Evidence of patient-to-patient transmission of hepatitis C virus through contaminated intravenous anaesthetic ampoules.

Two separate cases of acute hepatitis C virus (HCV) infection following medical procedures, arthroscopy and colonoscopy, are reported. In both episodes, patient risk factors were reviewed, and staff and other patients' sera were tested for HCV antibodies and RNA. HCV RNA positive samples were genotyped, sequenced, and subjected to phylogenetic analysis. No risk factors for HCV infection were identified for either case except for medical procedures. HCV RNA positive patients were identified preceding both cases on the respective theatre lists. HCV infection in a second low risk patient was also identified. Nucleic acid sequencing and phylogenetic analysis of HCV from the two putative source patients and the three recipient patients demonstrated a high degree of relatedness respectively. The results suggest that patient-to-patient transmission occurred in both episodes via contamination of intravenous anaesthetic ampoules with HCV used on multiple patients. Injectable medication ampoules should not be used for more than one patient.

Measles outbreak in young adults in Victoria, 1999.

OBJECTIVES: To describe an outbreak of measles in Victoria. DESIGN: Case series with cases identified through enhanced passive surveillance and outbreak-related active surveillance. SETTING: State of Victoria, 1999. MAIN OUTCOME MEASURES: Number of cases; epidemiological links and patterns of transmission; patient demographic features and vaccination status; complications. RESULTS: 75 cases were identified (74 laboratory-confirmed; and one epidemiologically linked to a laboratory-confirmed case), with onset between 11 February and 2 May 1999. The first case was in a 21-year-old woman who had recently holidayed in Bali and worked at a large cinema complex in Melbourne. Sixteen cases occurred in people who had contact with the index case at the cinema on one evening. The outbreak spread to regional Victoria and South Australia. Median age of patients was 22 years; 64 (85%) were born between 1968 and 1981, with only one patient in the age group targeted by the primary school component of the 1998 Australian Measles Control Campaign; this child had not been vaccinated. More than a third of patients (28) were hospitalised (total, 97 inpatient days), and five were healthcare workers. CONCLUSIONS: This outbreak was caused by international importation of measles virus. It highlights the change in epidemiology of measles in Australia, from a disease of childhood to one predominantly affecting young adults. A strong two-dose childhood vaccination program, vigilant surveillance, and rapid response to outbreaks will continue to be the basis of measles control, but better protection for young adults should be considered.

Health effects of exposure to cyanobacteria (blue-green algae) during recreational water-related activities.

The aim of this study was to investigate effects on health of exposure to cyanobacteria as a result of recreational water activities. Participants, who were aged six years and over, were interviewed at water recreation sites in South Australia, New South Wales and Victoria on selected Sundays during January and February 1995. Telephone follow-up was conducted two and seven days later to record any subsequent diarrhoea, vomiting, flu-like symptoms, skin rashes, mouth ulcers, fevers and eye or ear irritations. On the Sundays of interview, water samples from the sites were collected for cyanobacterial cell counts and toxin analysis. There were 852 participants, of whom 75 did not have water contact on the day of interview and were considered unexposed. The 777 who had water contact were considered exposed. No significant differences in overall symptoms were found between the unexposed and exposed after two days. At seven days, there was a significant trend to increasing symptom occurrence with duration of exposure (P = 0.03). There was a significant trend to increasing symptom occurrence with increase in cell count (P = 0.04). Participants exposed to more than 5000 cells per mL for more than one hour had a significantly higher symptom occurrence rate than the unexposed. Symptoms were not correlated with the presence of hepatotoxins. These results suggest symptom occurrence was associated with duration of contact with water containing cyanobacteria, and with cyanobacterial cell density. The findings suggest that the current safety threshold for exposure of 20,000 cells per mL may be too high.

High rate of transmission of tuberculosis in an office: impact of delayed diagnosis.

We identified two cases of tuberculosis (TB) in office co-workers in Melbourne, Victoria, Australia; the Mycobacterium tuberculosis isolates were found to be identical with use of restriction fragment length polymorphism. Contact tracing was performed for 195 of 210 workers by means of the tuberculin skin test. Risk of infection was assessed according to a number of variables. Office contacts were exposed to infectious TB for 4 months; at least 24% of employees were infected. There was an association between sitting in proximity to the case during the period of exposure (OR, 4.24; 95% CI, 1.06-19.67). On-site workers had a higher risk of being infected (OR, 5.48; CI, 1.51-23.54) than did visiting workers. Workers in this office were exposed to open pulmonary TB for prolonged periods. The prevalence of TB infection (24%) among these workers was high compared with the infection rate (2%-7%) in the general community. Delay in diagnosis was the major factor responsible for the spread of TB in this office.

Legionella pneumophila and water temperatures in Australian hospitals.

Thirty-four samples of warm waters from 12 psychiatric centres in Victoria and New South Wales were examined for legionellae by guinea-pig inoculation. Legionella pneumophila was isolated from 20 of the samples collected from ten of the establishments investigated. The detected prevalence proportion of L. pneumophila in waters of temperatures 36 to 43 degrees C was 0.9 (18/20), whereas the prevalence in waters of temperatures 45 to 54.2 degrees C was 0.14 (2/14). The two 'positive' waters within the latter range showed evidence of low numbers of L. pneumophila. No significant antibody titres to relevant serogroups were detected in the 112 exposed residents tested from seven psychiatric hospitals in New South Wales. The findings show that the temperature range with the greatest prevalence of L. pneumophila in warm waters is 36 to 43 degrees C. The presence of legionellae in these warm water-distribution systems contrasts with their absence from the water-distribution systems of Victorian hospitals in an earlier survey and underlines the value and simplicity of the usual Australian practice of maintaining hospital hot water temperatures at about 70 degrees C in the control of L. pneumophila.

Isolation of Legionella pneumophila from hospital water systems in Victoria.

A survey of water symptoms in 12 Victorian hospitals was undertaken to establish the prevalence of Legionella pneumophila in buildings not known to be associated with cases of Legionnaires' disease. Samples of hot, cold and shower water were taken, together with water from cooling towers, and isolation was attempted by guinea-pig inoculation. Legionella pneumophila was not isolated from any of the hot, cold or shower samples, but six strains were isolated from five of the cooling towers sampled.