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Biomedical subjects

D E Dwyer

Publications and source records attributed to D E Dwyer.

At least 19 recordsLinked to original sources
PubMed2006

Increase in rates of herpes simplex virus type 1 as a cause of anogenital herpes in western Sydney, Australia, between 1979 and 2003.

BACKGROUND/OBJECTIVE: Recent studies suggest that herpes simplex virus type 1 (HSV-1) is becoming more common as a cause for genital herpes, relative to HSV-2. We aimed to calculate trends in HSV type from isolates and serology samples sent to a reference virology laboratory in New South Wales (NSW), Australia. METHODS: We compared the proportions of HSV-1 and HSV-2 positive samples, adjusting for age and sex of source patient, in three datasets: anogenital isolates from 1979 to 1988; anogenital isolates from 1989 to 2003; and HSV type specific IgM seropositivity from 1994 to 2003. RESULTS: The number of specimens in each analysis was 17 512, 4359, and 497, respectively. There was a progressive rise in the proportions of typed specimens being HSV-1 in all analyses. The proportion of isolates that were HSV-1 ranged from 3% in 1980 to 41% in 2001. Female sex and age under 25 were associated with a greater proportion of HSV-1 isolates in both time periods. In the period 1979-88, comparing the proportions of HSV-1 and HSV-2 gave an odds ratio (OR) per additional year of 1.24 (95% confidence interval (CI) 1.20 to 1.27; p<0.005) after adjustment for age and sex. In the period 1989-2003 there was a steeper rise in the proportion of isolates that were HSV-1 in samples from younger individuals (OR per year 1.17, 1.12 to 1.22) compared to those over 25 (OR per year 1.06, 1.03 to 1.08). The rise in the proportion of IgM seropositive results reactive for HSV-1 compared to HSV-2 gave an OR of 1.36 per year (1.26 to 1.47; p<0.005). CONCLUSIONS: These data suggest that HSV-1 has become more common as a cause of anogenital herpes in NSW.

Age Factors↗
PubMed2005

Molecular epidemiology of enterovirus 71 over two decades in an Australian urban community.

Enterovirus 71 (EV71), first isolated in 1969, has been responsible for numerous outbreaks of hand, foot and mouth disease (HFMD) with a small proportion of cases associated with neurological disease. Since 1997 there has been a significant increase in both the prevalence and virulence of EV71 in the Asia-Pacific region. We have examined the genetic diversity of EV71 in a large Australian city (Sydney N.S.W.) over a nineteen-year period. We determined the VP1 gene sequence of forty-eight EV71 strains isolated between 1983 and 2001. Analysis by molecular phylogeny revealed the presence of four subgenogroups B2, B4, C1 and C2. The results indicate that the major lineage circulating in Sydney N.S.W. was subgenogroup C1 with a recent switch in dominance to B4 in 2000 and 2001.

Australia↗
PubMed2005

Summer outbreak of respiratory disease in an Australian prison due to an influenza A/Fujian/411/2002(H3N2)-like virus.

An outbreak of influenza A occurred in a prison system in New South Wales, Australia in January 2003 during the southern hemisphere summer. This report documents only the third confirmed outbreak of influenza in a prison environment. The outbreak investigation included case ascertainment, state-wide surveillance, a case-control study and interventions to limit the outbreak such as infection control, quarantine, cohorting of cases, and the use of antiviral medication for prophylaxis. A total of 37 clinical cases were identified. Influenza A virus was detected in 11 of the 22 respiratory tract specimens collected. The virus was typed as an influenza A/Fujian/411/2002 (H3N2)-like virus. This strain subsequently became the predominant virus strain during the northern hemisphere winter and the following 2003 Australian southern hemisphere winter influenza season.

Case-Control Studies↗
PubMed2004

HSV type specific serology in sexual health clinics: use, benefits, and who gets tested.

OBJECTIVES: To determine which sexual health clinic clients were tested for herpes simplex virus (HSV) type specific antibodies and whether this test was useful for patient management. METHODS: Demographic, sexual and reproductive history, reasons for performing type specific serology, results, and benefits were derived from patient records from Parramatta Sexual Health Clinic for all patients who were tested between 13 September1993 and 31 December 2001. The value of serology was defined under five categories-diagnostic, counselling, initiating suppressive antiviral therapy, pregnancy counselling, and not useful. To establish whether patients tested for HSV were representative of clinic attendees, a sex matched "control" group was randomly selected. RESULTS: 382/886 (43.1%) were HSV-2 antibody positive and 774/884 (80.8%) were HSV-1 positive. The commonest reasons for requesting serology were having a partner with genital herpes (30%), undiagnosed recurrent genital ulceration (26%), and first episode of genital ulceration (22%). The test was of value in confirming the diagnosis in 57% of men and 60% of women with recurrent genital ulceration and in 28% of men and 40% of women with first episode genital herpes. In patients with a partner with genital herpes the test was of value in making a diagnosis in 27% men and 50% of women and in counselling 50% of women and 73% of men. Patients offered serology were older and more likely to have had genital herpes in the past than controls. CONCLUSION: Type specific serology should be recommended for the management of couples where one has genital herpes and the other apparently does not and in individuals with genital complaints suggestive of herpes.

