A Salmonella Typhimurium 197 outbreak linked to the consumption of lambs' liver in Sydney, NSW.

We identified an increase in the number of cases of Salmonella Typhimurium phage type 197 in New South Wales in February 2005. Cases were predominantly of Lebanese descent. To identify risk factors for illness, we conducted an unmatched case-control study including 12 cases and 21 controls. Eight of 12 cases (67%) and no controls reported eating lambs' liver (OR incalculable, P<0.05), and seven of nine cases (78%) and one of 21 controls (5%) reported eating fresh fish (OR 70.0, P<0.05). Among participants who did not eat liver, there was a strong association between eating fish and illness (OR 60.0, P<0.05). The fish was from divergent sources. Five cases had bought the liver from two different butcher's shops, which obtained the lambs' liver from a single abattoir. Consumption of liver is a risk for salmonellosis. Traditional dishes may place some ethnic groups at increased risk of foodborne disease.

An outbreak of epidemic keratoconjunctivitis in a regional ophthalmology clinic in New South Wales.

The objective of the study was to identify the extent and cause of an outbreak of epidemic keratoconjunctivitis (EKC). The study design was active case finding and a case-control study of clinic patients who developed symptoms of EKC between 31 December 2005 and 31 March 2006. The main outcome measures were clinical procedures carried out and clinicians seen during clinic visit. Significantly more cases than controls had tonometry with instillation of anaesthetic drops (OR 16.5, 95% CI 3.9-145.1, P<0.01), optical coherence tomography (OR 4.7, 95% CI 1.2-21.9, P=0.01), or instillation of dilating drops by an orthoptist (OR 2.3, 95% CI 1.1-4.7, P=0.01). Significantly more cases than controls were seen by one orthoptist (OR 21.8, 95% CI 8.2-60.0, P<0.01). Transmission of EKC within the clinic was probably due to contamination of either or both the anaesthetic drops and the tonometer head in the room used by an orthoptist. A comprehensive suite of strategies is required to prevent healthcare-associated EKC.

A large outbreak of influenza A and B on a cruise ship causing widespread morbidity.

In September 2000 an outbreak of influenza-like illness was reported on a cruise ship sailing between Sydney and Noumea with over 1,100 passengers and 400 crew on board. Laboratory testing of passengers and crew indicated that both influenza A and B had been circulating on the ship. The cruise coincided with the peak influenza period in Sydney. Morbidity was high with 40 passengers hospitalized, two of whom died. A questionnaire was sent to passengers 3 weeks after the cruise and 836 of 1,119 (75%) responded. A total of 310 passengers (37%) reported suffering from an influenza-like illness (defined as cough, fever, myalgia and weakness) and 528 (63%) had seen a doctor for illness related to the cruise. One-third of passengers reported receipt of influenza vaccination in 2000; however neither their rates of influenza-like illness nor hospitalization were significantly different from those in unvaccinated passengers. A case-control study also found no significant protective effect of influenza vaccination. With the increasing popularity of cruise vacations, such outbreaks are likely to affect increasing numbers of people. Whilst influenza vaccination of passengers and crew may afford some protection, uptake and effectiveness may not be sufficient to prevent outbreaks. Surveillance systems and early intervention measures, such as antiviral therapies, should be considered to detect and control such outbreaks.

A statewide outbreak of cryptosporidiosis in New South Wales associated with swimming at public pools.

From December 1997 to April 1998, 1060 laboratory-confirmed cryptosporidiosis cases were reported in New South Wales, Australia. In a case-control study, compared with 200 controls, the 100 cases were younger (mean age 42 versus 71 years; P < 0.0001), more likely to report swimming at a public pool (59% versus 38%; adjusted OR and 95% CI = 27; 1.4-5.1) and swimming in a dam, river or lake (OR = 48; 1.1-20.3) but less likely to report drinking bottled water (OR = 0.4; 0.2-0.9). In subgroup analyses, in rural areas illness was associated mainly with contact with another person with diarrhoea, and in urban areas illness was associated with swimming in a public pool. Cryptosporidium oocysts were more commonly detected in pools to which at least two notified cases had swum (P = 004). Outbreaks of cryptosporidiosis can be prolonged, involve multiple pools and be difficult to control.

