Community perspectives on the benefits and risks of technologically enhanced communicable disease surveillance systems: a report on four community juries.

BACKGROUND: Outbreaks of infectious disease cause serious and costly health and social problems. Two new technologies - pathogen whole genome sequencing (WGS) and Big Data analytics - promise to improve our capacity to detect and control outbreaks earlier, saving lives and resources. However, routinely using these technologies to capture more detailed and specific personal information could be perceived as intrusive and a threat to privacy. METHOD: Four community juries were convened in two demographically different Sydney municipalities and two regional cities in New South Wales, Australia (western Sydney, Wollongong, Tamworth, eastern Sydney) to elicit the views of well-informed community members on the acceptability and legitimacy of: making pathogen WGS and linked administrative data available for public health researchusing this information in concert with data linkage and machine learning to enhance communicable disease surveillance systems Fifty participants of diverse backgrounds, mixed genders and ages were recruited by random-digit-dialling and topic-blinded social-media advertising. Each jury was presented with balanced factual evidence supporting different expert perspectives on the potential benefits and costs of technologically enhanced public health research and communicable disease surveillance and given the opportunity to question experts. RESULTS: Almost all jurors supported data linkage and WGS on routinely collected patient isolates for the purposes of public health research, provided standard de-identification practices were applied. However, allowing this information to be operationalised as a syndromic surveillance system was highly contentious with three juries voting in favour, and one against by narrow margins. For those in favour, support depended on several conditions related to system oversight and security being met. Those against were concerned about loss of privacy and did not trust Australian governments to run secure and effective systems. CONCLUSIONS: Participants across all four events strongly supported the introduction of data linkage and pathogenomics to public health research under current research governance structures. Combining pathogen WGS with event-based data surveillance systems, however, is likely to be controversial because of a lack of public trust, even when the potential public health benefits are clear. Any suggestion of private sector involvement or commercialisation of WGS or surveillance data was unanimously rejected.

Investigation and response to an outbreak of leptospirosis among raspberry workers in Australia, 2018.

BACKGROUND: In 2018, an outbreak of leptospirosis was identified among raspberry workers from a mixed-berry farm in New South Wales, Australia. Initial testing had not revealed a cause, but eventually leptospirosis was detected via polymerase chain reaction (PCR). Further serological testing detected Leptospira borgpetersenii serovar Arborea, of which rodents are the predominant reservoir. Leptospirosis is rare in Australia, with outbreaks usually related to flooding. We conducted an investigation to identify risk factors for infection, to inform control measures. METHODS: Cases were detected through laboratory notifications, hospital-based syndromic surveillance, awareness-raising among farm employees and clinician alerts. Confirmed cases had a four-fold rise in antibody titre or single titre ≥400 on microscopic agglutination test, and a positive IgM. Probable cases had a positive Leptospira PCR or IgM, and possible cases had a clinically compatible illness. We conducted a case-control study among raspberry workers on the farm and compared reported exposures between cases and seronegative controls. We assessed environmental risks on-site and tested rodents for leptospirosis. RESULTS: We identified 84 cases over a 5-month period (50 confirmed, 19 probable and 15 possible). Compared with controls, cases were less likely to wear gloves and more recently employed. Cases also more commonly reported always having scratched hands, likely from the thorns on raspberry plants. We observed evidence of rodent activity around raspberry plants and three of thirteen trapped mice tested positive for Leptospira Arborea. Control measures included enhanced glove use, doxycycline prophylaxis and rodent control. CONCLUSIONS: This is the largest known outbreak of leptospirosis in Australia. Workers were likely exposed through scratches inflicted during harvesting, which became contaminated with environmental leptospires from mice. Leptospirosis should be considered an occupational risk for raspberry workers, requiring protective measures. Chemoprophylaxis may assist in controlling outbreaks. PCR assists in the early diagnosis and detection of leptospirosis and should be included in surveillance case definitions.

First reported outbreak of locally acquired hepatitis E virus infection in Australia.

OBJECTIVE: To determine the source and extent of a locally acquired hepatitis E virus (HEV) infection outbreak. DESIGN, SETTING AND PARTICIPANTS: A cluster of notified cases of HEV infection linked to a single restaurant (X) was identified in May 2014. People with laboratory-confirmed HEV infection in New South Wales between January 2013 and December 2014 were interviewed about potential risk factors for HEV infection. Co-diners at restaurant X and patients with suspected but unexplained viral hepatitis were retrospectively tested. Foods eaten by the infected persons were compared with those of seronegative co-diners. HEV RNA detected in sera from infected persons was sequenced and genotyped. Implicated foods were traced back to their sources. MAIN OUTCOME MEASURES: Potential sources of infection, including overseas travel and foods eaten, and origin of implicated food products. RESULTS: In 55 serologically confirmed cases of HEV infection, 24 people had not travelled overseas during their incubation periods. Of the 24, 17 reported having eaten at restaurant X, 15 of whom could be interviewed. All reported consuming pork liver pâté, compared with only four of seven uninfected co-diners (P < 0.05). The other seven people with locally acquired infections each reported consuming a pork product during their incubation periods. HEV RNA was detected in 16 of the 24 cases; all were of genotype 3. Sequencing indicated greater than 99% homology among restaurant X isolates. HEV RNA was isolated from pork sausages from a batch implicated in one of the locally acquired infections not linked with restaurant X. The pork livers used for pâté preparation by restaurant X were traced to a single Australian farm. CONCLUSIONS: This is the first reported HEV outbreak in Australia. HEV should be considered in patients presenting with a compatible illness, even without a history of overseas travel. Pork products should be thoroughly cooked before consumption.