Adolescent↗
PubMed2002

Emerging viral infections in Australia.

Emerging viruses include known viruses that have increased in incidence or geographic range (such as enteroviruses and Japanese encephalitis virus), new viruses associated with known diseases (Australian bat lyssavirus) and new viruses associated with previously unrecognized diseases (Hendra and Nipah viruses). Some may have a predilection for children (Japanese encephalitis, influenza viruses and enterovirus 71) and vigilance is essential to ensure early recognition of these agents.

Animal Diseases↗
PubMed2000

Evidence for late stage compartmentalization of HIV-1 resistance mutations between lymph node and peripheral blood mononuclear cells.

OBJECTIVE: To determine the overall distribution of drug-resistance mutations to nucleoside reverse transcriptase inhibitors of HIV strains recovered from the lymph nodes (LN) and peripheral blood mononuclear cell (PBMC) compartments of four HIV-infected patients receiving zidovudine and didanosine and to compare them with antiretroviral-naive patients. DESIGN: Molecular comparison of major and minor HIV-1 env and pol region variants residing in LN and PBMC compartments. MATERIALS AND METHODS: Proviral DNA sequences were amplified by PCR from both PBMC and LN compartments, cloned into PGEM-T II Easy vector and sequenced. The clones were subjected to molecular and phylogenetic analysis. RESULTS: Comparison of PBMC and LN-derived HIV-1 variants in the env V3 region showed that nucleotide and amino acid variability was a characteristic feature of LN-derived variants. In contrast, a majority of resistance mutations to reverse transcriptase inhibitors were localized in the PBMC compartment rather than in LN, which is thought to be a reservoir of HIV. CONCLUSIONS: Distinct compartmentalization or independent evolution of pol and env gene variants between LN and PBMC could be due to the differential selection pressure imposed by the combination drug regimen, hence the bimodal distribution of resistance variants between LN and PBMC compartments.

Anti-HIV Agents↗
PubMed2000

Molecular and biological interactions between two HIV-1 strains from a coinfected patient reveal the first evidence in favor of viral synergism.

An intravenous drug user was found to be dually infected with two genetically and phylogenetically distinct human immunodeficiency virus type 1 (HIV-1) subtype B strains (designated groups I and II). Viral isolation revealed a simultaneous copassaging of two strains in PBMC. The culture of viral strains on monocytes and monocyte-derived macrophages preferentially segregated the two viral strains. The group I strain utilized CXCR4 and group II used CCR5 coreceptor for entry. Sequencing of >100 clones from uncultured PBMC consistently showed the predominance of group II virus in vivo. Importantly, the group II virus alone could not productively infect PBMC, but when used together with group I virus for infection, the group II virus regained its high replication potential and predominance in cultured PBMC. These data are the first to provide direct evidence in favor of molecular and biological interaction between two infecting strains in a coinfected patient and show their differential pathogenic effects, tropism, and modes of entry. In addition, our data provide the first evidence for synergism between these two strains. Cumulatively, these data emphasize that in order to clearly interpret coreceptor usage, biological segregation of viral strains from primary isolates in vitro may be imperative.

Amino Acid Sequence↗
PubMed2000

Arboviruses associated with human disease in Australia.

Mosquito-borne arboviruses are an important public health issue in Australia. The alphaviruses Ross River and Barmah Forest virus are widespread and active annually, and cause debilitating polyarthritis. The flaviviruses Murray Valley encephalitis, Kunjin and Japanese encephalitis virus are restricted in distribution and activity but may cause life-threatening illness, and dengue viruses are active in some areas.

Animals↗
PubMed1999

Significance of plasma and peripheral blood mononuclear cell derived HIV-1 sequences in establishing epidemiologic linkage between two individuals multiply exposed to HIV-1.

