In relation rto the size of viral inoculum, influenzal infection in ferrets caused by the inoculation of a mouse-adapted subline of PR 8 strain of type A influenza virus was studied. The results are summarized as follows; 1) When ferrets were inoculated with a highly diluted virus (10-7), a small proportion of them experienced inapparent infections and the rest of them escaped the infection. 2) With the increased size of viral inocula, there was a good correlation between the size of infecting does and the frequency of overt infections in ferrets. 3) Nasal tissues were the main locus of viral multiplication in ferrets at 72 hours after viral inoculation. Viral multiplication in nasal tissues was demonstrated only in a small proportion of ferrets which were inocu1ated with a 10-7 dilution of virus; however, when the size of vira1 inoculum was increased above this level, all ferrets had viral growth in their nasal tissues. 4) The involvement of pulmonary tissues, viral growth in those tissues and the development of gross lung lesions were significantly rare. There was no dear-cut relationship between the size of infecting doses and the frequency of such plumonary involvements in ferrets.
Animal ; Carnivora ; Female ; Influenza/microbiology* ; Orthomyxoviridae*

Acinetobacter Infections ; complications ; diagnosis ; therapy ; Acinetobacter baumannii ; Animals ; Birds ; Humans ; Influenza A Virus, H7N9 Subtype ; Influenza, Human ; complications ; diagnosis ; microbiology ; therapy

Adolescent ; Humans ; Influenza A Virus, H7N9 Subtype ; immunology ; pathogenicity ; Lymphopenia ; immunology ; microbiology ; Male ; T-Lymphocytes ; metabolism

Panton-Valentine leukocidin (PVL)-positive USA300 clone has been the most successful community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) clone spreading in North America. In contrast, PVL-negative ST72-CA-MRSA has been predominant in Korea, and there has been no report of infections by the USA300 strain except only one case report of perianal infection. Here, we describe the first case of pneumonia caused by the USA300 strain following pandemic influenza A (H1N1) in Korea. A 50-year-old man was admitted with fever and cough and chest radiograph showed pneumonic consolidation at the right lower lung zone. He received a ventilator support because of respiratory failure. PCR for pandemic influenza A (H1N1) in nasopharyngeal swab was positive, and culture of sputum and endotracheal aspirate grew MRSA. Typing of the isolate revealed that it was PVL-positive, ST 8-MRSA-SCCmec type IV. The analysis of the PFGE patterns showed that this isolate was the same pulsotype as the USA300 strain.
Community-Acquired Infections/*etiology/microbiology ; Humans ; Influenza A Virus, H1N1 Subtype ; Influenza, Human/*complications ; Male ; *Methicillin-Resistant Staphylococcus aureus/classification/isolation & purification ; Middle Aged ; Pneumonia, Staphylococcal/*etiology/microbiology ; Republic of Korea ; Staphylococcal Infections/*etiology/microbiology

Understanding inter-species transmission of influenza viruses is an important research topic. Scientists try to identify and evaluate the functional factors determining the host range of influenza viruses by generating the recombinant viruses through reverse genetics in laboratories, which reveals the viruses' molecular mechanisms of infection and transmission in different species. Therefore, the reverse genetic method is a very important tool for further understanding the biology of influenza viruses and will provide the insight for the prevention and treatment of infections and transmission. However, these recombinant influenza viruses generated in laboratories will become the potential threat to the public health and the environment. In this paper, we discussed the biological safety issues of recombinant influenza viruses and suggested we should set up protocols for risk management on research activities related to recombinant highly pathogenic influenza viruses.
Influenza A Virus, H5N1 Subtype ; genetics ; Laboratories ; Microbiology ; Orthomyxoviridae ; genetics ; Public Health ; Reassortant Viruses ; genetics ; Recombination, Genetic ; Safety

BACKGROUNDThe aim of this research was to evaluate long-term pulmonary sequelae on paired inspiration-expiration thin-section computed tomography (CT) scans 3 years after influenza A (H1N1) virus-associated pneumonia, and to analyze the affecting factors on pulmonary fibrosis.

METHODSTwenty-four patients hospitalized with H1N1 virus-associated pneumonia at our hospital between September 2009 and January 2010 were included. The patients underwent thin-section CT 3 years after recovery. Abnormal pulmonary lesion patterns (ground-glass opacity, consolidation, parenchymal bands, air trapping, and reticulation) and evidence of fibrosis (architectural distortion, traction bronchiectasis, or honeycombing) were evaluated on follow-up thin-section CT. Patients were assigned to Group 1 (with CT evidence of fibrosis) and Group 2 (without CT evidence of fibrosis). Demographics, rate of mechanical ventilation therapy, rate of intensive care unit admission, cumulative prednisolone-equivalent dose, laboratory tests results (maximum levels of alanine aminotransferase, aspartate transaminase [AST], lactate dehydrogenase [LDH], and creatine kinase [CK]), and peak radiographic opacification of 24 patients during the course of their illness in the hospital were compared between two groups.