The Australian Childhood Immunisation Register: validation of the immunisation status of children who are very overdue.

OBJECTIVES: To determine the true immunisation status of children identified by the Australian Childhood Immunisation Register (ACIR) as 90 days overdue, and determine why appropriately immunised children were flagged as overdue. METHODS: A telephone survey of immunisation providers and/or parents of a stratified random sample of 850 NSW children born on or after 1 January 1996 and identified by the ACIR as 90 days overdue for at least one scheduled immunisation at 17 June 1997. The survey was conducted in June to September 1997. RESULTS: Children in the sample ranged in age from 5 to 17 months. Only 526 (61.9%) could be traced. Of these, 452 (86.6%) were fully immunised, and 75% of immunisations were given on time (within 30 days of falling due). The overall proportion of NSW children identified by ACIR as 90 days overdue who were fully immunised was an estimated 85% (95% CI 82.6%-87.4%). For the 452 fully immunised children, a reason for the child's immunisation not appearing on the register could be attributed for only 248/452 (54.8%). There was evidence that the provider had failed to submit an encounter form for 141 of these children. CONCLUSIONS: In mid-1997, more than half the children identified by ACIR as 'overdue' were fully immunised. A significant reason for fully immunised continuing to be flagged as overdue was failure to return encounter forms. IMPLICATIONS: At the time of survey the ACIR could not accurately identify unimmunised children and was of limited use as a tool for public health services to follow up very overdue children.

Monitoring acute diseases during the Sydney 2000 Olympic and Paralympic Games.

The Sydney 2000 Olympic Games (the XXVII Olympiad) will be the biggest peacetime event ever held in Australia. During the Games, all public health decisions will be centralised, with daily briefing sessions held to review emerging public health issues and facilitate responses. Infectious diseases will be monitored and reported through the Olympic Surveillance System, with particular attention to foodborne diseases and conditions spread via the respiratory route. This system relies heavily on the cooperation of key notifiers such as emergency departments, laboratories and general practitioners. The lessons learned during the Games, and the new and enhanced systems and linkages that have been developed to support it, will strengthen future disease surveillance in NSW.

Contaminated drinking water in one town manifesting as an outbreak of cryptosporidiosis in another.

In early 1992 we identified an outbreak of cryptosporidiosis in Oregon and sought to identify and control its source. We used a series of studies to identify risk factors for illness: (i) a case-control study among employees of a long-term-care facility (LTCF); (ii) a matched case-control study of the general community; (iii) a cohort study of wedding attendees; and (iv) a cross-sectional survey of the general community. Drinking Talent water was associated with illness in the LTCF (OR = 22.7, 95 % CI = 2.7-1009.0), and in the community (matched OR = 9.5, 95% CI 2.3-84.1). Drinking Talent water was associated with illness only among non-Talent residents who attended the wedding (P < 0.001) and in the community (RR = 6.5, 95 % CI 3.3-12.9). The outbreak was caused by contaminated municipal water from Talent in the absence of a discernible outbreak among Talent residents, suggesting persons exposed to contaminated water may develop immunity to cryptosporidiosis.

Where's the beef? The role of cross-contamination in 4 chain restaurant-associated outbreaks of Escherichia coli O157:H7 in the Pacific Northwest.

BACKGROUND: From March through August 1993, outbreaks of Escherichia coli O157:H7 occurred at 4 separate Oregon and Washington steak and salad bar restaurants affiliated with a single national chain. OBJECTIVE: To determine the cause of outbreaks of E coli O157:H7 at 4 chain restaurants. METHODS: Independent case-control studies were performed for each outbreak. Available E coli O157:H7 isolates were subtyped by pulse-field gel electrophoresis and by phage typing. RESULTS: Infection was not associated with beef consumption at any of the restaurants. Implicated foods varied by restaurant but all were items served at the salad bar. Among the salad bar items, no single item was implicated in all outbreaks, and no single item seemed to explain most of the cases at any individual restaurant. Molecular subtyping of bacterial isolates indicated that the first 2 outbreaks, which occurred concurrently, were caused by the same strain, the third outbreak was caused by a unique strain, and the fourth was multiclonal. CONCLUSIONS: Independent events of cross-contamination from beef within the restaurant kitchens, where meats and multiple salad bar items were prepared, were the likely cause of these outbreaks. Meat can be a source of E coli O157:H7 infection even if it is later cooked properly, underscoring the need for meticulous food handling at all stages of preparation.

