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Papers by Emanuela Pelosi
Journal of Medical Virology, 2008
Hepatitis E indigenous to developed countries (hepatitis EIDC) is a form of hepatitis E in person... more Hepatitis E indigenous to developed countries (hepatitis EIDC) is a form of hepatitis E in persons with no travel history to highly endemic areas. It has been recognized recently as an emerging clinical entity in a significant number of economically developed countries including UK. However, it is still perceived as a rare disease and routine laboratory testing for hepatitis E is not performed. A series of 13 cases of hepatitis EIDC, diagnosed in a 13-month period from June 2005 within a single center in South Hampshire, UK, is presented. These patients were identified after implementing a novel-screening algorithm that introduced routine hepatitis E serological investigations. Patients were middle aged or elderly and males were affected more commonly. Four patients (31%) required hospital admission. All reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed cases carried hepatitis E virus (HEV) genotype-3, which bore close sequence homology to HEV circulating in UK pigs. None of these patients recalled eating undercooked pork products or close contact with pigs during the 2 months preceding the onset of acute hepatitis. In comparison, during the same period, only two cases of hepatitis A and five cases of acute hepatitis B were diagnosed. These data illustrate the importance of introducing routine hepatitis E testing in all patients with unexplained acute liver disease and absence of relevant travel history. Routine testing can clarify hepatitis E epidemiology whilst improving the clinical management of patients with acute liver disease. J. Med. Virol. 80:283–288, 2008. © 2007 Wiley-Liss, Inc.
Virology, 1998
Herpes simplex virus can infect the mammalian brain causing lethal encephalitis (neurovirulence).... more Herpes simplex virus can infect the mammalian brain causing lethal encephalitis (neurovirulence). Previously, herpes simplex virus mutants that are attenuated for neurovirulence have exhibited defects in replication in brain and/or blocks to replication in neuronal cells. We investigated the attenuation of neurovirulence of mutant PAA r 5, which exhibits resistance to antiviral drugs due to altered viral DNA polymerase. Following intracerebral inoculation of 7-week-old CD1 mice, PAA r 5 was 30-fold attenuated for neurovirulence compared to its wild-type parent. A drug-sensitive virus derived by marker rescue with DNA polymerase gene sequences exhibited neurovirulence that was essentially indistinguishable from that of wild-type virus, demonstrating that attenuation was due to a polymerase mutation. PAA r 5 replicated in brain similarly to wild-type virus unlike another polymerase mutant, 615.8, that exhibited a similar degree of attenuation. The attenuation of PAA r 5 was not associated with altered particle to PFU ratios nor with any obvious reductions in viral antigen expression in neurons, spread, histopathology, or TUNEL staining suggestive of apoptotic cells. Thus PAA r 5 differs from other mutants that are attenuated for neurovirulence. Understanding how a polymerase mutation specifically attenuates neurovirulence may shed light on how herpes simplex virus can cause lethal encephalitis.
Proceedings of The National Academy of Sciences, 1994
Clinical resistance to antiviral drugs requies that a virus evade drug therapy yet retain pathoge... more Clinical resistance to antiviral drugs requies that a virus evade drug therapy yet retain pathogenicity. Thymidine kinase (TK)-negative mutants ofherpes simplex virus are resistant to the drug, acyclovir, but are attenuated for pathogenicity in animal models. However, numerous cases of clinical resistance to acyclovir have been associated with viruses that were reported to express no TK activity. We studied an acyclovir-resistant clinical mutant that contains a single-base insertion in its tk gene, predicting the synthesis of a truncated TK polypeptide with no TK activity. Nevertheless, the mutant retained some TK activity and the ability to reactivate from latent infections of mouse trigeminal ganglia. The mutant expressed both the predicted truncated polypeptide and a low level of a polypeptide that comigrated with full-length TK on polyacrylamide gels and reacted with anti-TK antiserum, providing evidence for a frameshifting mechanism. In vitro transcription and tanslation ofmutant tkgenes, incuding constructs in which reporter epitopes could be expressed only if frameshiffing occurred, also gave rise to truncated and full-length polypeptides. Reverse transcriptase-polymerase chain reaction analysis coupled with open reading fram cloning failed to detect alterations Abbreviations: HSV, herpes simplex virus; TK, thymidine kinase; RT, reverse transcriptase.