An outbreak of enterovirus 71 in metropolitan Sydney: enhanced surveillance and lessons learnt.

OBJECTIVE: To report the findings of the enhanced surveillance set up in New South Wales in response to the recent outbreak of human enterovirus 71 (EV71) infection. DESIGN AND SETTING: A two-armed enhanced public health surveillance system including statewide emergency department surveillance and clinical surveillance at the Sydney Children's Hospitals Network. PARTICIPANTS: Children aged less than 10 years with suspected or confirmed enterovirus infection. MAIN OUTCOME MEASURES: Epidemiology of the outbreak, including weekly case counts, demographic information, geographic spread of the outbreak, and clinical presentation and progression. RESULTS: Statewide weekly case counts indicate that an epidemic of EV71 infection occurred in NSW from December 2012 until May 2013. Around 119 children were reported with disease severe enough to warrant admission to a tertiary Sydney children's hospital. Cases were spread throughout the Sydney metropolitan area and there is some evidence of geographic migration of the outbreak. Presenting features included fever, lethargy, myoclonus and skin rash. Only 24% of cases presented with classical hand, foot and mouth disease. CONCLUSIONS: EV71 infection is likely to continue to be a public health problem in Australia. Surveillance of routinely collected emergency department data can provide a useful indication of its activity in the community.

A state-wide information campaign during a pertussis epidemic in New South Wales, 2010.

Pertussis notifications increased dramatically in New South Wales in 2008, exceeding the rates in previous epidemic years. A state-wide, multi-faceted campaign was launched in March 2009 to provide information about pertussis prevention. A population-based survey was conducted using a Computer Assisted Telephone Interviewing facility to assess the effectiveness of sending letters to households with young infants. A representative sample of 1,200 adults across all 8 area health services was interviewed between July 2009 and September 2010, with responses weighted against the state population. Many respondents (39.7%) reported receiving the letter, while fewer (29.6%) reported receiving an adult pertussis booster in the last year, mostly in response to General Practitioner advice (40.4%). Letter receipt was associated with the uptake of an adult pertussis booster in the past 12 months by respondents (OR 5.8; 95%CI 4.1, 8.2) and other adults in the household (OR 5.1; 95%CI 3.5, 7.5), as well as knowledge about pertussis prevention. Health providers remain crucial for vaccination decision making; however letters may have contributed to an increased uptake of pertussis booster vaccination and knowledge. Health authorities may consider mailing households in future pertussis epidemics as a component of a wider communication strategy.

Field effectiveness of hepatitis A vaccine and uptake of post exposure prophylaxis following a change to the Australian guidelines.

BACKGROUND: In 2009, national guidelines for hepatitis A control in Australia changed to recommend hepatitis A vaccine (HAV), instead of normal human immune globulin (NHIG), for post-exposure prophylaxis (PEP). AIMS: (1) Determine whether the uptake of PEP among contacts of hepatitis A cases changed after the introduction of the new guidelines, and (2) assess the field effectiveness of the HAV used as PEP in preventing infection among contacts of hepatitis A cases. METHODS: A retrospective cohort of contacts from hepatitis A cases reported to metropolitan Public Health Units in Sydney, Australia, between October 2008 and June 2010, was identified. Contacts were analysed by time period, age, PEP type, and susceptibility to hepatitis A. The relative risk (RR) of hepatitis A infection among susceptible contacts who received HAV, compared with susceptible contacts who had not received HAV, was calculated to estimate the effectiveness of the HAV when used as PEP. RESULTS: The uptake of PEP by susceptible contacts increased from 76% (n=133) to 89% (n=127) after the introduction of the new guidelines. Before the change in guidelines, no one who received PEP was later reported with hepatitis A. After the change in guidelines, one of the 123 contacts who received HAV as PEP was subsequently reported with hepatitis A. However, this case was likely to have been co-exposed with a primary case. Conservatively, assuming this was a secondary case, the vaccine effectiveness of HAV was 95.6% (66.1%-99.4%). Nine of 10 incident cases of hepatitis A were contacts who did not receive any PEP. CONCLUSION: The improved uptake of PEP and the high estimate of the effectiveness of HAV provides support for using HAV for PEP. The very high occurrence of hepatitis A among contacts who did not receive any PEP further highlights the importance of PEP in preventing hepatitis A infection.

