Human T-cell leukaemia virus type 1 and Adult T-cell leukaemia/lymphoma in Queensland, Australia: a retrospective cross-sectional study.

OBJECTIVES: Human T-cell leukaemia virus type 1 (HTLV-1), an STI, is reported to be highly prevalent in Indigenous communities in Central Australia. HTLV-1 is an incurable, chronic infection which can cause Adult T-cell leukaemia/lymphoma (ATL). ATL is associated with high morbidity and mortality, with limited treatment options. We studied the prevalence of HTLV-1 and ATL in the state of Queensland, Australia. METHODS: Serum samples stored at healthcare services in Brisbane, Townsville and Cairns and at haemodialysis units in Brisbane (2018-2019) were screened for HTLV-1/2 antibodies using the Abbott ARCHITECT chemiluminescent microparticle immunoassay (CMIA) for antibodies against gp46-I, gp46-II and GD21 (Abbott CMIA, ARCHITECT). Reactive samples were confirmed through Western blot. Pooled Australian National Cancer Registry surveillance data reporting on cases coded for ATL (2004-2015) were analysed. RESULTS: Two out of 2000 hospital and health services samples were confirmed HTLV-1-positive (0.1%, 95% CI 0.02% to 0.4%), both in older women, one Indigenous and one non-Indigenous. All 540 haemodialysis samples tested negative for HTLV. All samples were HTLV-2-negative. Ten out of 42 (24.8%) reported cases of ATL in Australia were from Queensland (crude incidence rate 0.025/100 000; 95% CI 0.011 to 0.045); most cases were seen in adult men of non-Indigenous origin. Nineteen deaths due to ATL were recorded in Australia. CONCLUSION: We confirm that HTLV-1 and ATL were detected in Queensland in Indigenous and non-Indigenous people. These results highlight the need for HTLV-1 prevalence studies in populations at risk of STIs to allow the implementation of focused public health sexual and mother-to-child transmission prevention strategies.

A comparison of DNA extraction methods used in the direct molecular detection of Burkholderia pseudomallei from blood.

BACKGROUND: Melioidosis is caused by Burkholderia pseudomallei. Direct molecular detection from unamplified blood remains insensitive. METHODS: Three different extraction methods-QIAamp UCP Pathogen Mini Kit, High Pure PCR template and MagNA Pure Pathogen Universal-were trialled using spiked human ethylenediaminetetraacetic acid blood. A type III secretion system 1 (TTSS-1) polymerase chain reaction was used for detection. RESULTS: The QIAamp UCP Pathogen Mini Kit performed best, with a limit of detection of 1.5×102 cfu/ml. CONCLUSIONS: It is planned to use the QIAamp UCP Pathogen Mini Kit to do a larger study on blood collected from patients with melioidosis.

Hospital acquired viral respiratory tract infections: An underrecognized nosocomial infection.

BACKGROUND: Our study aimed to describe the incidence, epidemiology of respiratory viruses and outcomes in hospital acquired viral respiratory infections (HAVRI). METHODS: We conducted a retrospective observational study on all adults and children with hospital acquired viral respiratory infections between July 2012 and April 2019. Clinical and microbiological data were collected in a major tertiary level hospital in North Queensland. Morbidity indicators were the length of stay, need for intensive care and mechanical ventilation. Length of stay was analyzed with the Kruskal-Wallis test and mortality with the Chi-Square test. RESULTS: A total of 283 patients tested positive for a respiratory virus and fulfilled the criteria for a hospital acquired infection. Individuals in the younger age group were more likely to be admitted to intensive care and need mechanical ventilation. A higher mortality was found with individuals in the older age category. The morbidity and mortality did not differ based on the virus type. Influenza A was the most common respiratory virus associated with hospital acquired viral respiratory infections. CONCLUSION: Hospital acquired viral respiratory infections contribute significantly to morbidity and mortality regardless of the virus species.

Evaluation of a commercially available synthetic RNA lipid enveloped control molecule.

