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© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 HUME FIELD Biosecurity Queensland, Australia Epidemiology,

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Presentation on theme: "© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 HUME FIELD Biosecurity Queensland, Australia Epidemiology,"— Presentation transcript:

1 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 HUME FIELD Biosecurity Queensland, Australia Epidemiology, surveillance and control of Hendra virus

2 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 o background.. no evidence of infection in horses prior to 1994. 13 known spillover events. low infectivity, but high case fatality rate. human cases attributed to close contact with infected horses.

3 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 known spillovers.. Mackay2 horses & one humanAugust 1994 Brisbane (Hendra)20 horses & two humansSeptember 1994 Cairns (Trinity Beach)1 horseJanuary 1999 Cairns (Gordonvale)1 horse* & one humanOctober 2004 Townsville1 horseDecember 2004 Peachester1 horseJune 2006 Murwillimbah1 horseOctober 2006 Peachester1 horseJune 2007 Cairns (Clifton Beach)1 horseJuly 2007 Brisbane (Redlands)5 horses* & two humansJune 2008 Proserpine Cawarral Bowen 3 horses* 4 horses & one human 2 horses July 2008 July 2009 Aug 2009

4 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 o o Mackay 1994 o Cairns 1999, 2004, 2007 spatial pattern.. o Townsville 2004 o Peachester 2006, 2007 Brisbane 1994, 2008 o Murwillumbah 2006 o Proserpine 2008 o Cawarral 2009 Bowen 2009 o

5 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009..temporal pattern 19941,1 b19950 e19960 t19970 w19980 e19991 e20000 n20010 20020 y20030 e20041,1 a20050 r20061,1 20071,1 20081,1 20091,1 wjan1 ifeb0 tmar0 hapr0 imay0 njun1,1,1 jul1,1,1 yaug1,1 esep1 aoct1,1 rnov1 dec0

6 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 natural reservoir.. fruit bats identified as the natural host in 1996. antibodies in all 4 species. antibodies across the geographic range. no attributed clinical disease in flying foxes. antibodies in archived samples. Grey-headed flying fox

7 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009..HeV antibody prevalence Key: Horizontal hatching P. alecto Vertical hatching P. poliocephalus Solid black P. conspicillatus Broken line P. scapulatus (southern inland limit) Map adapted from Hall and Richards (2000). Data from Field (2005) 51% (95% CI 48-54) 27% (95% CI 17-39) 31% (95% CI 19-46) 29% (95% CI 21-39) P. alecto 13/13 P. scap 13/13 P. polio 5/13 P. consp 3/13

8 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

9 risk of spillover.. probability of spillover from any given colony depends on the proportion of susceptible flying foxes, the colony size, the presence of infection.. plus the number and density of horses, the number and density of flying foxes, management of the horses, the virus strain/virus dose/route of infection? potentialv iral load effective contact

10 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 modes of transmission.. plausible modes of direct bat-horse transmission: ingestion of partially eaten fruit. ingestion of ‘spats’. ingestion of urine-contaminated pasture/feed. licking/sniffing foetal tissues.

11 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 indirect transmission via an intermediate host? improbable because negative screening of non-bat species. phylogenetic clustering of bat and horse virus sequence. temporal overlap between equine cases and detection in flying foxes. direct horse-to-horse and horse-to-human transmission via infected body fluids. biological plausibility of direct transmission. Photo: Ian Temby

12 0.01 Peachester (SEQ) 2007 Proserpine (FNQ) 2008 Cairns (FNQ) 2007 FNQ 2008 Redlands (SEQ) 2008 SEQ 2009 Hendra (SEQ) 1994 for nucleotide 1500 to 2240 of the genome (carboxy terminal of the Nucleoprotein and the intergenic region) using Mega 4.0 (Neighbor-joining, p distances). Bat sequence in red italics. [Ina Smith, AAHL] Hendra virus phylogenetic analysis..

13 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 infection dynamics in bats.. antibody prevalence studies bat level variables age p=0.0028 season p=0.0025 [Andrew Breed, 2005.]

