Bats and viruses (1.5 MB)

cairns.qld.gov.au

Bats and viruses (1.5 MB)

Queensland Primary Industries and Fisheriesbats and viruses..HUME FIELDQueensland Centre for Emerging Infectious DiseasesBiosecurity Queensland DEEDI© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesemerging infectious disease..an infectious disease resulting from• a previously unrecognized pathogen, or• a known pathogen in a new location, or• a known pathogen re-emerging as a result ofhost, pathogen or environmental change.© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesemerging diseases impacting humans..• disease emergence hasincreased over time.• 61.4% representtransmission fromanimals - 75.3% ofthese from wildlife.• zoonotic EIDs fromwildlife reach highestproportion in the lastdecadeJones et al. Nature, 2008© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesorigins of emerging diseases..2134Woolhouse et al, Emerg Infect Dis, 2005© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesfactors promotingdisease emergence..• land-use change.• human demographic change.• global travel and commerce.• microbial change.• public health breakdown.• cultural & social practices.• economics.© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesin Australia..a cluster of diseases emerging from bats..• 1994 Hendra virus• 1996 Australian bat lyssavirus (ABLV)• 1997 Menangle virus© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and FisheriesHendra and Hendra-like detections globally..2009+2001+200220092001+2005 2001+19992002+2001+200920051994+© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesin Australia..HeV spillover to horses (between-year comparison)4Number of Hendra virus incidents321019941995199619971998199920002001200220032004200520062007200820092010Number of Spillover Events© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesin Australia..25Known Hendra virus casesNumber number of Hendra of cases virus cases20Cases1510501994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010YearEquine CasesHuman Cases© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and FisheriesHendra virusbackground..• novel paramyxovirus unknownprior to 1994.• zoonotic BSL4 agent.• 14 known spillover events.• low infectivity, but high casefatality rate.• human cases result frominfected horses.oPhoto: Kim Halpin© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesnatural reservoir..• flying foxes identified as anatural host in 1996.• antibodies in all 4 species.• antibodies across thegeographic range.• no attributed clinical diseasein flying foxes.• antibodies in archivedsamples.© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and FisheriesHeV prevalence in bats..associated with• age• pregnancy• ecological stress Andrew Breed 2007Raina Plowright 2007© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and FisheriesHeV prevalence in bats..40Hendra virus Proportion detection of PCR-positive at Queensland pools flying by month fox roosts(Pooled urine)Hendra virusprevalence (%)3020100Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecMonth© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesspillovers to horses (within year)..4HeV spillover to horses (within-year comparison)Number of Spillover Events3210J F M A M J J A S O N D© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and FisheriesCairns (3)Townsville (1)Bowen (1)Proserpine (1)Mackay (1)Cawarral (1)Tewantin (1)Peachester (2)Brisbane (2)© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009Murwillumbah (1)


Queensland Primary Industries and Fisheriesrisk of spillover..probability of spillover from any given colony depends on• the presence of infection,• the proportion of susceptible flying foxes,• the colony size..plus• the number and density of horses,• the management of the horses,• the virus strain/virus dose/route of infection?potentialviral loadeffectivecontact© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriespossible transmission pathways..direct bat-horse transmission:plausibly• ingestion of partially eaten fruit.• ingestion of ‘spats’.• ingestion of contaminated pasture/feed.• licking/sniffing foetal tissues.© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriespossible transmission pathways..indirect transmission via an intermediate host:less plausible because:• opportunity for direct contact with food debris/excretaaround feeding sites.• direct horse-to-horse and horse-to-human transmissionvia infected body fluids.• clustering of bat and horse virus sequence.• negative findings in non-bat species.© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisherieshuman cases..by occupation and putative exposure event:• 1994 horse owner– assisting vet necropsy infected horse.• 1994 horse trainer and stable-hand– force-feeding infected horse.• 2004 veterinarian– necropsy infected horse.• 2008 veterinarian & nurse– nasal lavage on infected horse.• 2009 veterinarian– respiratory endoscope on infected horse.© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesinfection rates..• Redlands 2008– 14 “high exposure”– 6 “low-moderate exposure”– infection rate : 10 %• Cawarral 2009– 4 “high exposure”– 8 “low-moderate exposure”– infection rate : 8 %Queensland HealthBrad McCall & Margaret Young QH PHU© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesemergence from wildlife..• primarily an ecological process.• landscape changes-> populations under stress-> changed population dynamics-> changed infection dynamics• a need to understand the ecologyof the natural host, the pressures,and the underlying factors.Flying fox roost, Hervey Bay QLDPhoto: Raina Plowright 2008© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and FisheriesA One Health approach..• a complex systemsapproach for acomplex situation.Chatou market, Guangzhou, China, May 2003Daszak et al, 2001Children in Guangzhou wildlife markets,May 2003© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009


Queensland Primary Industries and Fisheriesacknowledgements..• BQ/QCEID– Craig Smith & Carol de Jong– Debra Melville, Amanda McLaughlin & Nina Kung• QHealth/AAHL– Ina Smith & Alice Broos• AAHL– Linfa Wang, Gary Crameri and team• Australian Biosecurity CRC for Emerging Infectious Diseases© The State of Queensland, Department of Employment, Economic Development and Innovation, 2009

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