Climate change and Equine Infectious DiseasesManaging the uncertainty

Presented by Dr Gary Muscatello BVSc, PhDLecture, Applied Animal Microbiology

Theme Leader: Animal Biosecurity, Production and Health

Outline ….

Horse- Pathogen-Environment Interaction

Climate Impact on HPEI

Disease threatsNOW !!FUTURE ??

Adaptation to Disease Risk InformationStrategies

ENVIRONMENT PATHOGENS

HOST

HPEI and horse health

Temperature, land and waterSunlightAtmosphereFeed and nutrientsHusbandry and housingOther horses and other animal speciesInsects

Aim of good equine husbandry is to manipulate HPEI in favour of the horse.

‘Equine friendly ecosystem’Reduce host-pathogen interaction• Pathogen bias

S

Negative climate impact

Feed and water limitationWeather stressorsChanging weather patterns Monsoonal rain events Cyclonic/extreme eventsWarmer and drier Fitness Encroachment Insects Irritants and pollutants Microbes

Increase risk of specific infectious diseases in horses– Opportunistic– Insect borne– Wildlife borne

Climate impact and EID !!!

Reduced fitnessHeat stressMalnutrition ?Opportunistic disease

Drought associated diseasesRhodococcus equi

pneumoniaEAFL and MRLS

Warming Insect borne diseasesOpportunistic bacteria and

fungi

Limitation on natural resourcesEncroachment diseases

Pollutants and respiratory healthCOPD ??

Current EID events and climate

‘Rattles’

Inhalation of high concentrations of a saprophytic bacteria called virulent R. equi

Seasonal disease of foals

Exacerbated during dry and dusty conditions

Exacerbated in Thoroughbred IndustryIntensificationBreeding regime

Hunter Valley continue to experience on-going issues with this disease

Worsens if dry spells correspond with high numbers of susceptible foals on the ground

Current EID events and climate

Equine Amnionitis and foetal loss syndrome

2004-05 Hunter Valley and SE Queensland

Mares ingesting hairy caterpillars Moult from older larvae (Feb-April)Pupate in soil (May)Wind and heavy summer rains / drought breaking

Amniontis/foetal infection Setae allow bacterial invasion Gut microbes and soil bacteria

MRLS and nocardioform placentitis

Increase incidence of caterpillar associated reproductive disorders in 2011 -12Nest numbers where high during this summer !!

Current EID events and climate

Equine ArbovirusesKunjin, MVE and RR virusTypically seen in Nth AustraliaBirds, rodents and macropods act as reservoirs

2011 – cyclonic weather eventMild and wet autumnLocalized floodingIdeal for mosquito migration and breeding

Neurological disease (Kunjin and MVE)Sore muscles and joints (MVE and RR)~1,000 cases ~10% case fatalities

New strain of Kunjin virusNeuroinvasive mutantSimilar to WNV

MVE seen in Victoria 1974

Current EID events and climate

Hendra virus

Flying foxes reservoir hostSeen in Coastal Queensland and Northern NSWReduced natural food resources for batsUrbanization of batsIncreased likelihood of bat-horse interactionSeasonal spill-overStress, pregnant bats, bats giving birth2011 – 19 incidences (14 incidence 1994-2010)

Virus is fragile.Increased frequency of detection in bat urine during the summer…Mild autumn contribute to increased infectivity ??Changes in migration patterns related to cyclonic events ??More bat colonies becoming infected ??

‘Future’ EID events and climate

Mosquito populations

Increase in rainfall intensity Strong wind eventWarming Periodic migration of mosquitoes Sth

Increase frequency of arbovirus disease Establishment of tropical mosquitoes Sth

Seasonal arbovirus disease Increase the risk of emergence of virulent strains

Kunjin WNV (NY99)

Spread of other tropical arbovirusesEquine Infectious Anaemia

Introduction of exotic arbovirusesJapanese Encephalitis Virus

Most of SE AsiaSeen in Torres Strait

‘Future’ EID events and climate

Mosquito populations

Bacterial associated insect disease ‘Pigeon fever’

Corynebacterium pseudotuberculosis

Endemic in sheep in goats in Australia ‘Cheesy gland’

Biting insects inoculating pectoral muscles with bacteria from the soil

Spread from West coast to central and eastern U.S.

Bot fly

Tick borne diseases

‘Future’ EID events and climate

Warming

Bacterial proliferation Opportunistic infection Rain intensity / monsoonal rains ?

‘Rain Scald’ ‘Greasy heal’ Dermatophilus congolensis

Bacterial respiratory tract disease StablesPseudomonas aeruginosaKlebsiella pneumoniaeSaprophytes, biofilms

Migration of tropical bacterial disease Melioidosis

‘Future’ EID events and climate

Wildlife encroachment

Bats !!Kangaroos ??Migratory birds !!Feral Pigs ??

Adaptation to Disease Risk

Understanding HPEI

Awareness of climate impact

Surveillance and monitoring BOM !!Sentinel animals !!Mosquito traps !!Horse environment !!

Breaking the connection

Strategic environmental measures

Strategic host management measures

Aim to favour the HORSE !!!

Adaptation to Disease Risk

Understanding HPEI

Awareness of climate impact

Surveillance and monitoring

Breaking the connection

Strategic environmental measures

Strategic host management measures

Aim to favour the HORSE !!!

Adaptation to Disease Risk

Understanding HPEI

Awareness of climate impact

Surveillance and monitoring

Breaking the connection

Strategic environmental measures

Strategic host management measures

Aim to favour the HORSE !!!

Questions ??