Virus can replicate in several common cell lines, sometimes without cytopathic effect.

Respiratory viruses were identified by the polymerase chain reaction (PCR) in more than 4,200 specimens collected during 2002 and 2003 in Victoria, Australia from patients admitted to hospitals or participating in an influenza surveillance program. Influenza viruses and picornaviruses were important causes of morbidity in both years. Additional testing of picornavirus-positive samples suggested that rhinoviruses but not enteroviruses were more likely to be associated with respiratory symptoms, irrespective of the season in which they circulated. Detection of influenza viruses was strongly associated with the clinical symptoms of cough, fever, and fatigue; but each of the other respiratory viruses occasionally caused these symptoms or was responsible for symptoms severe enough to require hospitalization. Human coronaviruses HCoV-OC43 and HCoV-229E circulated at low levels throughout the study period with peak activity in winter, but overall did not circulate as widely as has often been reported for these agents. Evidence for the human metapneumovirus (hMPV) was only sought in the second year of the study and revealed low-level circulation of this virus, mainly in the cooler months among the very young and adult populations. The detection rate of all viruses declined with increasing age of the patient, particularly in hospital patients. Infection with more than one respiratory virus occurred in a small number of patients; picornaviruses were most commonly implicated in these dual infections.

SummaryThe declining incidence of AIDS-related opportunistic diseases among people with HIV infection has shifted the focus of clinical management to prevention and treatment of comorbidities such as chronic liver disease. The increased risk of hepatitis C virus (HCV)-related advanced liver disease in people with HIV infection makes early HCV diagnosis a priority. To assess HCV prevalence and predictors of HIV/HCV coinfection, we have conducted a retrospective analysis of people enrolled in the CAESAR (Canada, Australia, Europe, South Africa) study, a multinational randomized placebo-controlled study of the addition of lamivudine to background antiretroviral therapy. The impact of HCV on HIV disease progression was also examined. Anti-HCV antibody testing on 1649 CAESAR study participants demonstrated a HIV/HCV coinfection prevalence of 16.1%, which varied from 1.9% in South Africa to 48.6% in Italy. The strongest predictor of HIV/HCV coinfection was HIV exposure category (Po0.0001), with odds ratios (ORs) compared to homosexual as follows: injecting drug use (IDU), 365 [95% confidence interval (CI): 179-742]; transfusion or blood products, 32.2 (95% CI: 15.2-67.6); homosexual and IDU, 22.9 (95% CI: 8.5-62.1). The prevalence of HIV/HCV was low (3.7%) among homosexual men without reported IDU. Other predictors of HIV/HCV coinfection were alanine aminotransferase (ALT), country of residence, ethnicity and stage of HIV disease. A history of IDU or ALT ! 40 U/L at baseline had a positive predictive value (PPV) of 35%, negative predictive value (NPV) of 96%, sensitivity of 82% and specificity of 71% for HIV/HCV coinfection. HIV disease progression was similar in HIV monoinfected and HIV/HCV coinfected patients. People with HIV and a history of IDU or elevated liver function tests should be targeted for HCV testing. The low prevalence of HIV/HCV coinfection among homosexual men without a history of IDU suggests low efficiency of sexual HCV transmission.

Pol sequences generated during baseline resistance genotyping for newly HIV-infected patients provide the opportunity for real-time phylogenetics to identify sources of multiple HIV transmission events. This study demonstrated the existence of several distinct clusters of patients whose TDR strains were linked. Several discrete clusters involving transmission of K103N- and/or M41L-resistant virus to multiple recipients were detected, suggesting that multiple transmission pathways can exist for viruses with the same resistance mutations.

Both influenza and respiratory syncytial virus (RSV) cause epidemics of respiratory illness of variable severity during the winter season. Influenza in particular has been blamed for hospital winter bed pressures, although it is thought that RSV may also play a role. Human metapneumovirus (hMPV) is a new respiratory virus reported to be important in children; only a limited number of studies are available for adult populations. We aimed to determine initially the burden of virologically confirmed infections, i.e. influenza, RSV and hMPV using polymerase chain reaction (PCR) technology and, in addition, to assess the feasibility of this approach as a surveillance tool for these respiratory viruses. Adult patients admitted to hospital in the previous 24 hours with onset of acute respiratory symptoms in the last 14 days were asked to participate. Informed written consent was obtained and nose and throat swabs taken. Multiplex PCR for influenza A (H1N1 and H3N2), influenza B and RSV A and B were carried out together with a separate PCR for hMPV. A total of 219 patients in 2001-2002 and 216 in 2002-2003 were tested and the combined results for both seasons were: 8 positive for influenza A/H1N1, 14 for influenza A/H3N2, 2 for influenza B, 14 for RSV A and 6 for RSV B. Most patients (261/435) were >65 years and most positives (30/44) were found within this age group. A number of patients aged >65 years who were positive for influenza (12/15) reported having had vaccine. In total, 373 samples were tested for hMPV and 20 were found positive across all age groups except the 45-54 years age group. As influenza activity was low during the study period the impact of infection on admissions could not be assessed. Nevertheless the viruses studied accounted for 15% of hospital admissions for respiratory infection. Most patients were aged >65 years, as expected. In the two years studied RSV and hMPV were each responsible for as many hospitalized cases of respiratory infection as influenza. Influenza infection must be considered even in those who give a history of vaccination. The molecular methods used in this study showed that surveillance of these respiratory viruses can be conducted and may help in the management of patients.