Veronica C. Hoad

First reported case of transfusion-transmitted Ross River virus infection

PathWest Laboratory Medicine WA detected RRV IgM antibodies using an inhouse indirect immunofluorescence antibody (IFA) test, but no RRV antibodies were detected using an inhouse haemagglutination inhibition (HI) antibody test 10 days after blood donation. RRV IgM antibodies are detected by IFA testing within a few days of onset of illness and routinely persist for several weeks or, occasionally, months or years. IFA tests are less prone to false-positive results compared with enzyme immunoassays. The HI antibody test primarily detects IgG antibodies, which appear within several weeks but after the IgM response.

High body mass index overtakes tobacco as the leading independent risk factor contributing to disease burden in Western Australia

Until recently, smoking was estimated as the leading independent risk factor contributing to the burden of disease in Australia. However, the prevalence of overweight and obesity is increasing in Australia, which now has one of the highest rates of overweight and obesity in the world. Concurrently, the prevalence of tobacco smoking has significantly decreased as a result of public health efforts. This letter presents results of a recent investigation into the contribution of selected risk factors to the burden of disease in Western Australia (WA) in 2006. The study was based on the comparative risk assessment (CRA) approach developed by the Global Burden of Disease study. This approach represents a systematic evaluation of the changes in population health, which would result from modifying the distribution of exposure to a risk factor or group of risk factors in the population. Central to CRA is the calculation of the Population Attributable Fraction (PAF), reflecting the proportion of current disease burden attributable to current and past exposure to a risk factor. The PAF is determined from the relative risks (RR) of disease in those exposed (compared to those not exposed) and the prevalence of the risk factor in the population. The RRs used in the calculation of PAFs in the WA study were consistent with those used in the Australian 2003 study, while estimates of the prevalence of high body mass and tobacco use were obtained from the WA Health and Wellbeing Surveillance System. The population burden was estimated in Disability Adjusted Life Years (DALYs). DALYs provide comparable information on the years of life lost to premature mortality and the equivalent ‘healthy’ years lost due to disability, thus reflecting both fatal and non-fatal burden. Mortality data for WA in 2006 were used to determine mortality burden. Disability burden was derived by applying the Australian 2003 baseline disease models, derived for the Australian 2003 study to more recent WA data derived from death and hospitalisation trends Table 1: The changing impact of high body mass and tobacco as independent risk factors for disease burden in various Australian studies. Study High BMI Tobacco Ranka % total DALY Ranka % total DALY Australia 19962 4 4.30% 1 9.70% WA 20003 4 3.90% 1 8.60% Australia 20031 3 7.50% 1 7.80% WA 2006 1 8.70% 2 6.50%

Hepatitis E virus RNA in Australian blood donations

Hepatitis E virus (HEV) poses a risk to transfusion safety. In Australia, locally acquired HEV is rare and cases are mainly reported in travelers returning from countries endemic for HEV. The risk posed by HEV to transfusion safety in Australia is unknown; therefore, we aimed to measure the rate of current HEV infection in Australian blood donations.

Risk of measles transmission on aeroplanes: Australian experience 2007-2011.

Objective: To quantify the risk of transmission of measles associated with infectious people who travelled on aeroplane flights to or within Australia.

First confirmed case of transfusion-transmitted hepatitis E in Australia

In July 2014, a 6-year-old boy underwent a split liver transplant following liver failure of unknown cause and received 18 blood components peri-operatively. In January 2015, routine monitoring revealed elevated levels of serum liver enzymes (alanine aminotransferase, 289 U/L; reference interval, < 30 U/L). Two biopsies showed possible but inconclusive evidence of rejection, and alanine aminotransferase levels continued to rise, reaching 1170 U/L, despite anti-rejection treatment. Hepatitis E virus (HEV) testing was performed on a third biopsy sample and HEV RNA was detected by reverse transcription polymerase chain reaction. Retrospective testing of the patient’s blood and liver samples showed that he was HEV RNA negative before transplantation, but HEV RNA positive in post-transplant blood from September 2014. After 3 months of ribavirin therapy, the patient’s liver enzyme levels normalised and HEV RNA became undetectable.

Refining the risk estimate for transfusion‐transmission of occult hepatitis B virus

We previously published a model to estimate the residual risk (RR) for occult hepatitis B infection (OBI) in the absence of universal anti‐HBc testing. To incorporate new information on the epidemiology of OBI, we describe model refinements and estimate a more accurate HBV RR due to OBI in Australia.

Re-evaluating the residual risk of transfusion-transmitted Ross River virus infection

Ross River virus (RRV) is an enveloped, RNA alphavirus in the same antigenic group as chikungunya virus. Australia records an annual average of 5000 laboratory‐confirmed RRV infections. While RRV is currently geographically restricted to the Western Pacific, the capacity of arboviruses for rapid expansion is well established. The first case of RRV transfusion‐transmission was recently described prompting a comprehensive risk assessment.

Reconsideration of blood donation testing strategy for human T-cell lymphotropic virus in Australia

Universal testing of blood donations for human T‐cell lymphotropic virus (HTLV) in Australia may no longer be appropriate given the low prevalence of HTLV infection and the mitigating effect of universal leucodepletion for cellular components. This study aimed to determine the most appropriate HTLV testing strategy using the Risk‐Based Decision‐Making Framework for Blood Safety.

The infectious disease blood safety risk of Australian hemochromatosis donations

It has been suggested that blood donors with hereditary hemochromatosis may pose an increased infectious disease risk and adversely affect recipient outcomes. This study compares the infectious disease risk of whole blood (WB) donors enrolled as therapeutic (T) donors to voluntary WB donors to evaluate the safety of blood products provided by the T donors.

Ross River virus in Australian blood donors: possible implications for blood transfusion safety: RRV IN BLOOD DONATIONS

Emerging transfusion‐transmissible pathogens, including arboviruses such as West Nile, Zika, dengue, and Ross River viruses, are potential threats to transfusion safety. The most prevalent arbovirus in humans in Australia is Ross River virus (RRV); however, prevalence varies substantially around the country. Modeling estimated a yearly risk of 8 to 11 potentially RRV‐viremic fresh blood components nationwide. This study aimed to measure the occurrence of RRV viremia among donors who donated at Australian collection centers located in areas with significant RRV transmission during one peak season.