Infectious diseases in returned travellers, NSW, 2010-2011.

AIM: To quantify the proportion of selected notified diseases in NSW attributable to overseas travel and assess the quality of data on travel-associated risk factors, to inform prevention strategies. METHODS: 2010 and 2011 notification data for dengue, hepatitis A, hepatitis E, malaria, paratyphoid fever, shigellosis and typhoid fever were extracted from the NSW Notifiable Conditions Information Management System and analysed for travel-associated risk factors. RESULTS: Where place of acquisition was known, the proportion of cases for whom the disease was acquired overseas ranged from 48.7% for shigellosis to 100% for hepatitis E, malaria and typhoid. Over half of hepatitis A (53.3%), hepatitis E (74.2%), malaria (54.5%), paratyphoid (53.3%) and typhoid (65.7%) cases were associated with travel to the person's country of birth. Hepatitis A vaccination rates were significantly lower among overseas-acquired than locally-acquired cases (4.8% vs 22.2%, Χ(2)=6.58, p<0.02). CONCLUSION: A large proportion of selected enteric and vectorborne disease case notifications were associated with overseas travel. All potential travellers should be made aware of the risks and available preventive measures, such as vaccination against hepatitis A and typhoid fever, taking precautions with food and water and use of malaria chemoprophylaxis, where appropriate. Improvements in data on risk factors, reason for travel and barriers to the use of preventive measures would better inform prevention strategies.

Airport arrivals screening during pandemic (H1N1) 2009 influenza in New South Wales, Australia.

OBJECTIVE: To examine the effectiveness of airport screening in New South Wales during pandemic (H1N1) 2009 influenza. DESIGN, SETTING AND PARTICIPANTS: Analysis of data collected at clinics held at Sydney Airport, and of all notified cases of influenza A(H1N1)pdm09, between 28 April 2009 and 18 June 2009. MAIN OUTCOME MEASURES: Case detection rate per 100,000 passengers screened, sensitivity, positive predictive value and specificity of airport screening. The proportion of all cases in the period detected at airport clinics was compared with the proportion detected in emergency departments and general practice. RESULTS: Of an estimated 625,147 passenger arrivals at Sydney Airport during the period, 5845 (0.93%) were identified as being symptomatic or febrile, and three of 5845 were subsequently confirmed to have influenza A(H1N1)pdm09, resulting in a detection rate of 0.05 per 10,000 screened (95% CI, 0.02-1.14 per 10,000). Forty-five patients with overseas-acquired influenza A(H1N1)pdm09 in NSW would have probably passed through the airport during this time, giving airport screening a sensitivity of 6.67% (95% CI, 1.40%-18.27%). Positive predictive value was 0.05% (95% CI, 0.02%-0.15%) and specificity 99.10% (95% CI, 99.00%-100.00%). Of the 557 confirmed cases across NSW during the period, 290 (52.1%) were detected at emergency departments and 135 (24.2%) at general practices, compared with three (0.5%) detected at the airport. CONCLUSIONS: Airport screening was ineffective in detecting cases of influenza A(H1N1)pdm09 in NSW. Its future use should be carefully considered against potentially more effective interventions, such as contact tracing in the community.

EpiReview: tuberculosis in NSW, 2009-2011.

AIM: To describe the epidemiology of tuberculosis in NSW between 2009 and 2011 and compare with previous years. METHODS: Data from all cases of tuberculosis notified in NSW during this period were extracted from the Notifiable Conditions Information Management System. Descriptive analyses of notification data were undertaken. Incidence rates were calculated per 100000 population. RESULTS: Between 2009 and 2011, there were 1548 cases of tuberculosis notified in NSW, translating to an average annual notification rate of 7.2 per 100000 population for this period. A total of 89% (n=1371) of notified cases were overseas-born, and 1.6% (n=24) of cases were recorded as Aboriginal persons. The most common site of infection was the lung (60% of cases). Of notified cases, 68% were reported as having been tested for HIV, of which 3%(n=28) of cases had HIV/tuberculosis co-infection. There were 20 cases of multidrug-resistant tuberculosis, including one case of extensively drug-resistant tuberculosis. CONCLUSION: The notification rate of tuberculosis in NSW has remained relatively stable over the past two decades, though small incremental increases since 2003 are evident. Endemic transmission of tuberculosis within sub-groups of the NSW population, as well as the ongoing high endemnicity for tuberculosis in neighbouring countries, highlight the importance of tuberculosis control as a continued strategic priority for disease control in NSW.