Hepatitis A in New South Wales, Australia from consumption of oysters: the first reported outbreak.

Between 22 January and 4 April 1997, 467 hepatitis A cases were reported to the New South Wales Health Department, Australia. To identify the cause of the outbreak, we conducted a matched case-control study, and an environmental investigation. Among 66 cases and 66 postcode-matched controls, there was a strong association between illness and consumption of oysters (adjusted odds ratio 42; 95 % confidence interval 5-379). More than two-thirds of cases reported eating oysters, including one third of cases and no controls who reported eating oysters in the Wallis Lake area. A public warning was issued on 14 February, and Wallis Lake oysters were withdrawn from sale. Hepatitis A virus was subsequently identified in oyster samples taken from the lake. Hepatitis A virus poses a special risk to consumers who eat raw oysters because it can survive for long periods in estuaries and cause severe disease.

Cryptosporidiosis in the immunocompromised: weighing up the risk.

Cryptosporidiosis has been increasingly recognised as a cause of diarrhoeal illness in both immunocompetent and immunocompromised people. Massive outbreaks have been linked to municipal drinking water supplies in North America and Europe, but so far none have been reported in Australia. There is evidence that modes of transmission other than drinking water are more important. There can be no guarantee that infective Cryptosporidium oocysts will not contaminate an Australian water supply. Therefore, a permanent "boil water" warning may be warranted on medical advice in severely immunocompromised people, for whom cryptosporidiosis could be persistent and life threatening.

Improved AIDS surveillance through laboratory-initiated CD4 cell count reporting.

OBJECTIVE: To evaluate laboratory-initiated CD4 reporting (LICR) for AIDS surveillance and for differences in cases found by LICR and traditional surveillance methods (i.e., health care provider or death certificate reports and medical record searches). METHODS: We compared the characteristics of persons reported with AIDS between May 1993 and April 1994 by traditional methods or by LICR reports <200/microl. RESULTS: We received 643 LICR reports and 278 AIDS case reports. HIV status was available on 94% of LICR reports; 96% of these persons were HIV-infected. LICR reports were received on 250 (90%) AIDS cases. Cases found by LICR were less likely to be persons of color and to have opportunistic illnesses and more likely to live in rural areas. Cost of LICR to the health department was less than the salary of one research analyst. CONCLUSIONS: LICR, with a high positive predictive value, is a highly sensitive, timely, and relatively inexpensive method of surveillance and its use should be considered in other jurisdictions.

Outbreak of cryptosporidiosis linked to an indoor swimming pool.

OBJECTIVE: To determine the extent and source of a community outbreak of cryptosporidiosis. DESIGN: Questionnaire-based survey and matched case-control study. SETTING: Sutherland area in southern Sydney, September 1994 to January 1995. PARTICIPANTS: 70 patients reported by pathology laboratories to have stool specimens positive for cryptosporidia, of whom 43 were surveyed; 35 were compared with age- and neighbourhood-matched controls. MAIN OUTCOME MEASURES: Demographic characteristics and potential risk factors in the two weeks before onset of illness. RESULTS: Laboratories reported 70 cases of cryptosporidiosis between September 1994 and January 1995. We found no association between illness and foods consumed or contact with people with diarrhoea or sick animals in the two weeks before onset. Seventeen of the case group (49%) reported swimming in a particular indoor swimming pool, compared with only seven controls (20%) (odds ratio, 3.7; P = 0.015). Cryptosporidial oocysts were detected in water from the swimming pool in January 1995. CONCLUSIONS: The outbreak of cryptosporidiosis was probably associated with ingestion of water from the indoor swimming pool, presumably contaminated by infected bathers. RECOMMENDATIONS: As it is difficult to eradicate cryptosporidia from swimming pools by either disinfection or filtration, we recommend that: People with recent diarrhoea should avoid public swimming pools; and Non-toilet-trained and faecally incontinent swimmers should be provided with alternative swimming facilities with separate water and filtration systems. To enable appropriate public health responses: Doctors and pathology laboratories should consider cryptosporidiosis in patients with diarrhoea lasting longer than three days; and Laboratory reporting of cryptosporidia to local health departments should be mandatory in all States and Territories.

