been maintained in the southern part of Hokkaido until recently. In this study, we sought to isolate TBEV from wild rodents in the area. One virus, designated Oshima 08-As, was isolated from an Apodemus speciosus captured in Hokuto in 2008. Oshima 08-As was classified as the Far Eastern subtype of TBEV and formed a cluster with the other strains isolated in Hokkaido from 1995 to 1996. Thirty-six nucleotide differences resulted in 12 amino acid changes between Oshima 08-As and Oshima 5-10 isolated in 1995. Oshima 08-As caused high mortality and morbidity in a mouse model compared with Oshima 5-10. Although similar transient viral multiplication in the spleen was observed in the mice infected with Oshima 08-As and Oshima 5-10, greater viral multiplication with an inflammatory response was noted in the brains of mice infected with Oshima 08-As than those infected with Oshima 5-10. These data indicate that a few naturally occurring mutations affect the pathogenicity of the Oshima strains endemic in the southern part of Hokkaido

Stringent Requirement for the C Protein of Wild-Type Measles Virus for Growth both In Vitro and in Macaques

The P gene of measles virus (MV) encodes the P protein and three accessory proteins (C, V, and R). However, the role of these accessory proteins in the natural course of MV infection remains unclear. For this study, we generated a recombinant wild-type MV lacking the C protein, called wtMV(C−), by using a reverse genetics system (M. Takeda, K. Takeuchi, N. Miyajima, F. Kobune, Y. Ami, N. Nagata, Y. Suzaki, Y. Nagai, and M. Tashiro, J. Virol. 74:6643-6647). When 293 cells expressing the MV receptor SLAM (293/hSLAM) were infected with wtMV(C−) or parental wild-type MV (wtMV), the growth of wtMV(C−) was restricted, particularly during late stages. Enhanced green fluorescent protein-expressing wtMV(C−) consistently induced late-stage cell rounding and cell death in the presence of a fusion-inhibiting peptide, suggesting that the C protein can prevent cell death and is required for long-term MV infection. Neutralizing antibodies against alpha/beta interferon did not restore the growth restriction of wtMV(C−) in 293/hSLAM cells. When cynomolgus monkeys were infected with wtMV(C−) or wtMV, the number of MV-infected cells in the thymus was >1,000-fold smaller for wtMV(C−) than for wtMV. Immunohistochemical analyses showed strong expression of an MV antigen in the spleen, lymph nodes, tonsils, and larynx of a cynomolgus monkey infected with wtMV but dramatically reduced expression in the same tissues in a cynomolgus monkey infected with wtMV(C−). These data indicate that the MV C protein is necessary for efficient MV replication both in vitro and in cynomolgus monkeys

Genome Organization and Pathogenicity of Corynebacterium diphtheriae C7(−) and PW8 Strains ▿ †

Corynebacterium diphtheriae is the causative agent of diphtheria. In 2003, the complete genomic nucleotide sequence of an isolate (NCTC13129) from a large outbreak in the former Soviet Union was published, in which the presence of 13 putative pathogenicity islands (PAIs) was demonstrated. In contrast, earlier work on diphtheria mainly employed the C7(−) strain for genetic analysis; therefore, current knowledge of the molecular genetics of the bacterium is limited to that strain. However, genomic information on the NCTC13129 strain has scarcely been compared to strain C7(−). Another important C. diphtheriae strain is Park-Williams no. 8 (PW8), which has been the only major strain used in toxoid vaccine production and for which genomic information also is not available. Here, we show by comparative genomic hybridization that at least 37 regions from the reference genome, including 11 of the 13 PAIs, are considered to be absent in the C7(−) genome. Despite this, the C7(−) strain still retained signs of pathogenicity, showing a degree of adhesion to Detroit 562 cells, as well as the formation of and persistence in abscesses in animal skin comparable to that of the NCTC13129 strain. In contrast, the PW8 strain, suggested to lack 14 genomic regions, including 3 PAIs, exhibited more reduced signs of pathogenicity. These results, together with great diversity in the presence of the 37 genomic regions among various C. diphtheriae strains shown by PCR analyses, suggest great heterogeneity of this pathogen, not only in genome organization, but also in pathogenicity

An Attenuated Strain of Enterovirus 71 Belonging to Genotype A Showed a Broad Spectrum of Antigenicity with Attenuated Neurovirulence in Cynomolgus Monkeys▿

Enterovirus 71 (EV71) is a causative agent of hand, foot, and mouth disease and is also sometimes associated with serious neurological disorders. In this study, we characterized the antigenicity and tissue specificity of an attenuated strain of EV71 [EV71(S1-3′)], which belongs to genotype A, in a monkey infection model. Three cynomolgus monkeys were inoculated with EV71(S1-3′), followed by lethal challenge with the parental virulent strain EV71(BrCr-TR) via an intravenous route on day 45 postinoculation of EV71(S1-3′). Monkeys inoculated with EV71(S1-3′) showed a mild neurological symptom (tremor) but survived lethal challenge by virulent EV71(BrCr-TR) without exacerbation of the symptom. The immunized monkey sera showed a broad spectrum of neutralizing activity against different genotypes of EV71, including genotypes A, B1, B4, C2, and C4. For the strains examined, the sera showed the highest neutralization activity against the homotype (genotype A) and the lowest neutralization activity against genotype C2. The order of decreasing neutralization activity of sera was as follows: A > B1 > C4 > B4 > C2. To examine the tissue specificity of EV71(S1-3′), two monkeys were intravenously inoculated with EV71(S1-3′), followed by examination of virus distribution in the central nervous system (CNS) and extraneural tissues. In the CNS, EV71(S1-3′) was isolated only from the spinal cord. These results indicate that EV71(S1-3′) acts as an effective antigen, although this attenuated strain was still neurotropic when inoculated via the intravenous route

Impacts of allergic airway inflammation on lung pathology in a mouse model of influenza A virus infection.

Influenza A virus is the respiratory pathogen responsible for influenza. Infection by the 2009 pandemic influenza A (H1N1) virus caused severe lower airway inflammation and pneumonia. Asthma is a chronic inflammatory disorder of the airways that affects the entire brachial tree, and was one of the commonest underlying medical conditions among patients hospitalized with the 2009 pandemic influenza virus infection. Although respiratory virus infections are the major causes of asthma exacerbation, the mechanism by which influenza exacerbates asthma is poorly understood. Animal models of disease comorbidity are crucial to understanding host-pathogen interactions and elucidating complex pathologies. Existing murine models of influenza virus infection in asthmatics show that asthmatic mice are highly resistant to influenza virus infection, which contradicts clinical observations in humans. Here, we developed a murine model of influenza virus/asthma comorbidity using NC/Nga mice, which are highly sensitive to allergic reactions such as atopic dermatitis and allergic airway inflammation. This model was then used to examine the impact of allergic airway inflammation on lung pathology in the 2009 pandemic influenza virus infected mice. The results showed that induction of acute allergic airway inflammation in pre-existing influenza virus infection had additive effects on exacerbation of lung pathology, which mirrors findings in human epidemiological studies. In contrast, pre-existing allergic airway inflammation protected from subsequent influenza virus infection, which was compatible with those of previous murine models of influenza virus infection in asthmatic mice. These variable outcomes of this murine model indicate that the temporal relation between allergic airway inflammation and influenza virus infection might play a critical role in asthma and influenza comorbidity. Thus, this murine model will further our understanding of how influenza virus infection affects an asthmatic host and may aid the development of strategies to improve treatments and outcomes for asthmatics harboring influenza virus infection