RESULTSParenchymal abnormality was present in 17 of 24 (70.8%) patients and fibrosis occurred in 10 of 24 (41.7%) patients. Patients in Group 1 (10/24; 41.7%) had a higher rate of mechanical ventilation therapy (Z = -2.340, P = 0.019), higher number of doses of cumulative prednisolone-equivalent (Z = -2.579, P = 0.010), higher maximum level of laboratory tests results (AST [Z = -2.140, P = 0.032], LDH [Z = -3.227, P = 0.001], and CK [Z = -3.345, P = 0.019]), and higher peak opacification on chest radiographs (Z = -2.743, P = 0.006) than patients in group 2 (14/24; 58.3%).

CONCLUSIONSH1N1 virus-associated pneumonia frequently is followed by long-term pulmonary sequelae, including fibrotic changes, in lung parenchyma. Patients who need more steroid therapy, need more mechanical ventilation therapy, had higher laboratory tests results (maximum levels of AST, LDH, and CK), and had higher peak opacification on chest radiographs during treatment are more likely to develop lung fibrosis.

Adult ; Female ; Humans ; Influenza A Virus, H1N1 Subtype ; pathogenicity ; Influenza, Human ; complications ; virology ; Lung ; diagnostic imaging ; pathology ; virology ; Male ; Middle Aged ; Pneumonia ; complications ; diagnostic imaging ; microbiology ; Tomography, X-Ray Computed ; methods

OBJECTIVEAn outbreak of acute respiratory infections in children occurred in Beijing from November to December, 2002. To investigate the etiological agents of affected children who were in day care centers and primary schools.

METHODSThroat swab specimens were collected from one primary school children with acute respiratory infections visiting one outpatient department. After centrifuging, supernatant from the specimens were inoculated into MDCK and Hep-2 cells for virus isolation and pallets for viral antigen detection and using indirect immunofluorescent assay on common respiratory viruses. Nested polymerase chain reaction was used at the same time for detection of respiratory viruses and Mycoplasma pneumoniae (Mp).

RESULTSA total number of 80 specimens were collected during the outbreak. Among them influenza B virus were detected from 18 specimens, with a positive rate of 22.5% (18/80) while Mp were detected from 13 specimens, with a positive rate of 16.3% (13/80). Influenza A3 were also detected from 2 patients (2.5%, 2/80). However, influenza A1, RSV, adenovirus and parainfluenza viruses were not found from these specimens. Influenza B virus and Mp were detected simultaneity in two specimens and influenza A3 virus and Mp were detected in one specimen.

CONCLUSIONThe outbreak of acute respiratory infection in children during the period of investigation was caused by both influenza B virus and Mp.

Adolescent ; Child ; Child, Preschool ; China ; epidemiology ; Disease Outbreaks ; Female ; Humans ; Infant ; Influenza B virus ; isolation & purification ; Influenza, Human ; epidemiology ; Male ; Mycoplasma Infections ; epidemiology ; Mycoplasma pneumoniae ; isolation & purification ; Respiratory Tract Infections ; epidemiology ; microbiology

OBJECTIVETo evaluate the effect of supply of fresh poultry products on reducing environment contamination of avian influenza virus (AIV) in markets in Guangzhou.

METHODSA total of 40 markets, including 20 selling alive poultry and 20 selling fresh poultry products, were selected randomly in Guangzhou to conduct environment surveillance in 80 poultry stalls every 4 months from July 2014 to April 2015. Four smear samples were collected from different sites of each poultry stall to detect nucleic acid of AIV. The positive samples were further detected for AIV subtype H5, H7 and H9 nucleic acids.

RESULTSAmong 40 alive poultry stalls, 95.0% (38/40) kept alive poultry overnight, 25.0% (10/40) were disinfected daily, 95.0% (38/40) were cleaned up weekly, 95.0% (38/40) were closed for one day every month. Among 40 fresh poultry product stalls, 20.0% (8/40) were disinfected daily, 90.0% (36/40) were cleaned up weekly, and 96.0% (38/40) ever sold dressed poultry from alive poultry markets. The positive rate of AIV in alive poultry markets was 40.4% (252/623), higher than that in fresh poultry product markets (32.3%, 197/610), the difference was significant (χ(2)=8.85, P=0.003), and the positive rate of subtype H9 virus in alive poultry markets was 28.6% (178/623), higher than that in fresh poultry product markets (16.2%, 99/610), the difference was significant (χ(2)=26.95, P<0.001). In fresh poultry product markets, the positive rate of AIV in stalls selling dressed poultry was 37.3% (180/482), higher than that in stalls selling no dressed poultry (13.3%, 17/128), the difference was significant (χ(2)=26.78, P<0.001), and the positive rate of subtype H9 virus in stalls selling dressed poultry was 19.1% (92/482), higher than that in stalls selling no dressed poultry (5.5%, 7/128), the difference was significant (χ(2)=13.80, P<0.001). Both the positive rate of AIV and the positive rate of subtype H9 virus were highest in the second round surveillance (October 2014). The differences in AIV and its subtype H5, H7 and H9 virus positive rates of environmental samples from four different sites were not significant, respectively. In the same sample site, the positive rate of subtype H9 virus in alive poultry markets was higher than that in fresh poultry product markets the difference was significant (P<0.05).

