NSW Arbovirus Surveillance NSW Arbovirus Surveillance Programme:Programme:

Sentinel FlocksSentinel Flocks

Linda HuestonLinda Hueston

Arbovirus & Emerging Diseases UnitArbovirus & Emerging Diseases Unit

CIDMLS - ICPMRCIDMLS - ICPMR

Surveillance ProgrammesSurveillance Programmes

Gather information about the occurrence Gather information about the occurrence of diseaseof disease

Information gathered may allow prediction Information gathered may allow prediction of outbreaks or epidemics or disease of outbreaks or epidemics or disease presentationspresentations

““buy time” so we may be able to prevent buy time” so we may be able to prevent an outbreak or reduce the number of an outbreak or reduce the number of casescases

Surveillance is not InterventionSurveillance is not Intervention

It precedes interventionIt precedes interventionData collected may assist in determiningData collected may assist in determining

- the type of intervention (health warnings, - the type of intervention (health warnings, advice to people advice to people eg personal protective eg personal protective

measuresmeasures,, vector control, vaccinations etc) vector control, vaccinations etc) the level of intervention (local areas, state the level of intervention (local areas, state

or federal)or federal)

NSW Arbovirus Surveillance NSW Arbovirus Surveillance ProgrammeProgramme

Instituted by NSW Health in 1979 as a Instituted by NSW Health in 1979 as a result of the outbreak in 1974result of the outbreak in 1974

Involved 3 states; NSW, Vic & SAInvolved 3 states; NSW, Vic & SA- areas of previously large outbreaks with - areas of previously large outbreaks with high morbidity & mortality & significant high morbidity & mortality & significant economic losseseconomic losses

Function was to detect the presence of Function was to detect the presence of MVE and Kun as soon as possible to allow MVE and Kun as soon as possible to allow suitable, appropriate intervention.suitable, appropriate intervention.

NSW Arbovirus Surveillance NSW Arbovirus Surveillance ProgrammeProgramme

InvolvesInvolvesMonitoring sentinel flocks for virus activityMonitoring sentinel flocks for virus activityMonitoring mosquito populations & testing for Monitoring mosquito populations & testing for

presence of viruspresence of virusMonitoring human casesMonitoring human cases

Chicken Sentinel ProgrammeChicken Sentinel Programme

How is it done?How is it done?

- flocks of 12 wks old chooks are placed in - flocks of 12 wks old chooks are placed in “hotspots” and are bled weekly to look for “hotspots” and are bled weekly to look for the appearance of antibodythe appearance of antibody

What does it tell us?What does it tell us?

- that the amount of virus present in an - that the amount of virus present in an area has increased to a level that has area has increased to a level that has allowed transmission.allowed transmission.

The What and Where of Finding The What and Where of Finding VirusVirus

Finding virus in mossiesFinding virus in mossies

- tells us only the virus is present but not - tells us only the virus is present but not how much is therehow much is there

Finding virus in sentinel chooks tells us the Finding virus in sentinel chooks tells us the amount of virus present has increased to amount of virus present has increased to the point where it is transmitting to hoststhe point where it is transmitting to hosts

Human transmission may be possibleHuman transmission may be possible

Chickens and MVE & KunChickens and MVE & Kun

Chooks are “on the job” 24/7Chooks are “on the job” 24/7Each chook may receive 1000 bites/nightEach chook may receive 1000 bites/nightOver a week each chook may have Over a week each chook may have

“sampled” at least 7000 mossies → “sampled” at least 7000 mossies → efficient & inexpensive systemefficient & inexpensive system

Has been shown that serocoversions in Has been shown that serocoversions in chooks preceeds human infection by 10 to chooks preceeds human infection by 10 to 21 days → valuable time for health 21 days → valuable time for health warnings & interventionswarnings & interventions

Surveillance System CommentsSurveillance System Comments

It’s a numbers gameIt’s a numbers game If mossie numbers are high and lots of mossies are If mossie numbers are high and lots of mossies are

infected they may trigger firstinfected they may trigger first Mossie trapping represents one night onlyMossie trapping represents one night only When mossie numbers are low chooks may be a When mossie numbers are low chooks may be a

better bet because they are bitten many times/nightbetter bet because they are bitten many times/night Chook testing represents 1000 bites per night per Chook testing represents 1000 bites per night per

chook. There are 7 nights & 15 chooks → 105,000 chook. There are 7 nights & 15 chooks → 105,000 chances that one or more birds could be infectedchances that one or more birds could be infected

Surveillance System CommentsSurveillance System Comments

Examples of this numbers gameExamples of this numbers game 1991 Griffith - mossie numbers were high and they 1991 Griffith - mossie numbers were high and they

triggered first notification of Kun; chooks seroconverted next triggered first notification of Kun; chooks seroconverted next bleedbleed

