Hendra Virus and Horse Owners – Risk Perception and Management

Hendra virus is a highly pathogenic novel paramyxovirus causing sporadic fatal infection in horses and humans in Australia. Species of fruit-bats (genus Pteropus), commonly known as flying-foxes, are the natural host of the virus. We undertook a survey of horse owners in the states of Queensland and New South Wales, Australia to assess the level of adoption of recommended risk management strategies and to identify impediments to adoption. Survey questionnaires were completed by 1431 respondents from the target states, and from a spectrum of industry sectors. Hendra virus knowledge varied with sector, but was generally limited, with only 13% of respondents rating their level of knowledge as high or very high. The majority of respondents (63%) had seen their state’s Hendra virus information for horse owners, and a similar proportion found the information useful. Fifty-six percent of respondents thought it moderately, very or extremely likely that a Hendra virus case could occur in their area, yet only 37% said they would consider Hendra virus if their horse was sick. Only 13% of respondents stabled their horses overnight, although another 24% said it would be easy or very easy to do so, but hadn’t done so. Only 13% and 15% of respondents respectively had horse feed bins and water points under solid cover. Responses varied significantly with state, likely reflecting different Hendra virus history. The survey identified inconsistent awareness and/or adoption of available knowledge, confusion in relation to Hendra virus risk perception, with both over-and under-estimation of true risk, and lag in the uptake of recommended risk minimisation strategies, even when these were readily implementable. However, we also identified frustration and potential alienation by horse owners who found the recommended strategies impractical, onerous and prohibitively expensive. The insights gained from this survey have broader application to other complex risk-management scenarios

Hendra Virus Infection Dynamics in Australian Fruit Bats

Hendra virus is a recently emerged zoonotic agent in Australia. Since first described in 1994, the virus has spilled from its wildlife reservoir (pteropid fruit bats, or ‘flying foxes’) on multiple occasions causing equine and human fatalities. We undertook a three-year longitudinal study to detect virus in the urine of free-living flying foxes (a putative route of excretion) to investigate Hendra virus infection dynamics. Pooled urine samples collected off plastic sheets placed beneath roosting flying foxes were screened for Hendra virus genome by quantitative RT-PCR, using a set of primers and probe derived from the matrix protein gene. A total of 1672 pooled urine samples from 67 sampling events was collected and tested between 1 July 2008 and 30 June 2011, with 25% of sampling events and 2.5% of urine samples yielding detections. The proportion of positive samples was statistically associated with year and location. The findings indicate that Hendra virus excretion occurs periodically rather than continuously, and in geographically disparate flying fox populations in the state of Queensland. The lack of any detection in the Northern Territory suggests prevalence may vary across the range of flying foxes in Australia. Finally, our findings suggest that flying foxes can excrete virus at any time of year, and that the apparent seasonal clustering of Hendra virus incidents in horses and associated humans (70% have occurred June to October) reflects factors other than the presence of virus. Identification of these factors will strengthen risk minimization strategies for horses and ultimately humans

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

Epidemiological studies of Avian influenza viruses in Hong Kong : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand

Eight studies of the epidemiological dynamics of avian influenza viruses were conducted on poultry in Hong Kong, with special focus on the movement of birds through the live poultry marketing system, and the implications for avian influenza transmission. The first involved analysis of virus isolation data from faecal samples obtained from cooperating stalls in live poultry markets in Hong Kong in a routine sampling program undertaken between 1999 and 2001. This showed that two subtypes of avian influenza viruses, H9N2 and H6N1, have become well established in the Hong Kong live poultry markets, especially in chickens (mainly H9N2) and quail (mainly H6N1). In addition, a wave of H5N1 virus infection occurred in 2001 after it had been absent through the earlier period of the study. The second study was an evaluation of long term changes in the marketing systems for live poultry in Hong Kong, their likely effects on avian influenza epidemiology, and documented evidence of the prevalence of various H subtypes of avian influenza in sampling undertaken during three periods from 1975 to 2001. The third project involved two cross-sectional studies and one longitudinal study on local quail farms in Hong Kong. Results showed that quail could act as a reservoir host for H9N2 and H6N1 subtype viruses, but each subtype differed in its epidemiology. H9 virus usually infected quail at around 10 days of age, whereas H6 infected quail at 15-20 days of age. At 35 days of age (usual market age in Hong Kong), a proportion of market quail were likely to be susceptible to H6 (50%) and H9 viruses (20%), and were able to transmit the virus in the markets. Due to these findings, the Hong Kong Government closed the quail farming operations and restricted the sale of quail in live poultry markets. A longitudinal study was conducted on three live poultry market stalls to assess the time from stall entry to sale, and evaluate the influence of this delay on avian influenza virus transmission to other poultry in the same stall. Participating stalls varied from high volume/rapid turnover to low volume/slow turnover. Turnover for tagged poultry was rapid, although some chickens became infected with H9 virus before sale. Birds which stayed longer, such as quail, became infected and maintained infection in the stall. As well as spread by direct contact and on typical fomites, keeping of pet roosters and re-use of washing water were identified as factors increasing the ability of avian influenza strains to persist in market stalls. An experimental replica of a market stall was created to study the transmission of low pathogenic avian influenza virus (H9N2) in a controlled environment, with different rates of population turnover and different immune status with respect to both H5 and H9 subtypes. Transmission was influenced by distance between birds, the proportion of birds carrying antibody to H9 and the rate of introduction of susceptible birds, but not by the use of H5N2 vaccine. In order to assess the effectiveness of temporary depopulation of stalls, a study was conducted to compare the prevalence of avian influenza virus and Newcastle disease virus before and shortly after the monthly rest day in live poultry markets in Hong Kong, by virus isolation. Prevalence of H9N2 avian influenza virus was reduced by the rest day, but Newcastle disease virus prevalence was unaffected. During the 2002 avian influenza H5N1 outbreak in local chicken farms, a case-control study was undertaken to identify risk factors that may have contributed to this outbreak. A questionnaire was administered by interview to collect the data for this study. Multivariate logistic regression models showed that movement of people and fomites from live poultry markets to farms were important influences on transmission, and that the live bird markets were the likely source of virus for farms. A spatial stochastic computer model was constructed to predict the spread of avian influenza virus in local chicken farms and live poultry markets in Hong Kong, and the effectiveness of control measures. The data used in model parameter setting was derived from the case-control study. The reference model produced an epidemic curve which was similar to the true epidemic curve in the 2002 outbreak. Control strategies such as rest day and vaccination were evaluated within the model, and found to produce results comparable with field experience. Results from these studies clarify various aspects of the epidemiological features and transmission dynamics of avian influenza viruses, and provide guidance on appropriate control and prevention strategies for highly pathogenic avian influenza viruses within poultry marketing systems in Asia