Missed opportunities for tuberculosis prevention.

BACKGROUND: With the recent resurgence of tuberculosis in the United States, it is unclear whether existing prevention strategies can successfully control and eliminate the disease. We determined the extent to which opportunities for prevention were missed among patients with tuberculosis. METHODS: For all patients with active tuberculosis reported to the Oregon Health Division, Portland, from July 1991 through June 1992, we determined previous history of tuberculosis therapy, previous tuberculin skin test status, the presence of medical conditions for which skin testing is recommended, and previous health care. We then determined whether they had undergone preventive procedures in accordance with current recommendations of the Advisory Council for the Elimination of Tuberculosis. RESULTS: Of 153 patients with active tuberculosis, 90 (59%) had indications for--but had not previously undergone--recommended procedures. Ten patients (7%) did not complete therapy for previous disease; two (1%) did not complete preventive therapy; 12 (8%) with known previous positive tuberculin skin tests and an indication for preventive therapy never received it; and 66 (43%) with known indications for screening never received a skin test. Indications for skin testing included exposure to active tuberculosis (44%), predisposing medical conditions (83%), previous residence in an institution (24%), and birth in a country with a high prevalence of tuberculosis (29%). CONCLUSIONS: Based on their known effectiveness, a major reduction in tuberculosis morbidity could occur if preventive measures were fully implemented. Appropriate skin testing is a prevention strategy of major importance. Priorities should include working to change provider practice to better ensure that persons with indications routinely receive tuberculin skin tests.

A community-wide outbreak of cryptosporidiosis associated with swimming at a wave pool.

OBJECTIVE: To determine the cause of a community-wide outbreak of cryptosporidiosis. DESIGN: A matched case-control study. SETTING: General community of Lane County, Oregon. PATIENTS AND OTHER PARTICIPANTS: Persons with Cryptosporidium detected in their stool from June to October 1992 were identified by contacting laboratories serving the area. Exposures of the first 18 case patients identified were compared with those of 18 age- and neighborhood-matched controls selected from a reverse telephone directory. MAIN OUTCOME MEASURES: Reported exposures to risk factors for cryptosporidiosis and abatement of cryptosporidiosis outbreak. RESULTS: Fifty-five patients with cryptosporidiosis were detected, including 37 who were the first individuals ill in their households. The case-control study involving the first 18 case patients showed no association between illness and attendance at day care or drinking municipal water or drinking untreated surface waters (river or lake water) in the 2 weeks before onset of illness. However, nine of 18 case patients reported swimming at a local wave pool, compared with none of 18 controls. We ultimately identified 17 case patients who reported swimming at the same wave pool during their incubation periods, whose exposure dates spanned a 2-month period. Inspection of the pool's filtration system did not detect any abnormalities. The outbreak subsided after the pool water was drained and replaced. CONCLUSIONS: This prolonged outbreak of cryptosporidiosis was likely caused by exposure to fecally contaminated wave pool water. Since Cryptosporidium is highly chlorine resistant and inadequately removed by sand filters, such outbreaks may represent an unrecognized hazard of wave pools, where the likelihood of inadvertent water ingestion is high. Such outbreaks may go undetected in areas where cryptosporidiosis is not reportable or laboratory screening is infrequent.

A swimming-associated outbreak of hemorrhagic colitis caused by Escherichia coli O157:H7 and Shigella sonnei.