Case-control study of risk factors for hospitalization caused by pandemic (H1N1) 2009.

We conducted a case-control study to identify risk factors for hospitalization from pandemic (H1N1) 2009 virus infection among persons >16 years of age in Sydney, Australia. The study comprised 302 case-patients and 603 controls. In a logistic regression model, after adjusting for age and sex, risk factors for hospitalization were pregnancy (odds ratio [OR] 22.4, 95% confidence interval [CI] 9.2-54.5), immune suppression (OR 5.5, 95% CI 2.8-10.9), pre-existing lung disease (OR 6.6, 95% CI 3.8-11.6), asthma requiring regular preventive medication (OR 4.3, 95% CI 2.7-6.8), heart disease (OR 2.3, 95% CI 1.2-4.1), diabetes (OR 3.8, 95% CI 2.2-6.5), and current smoker (OR 2.0, 95% CI 1.3-3.2) or previously smoked (OR 2.0, 95% CI 1.3-3.0). Although obesity was not independently associated with hospitalization, it was associated with an increased risk of requiring mechanical ventilation. Public health messages should give greater emphasis on the risk for severe disease among pregnant women and smokers.

Outbreaks of pandemic (H1N1) 2009 and seasonal influenza A (H3N2) on cruise ship.

To determine the extent and pattern of influenza transmission and effectiveness of containment measures, we investigated dual outbreaks of pandemic (H1N1) 2009 and influenza A (H3N2) that had occurred on a cruise ship in May 2009. Of 1,970 passengers and 734 crew members, 82 (3.0%) were infected with pandemic (H1N1) 2009 virus, 98 (3.6%) with influenza A (H3N2) virus, and 2 (0.1%) with both. Among 45 children who visited the ship's childcare center, infection rate for pandemic (H1N1) 2009 was higher than that for influenza A (H3N2) viruses. Disembarked passengers reported a high level of compliance with isolation and quarantine recommendations. We found 4 subsequent cases epidemiologically linked to passengers but no evidence of sustained transmission to the community or passengers on the next cruise. Among this population of generally healthy passengers, children seemed more susceptible to pandemic (H1N1) 2009 than to influenza (H3N2) viruses. Intensive disease control measures successfully contained these outbreaks.

EpiReview: tuberculosis in NSW, 2008.

AIM: To describe the epidemiology of tuberculosis cases notified in NSW in 2008. METHOD: Data on tuberculosis cases resident in NSW that were reported in 2008 were extracted from the Notifiable Diseases Database. Demographic, microbiological, clinical and other characteristics of cases were described. Incidence rates per 100 000 were calculated. RESULTS: In 2008, 498 tuberculosis cases were notified in NSW (7.1 cases per 100 000 population). Most cases were newly diagnosed (n = 479, 96%). The lung was the most common site of disease (n = 304, 61%). Eight of 269 tested cases (1.6%) had a HIV-tuberculosis co-infection. One case had multidrug-resistant tuberculosis. Most cases reported past residence (n = 429, 86%) or birth (n = 378, 76%) in a country with a high incidence of tuberculosis. CONCLUSION: The incidence of tuberculosis in NSW increased slightly in 2008. Most cases had links to countries with a high tuberculosis incidence.

Review of the 2008-2009 pertussis epidemic in NSW: notifications and hospitalisations.

In 2008 and 2009 increased numbers of pertussis notifications were reported in NSW. During the epidemic period, the pertussis notification rate was 2.7 times higher than the previous 5-year average. Rates of pertussis notifications and hospitalisations were highest among infants aged less than 1 year across all years studied. Compared to previous years, the notification rate for children aged 1-4 years increased dramatically and was particularly striking for children aged 3 years with notifications exceeding those for infants in 2009. Changes in testing practices during the epidemic period, including a significant increase in the use of polymerase chain reaction, may account for some of the relative increase in size of the 2008-2009 outbreak compared with previous outbreak years.

Investigation of equine influenza transmission in NSW: walk, wind or wing?

OBJECTIVES: An outbreak of equine influenza occurred in New South Wales in 2007. In addition to the local spread of the disease between bordering properties, windborne spread over several kilometres had been postulated as a possible method of transmission in this outbreak. This study aimed to describe potential modes of transmission for a property infected with equine influenza where no apparent epidemiological links to other infected properties were reported. METHODS: A semi-structured questionnaire was administered to owners of affected properties. The questionnaire collected detailed transmission-risk information, including personnel movements, equipment sharing, and horse and other animal movements. RESULTS: Interviews with property owners from one geographic area suggested the potential for birds and other animals - rather than wind - to facilitate transmission of equine influenza. CONCLUSION: This study described the potential for mechanical spread of equine influenza. Further research, including laboratory testing of bird plumage following contact with infected horses, may be useful to confirm the possibility of avian fomite transmission.