Detection of viral ribonucleic acid with RT PCR is a useful tool for viral detection. One of the drawbacks of this technique is the difficulty in including an internal control molecule to ensure the validity of the extraction and amplification process. In this study the potential usefulness of a novel lipid enveloped commercially available RNA control molecule is investigated. Initial optimisation of the detection assay was performed by amplification of IC (internal control) spiked into PCR water. Thirty-two clinical respiratory samples were spiked with the IC before and after extraction and RT PCR was then performed. Inefficient extraction was simulated. Inhibition of the RT PCR was achieved by serial dilution of heparin sulfate into samples post extraction. No Targets that matched the IC (Internal Control) primers were identified in 32 extracted sputum samples as determined by the absence of non specific amplification curves. The unextracted IC had an increased CT (cycle threshold) value compared to IC that had been extracted. Inefficient extraction was detected by an increased CT. Increasing concentrations of heparin inhibited the PCR in a predictable fashion. The Bioline IC molecule provides a stable RNA IC that has acceptable performance characteristics.

Pandemic influenza H1N1 2009 in north Queensland--risk factors for admission in a region with a large indigenous population.

This study describes the epidemiology of laboratory-confirmed pandemic influenza H1N1 within north Queensland, Australia. We collected data on all specimens tested for influenza (including H1N1) by polymerase chain reaction between May and August 2009 at Townsville Hospital. Patients requiring admission to hospital and a proportion of non-admitted patients had clinical characteristics recorded. Multi-variable logistic regression analysis was used to identify independent predictors for admission. Patients requiring admission were on average older, less likely to be of Aboriginal or Torres Strait Islander descent and more likely to be pregnant, female or suffer from diabetes mellitus. Oseltamivir provision was significantly higher within the Aboriginal or Torres Strait Islander patient population. However, when the relative sizes of the local Indigenous and non-Indigenous populations were considered, the relative risk of hospital admission for Indigenous people was found to be 7.9 (4.7-13.2) in comparison to non-indigenous.

Predicting respiratory syncytial virus hospitalisation in Australian children.

BACKGROUND: There is limited information on respiratory syncytial virus infections among Australians, particularly those of Indigenous descent. AIM: This study identifies groups of infants at risk of hospitalisation with respiratory syncytial virus-positive lower respiratory tract infection who may be targeted for prevention with palivizumab. METHODS: Case control study: the case notes of 271 children with cases of respiratory syncytial virus-positive lower respiratory tract infection admitted to The Townsville Hospital were studied for risk factors. Controls were chosen randomly from babies born in The Townsville Hospital during that period. Multiple logistic regression analysis and classification and regression tree analysis were used to identify risk factors. RESULTS: Multiple logistic regression analysis identified birthweight <2500 g, maternal parity and marital status to be independent predictors of hospitalisation with respiratory syncytial virus-positive lower respiratory tract infection. Classification and regression tree analysis identified babies born weighing <2500 g who possessed older siblings to be at highest risk. Single mothers and smoking were additional risk factors. Indigenous babies were significantly more likely to be exposed to all of the identified risk factors. CONCLUSION: Babies born weighing <2500 g (especially with siblings) could be targeted for prevention. All Indigenous babies should be considered at high risk because of their exposure to multiple risk factors.

Cost-effectiveness of respiratory syncytial virus prophylaxis with palivizumab.

BACKGROUND: A monoclonal antibody, palivizumab, directed against respiratory syncytial virus (RSV) has been shown to decrease hospitalisation rates. Because of its expense, the cost-effectiveness of this agent should be determined for high-risk groups. AIM: To determine characteristics of RSV infection in Townsville and the economic feasibility of palivizumab immunoprophylaxis in high-risk groups. METHODS: Cases of RSV-positive bronchiolitis were retrospectively identified. Cases were grouped according to recognised risk factors. The hypothetical costs of palivizumab immunoprophylaxis for infants at risk were calculated. RESULTS: The rate of hospitalisation with RSV-positive lower respiratory tract infection was 22 per 1000 live births but increased to 50 per 1000 among Indigenous babies born weighing <2500 g. The cost of preventing an admission in each of the identified high-risk groups, based on drug costs alone, ranged from AD 69,861 to AD 88,547. CONCLUSION: Palivizumab was not cost-effective in the prophylaxis of RSV in the high-risk group of infants tested here.