Role of angiotensin II in experimental Venezuelan equine encephalitis in ratsBermúdez, John; Valero, Nereida; Mosquera, Jesús; Vargas, Renata; Hernández-Fonseca, Juan; Quiroz, Yasmir; Godoy, Rosario
doi: 10.1007/s00705-015-2521-0pmid: 26156105
Venezuelan equine encephalitis (VEE) is a viral disease transmitted by mosquitoes. The inflammation induced by the VEE virus is associated with a high mortality rate in mice. Angiotensin II (Ang II), a pro-inflammatory molecule, is produced in the normal rat brain. There is no information about the role of this molecule in the inflammatory events occurring during VEE and the effect of inflammation on the mortality rate in VEE-virus-infected rats. This study was designed to determine the role of Ang II in VEE and to analyze the effect of inflammation on mortality in infected rats. Two groups of rats were studied: 1) Virus-infected animals and controls (n = 60) were treated with losartan (a blocker of the Ang II-AT1 receptor) or with pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-κB) or left untreated and analyzed for morbidity and mortality. 2) Animals treated using the same protocol (n = 30) were sacrificed at day 4 postinfection and analyzed by immunohistochemistry and histopathology and for cytokine production. Increased expression of Ang II, ICAM-1, ED-1 and cytokines (IL-1α, MCP-1, IL-6 and IL-10) in infected animals was observed. The main histopathology findings were dilated capillaries and capillaries with endothelial detachment. Losartan and PDTC reduced the expression of IL-1α, MCP-1, and IL-10, and the number of dilated capillaries and capillaries with endothelial detachment. Survival analysis showed that 100 % mortality was reached earlier in infected rats treated with losartan (day 14) or PDTC (day 11) than in untreated animals (day 19). These findings suggest that Ang II plays a role in VEE and that brain inflammation is protective against viral infection.
Dose response of red imported fire ant colonies to Solenopsis invicta virus 3Valles, Steven; Porter, Sanford
doi: 10.1007/s00705-015-2520-1pmid: 26162304
Baiting tests were conducted to evaluate the effect of increasing Solenopsis invicta virus 3 (SINV-3) dose on fire ant colonies. Actively growing early-stage fire ant ( Solenopsis invicta Buren) laboratory colonies were pulse-exposed for 24 hours to six concentrations of SINV-3 (10 1 , 10 3 , 10 5 , 10 7 , 10 9 genome equivalents/μl) in 1 ml of a 10 % sucrose bait and monitored regularly for two months. SINV-3 concentration had a significant effect on colony health. Brood rating (proportion of brood to worker ants) began to depart from the control group at 19 days for the 10 9 concentration and 26 days for the 10 7 concentration. At 60 days, brood rating was significantly lower among colonies treated with 10 9 , 10 7 , and 10 5 SINV-3 concentrations. The intermediate concentration, 10 5 , appeared to cause a chronic, low-level infection with one colony ( n = 9) supporting virus replication. Newly synthesized virus was not detected in any fire ant colonies treated at the 10 1 concentration, indicating that active infections failed to be established at this level of exposure. The highest bait concentration chosen, 10 9 , appeared most effective from a control aspect; mean colony brood rating at this concentration (1.1 ± 0.9 at the 60 day time point) indicated poor colony health with minimal brood production. No clear relationship was observed between the quantity of plus genome strand detected and brood rating. Conversely, there was a strong relationship between the presence of the replicative genome strand and declining brood rating, which may serve as a predictor of disease severity. Recommendations for field treatment levels to control fire ants with SINV-3 are discussed.
Pregnancy outcome and clinical status of gilts following experimental infection by H1N2, H3N2 and H1N1pdm09 influenza A viruses during the last month of gestationKwit, Krzysztof; Pomorska-Mól, Małgorzata; Markowska-Daniel, Iwona
doi: 10.1007/s00705-015-2518-8pmid: 26162303
The present study was planned to study the effect of various subtypes of swine influenza virus (SIV) circulating among pigs (H1N2, H3N2 and emerging pandemic strain of H1N1 influenza A virus (H1N1pdm09) on the course of pregnancy in naïve gilts experimentally infected during the last month of pregnancy. In addition, the clinical course of infection, distribution of viruses in various tissues (blood, placenta, fetal lung), and selected immunological, reproductive and productive parameters were also investigated. All SIV-inoculated gilts became infected. No abortions, stillbirths, intrauterine deaths or mummified fetuses were observed. No clinical signs of influenza virus infection or other disorders were observed in piglets born from infected and control gilts. There was a significant decrease in the number and frequency of lymphocytes in gilts inoculated with all influenza viruses. In general, the concentrations of IL-6, IL-10 and TNF-α were significantly higher in SIV-inoculated gilts as than in control animals, while IL-4 and IFN-γ were not detected in plasma at any time post-inoculation in SIV- or mock-inoculated gilts. No evidence for transplacental transmission of SIV was found. Viremia was also not observed in any of the infected females. On the basis of recent results, we hypothesize that pregnancy failure observed during SIV infection under field conditions is probably related to high fever and pro-inflammatory cytokines rather than a direct effect of the virus on the placenta, embryo or fetus.
