Keith Eastwood

Evidence supporting zoonotic transmission of Cryptosporidium in rural New South Wales

Cryptosporidium hominis, which has an anthroponotic transmission cycle and Cryptosporidium parvum, which is zoonotic, are the primary species of Cryptosporidium that infect humans. The present study identified the species/genotypes and subgenotypes of Cryptosporidium in 7 human and 15 cattle cases of sporadic cryptosporidiosis in rural western NSW during the period from November 2005 to January 2006. The species/genotype of isolates was determined by PCR sequence analysis of the 18S rRNA and C. parvum and C. hominis isolates were subgenotyped by sequence analysis of the GP60 gene. Fourteen of 15 cattle-derived isolates were identified as C. parvum and 1 as a C. bovis/C. parvum mixture. Of the human isolates, 4 were C. parvum and 3 were C. hominis. Two different subgenotypes were identified with the human C. hominis isolates and six different subgenotypes were identified within the C. parvum species from humans and cattle. All four of the C. parvum subtypes found in humans were also found in the cattle, indicating that zoonotic transmission may be an important contributor to sporadic human cases cryptosporidiosis in rural NSW.

Evidence of Cryptosporidium transmission between cattle and humans in northern New South Wales

Cryptosporidium is an enteric parasite of public health significance that causes diarrhoeal illness through faecal oral contamination and via water. Zoonotic transmission is difficult to determine as most species of Cryptosporidium are morphologically identical and can only be differentiated by molecular means. Transmission dynamics of Cryptosporidium in rural populations were investigated through the collection of 196 faecal samples from diarrheic (scouring) calves on 20 farms and 63 faecal samples from humans on 14 of these farms. The overall prevalence of Cryptosporidium in cattle and humans by PCR and sequence analysis of the 18S rRNA was 73.5% (144/196) and 23.8% (15/63), respectively. Three species were identified in cattle; Cryptosporidium parvum, Cryptosporidium bovis and Cryptosporidium ryanae, and from humans, C. parvum and C. bovis. This is only the second report of C. bovis in humans. Subtype analysis at the gp60 locus identified C. parvum subtype IIaA18G3R1 as the most common subtype in calves. Of the seven human C. parvum isolates successfully subtyped, five were IIaA18G3R1, one was IIdA18G2 and one isolate had a mix of IIaA18G3R1 and IIdA19G2. These findings suggest that zoonotic transmission may have occurred but more studies involving extensive sampling of both calves and farm workers are needed for a better understanding of the sources of Cryptosporidium infections in humans from rural areas of Australia.

Consensus guidelines for the investigation and management of encephalitis in adults and children in Australia and New Zealand

Encephalitis is a complex neurological syndrome caused by inflammation of the brain parenchyma. The management of encephalitis is challenging because: the differential diagnosis of encephalopathy is broad; there is often rapid disease progression; it often requires intensive supportive management; and there are many aetiologic agents for which there is no definitive treatment. Patients with possible meningoencephalitis are often encountered in the emergency care environment where clinicians must consider differential diagnoses, perform appropriate investigations and initiate empiric antimicrobials. For patients who require admission to hospital and in whom encephalitis is likely, a staged approach to investigation and management is preferred with the potential involvement of multiple medical specialties. Key considerations in the investigation and management of patients with encephalitis addressed in this guideline include: Which first-line investigations should be performed?; Which aetiologies should be considered possible based on clinical features, risk factors and radiological features?; What tests should be arranged in order to diagnose the common causes of encephalitis?; When to consider empiric antimicrobials and immune modulatory therapies?; and What is the role of brain biopsy?

Using epidemiological and molecular methods to investigate an outbreak of gonorrhoea associated with heterosexual contact in Newcastle, NSW, Australia

BACKGROUND We report a cluster of gonorrhoea among mainly heterosexual men that occurred in October 2005, which was first identified when routine weekly surveillance review procedures indicated a three-fold increase in reporting rates compared with historical data. METHODS Each case was followed up with the treating medical officer to review treatment regimes and risk exposures, and to carry out enhanced contact tracing. The phenotype and genotype of the outbreak gonococcal isolates and gonococci prevalent in the months preceding and following the cluster were determined. Links between cases reported from the local Sexual Health Clinic and those reported by general practitioners were established. RESULTS Laboratory data indicated that a particular gonococcal subtype (ST 225 and NR/Brpyst) was prevalent during the outbreak. CONCLUSIONS Gonorrhoea rates returned to pre-outbreak levels following a targeted health promotion intervention with no further cases of the outbreak subtype detected.

Responses to Pandemic (H1N1) 2009, Australia

Perception of risk affects compliance with public health control measures.

Identifying pneumonia outbreaks of public health importance: can emergency department data assist in earlier identification?

Objective: To retrospectively review the performance of a near real‐time Emergency Department (ED) Syndromic Surveillance System operating in New South Wales for identifying pneumonia outbreaks of public health importance.

Epidemiology of enteroviral meningoencephalitis in neonates and young infants

To describe the epidemiology of enteroviral meningoencephalitis in northern New South Wales, Australia, with a specific focus on neonatal and young infant cases.

Understanding human - bat interactions in NSW, Australia: improving risk communication for prevention of Australian bat lyssavirus

BackgroundAustralian bat lyssavirus (ABLV) infects a number of flying fox and insectivorous bats species in Australia. Human infection with ABLV is inevitably fatal unless prior vaccination and/or post-exposure treatment (PET) is given. Despite ongoing public health messaging about the risks associated with bat contact, surveillance data have revealed a four-fold increase in the number of people receiving PET for bat exposure in NSW between 2007 and 2011. Our study aimed to better understand these human – bat interactions in order to identify additional risk communication messages that could lower the risk of potential ABLV exposure. All people aged 18 years or over whom received PET for non-occupation related potential ABLV exposure in the Hunter New England Local Health District of Australia between July 2011 and July 2013 were considered eligible for the study. Eligible participants were invited to a telephone interview to explore the circumstances of their bat contact. Interviews were then transcribed and thematically analysed by two independent investigators.ResultsOf 21 eligible participants that were able to be contacted, 16 consented and participated in a telephone interview. Participants reported bats as being widespread in their environment but reported a general lack of awareness about ABLV, particularly the risk of disease from bat scratches. Participants who attempted to ‘rescue’ bats did so because of a deep concern for the bat’s welfare. Participants reported a change in risk perception after the exposure event and provided suggestions for public health messages that could be used to raise awareness about ABLV.ConclusionsReframing the current risk messages to account for the genuine concern of people for bat welfare may enhance the communication. The potential risk to the person and possible harm to the bat from an attempted ‘rescue’ should be promoted, along with contact details for animal rescue groups. The potential risk of ABLV from bat scratches merits greater emphasis.

Improving communicable disease outbreak preparedness in residential aged care facilities using an interventional interview strategy

Objective:  To improve the capacity of residential aged care facilities (RACFs) to respond to communicable disease outbreaks.

Consensus guidelines for the investigation and management of encephalitis.

Encephalitis is caused by inflammation of the brain and is a challenging condition for clinicians to identify and manage. It manifests as a complex neurological syndrome with protean clinical manifestations that may be caused by a large number of aetiologies, many without effective treatments. It can be fatal and survivors often experience significant neurological morbidity. Studies have shown variable quality in case management in multiple settings,1-3 emphasising the need for consensus guidelines.