NSW public health units (PHUs) are located with local health districts. PHUs do the day to day work of protecting the community’s health – through a range of activities including the gathering of notifications of diseases from doctors, hospitals, laboratories, childcare facilities and schools, the investigation of cases and outbreaks, the implementation of control measures such as counselling, vaccination or chemoprophylaxis for contacts of cases at increased risk of diseases, as well as communication about health risks and promotion of immunisation. Here we present some case studies of what public health units got up to in 2013.
Avian influenza is a common infection in wild birds, and rarely causes outbreaks in domestic poultry. Humans in close contact with infected birds have rarely been infected with some strains of avian influenza, causing conjunctivitis or a respiratory illness. In October 2013, the NSW Department of Primary Industries (DPI) notified NSW Health of an outbreak of highly pathogenic H7N2 avian influenza at a Murrumbidgee poultry farm housing approximately 450,000 chickens. DPI initiated control measures, including a cull of all chickens on the property. Ten days later a second outbreak was detected on a poultry farm with approximately 55,000 chickens 30 km away, possibly linked to the first property by a common egg collector or feed truck.
NSW Health daily convened an expert teleconference involving DPI, HPNSW, virologists and Murrumbidgee Local Health District Public Health Unit (PHU) to review the available data, and assess whether human contacts of the chickens were at risk. PHU staff worked with the farm managers and identified 55 workers who were potentially exposed to infectious chickens, counselled them about any risk of infection and symptoms, and offered oseltamivir prophylaxis to those at potential risk of infection.
As part of enhanced surveillance for disease during the possible 10 day incubation period, PHU staff sent a daily mobile text message to the exposed workers asking if they had symptoms, and to take their tablet if they had been prescribed oseltamivir. Their text responses were automatically forwarded to a PHU staff member for review and follow up. If no response was received, a call was made to check on their health and their reason for not responding.
The PHU alerted local hospitals and general practitioners and adjacent PHUs of the situation. Seven exposed workers developed influenza-like symptoms in the 10 day surveillance period were tested for influenza and other viral infections. One tested positive for rhinovirus, one for respiratory syncytial virus and none for influenza. SMS for contact follow up was found to be very valuable with an average response rate of 66% over the follow up period.
Trachoma is an infectious eye infection that can lead to blindness. It was endemic in parts of western NSW last century and remains endemic in remote parts of Australia, but there has been little evidence of its presence in NSW in recent decades. As part of its efforts to eradicate trachoma, the Australian Department of Health funded NSW Health to investigate whether trachoma was present in western NSW. NSW Health convened an expert group and identified 10 communities likely to be at highest risk for trachoma. Western NSW PHU undertook extensive consultation in each of these communities, including schools, healthcare providers, and key Aboriginal people prior to commencing screening.
Screening was completed in May 2013 with all ten identified sites screened. A total of 690 children were assessed for facial cleanliness and of these, 652 had their eyes screened for trachoma. The interest from the schools and parents was positive and the number of children assessed for clean faces and screened for trachoma was encouraging. Such a screening project was the first of its kind to be conducted in NSW primary schools.
Active trachoma was identified in only 3 children in only one school community. The children and their household contacts were promptly treated and systems initiated to ensure the ongoing management and support of this community.
The data collected has provided valuable information regarding the prevalence of trachoma in Aboriginal children living in rural and remote communities in NSW. This information has been used to determine future decisions regarding the need for ongoing screening, treatment and community level interventions. A second phase of the Trachoma Screening Project commenced in 2014, funded by the Commonwealth Department of Health.
During June and July 2013 Hendra virus infection was confirmed in 4 unvaccinated horses and 1 dog on 4 separate properties on the NSW Mid North Coast. Hendra virus is a zoonosis, the natural reservoir being fruit bats (flying foxes) which are believed to be the source of infection in horses. Transmission from infected horses to humans occurs rarely and there is no record of transmission from flying foxes to humans or dogs to humans.
On the second of the infected properties [IP2], a horse was confirmed with Hendra virus infection after being diagnosed with severe colic, euthanized late on Thursday 4 July and buried the next day.
IP2 was quarantined by the NSW Department of Primary Industries [DPI]. On days 0 and 12 of the quarantine period, the local Livestock Health and Pest Authority (LHPA) vet took samples for Hendra virus testing from 2 horses and 3 companion dogs from IP2. A family cat was assessed as low risk by the vet and not tested.
On 19 July, DPI advised the North Coast Public Health Unit [NCPHU] that one of the 3 dogs had tested positive for Hendra virus by blood polymerase chain reaction [PCR]. This was the first ever dog detected with a naturally-occurring Hendra infection and, after consultation with its owners, it was euthanized the next day. The dog had been seen in the paddock after the horse was euthanised and was likely to have contacted the dead horse’s body fluids. In July 2011, a red Kelpie from an infected Queensland property attracted a lot of public attention when it became the first dog to show evidence of Hendra infection after testing antibody positive (but was PCR negative).
The risk of transmission of Hendra virus from a dog to a human is unknown. Based on the possible infectious period of horses, PHU staff assessed that the dog may have been potentially infectious from 6 July. NCPHU interviewed the dog’s 2 adult contacts late on the Friday evening of 19 July, using a custom built “well-being” and exposure risk assessment of the human contacts of the infected dog. The assessment addressed whether the dog was “licky” or “nippy”, the type and frequency of contacts, including petting; sleeping arrangements; ball games; presence of wounds on hands; salivary exposure to the face, mouth or open lesions; exposure to dog excreta; hand-washing frequency; other personal hygiene practices; and for veterinarians, venepuncture technique and use of personal protective equipment such as gloves and gowns.