Higher levels of dengue-virus-specific IgG and IgA during pre-defervescence associated with primary dengue hemorrhagic feverBachal, Rupali; Alagarasu, Kalichamy; Singh, Anand; Salunke, Asha; Shah, Paresh; Cecilia, Dayaraj
doi: 10.1007/s00705-015-2519-7pmid: 26175069
Dengue hemorrhagic fever (DHF), although predominantly associated with secondary infections, has also been reported in primary infections. An enhanced immune response including antibodies and cytokines is implicated in the pathogenesis of secondary DHF. However, the factors operating in primary DHF are poorly understood. To understand the role of the antibody response, the relative levels of different antibody isotypes during the acute phase of infection in primary and secondary dengue infections were determined. Levels of DENV-specific IgM, IgG, IgA and IgE were measured in the serum samples of 200 dengue patients and 20 dengue-naïve individuals. Samples were collected within 15 days of onset of illness. The DENV-specific IgM levels were significantly higher in DF cases compared to DHF, which was more evident in secondary infections and in post-defervescence samples. The levels of IgG, IgA and IgE were higher in DHF cases, with greater significance in primary infections. A higher level of IgG in DHF cases was evident in pre-defervescence samples, whilst the IgE level was higher in pre- and post-defervescence samples. There was a significant correlation of IgG titres with platelet counts, with higher titres associated with lower platelet counts. It is speculated that IgG, IgA and IgE produced in response to primary infections may contribute to pathogenesis, whilst IgM produced in response to secondary infections may protect against progression to severe disease.
Serial passage in ducks of a low-pathogenic avian influenza virus isolated from a chicken reveals a high mutation rate in the hemagglutinin that is likely due to selection in the hostRidenour, Callie; Williams, Susan; Jones, Les; Tompkins, S.; Tripp, Ralph; Mundt, Egbert
doi: 10.1007/s00705-015-2504-1pmid: 26179620
A comparative study of the ability of three low-pathogenic avian influenza virus (LPAIV) isolates to be transmitted from duck to duck was performed. Pekin ducks were inoculated with two LPAIV isolates from chickens (A/Ck/PA/13609/93 (H5N2), H5N2-Ck; A/Ck/TX/167280-4/02 (H5N3), H5N3-Ck) and one isolate from a wild bird (A/Mute Swan/ MI/451072/06 (H5N1), H5N1-WB). During the establishment of the passage model, only two viruses (H5N1, H5N2) were able to be transmitted from duck to duck. Transmission of these isolates was dependent on the inoculation dose and route of infection. Analysis of swab samples taken from ducks revealed that the wild-bird isolate, H5N1-WB, was primarily shed via the cloacal route. The chicken isolate, H5N2-Ck, was isolated from cloacal as well as oro-pharyngeal swabs. Analysis of the amino acid sequences of the viral surface glycoproteins showed that the hemagglutinin (HA) of the H5N2-Ck isolate was under a stronger evolutionary pressure than the HA of the H5N1-WB isolate, as indicated by the presence of a larger number of amino acid changes observed during passage. The neuraminidase (NA) of both viruses showed either no (in the case of H5N1-WB) or very few amino acid changes.