Antiviral Research, 1998
We compared the penciclovir susceptibilities and pathogenesis phenotypes of mutants of Herpes sim... more We compared the penciclovir susceptibilities and pathogenesis phenotypes of mutants of Herpes simplex virus type 1 that are resistant to acyclovir and/or foscarnet. The mutants, which were derived from laboratory strain KOS, included six DNA polymerase mutants, a thymidine kinase negative mutant, a thymidine kinase partial mutant, and a double mutant. Two of four polymerase mutants not previously examined for penciclovir susceptibility exhibited modest resistance to this drug. A thymidine kinase negative mutant exhibited approximately 20-fold resistance while a thymidine kinase partial mutant was penciclovir-sensitive. Following intracerebral inoculation of 7-week old CD1 mice, the mutants ranged from exhibiting near wild-type neurovirulence (thymidine kinase partial) to modest attenuation (e.g. thymidine kinase negative) to more severe attenuation. Following corneal inoculation, three polymerase mutants exhibited modest deficits (relative to those of thymidine kinase negative mutants) in their abilities to replicate acutely in the ganglion and reactivate from latency. For mutant AraA(r)13, the deficit in ganglionic replication was shown to be due to its polymerase mutation by analysis of recombinant viruses derived by marker rescue. These results may have implications for issues of penciclovir action and resistance, for drug resistance in the clinic, and for the interactions of herpes viruses with the peripheral and central nervous systems.
Journal of Medical Microbiology, 1998
A competitive polymerase chain reaction (cPCR) assay for the quantitative evaluation of Mycobacte... more A competitive polymerase chain reaction (cPCR) assay for the quantitative evaluation of Mycobacteriurn tuberculosis growth was developed based on co-amplification of genomic DNA and a modified DNA fragment derived from a well-conserved region of the 16s rRNA gene. There was a good correlation between the number of DNA copies in the sample, indicated by competitive PCR, and the number of colony forming units determined by conventional culture methods.
European Journal of Clinical Microbiology & Infectious Diseases, 1988
Susceptibility testing of clinical isolates of several gram-negative and gram-positive species sh... more Susceptibility testing of clinical isolates of several gram-negative and gram-positive species showed LY163892 to be more active than cefaclor and cephalexin. OXA-2, TEM-1, TEM-2, PSE-1, CEP-1, CARB-3 and SHV-1 beta-lactamases showed similar activity against LY163892 and cefaclor, whereas OXA-1 hydrolyzed the latter more rapidly. Organisms producing these beta-lactamases, but not TEM-2 and CEP-1, appeared to be more susceptible to LY163892 than cephalexin, although cephalexin proved to be more resistant to beta-lactamase activity. Strains producing TEM-2 and CEP-1 were resistant to LY163892, cefaclor and cephalexin.
Journal of Medical Virology, 1999
Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterise... more Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterised recently and belong to two separate genogroups. The capsid genes of these viruses were expressed in insect cells using recombinant baculoviruses. Both SV (genogroup 1) and LV (genogroup 2) capsid proteins self-assembled to form virus-like particles (VLPs). The VLPs were used in a standard enzyme-linked immunosorbent assay (ELISA) to screen for antibodies to SV and LV in 1,729 age-stratified human sera collected in Verona, Italy between January and November 1996. SV VLPs were labile compared with LV VLPs. There was a large difference in the prevalence of SV (28.7%) compared with LV (91.2%). However, presentation of SV VLPs using chicken egg yolk antibody-coated wells (IgY capture ELISA) with a subset of serum samples from patients (0-19 years) increased the number of positive sera significantly (50.5%), indicating that SV antigen integrity is an important factor in the assay. Recent reverse transcription-polymerase chain reaction (RT-PCR) studies have shown that LV is circulating currently and analysis of IgY capture ELISA data showed greater reactivity for LV than SV, reflecting a genuinely lower rate of recent infection by this genogroup 1 virus.