Establishing epidemiologic linkage in individuals multiply exposed to HIV can be a difficult task. To date, only peripheral blood mononuclear cell (PBMC)-derived sequences have been used in studying HIV-1 transmission between individuals. So far, the combined utility of plasma and PBMC-derived HIV-1 sequences has not been assessed in establishing epidemiologic linkage in people involved in transmission of HIV. In this study, both PBMC (DNA) and plasma (RNA) derived viral quasispecies was used in establishing epidemiologic linkage between two infected individuals (B-90 and B-69) multiply exposed to HIV-1 via injecting drug use. A detailed sequence, and phylogenetic analyses of HIV-1V3 region quasispecies derived from these two compartments clearly demonstrated compartmentalization of viral quasispecies between PBMC and plasma. More importantly, these data also demonstrate that in order to establish epidemiologic linkage between individuals multiply exposed to HIV-1, analyses of viral strains from both plasma and PBMC compartments may be necessary. The PBMC compartment alone may not provide sufficient information on epidemiologic linkage, overall diversification of viral quasispecies, replacement of older strains and the emergence of new viral recombinant strains in vivo. These are the first analyses that demonstrate the incremental value of plasma derived sequences, when used in conjunction with PBMC-derived sequences, in establishing the epidemiologic linkage between individuals multiply exposed to HIV parenterally. Further, the plasma derived HIV-1 sequences may prove to be invaluable in predicting a recent transmission between two epidemiologically-linked individuals.

Amino Acid Sequence↗
PubMed1999

Comparison of three commercial assays for the quantification of HIV-1 RNA in plasma from individuals infected with different HIV-1 subtypes.

BACKGROUND: Commercial human immunodeficiency virus 1 (HIV-1) ribonucleic acid (RNA) quantification assays vary in their ability to quantify different subtypes of HIV-1, a problem in regions where multipte HIV-1 subtypes may be circulating. OBJECTIVES: To assess commercial HIV-1 RNA quantification assays on two plasma panels. Panel 1 consisted of HIV-1 seronegative plasma 'spiked' with a known amount of cultured virus of different subtypes, and Panel 2 comprised plasma collected from individuals infected with different HIV-1 subtypes. STUDY DESIGN: The comparison involved the Amplicor HIV-1 reverse transcriptase-polymerase chain reaction (RT-PCR), Quantiplex branched DNA, and NucliSens HIV-1 QT assays. Panel 1 consisted of 11 plasma 'spiked' with cultured viruses of HIV-1 subtypes A-F, and Panel 2 included 33 plasma samples from 16 patients infected with subtypes A, B, C, E and G. RESULTS: In Panel 1, the Quantiplex branched deoxyribonucleic acid (bDNA) assay quantified subtypes A-F efficiently, comparable to published results from two other laboratories. The Amplicor RT-PCR assay quantified subtypes B, C, and D but was relatively less efficient with subtypes E, F, and did not or poorly quantified subtype A. Testing of Panel 2 showed some inter-assay differences. In contrast to Panel 1, the Amplicor RT-PCR assay performed variably with subtype A when compared with the Quantiplex bDNA and NucliSens QT assays, and higher viral load levels were generated with subtype E using the Amplicor RT-PCR assay. Subtypes B and C showed some inter-patient differences but the Quantiplex bDNA generally gave a lower quantification than the Amplicor RT-PCR and NucliSens QT assays. CONCLUSIONS: These studies confirm that commercial HIV-1 load assays vary in their ability to quantify different HIV-1 subtypes. This may be more apparent with individual patient samples than with 'spiked' panels. This variability emphasizes that it is preferable for patient samples to be tested with the same assay, and care should be taken where infection with unusual subtypes is suspected.

DNA, Viral↗
PubMed1999

The diagnosis and management of influenza. An update.

BACKGROUND: Disease resulting from influenza virus infection ranges from mild respiratory illness to fatal pneumonia. Influenza is a significant cause of morbidity and mortality throughout the world, and there are annual epidemics in Australia in late autumn and winter. OBJECTIVE: This article examines the latest diagnostic tests and treatment available for influenza. DISCUSSION: In addition to traditional viral culture or antigen detection assays, office based techniques for rapid diagnosis and polymerase chain reaction (PCR) for the detection and typing of influenza viruses have been developed recently. The combination of sensitive and more rapid tissue culture systems, PCR and office based rapid techniques provide the possibility of verifying the clinical diagnosis of influenza and improving the quality of surveillance systems. Accurate diagnosis is essential for the appropriate use of new antivirals to control influenza infection.

Antiviral Agents↗
PubMed1998

Ross River virus infection in the north-west outskirts of the Sydney basin.

In early 1997, 69 cases of Ross River virus infection were reported in the north-western outskirts of Sydney. This represents a substantial increase over the maximum of 12 cases reported in any one year since 1991. The majority of cases (71%) are thought to have been locally acquired. This is the first reported outbreak of Ross River virus infection in this area and highlights the need for metropolitan health services to be vigilant about a disease that has primarily been associated with rural and semirural areas in New South Wales.

Adolescent↗