1991 Hay - almost all the flock seroconverted to Kun but 1991 Hay - almost all the flock seroconverted to Kun but virus not isolated from mossies in Hay that season maybe virus not isolated from mossies in Hay that season maybe numbers were down on the trapping night numbers were down on the trapping night

2000/2001- large numbers of seroconversions to MVE & 2000/2001- large numbers of seroconversions to MVE & Kun through the flocks along Darling River no isolation of Kun through the flocks along Darling River no isolation of MVE virus at all in mossies but some isolates of Kun. But MVE virus at all in mossies but some isolates of Kun. But chook Kun seroconversions preceded the isolation of virus chook Kun seroconversions preceded the isolation of virus in mossiesin mossies

Surveillance System CommentsSurveillance System Comments

Examples of this numbers gameExamples of this numbers game Isolates of RRV from mossies most yearsIsolates of RRV from mossies most yearsBut human cases appear before the But human cases appear before the

collection season startscollection season starts

Surveillance System CommentsSurveillance System Comments

What does it all mean then?What does it all mean then?Means that surveillance is a complex system Means that surveillance is a complex system Relies on many different interactionsRelies on many different interactionsSome systems are better than others in Some systems are better than others in

some situationssome situationsSo keep options and minds openSo keep options and minds open

Surveillance System CommentsSurveillance System Comments

Never be free of arbovirus infectionsNever be free of arbovirus infectionsCan’t remove all the mossiesCan’t remove all the mossiesCan’t remove all the hostsCan’t remove all the hostsVaccination (if available) won’t irradicate these Vaccination (if available) won’t irradicate these

diseases in humans because humans are not diseases in humans because humans are not the only host (but it can reduce the number and the only host (but it can reduce the number and severity of cases)severity of cases)

Surveillance System CommentsSurveillance System Comments

We can be vigilant and responsiveWe can be vigilant and responsiveWe can improve our surveillance methods to We can improve our surveillance methods to

target organisms of interest - fastertarget organisms of interest - faster

Remember time spent in reconnaissance is Remember time spent in reconnaissance is never wastednever wasted

NSW Arbovirus Surveillance NSW Arbovirus Surveillance Programme:Programme:

Sentinel Flock CareSentinel Flock Care

Linda HuestonLinda Hueston

Arbovirus & Emerging Diseases UnitArbovirus & Emerging Diseases Unit

CIDMLS - ICPMRCIDMLS - ICPMR

Animal EthicsAnimal Ethics Project is overseen by the Animal Ethics Project is overseen by the Animal Ethics

Committee at Westmead HospitalCommittee at Westmead Hospital Subject to the Code of Practice for NSW Animal Subject to the Code of Practice for NSW Animal

Research ProgrammeResearch Programme Approval is given only for 3 years after this time we Approval is given only for 3 years after this time we

must reapplymust reapply Approval is not guaranteed Approval is not guaranteed Project must be subjected to vet inspections and the Project must be subjected to vet inspections and the

supervising vet receives notification each week on the supervising vet receives notification each week on the condition of each bird in each flockcondition of each bird in each flock

It is the only programme with ethics approval in It is the only programme with ethics approval in the countrythe country

Animal EthicsAnimal Ethics

Every 3 years we must:Every 3 years we must:Demonstrate that the work we do is valid, Demonstrate that the work we do is valid,

humane, justifiable and consideratehumane, justifiable and considerateWe must actively seek alternatives to animal We must actively seek alternatives to animal

use in researchuse in researchWe must justify why animal use is essential We must justify why animal use is essential

for this projectfor this project

RememberRemember

Choose the right breed of chook (must be Choose the right breed of chook (must be layers not meat birds)layers not meat birds)

The birds health is paramount healthy The birds health is paramount healthy birds make the best sentinelsbirds make the best sentinels

Birds naturally don’t like to be handledBirds naturally don’t like to be handledTake a little time to get the chooks Take a little time to get the chooks

accustomed to being handled and accustomed to being handled and accustomed to you.accustomed to you.

All Chooks RequireAll Chooks Require

Adequate spaceAdequate spaceAdult birds should be provided with a Adult birds should be provided with a

minimum floor space of 0.4 square metres per minimum floor space of 0.4 square metres per bird. Overcrowding results in poorer bird. Overcrowding results in poorer performance and can lead to feather pecking, performance and can lead to feather pecking, bullying, cannibalism and disease. bullying, cannibalism and disease.

All Chooks RequireAll Chooks Require

Adequate shade to ensure they are protected Adequate shade to ensure they are protected from heat radiating through roofing. A good from heat radiating through roofing. A good balance of shade and light is required, bearing in balance of shade and light is required, bearing in mind that birds can do better with good light and mind that birds can do better with good light and that a very shady yard (and a too dark pen) may that a very shady yard (and a too dark pen) may not dry out properly causing disease problems. not dry out properly causing disease problems.