Emerging Health Threats Journal, 2008
Thirty years after its discovery, the hepatitis E virus (HEV) continues to represent a major publ... more Thirty years after its discovery, the hepatitis E virus (HEV) continues to represent a major public health problem in developing countries. In developed countries, it has emerged as a significant cause of non-travel-associated acute hepatitis. HEV infects a wide range of mammalian species and a key reservoir worldwide appears to be swine. Genomic sequence similarity between some human HEV genotypes and swine HEV strains has been identified and we know that humans can acquire HEV infection from animals. Although for the most part the clinical course of HEV infection is asymptomatic or mild, significant risk of serious disease exists in pregnant women and those with chronic liver disease. In addition, there are data on the threat of chronic infections in immunocompromised patients. Beyond management of exposure by public health measures, recent data support that active immunisation can prevent hepatitis E, highlighting the need for vaccination programmes. Here we review the current knowledge on HEV, its epidemiology, and the management and prevention of human disease. This is an Open Access article distributed under the terms of the Creative Commons Attribution licence which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Journal of Medical Virology, 1999
Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterise... more Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterised recently and belong to two separate genogroups. The capsid genes of these viruses were expressed in insect cells using recombinant baculoviruses. Both SV (genogroup 1) and LV (genogroup 2) capsid proteins self-assembled to form virus-like particles (VLPs). The VLPs were used in a standard enzyme-linked immunosorbent assay (ELISA) to screen for antibodies to SV and LV in 1,729 age-stratified human sera collected in Verona, Italy between January and November 1996. SV VLPs were labile compared with LV VLPs. There was a large difference in the prevalence of SV (28.7%) compared with LV (91.2%). However, presentation of SV VLPs using chicken egg yolk antibody-coated wells (IgY capture ELISA) with a subset of serum samples from patients (0-19 years) increased the number of positive sera significantly (50.5%), indicating that SV antigen integrity is an important factor in the assay. Recent reverse transcription-polymerase chain reaction (RT-PCR) studies have shown that LV is circulating currently and analysis of IgY capture ELISA data showed greater reactivity for LV than SV, reflecting a genuinely lower rate of recent infection by this genogroup 1 virus.
Journal of Medical Virology, 2008
Hepatitis E indigenous to developed countries (hepatitis EIDC) is a form of hepatitis E in person... more Hepatitis E indigenous to developed countries (hepatitis EIDC) is a form of hepatitis E in persons with no travel history to highly endemic areas. It has been recognized recently as an emerging clinical entity in a significant number of economically developed countries including UK. However, it is still perceived as a rare disease and routine laboratory testing for hepatitis E is not performed. A series of 13 cases of hepatitis EIDC, diagnosed in a 13-month period from June 2005 within a single center in South Hampshire, UK, is presented. These patients were identified after implementing a novel-screening algorithm that introduced routine hepatitis E serological investigations. Patients were middle aged or elderly and males were affected more commonly. Four patients (31%) required hospital admission. All reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed cases carried hepatitis E virus (HEV) genotype-3, which bore close sequence homology to HEV circulating in UK pigs. None of these patients recalled eating undercooked pork products or close contact with pigs during the 2 months preceding the onset of acute hepatitis. In comparison, during the same period, only two cases of hepatitis A and five cases of acute hepatitis B were diagnosed. These data illustrate the importance of introducing routine hepatitis E testing in all patients with unexplained acute liver disease and absence of relevant travel history. Routine testing can clarify hepatitis E epidemiology whilst improving the clinical management of patients with acute liver disease. J. Med. Virol. 80:283–288, 2008. © 2007 Wiley-Liss, Inc.