Australia as a global sink for the genetic diversity of avian influenza A virus.

Most of our understanding of the ecology and evolution of avian influenza A virus (AIV) in wild birds is derived from studies conducted in the northern hemisphere on waterfowl, with a substantial bias towards dabbling ducks. However, relevant environmental conditions and patterns of avian migration and reproduction are substantially different in the southern hemisphere. Through the sequencing and analysis of 333 unique AIV genomes collected from wild birds collected over 15 years we show that Australia is a global sink for AIV diversity and not integrally linked with the Eurasian gene pool. Rather, AIV are infrequently introduced to Australia, followed by decades of isolated circulation and eventual extinction. The number of co-circulating viral lineages varies per subtype. AIV haemagglutinin (HA) subtypes that are rarely identified at duck-centric study sites (H8-12) had more detected introductions and contemporary co-circulating lineages in Australia. Combined with a lack of duck migration beyond the Australian-Papuan region, these findings suggest introductions by long-distance migratory shorebirds. In addition, on the available data we found no evidence of directional or consistent patterns in virus movement across the Australian continent. This feature corresponds to patterns of bird movement, whereby waterfowl have nomadic and erratic rainfall-dependant distributions rather than consistent intra-continental migratory routes. Finally, we detected high levels of virus gene segment reassortment, with a high diversity of AIV genome constellations across years and locations. These data, in addition to those from other studies in Africa and South America, clearly show that patterns of AIV dynamics in the Southern Hemisphere are distinct from those in the temperate north

Australia as a global sink for the genetic diversity of avian influenza A virus

Most of our understanding of the ecology and evolution of avian influenza A virus (AIV) in wild birds is derived from studies conducted in the northern hemisphere on waterfowl, with a substantial bias towards dabbling ducks. However, relevant environmental conditions and patterns of avian migration and reproduction are substantially different in the southern hemisphere. Through the sequencing and analysis of 333 unique AIV genomes collected from wild birds collected over 15 years we show that Australia is a global sink for AIV diversity and not integrally linked with the Eurasian gene pool. Rather, AIV are infrequently introduced to Australia, followed by decades of isolated circulation and eventual extinction. The number of co-circulating viral lineages varies per subtype. AIV haemagglutinin (HA) subtypes that are rarely identified at duck-centric study sites (H8-12) had more detected introductions and contemporary co-circulating lineages in Australia. Combined with a lack of duck migration beyond the Australian-Papuan region, these findings suggest introductions by long-distance migratory shorebirds. In addition, we found no evidence of directional or consistent patterns in virus movement across the Australian continent. This feature corresponds to patterns of bird movement, whereby waterfowl have nomadic and erratic rainfall-dependant distributions rather than consistent intra-continental migratory routes. Finally, we detected high levels of virus gene segment reassortment, with a high diversity of AIV genome constellations across years and locations. These data, in addition to those from other studies in Africa and South America, clearly show that patterns of AIV dynamics in the Southern Hemisphere are distinct from those in the temperate north.Author Summary A result of the ever-growing poultry industry is a dramatic global increase in the incidence of high pathogenicity avian influenza virus outbreaks. In contrast, wild birds are believed to be the main reservoir for low pathogenic avian influenza A virus. Due to intensive research and surveillance of AIV in waterfowl in the Northern Hemisphere, we have a better understanding of AIV ecology and evolution in that region compared to the Southern Hemisphere, which are characterised by different patterns of avian migration and ecological conditions. We analysed 333 unique AIV genomes collected from wild birds in Australia to understand how Australia fits into global AIV dynamics and how viruses are maintained and dispersed within the continent of Australia. We show that the Southern Hemisphere experiences differing evolutionary dynamics to those seen in Northern Hemisphere with Australia representing a global sink for AIV.Competing Interest StatementThe authors have declared no competing interest

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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