The enclosure should usually face towards the The enclosure should usually face towards the north. north.

A dry area protected from the rain A dry area protected from the rain

All Chooks RequireAll Chooks Require Protection from predatorsProtection from predators Good quality food.Good quality food. Feed must be balanced and appropriate to the age of the Feed must be balanced and appropriate to the age of the

birds. Chick starter is fed to birds from 0 to 6-8 weeks, birds. Chick starter is fed to birds from 0 to 6-8 weeks, then grower feed up to 16-18 weeks when the birds are then grower feed up to 16-18 weeks when the birds are put on layer mash or pellets. Commercially balanced put on layer mash or pellets. Commercially balanced rations are generally adequate and readily available, rations are generally adequate and readily available, though layer rations should be supplemented with extra though layer rations should be supplemented with extra shell grit, at least in the peak laying period. During very shell grit, at least in the peak laying period. During very hot periods a ration with extra protein can be fed to hot periods a ration with extra protein can be fed to compensate for the birds not eating as much.compensate for the birds not eating as much.

Chook CareChook Care Housing – see the enclosed Dept of Ag booklet Housing – see the enclosed Dept of Ag booklet

for diagrams of suitable housing enclosuresfor diagrams of suitable housing enclosures

Position the enclosure so that the birds get morning Position the enclosure so that the birds get morning sun but are protected from afternoon sun. Placement sun but are protected from afternoon sun. Placement near shade trees or other structures which can given near shade trees or other structures which can given shade particularly on the west side will help with heat shade particularly on the west side will help with heat problemproblem

The size of the enclosure should provide half a The size of the enclosure should provide half a

square metre of floor space per bird at a minimumsquare metre of floor space per bird at a minimum

All Chooks RequireAll Chooks Require

Adequate cool water Adequate cool water Protection from winds especially westerlies in Protection from winds especially westerlies in

winter. However a gentle breeze and a winter. However a gentle breeze and a reasonably high roof should prevent ammonia reasonably high roof should prevent ammonia building up which can cause respiratory disease. building up which can cause respiratory disease. It also helps to dry the pen, keep the dust down It also helps to dry the pen, keep the dust down and prevent other disease problems. and prevent other disease problems.

Regular inspection for their own health and the Regular inspection for their own health and the condition of their environmentcondition of their environment

Chook CareChook Care

Housing Housing The coop should have adequate ventilation The coop should have adequate ventilation

plus a draft free area for nesting. Having a plus a draft free area for nesting. Having a chicken mesh front and a partly enclosed chicken mesh front and a partly enclosed back portion with solid side walls is a good back portion with solid side walls is a good combination. To make the coop hygienic and combination. To make the coop hygienic and easy to clean, the walls are best made from a easy to clean, the walls are best made from a non-porous material such as fibro sheeting, non-porous material such as fibro sheeting, marine ply or metal. Avoid metal sheeting as it marine ply or metal. Avoid metal sheeting as it does not provide protection from the heat. does not provide protection from the heat.

Chook CareChook Care

HousingHousingEnsure that the door is big enough to allow Ensure that the door is big enough to allow

easy cleaning of the pen. Deep litter system is easy cleaning of the pen. Deep litter system is preferred. The floor should slope towards the preferred. The floor should slope towards the door to allow drainage and to make the door to allow drainage and to make the cleaning of the coop easy. The coop also cleaning of the coop easy. The coop also needs to be predator proof (see DPI booklet)needs to be predator proof (see DPI booklet)

Chook CareChook Care

HousingHousingAllow at least 200mm of perch length per Allow at least 200mm of perch length per

chicken. Make the perches from timber chicken. Make the perches from timber roughly 75mm x 50mm in dimensions and roughly 75mm x 50mm in dimensions and place them about 500mm from the floor. place them about 500mm from the floor.

Provide nesting boxes. Mounted on the Provide nesting boxes. Mounted on the southernside of the enclosure about 600mm southernside of the enclosure about 600mm from the ground. Provide one nesting box per from the ground. Provide one nesting box per four to five hens. Nesting boxes should be four to five hens. Nesting boxes should be about 300mm square. about 300mm square.

FinallyFinally

Blood collection & sample transport – see Blood collection & sample transport – see the demothe demo

The chooks remain the property of the The chooks remain the property of the programme for the whole season and programme for the whole season and must be treated according to ethical must be treated according to ethical guidelines for the use of animals in guidelines for the use of animals in researchresearch

After the season the birds go to happy After the season the birds go to happy homeshomes

Contacting UsContacting Us

You can contact the Arbovirus Lab by You can contact the Arbovirus Lab by phone on (02) 9845-7750 weekdaysphone on (02) 9845-7750 weekdays

You can contact me on the same number You can contact me on the same number during the week or by email:during the week or by email:

linda.hueston@.health.nsw.gov.au