Virology, 1998
Herpes simplex virus can infect the mammalian brain causing lethal encephalitis (neurovirulence).... more Herpes simplex virus can infect the mammalian brain causing lethal encephalitis (neurovirulence). Previously, herpes simplex virus mutants that are attenuated for neurovirulence have exhibited defects in replication in brain and/or blocks to replication in neuronal cells. We investigated the attenuation of neurovirulence of mutant PAA r 5, which exhibits resistance to antiviral drugs due to altered viral DNA polymerase. Following intracerebral inoculation of 7-week-old CD1 mice, PAA r 5 was 30-fold attenuated for neurovirulence compared to its wild-type parent. A drug-sensitive virus derived by marker rescue with DNA polymerase gene sequences exhibited neurovirulence that was essentially indistinguishable from that of wild-type virus, demonstrating that attenuation was due to a polymerase mutation. PAA r 5 replicated in brain similarly to wild-type virus unlike another polymerase mutant, 615.8, that exhibited a similar degree of attenuation. The attenuation of PAA r 5 was not associated with altered particle to PFU ratios nor with any obvious reductions in viral antigen expression in neurons, spread, histopathology, or TUNEL staining suggestive of apoptotic cells. Thus PAA r 5 differs from other mutants that are attenuated for neurovirulence. Understanding how a polymerase mutation specifically attenuates neurovirulence may shed light on how herpes simplex virus can cause lethal encephalitis.
Proceedings of The National Academy of Sciences, 1994
Clinical resistance to antiviral drugs requies that a virus evade drug therapy yet retain pathoge... more Clinical resistance to antiviral drugs requies that a virus evade drug therapy yet retain pathogenicity. Thymidine kinase (TK)-negative mutants ofherpes simplex virus are resistant to the drug, acyclovir, but are attenuated for pathogenicity in animal models. However, numerous cases of clinical resistance to acyclovir have been associated with viruses that were reported to express no TK activity. We studied an acyclovir-resistant clinical mutant that contains a single-base insertion in its tk gene, predicting the synthesis of a truncated TK polypeptide with no TK activity. Nevertheless, the mutant retained some TK activity and the ability to reactivate from latent infections of mouse trigeminal ganglia. The mutant expressed both the predicted truncated polypeptide and a low level of a polypeptide that comigrated with full-length TK on polyacrylamide gels and reacted with anti-TK antiserum, providing evidence for a frameshifting mechanism. In vitro transcription and tanslation ofmutant tkgenes, incuding constructs in which reporter epitopes could be expressed only if frameshiffing occurred, also gave rise to truncated and full-length polypeptides. Reverse transcriptase-polymerase chain reaction analysis coupled with open reading fram cloning failed to detect alterations Abbreviations: HSV, herpes simplex virus; TK, thymidine kinase; RT, reverse transcriptase.
Antiviral Research, 1998
We compared the penciclovir susceptibilities and pathogenesis phenotypes of mutants of Herpes sim... more We compared the penciclovir susceptibilities and pathogenesis phenotypes of mutants of Herpes simplex virus type 1 that are resistant to acyclovir and/or foscarnet. The mutants, which were derived from laboratory strain KOS, included six DNA polymerase mutants, a thymidine kinase negative mutant, a thymidine kinase partial mutant, and a double mutant. Two of four polymerase mutants not previously examined for penciclovir susceptibility exhibited modest resistance to this drug. A thymidine kinase negative mutant exhibited approximately 20-fold resistance while a thymidine kinase partial mutant was penciclovir-sensitive. Following intracerebral inoculation of 7-week old CD1 mice, the mutants ranged from exhibiting near wild-type neurovirulence (thymidine kinase partial) to modest attenuation (e.g. thymidine kinase negative) to more severe attenuation. Following corneal inoculation, three polymerase mutants exhibited modest deficits (relative to those of thymidine kinase negative mutants) in their abilities to replicate acutely in the ganglion and reactivate from latency. For mutant AraA(r)13, the deficit in ganglionic replication was shown to be due to its polymerase mutation by analysis of recombinant viruses derived by marker rescue. These results may have implications for issues of penciclovir action and resistance, for drug resistance in the clinic, and for the interactions of herpes viruses with the peripheral and central nervous systems.
Journal of Medical Microbiology, 1998
A competitive polymerase chain reaction (cPCR) assay for the quantitative evaluation of Mycobacte... more A competitive polymerase chain reaction (cPCR) assay for the quantitative evaluation of Mycobacteriurn tuberculosis growth was developed based on co-amplification of genomic DNA and a modified DNA fragment derived from a well-conserved region of the 16s rRNA gene. There was a good correlation between the number of DNA copies in the sample, indicated by competitive PCR, and the number of colony forming units determined by conventional culture methods.