14 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 infection dynamics in bats.. UC Davis US NSF funding [Raina Plowright, 2002.]

15 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 limiting infection in horses.. awareness. exposure risk minimisation strategies. early consideration of Hendra virus. appropriate management/PPE in suspects. rapid rule-out/-in. quarantine of identified case properties.

16 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 limiting infection in horses.. remains a rare infection –2 in 200,000 horses pa. –13 in 5 million horse-years at risk. likelihood vs consequence.

17 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 research directions.. infection dynamics in bats. drivers for virus emergence from bats. modes of transmission. exposure risk management. early detection methods. therapeutics.

18 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 drivers for emergence.. emergence or awareness? the more you look, the more you find? St. George (1989) suggested the possibility of a rabies- like virus in Australian bats in 1989.. ‘might not become evident unless active surveillance of bats was undertaken, or man or a domestic animal became infected’.

19 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 changed bat population dynamics.. in recent decades, decreased total population. altered distribution. change in the number and permanency of roosts. altered frequency of contact. Plowright, Foley, Field et al 2009 (submitted) [Raina Plowright, 2002.]

20 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 increasing urbanization.. major shift in the distribution of flying foxes into urban areas. perception of plague proportions. Plowright, Foley, Field et al 2009 (submitted)

21 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

22 changed risk of spill-over.. in urban areas, more flying foxes plus higher contact rates means larger outbreaks more infectious individuals, a greater total viral load, and a greater probability of exposure and infection = Plowright, Foley, Field et al 2009 (submitted)

23 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 in summary.. landscape changes resulted in changed population dynamics that promoted emergence and spillover. further landscape changes and climate change may further de-stabilize the system. Plowright, Foley, Field et al 2009 (submitted)

24 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 If you suspect Hendra virus, please contact Biosecurity Queensland immediately on 13 25 23 or contact the Emergency Disease Watch Hotline on 1800 675 888. Overview  Hendra virus overview Hendra virus overview Get a copy of the report  Download: 'Independent review of Hendra virus cases' (PDF, 480 kB)'Independent review of Hendra virus cases' (PDF, 480 kB) For veterinarians  Updates from the Chief Veterinary Officer: 2009, April 3 | 2008, August 19 | 2008, August 8 | 2008, July 28 2009, April 32008, August 192008, August 82008, July 28  Guidelines for veterinarians handling potential Hendra virus infection in horses Version 3, April 2009 Guidelines for veterinarians handling potential Hendra virus infection in horses  Submitting samples for analysis Submitting samples for analysis  Safe use of personal protective equipment (PPE) Safe use of personal protective equipment (PPE) For communities  Hendra virus: important information for horse owners (PDF, 262 kB) Download your copy today. Hendra virus: important information for horse owners (PDF, 262 kB)  Fact sheet: important community information (PDF, 71 kB) (including advice to horse owners) Fact sheet: important community information (PDF, 71 kB)  Fact sheet: Hendra virus infection (from Queensland Health) Fact sheet: Hendra virus infection Research  Initial experimental characterisation of HeV (Redland Bay 2008) infection in horses (PDF, 222 kB) Report authored by Deborah Middleton, CSIRO AAHL Initial experimental characterisation of HeV (Redland Bay 2008) infection in horses (PDF, 222 kB)  Research into Hendra virus: the story so far Research participants, progress, challenges and current work. Research into Hendra virus: the story so far  Hendra virus: the initial research This information sheet reports on the emergence of Hendra virus in horses and on research into reservoir hosts and transmission studies in fruit bats, horses and cats. Hendra virus: the initial research  Scientific papers Link to the PubMed website (published research papers). Search for "Hendra virus". Scientific papers QPIF Hendra virus webpage..

25 © The State of Queensland, Department of Employment, Economic Development and Innovation, 2009 acknowledgements.. Queensland Primary Industries & Fisheries/Biosecurity Queensland. CSIRO Australian Animal Health Laboratory. Australian Biosecurity CRC for Emerging Infectious Diseases. Australian Dept. of Agriculture, Forestry & Fisheries. US Wildlife Trust/Consortium for Conservation Medicine.


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