Evaluation and application of a one-step duplex real-time reverse transcription polymerase chain reaction assay for the rapid detection of influenza A (H7N9) virus from poultry samplesBao, Hongmei; Ma, Yong; Shi, Jianzhong; Zeng, Xianying; Zhao, Yuhui; Wang, Xiurong; Chen, Hualan
doi: 10.1007/s00705-015-2511-2pmid: 26179621
In China, a novel reassortant influenza A (H7N9) virus, which has caused 435 cases of human infection, has recently emerged. Most cases of human infections with the H7N9 virus are known to be associated with a poultry farm and live-poultry markets. In this study, a one-step duplex real-time reverse transcription polymerase chain reaction (RRT-PCR) assay was developed for the simultaneous detection of the hemagglutinin (HA) and neuraminidase (NA) genes of the H7N9 virus for effective surveillance and early diagnosis of cases from clinical samples collected from live-poultry markets or poultry farms. The detection limit of this assay was as low as 0.1 EID 50 of H7N9 viruses, which is similar to the detection limit of the real-time RT-PCR assay released by the Word Health Organization. The coefficients of variation (CVs) of both inter-assay and intra-assay reproducibility were less than 1.55 %, showing good reproducibility. No cross-reactivity was observed with RNA of other subtypes of influenza virus or other avian respiratory viruses. The assay can effectively detect H7N9 influenza virus RNA from multiple sources, including chickens, pigeons, ducks, humans, and the environment. Furthermore, the RRT-PCR assay was evaluated with more than 700 clinical samples collected from live-poultry markets and 120 experimentally infected chicken samples. Together, these results indicate that the duplex RRT-PCR assay is a specific, sensitive, and efficient diagnostic method for the epidemiological surveillance and diagnosis of H7N9 virus from different sources, particularly poultry samples.
Variation analysis of E1 and E2 in HCV subtypesCheng, Xue-Di; Xu, Hua-Feng; Wei, Xue-Mei; Zhou, Hai-Zhou
doi: 10.1007/s00705-015-2533-9pmid: 26199129
Pegylated interferon and ribavirin combination therapy effectively suppresses viral replication in 50 %–60 % of hepatitis C virus (HCV)-infected patients. However, HCV-infected patients often display varied responses to therapy, and strains of subtype lb (the most widespread HCV subtype worldwide) have more-severe clinical manifestations, greater viral loads, and poorer responses to interferon treatment. Therefore, understanding the genomic variability of HCV is crucial to treatment of HCV infection. In this study, we used the appropriate software to analyze the nucleotide, and amino acid sequences of the envelope proteins (E1 and E2) of HCV to investigate the extent of their variability in several HCV subtypes (1a, 1b, 2a, 2b, 3a, 4a, 5a and 6a) and calculated the ratio of nonsynonymous to synonymous substitutions (dN/dS) in these proteins to investigate the immunological pressure acting on them. We also predicted the N-glycosylation sites in E1 and E2 to determine their association with viral neutralization. We found that E1 is more variable, has a higher dN/dS ratio, and has more N-glycosylation sites than E2 in HCV subtype 1b. This indicates that the variability of E1, its dN/dS ratio, and its degree of N-glycosylation might play an important role in the treatment of infection with HCV subtype 1b.
Human cytomegalovirus miR-UL36-5p inhibits apoptosis via downregulation of adenine nucleotide translocator 3 in cultured cellsGuo, Xin; Huang, Yujing; Qi, Ying; Liu, Zhongyang; Ma, Yanping; Shao, Yaozhong; Jiang, Shujuan; Sun, Zhengrong; Ruan, Qiang
doi: 10.1007/s00705-015-2498-8pmid: 26212361
Human cytomegalovirus (HCMV) encodes at least 26 microRNAs (miRNA). These miRNAs are utilized by HCMV to regulate its own genes as well as the genes of the host cell during infection. It has been reported that a cellular gene, solute carrier family 25, member 6 (SLC25A6), which is also designated adenine nucleotide translocator 3 (ANT3), was identified as a candidate target of hcmv-miR-UL36-5p by hybrid PCR. In this study, ANT3 was further demonstrated to be a direct target of hcmv-miR-UL36-5p by luciferase reporter assays. The expression level of ANT3 protein was confirmed, by western blotting, to be directly downregulated by overexpression of hcmv-miR-UL36-5p in HEK293 cells, U373 cells and HELF cells. Moreover, HCMV-infected cells showed a decrease in the ANT3 protein level. Using ANT3-specific small interfering RNA (siRNA) and an inhibitor for hcmv-miR-UL36-5p, it was shown that inhibition of apoptosis by hcmv-miR-UL36-5p in these cells specifically occurred via inhibition of ANT3 expression. These results imply that hcmv-miR-UL36-5 may play the same role during actual HCMV infection in order to establish a balance between the host cell and the virus.