European Journal of Clinical Microbiology & Infectious Diseases, 1988
Susceptibility testing of clinical isolates of several gram-negative and gram-positive species sh... more Susceptibility testing of clinical isolates of several gram-negative and gram-positive species showed LY163892 to be more active than cefaclor and cephalexin. OXA-2, TEM-1, TEM-2, PSE-1, CEP-1, CARB-3 and SHV-1 beta-lactamases showed similar activity against LY163892 and cefaclor, whereas OXA-1 hydrolyzed the latter more rapidly. Organisms producing these beta-lactamases, but not TEM-2 and CEP-1, appeared to be more susceptible to LY163892 than cephalexin, although cephalexin proved to be more resistant to beta-lactamase activity. Strains producing TEM-2 and CEP-1 were resistant to LY163892, cefaclor and cephalexin.
Journal of Medical Virology, 1999
Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterise... more Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterised recently and belong to two separate genogroups. The capsid genes of these viruses were expressed in insect cells using recombinant baculoviruses. Both SV (genogroup 1) and LV (genogroup 2) capsid proteins self-assembled to form virus-like particles (VLPs). The VLPs were used in a standard enzyme-linked immunosorbent assay (ELISA) to screen for antibodies to SV and LV in 1,729 age-stratified human sera collected in Verona, Italy between January and November 1996. SV VLPs were labile compared with LV VLPs. There was a large difference in the prevalence of SV (28.7%) compared with LV (91.2%). However, presentation of SV VLPs using chicken egg yolk antibody-coated wells (IgY capture ELISA) with a subset of serum samples from patients (0-19 years) increased the number of positive sera significantly (50.5%), indicating that SV antigen integrity is an important factor in the assay. Recent reverse transcription-polymerase chain reaction (RT-PCR) studies have shown that LV is circulating currently and analysis of IgY capture ELISA data showed greater reactivity for LV than SV, reflecting a genuinely lower rate of recent infection by this genogroup 1 virus.
Emerging Health Threats Journal, 2008
Thirty years after its discovery, the hepatitis E virus (HEV) continues to represent a major publ... more Thirty years after its discovery, the hepatitis E virus (HEV) continues to represent a major public health problem in developing countries. In developed countries, it has emerged as a significant cause of non-travel-associated acute hepatitis. HEV infects a wide range of mammalian species and a key reservoir worldwide appears to be swine. Genomic sequence similarity between some human HEV genotypes and swine HEV strains has been identified and we know that humans can acquire HEV infection from animals. Although for the most part the clinical course of HEV infection is asymptomatic or mild, significant risk of serious disease exists in pregnant women and those with chronic liver disease. In addition, there are data on the threat of chronic infections in immunocompromised patients. Beyond management of exposure by public health measures, recent data support that active immunisation can prevent hepatitis E, highlighting the need for vaccination programmes. Here we review the current knowledge on HEV, its epidemiology, and the management and prevention of human disease. This is an Open Access article distributed under the terms of the Creative Commons Attribution licence which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Journal of Medical Virology, 1999
Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterise... more Southampton virus (SV) and Lordsdale viruses (LV) are small round structured viruses characterised recently and belong to two separate genogroups. The capsid genes of these viruses were expressed in insect cells using recombinant baculoviruses. Both SV (genogroup 1) and LV (genogroup 2) capsid proteins self-assembled to form virus-like particles (VLPs). The VLPs were used in a standard enzyme-linked immunosorbent assay (ELISA) to screen for antibodies to SV and LV in 1,729 age-stratified human sera collected in Verona, Italy between January and November 1996. SV VLPs were labile compared with LV VLPs. There was a large difference in the prevalence of SV (28.7%) compared with LV (91.2%). However, presentation of SV VLPs using chicken egg yolk antibody-coated wells (IgY capture ELISA) with a subset of serum samples from patients (0-19 years) increased the number of positive sera significantly (50.5%), indicating that SV antigen integrity is an important factor in the assay. Recent reverse transcription-polymerase chain reaction (RT-PCR) studies have shown that LV is circulating currently and analysis of IgY capture ELISA data showed greater reactivity for LV than SV, reflecting a genuinely lower rate of recent infection by this genogroup 1 virus.