The impact of the pandemic influenza A(H1N1) 2009 virus on seasonal influenza A viruses in the southern hemisphere, 2009.

Data collected over winter 2009 by five World Health Organisation National Influenza Centres in the southern hemisphere were used to examine the circulation of pandemic and seasonal influenza A strains during the first pandemic wave in the southern hemisphere.There is compelling evidence that the pandemic influenza A(H1N1) 2009 virus significantly displaced seasonal influenza A(H1N1) and, to a lesser extent, A(H3N2) viruses circulating in the southern hemisphere. Complete replacement of seasonal influenza A strains, however, was not observed during the first pandemic wave.

A quantitative assessment of the efficacy of surgical and N95 masks to filter influenza virus in patients with acute influenza infection.

We assessed the in vivo efficacy of surgical and N95 (respirator) masks to filter reverse transcription-polymerase chain reaction (RT-PCR)-detectable virus when worn correctly by patients with laboratory-confirmed acute influenza. Of 26 patients with a clinical diagnosis of influenza, 19 had the diagnosis confirmed by RT-PCR, and 9 went on to complete the study. Surgical and N95 masks were equally effective in preventing the spread of PCR-detectable influenza.

Human coronavirus OC43 causes influenza-like illness in residents and staff of aged-care facilities in Melbourne, Australia.

Three outbreaks of respiratory illness associated with human coronavirus HCoV-OC43 infection occurred in geographically unrelated aged-care facilities in Melbourne, Australia during August and September 2002. On clinical and epidemiological grounds the outbreaks were first thought to be caused by influenza virus. HCoV-OC43 was detected by RT-PCR in 16 out of 27 (59%) specimens and was the only virus detected at the time of sampling. Common clinical manifestations were cough (74%), rhinorrhoea (59%) and sore throat (53%). Attack rates and symptoms were similar in residents and staff across the facilities. HCoV-OC43 was also detected in surveillance and diagnostic respiratory samples in the same months. These outbreaks establish this virus as a cause of morbidity in aged-care facilities and add to increasing evidence of the significance of coronavirus infections.

Changing epidemiology of genital herpes simplex virus infection in Melbourne, Australia, between 1980 and 2003.

OBJECTIVE: To investigate changes in the proportions of patients infected with genital herpes simplex virus (HSV) types 1 and 2 from 1980 to 2003 in Melbourne, Australia. METHODS: A total of 25 372 patients were studied retrospectively. The proportions of HSV-1 and HSV-2 detected in these individuals were analysed by age, sex, and genital site. RESULTS: In 1980 only 15.8% of HSV positive genital specimens were HSV-1 compared to 34.9% in 2003. In 2003 HSV-1 was detected in 77% of patients aged less than 20 years. Females were more likely to be infected with HSV-1, although the rate of increased detection was more pronounced in males. Except for females over the age of 40, the trend for the increase in HSV-1 was detected in all age groups. No specific genital site in either sex was associated with the increase. CONCLUSIONS: The proportion of genital HSV-1 has increased in Australian patients, although HSV-2 is still the most common cause of genital infection. Confirmation of HSV type is necessary for optimal patient management.

Detection of varicella zoster virus in genital specimens using a multiplex polymerase chain reaction.

OBJECTIVE: To compare the relative proportions of varicella zoster virus (VZV) and herpes simplex viruses in specimens obtained from the genital lesions of adults presenting with presumed genital herpes infection. METHODS: Swabs of genital lesions from 6210 patients attending general practices, infectious diseases clinics within hospitals, or sexual health centres for treatment of their genital lesions were tested using polymerase chain reaction (PCR) technology. The multiplexed PCR was capable of detecting herpes simplex virus types 1 and 2 (HSV-1, HSV-2), VZV, and cytomegalovirus in a single sample. RESULTS: A total of 2225 patients had viruses detected by PCR. HSV-1 was detected in 36%, HSV-2 in 61%, and VZV in 2.9% of PCR positive samples. Of the 65 patients with VZV genital infection, many were thought to have HSV infection before laboratory testing. CONCLUSIONS: The finding of VZV in nearly 3% of virus positive genital specimens demonstrates that this virus needs to be considered as a differential diagnosis for genital herpetic lesions. Advice provided to patients with VZV genital infection regarding the source of infection, likelihood of recurrence, and potential for transmission of the virus will be different from that given to patients with HSV infection.

Individuals from North America, Australasia, and Africa are infected with four different genotypes of human herpesvirus 8.