CONCLUSIONSThe supply of fresh poultry products could effectively reduce the level of environment contamination of AIV in markets. Dressed poultry supplement caused the risk of AIV spread in fresh poultry product markets.

Animals ; China ; Commerce ; statistics & numerical data ; Disinfection ; statistics & numerical data ; Environmental Microbiology ; Influenza A virus ; isolation & purification ; Poultry ; Poultry Products ; supply & distribution

OBJECTIVETo evaluate the relationship between infection burden and coronary atherosclerosis and the plaque feature.

METHODSOne hundred and eighty two patients underwent coronary angiography in Zhongshan Hospital from 2002 - 2003. Atherosclerosis and vulnerable plaque were determined by intravascular ultrasound (IVUS). Seropositivity of cytomegalovirus, helicobacter pylori, chlamydia pneumonia, hepatitis B virus, EB virus, CoxB virus, influenza A virus, influenza B virus and mycobacterium tuberculosis were determined by ELISA. The serum hs-CRP was detected by Dade Behring prospect (Immuno-nehelomitery). Patients were divided into three groups according to the pathogen burden: group A, n or= 6.

RESULTSThe pathogen burden was independent of the C-reactive protein level. Increasing pathogen burden was significantly associated with increasing atherosclerosis risk, the prevalence of atherosclerosis was 44.4%, 70.6% and 76.7% in group A, B and C. The risk associated with elevated pathogen burden was much higher when CRP was also elevated (> 5.0 mg/L) (43.8%, 70.0%, 70.8%) vs (45.5%, 63.7%, 96.8%). The positively of vulnerable plaque increased significantly when the pathogen burden was high (n > 5) (33.3%, 32.4% and 51.7% P < 0.05).

CONCLUSIONOur data suggested that infection burden was associated with prevalence of coronary atherosclerosis, and it was particularly important when C-reactive protein was elevated. The high level infection burden could predict vulnerable plaque.

Aged ; Atherosclerosis ; microbiology ; pathology ; C-Reactive Protein ; analysis ; Chlamydophila pneumoniae ; Cytomegalovirus ; Female ; Helicobacter pylori ; Herpesvirus 4, Human ; Humans ; Influenza B virus ; Male ; Middle Aged ; Viral Load

OBJECTIVETo investigate the prevalence of viral infections and putative association of viral infection with illness severity in young children with severe lower respiratory tract infection (LRTI) in Chongqing.

METHODRespiratory secretion specimens were collected from 119 hospitalized patients with severe pneumonia from December 2006 to March 2008.After being processed, the samples were detected for respiratory viruses including respiratory syncytial virus (RSV), adenovirus (ADV), human metapneumovirus (hMPV), human bocavirus (HBoV), parainfluenza virus 1, 2, 3 (PIV 1, 2, 3), influenza virus A and B (IVA and IVB) either by PCR or RT-PCR. Clinical data were analyzed along with virological data by using appropriate statistical methods.

RESULTViral pathogens were identified in specimens of 86 (72.3%) cases, among which RSV was detected in 49 (41.2%) patients. More than one virus was detected in 23 individual (26.7%) samples, of which 19 were dual positive for RSV and another virus. Bacterial cultures were performed for 69 patients. Both bacterial and viral pathogens were identified in 53 (76.8%) patients. Bacterial and viral coinfection was demonstrated in samples from 41 (59.4%) cases.

CONCLUSIONViral pathogens are the main etiology of severe pneumonia in young children in Chongqing area during the study period. RSV was the most frequent viral pathogens, followed by ADV and hMPV. Coinfection with respiratory common viruses was relatively common, though co-infection with viruses did not appear to aggravate the patients' condition.

Adenoviridae ; isolation & purification ; Child, Preschool ; China ; epidemiology ; Human bocavirus ; isolation & purification ; Humans ; Infant ; Infant, Newborn ; Influenza A virus ; isolation & purification ; Metapneumovirus ; isolation & purification ; Pneumonia, Bacterial ; microbiology ; virology ; Pneumonia, Viral ; microbiology ; virology ; Respiratory Syncytial Viruses ; isolation & purification ; Virus Diseases ; virology