BACKGROUND: In the summer of 1991, simultaneous outbreaks of bloody diarrhea and hemolytic-uremic syndrome caused by Escherichia coli O157:H7 and of bloody diarrhea caused by Shigella sonnei were traced to a lakeside park near Portland, Oregon. METHODS: We identified cases primarily from routine surveillance reports. In case-control studies, the activities of persons with park-associated E. coli O157:H7 or S. sonnei infections were compared independently with those of three sets of controls. We also evaluated environmental conditions at the park and subtyped the bacterial isolates. RESULTS: We identified 21 persons with park-associated E. coli O157:H7 infections (all of them children; median age, six years) and 38 persons with S. sonnei infections (most of them children). These 59 people had visited the park over a 24-day period. Their illnesses were not associated with food or beverage consumption. All the case patients reported swimming, however, and in case-control studies swimming was strongly associated with both types of infection (P = 0.015 or less). The case patients were more likely than the controls to report having swallowed lake water, and they had spent more time in the lake. Numbers of enterococci indicative of substantial fecal contamination (geometric mean, > 50 per deciliter) were detected in the swimming area during some but not all of the outbreak period. Park-associated E. coli O157:H7 isolates were identical by pulsed-field gel electrophoresis and were distinguishable from other isolates in the Portland area. CONCLUSIONS: Lake water that was fecally contaminated by bathers was the most likely vehicle for the transmission of both the E. coli O157:H7 and the S. sonnei infections. The unusually prolonged outbreak suggests both the survival of these enteric organisms in lake water and a low infectious dose.

An outbreak of Norwalk-like gastroenteritis associated with contaminated drinking water at a caravan park.

During the 1989 Christmas holiday period, a large outbreak of gastroenteritis occurred among persons staying at a caravan park in southern New South Wales. Review of local hospital records found that 77 per cent of patients presenting with infective diarrhoea between 29 December and 3 January had stayed at the caravan park. In a retrospective cohort study we compared rates of illness among caravan park patrons exposed to different water sources. Stools were tested for pathogens and convalescent sera for viral antibodies. Rain and reticulated river water sampled from the caravan park were tested for bacteria and viruses. Of 351 persons interviewed at the caravan park, 305 (87 per cent) reported an illness characterised by diarrhoea, vomiting and abdominal pain. Of 196 persons who used reticulated river water for drinking or ablutions, 175 (89 per cent) became ill compared with 47 of 72 persons (65 per cent) who did not use this water (relative risk 1.4, 95 per cent confidence interval 1.2 to 1.6). The outbreak was probably caused by a 27-28 nm small round structured virus found in the stool from one ill person. High levels of faecal coliforms in the reticulated river water and enterovirus in sediment samples suggest that the outbreak was caused by sewage contaminating the reticulated river water through a break in the pipe directly over the underground water tanks. To prevent such outbreaks, poor water and sewerage system layouts should be avoided and nonpotable water should be clearly labelled. Where feasible, all camping-ground water should stem from town supplies.

Mycobacterial disease and AIDS in New South Wales.

OBJECTIVE: To determine the coincidence of mycobacterial disease and acquired immunodeficiency syndrome (AIDS), and whether persons with mycobacterial disease and human immunodeficiency virus (HIV) infection differ from those with mycobacterial disease alone, by age, sex and country of birth. DESIGN: A descriptive study. PARTICIPANTS: Persons on the NSW Tuberculosis Register in 1989 and those on the NSW AIDS database in 1982-1989. MAIN OUTCOME MEASURE: Coincident appearance on the Tuberculosis Register and the AIDS database. RESULTS: People with atypical mycobacterial infection and HIV infection were younger and more likely to be male compared with those with mycobacterial disease alone. There was a strong association between mycobacterial disease and HIV infection. Of 438 patients newly diagnosed with mycobacterial disease in 1989, 75 (17.1%) had HIV infection. Of 318 tuberculosis patients, 8 (2.5%) had HIV infection, and of 120 patients with atypical mycobacterial infection, 67 (55.8%) had HIV infection. CONCLUSION: Close monitoring of HIV patients for mycobacterial infection, and chemoprophylaxis for persons infected with HIV who have positive Mantoux test results will assist in the control of mycobacterial disease. HIV testing and counselling should be considered for all persons with mycobacterial disease.