To study human herpesvirus 8 (HHV-8) transmission between individuals and in populations, we developed a system for genetic fingerprinting of HHV-8 strains based on variation in the HHV-8 K1, glycoprotein B (gB), and glycoprotein H (gH) genes. Using this system, we sequenced nearly the entire K1 gene (840 bp); two segments of the gB gene (open reading frame 8), totaling 813 bp; and a 702-bp segment of the gH gene (open reading frame 22) from blood and tissue samples obtained from 40 human immunodeficiency virus-infected and noninfected individuals, including those with Kaposi's sarcoma, primary effusion lymphoma, or Castleman's disease. The specimen collection was assembled from individuals living in diverse geographical locations, including the United States, Australia, New Zealand, Uganda, and Zambia. As reported by others, K1 was the most variable gene, with up to 16% variation at the nucleotide sequence level and up to 32% variation at the amino acid sequence level. Despite this extensive sequence variation, the K1 amino acid sequence contained 14 conserved cysteine sites, suggesting a conserved tertiary structure. gB and gH sequences were highly conserved, in most cases differing by <0.6% in pairwise comparisons. K1 was the most useful gene for strain discrimination, but the other genes enabled the discrimination of strains with identical K1 sequences. Individuals from diverse geographic locations were infected with four different HHV-8 genotypes; strains did not strictly segregate by continent of origin. The majority of HHV-8 strains from the United States and Europe were relatively closely related, whereas some strains identified from Uganda and Australia were phylogenetically distant. Genotype I strains were the most common and were found on three continents. Identical sequences were found in specimens obtained from different body sites and at different times from the same individual.

Inactivation of feline calicivirus, a Norwalk virus surrogate.

Norwalk and Norwalk virus-like particles (NVLPs) [also known as small round structured viruses (SRSVs)] are members of the family Caliciviridae and are important causes of gastroenteritis in humans. Little is known about their survival in the environment or the disinfection procedures necessary to remove them from contaminated settings. As NVLPs cannot be grown in tissue culture, survival studies require the use of a closely related cultivable virus. This study assesses the survival of the surrogate feline calicivirus (FCV) after exposure to commercially available disinfectants and a range of environmental conditions. Disinfectants tested included glutaraldehyde, iodine, hypochlorite, a quaternary ammonium-based product, an anionic detergent and ethanol. Complete inactivation of FCV required exposure to 1000 ppm freshly reconstituted granular hypochlorite, or 5000 ppm pre-reconstituted hypochlorite solution. Glutaraldehyde and the iodine-based product effectively inactivated FCV whereas the quaternary ammonium product, detergent and ethanol failed to completely inactivate the virus. The stability of FCV in suspension and in a dried state was assessed after exposure to 4 degrees C, room temperature (20 degrees C) and 37 degrees C. With increasing temperature, the stability of FCV was found to diminish both in suspension and in the dried state. FCV in the dried state did not survive for one day at 37 degrees C. This study provides a basis for establishing guidelines for disinfection protocols to decrease the spread of NVLPs in a community setting.

Transmission of human and feline immunodeficiency viruses via reused suture material.

Several documented cases of human immunodeficiency virus (HIV) infection have involved unconventional or unknown modes of transmission of the virus. Some such cases have occurred within a surgical setting. We investigated the potential for transmission of HIV on suture material that had been reused following passage through an HIV-infected patient. Initial experiments were conducted in vitro using HIV. To provide stronger evidence that HIV could be transmitted via this route, further experiments were undertaken in vivo using a feline immunodeficiency virus (FIV)/cat model. Both methods indicated the possibility of transmission of virus if suture materials were reused.

Susceptibility of HIV to inactivation by disinfectants and ultraviolet light.

Assays were developed to assess a variety of conditions and presentations of infectious HIV to potential inactivating sources. A range of commercially available disinfectants with active constituents including glutaraldehyde, chlorine, phenolics, alcohol, iodine and quaternary ammonium compounds was tested. In addition, u.v. light was investigated as a potential inactivating source. All products were assessed against cell-free HIV in culture medium and cell-associated HIV suspended in medium or whole human blood. All products completely inactivated cell-free HIV following a 1 min exposure. However, cell-associated HIV was more resilient, requiring exposure of 5 min or more for some disinfectants. The effectiveness of the disinfectants was further compromised in the presence of blood.

Isolation of HIV-1 from experimentally contaminated multidose local anaesthetic vials.

OBJECTIVE: To investigate the hypothesis that HIV can be transmitted via contamination of multidose vials of local anaesthetic solution through reuse of needles and syringes. DESIGN AND SETTING: Laboratory study. (1) By experiments with multidose vials and disposable needles and syringes, we identified a sequence of events in which HIV could contaminate the anaesthetic solution. (2) Three anaesthetic solutions were contaminated with a laboratory strain of HIV and tested by viral culture and p24 enzyme immunoassay one, two and four hours later to see how long the virus remained active. RESULTS: (1) Needles and syringes retained small volumes of fluid after use (mean, 25 microL; in syringe alone, mean 16 microL) which could be transferred to multidose vials of local anaesthetic. (2) 10 mL of anaesthetic solution contaminated with 8 microL of HIV-infected solution (equivalent to 1% infected lymphocytes in vivo) contained active virus one hour later. In some settings, HIV could be isolated four hours after exposure. CONCLUSION: When inadvertently contaminated with HIV, multidose solutions represent a potential source of transmissible virus.