Knowledge about the infectivity of Hendra virus in different species and routes of transmission continues to emerge. Owners need to separate companion animals from sick and deceased horses and other potentially contaminated areas of Hendra-infected properties. After detection of Hendra virus on a property, DPI will assess all companion animals for risk of infection, conduct tests for evidence of infection and prohibit movement of companion animals from the infected property during the quarantine period.
Australian Bat Lyssavirus is endemic in Australian bats but apart from 3 human infections, is not known to naturally infect other species. On 20 August NCPHU DPI notified by of positive Australian Bat Lyssavirus (ABL) serology in an 8 year old dog whose owners reported it had caught, killed and partially eaten a flying fox in June. The local vet screened the dog, with Hendra and ABL serology tests on 15 July. The Hendra result was negative but the ABL result was “borderline”. Repeated ABL testing on 29 July returned a positive result.
NSW Health convened an expert teleconference on 21 August involving HPNSW, DPI, North Coast PHU, and human and veterinary laboratory and public health experts. The group developed the following plan, based on the owners’ informed consent. If the owners elected to euthanise the dog, samples of tissue would be sent for confirmatory testing. If the owners elected not to euthanize the dog, it would be quarantined and samples of corneal smears and saliva would be tested for evidence of infection. As a precaution, the dog’s owners and other people exposed to the dog’s saliva were provided with rabies post exposure prophylaxis (which is recommended for people exposed to bats potentially infected with ABL).
Further investigation found that the owners had already had the dog euthanized and that the body was in the vet’s freezer. The body was sent to the Australian Animal Health Laboratory in Geelong for further testing. The results for antigen testing, PCR and PteropidRT-Taqman Assay from various parts of the brain, salivary glands and other parts of the nervous system were all negative. The dog may have had an aborted ABL infection with serological evidence of that infection suggested by the tests conducted on 15th and 29th July.
In April 2013 Nepean Blue Mountains PHU was notified of a positive serology for psittacosis in a 98-year-old man who had presented to hospital with an upper respiratory tract infection, slurred speech and a decreased level of consciousness. Respiratory screens were performed which showed a raised single titre to Chlamydia psittaci.
Investigation by the public health unit revealed that the case was a resident of an aged care facility (ACF) at the base of the Blue Mountains. Further investigation discovered that he had resided in the mid-Blue Mountains for many years before his admission into the ACF. He had been in the facility for some time with no history of a similar illness, and no other residents were symptomatic.
A site visit revealed that the ACF had open verandas for the residents and that wild birds often visited the gardens. They also had a pet cockatiel, which was kept in a cage inside and who was very popular with the residents. Our case was not mobile and rarely was seen in the grounds of the ACF, but he did go past the cockatiel (who looked increasingly nervous as our investigation proceeded) on the way to and from the dining room.
After discussion with the manager regarding the carriage of psittacosis in birds, he then informed us that he had recently purchased the cockatiel following the demise of the previous bird. Although the cause of death was a tumour, he decided to thoroughly bleach and clean the cage and closely watch the newcomer for any signs of disease, when he would be quickly removed.
Convalescent serology in June 2013 indicated that the man’s illness was unlikely to be due psittacosis as it showed an identical high titre result (probably due infection in the past). The resident went on to make a full recovery and the nervous cockatiel was finally able to relax in his cage and continue his role as the darling of the aged care set.
Like other public health units in NSW, Western Sydney’s work in the latter half of 2013 and in early 2014 was dominated by ongoing measles transmission. Staff completed a project with 10 of the largest medical centres in the LHD to ensure that they were fully aware of the need to immunise staff and isolate potential cases of measles in their large and busy waiting rooms.
Astute and vigilant colleagues in Microbiology and Infectious Disease physicians at the Children’s Hospital Westmead alerted PHU staff to two unusual outbreaks of illness.
The first was a cluster of “red, angry and unwell” neonates and infants who were subsequently found to have been infected with the parechovirus. Subsequent investigation and surveillance showed that there was in the last quarter of 2013 a state-wide epidemic of this condition, the first documented outbreak of this disease in Australia.
The second was the identification of a large cluster of post-operative infections with Shewenella putrefecans in adolescent Tongan and Samoan boys who had recently undergone ritual circumcision. This is a marine organism and the infection was acquired because boys are instructed to swim in the sea post-operatively. The PHU circulated advice to the community on how to prevent these infections, through appropriate post-operative wound care and the avoidance of swimming.
Based on a qualitative research study conducted in the Auburn LGA to identify the causes of persistent under-immunisation in that population, the PHU piloted an immunisation toolkit for primary schools and child care centres. We also organised and conducted immunisation catch up clinics and campaigns through the Samoan Church and the Aboriginal Medical Service Western Sydney.
PHU staff have been negotiating an agreement with the NSW Health, Housing NSW and the NSW Land and Housing Corporation to conduct a Housing for Health Project in the homes of Aboriginal families in Mt Druitt. This will be the first time that a project such as this has been carried out in public housing in NSW.