Oxalate nephrosis and its management in a captive environment Dr. Mel Burford-Pettigrew | Senior Koala Keeper

Cleland Wildlife Park

Photo Credit: Michelle Birkett

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Koalas in South

Australia

John Oxley Library Brisbane

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Koalas in South Australia

1923: Professor Wood Jones releasing the first Koala introduced onto Kangaroo island.

Photo: State Library of South Australia, B49818

Threats to Koalas in South Australia

• Low genetic diversity

• Habitat Loss/over population

• Kidney Disease

• Sarcoptic Mange

• Urbansiation Source: Byron Manning

Source:

http://hancockwatch.nfshost.com/docs/koala2005a.ht

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Oxalate Nephrosis

• Not a common cause of mortality

in koalas in the eastern states

• The Mount Lofty Ranges koala

population in SA has a high

occurrence of renal dysfunction

and oxalate nephrosis continues

to be one of the predominant

issues facing the population Source:

https://www.vettails.com/vettails/2015/9/30

/calcium-oxalate-nephrosis-what-does-that-

mean

Source: Byron Manning

What Causes Oxalate Nephrosis?

Possible Theories

- Genetics

- Diet

- Liver function

More Research Required!

How to determine a healthy koala

from a renal compromised koala?

• Demeanour

• Position sitting in or

sleeping

• Hydration

• Body Condition

• Faeces

• Gut Fill

• Coat, skin, nails

• Urine (USG, Oxalates)

• Drinking

• Eyes

• Gum/Nasal Colour

• Body Temperature

• Breathing

• Feeding

• Pain (Kidney Pain)

• Movement

Urine Analysis

Dip stick

- pH

- Protein

- Blood

- Leukocytes

Refractometer

-Healthy =

>1.050

Microscope

- Oxalate crystals

Drinking

Body Condition/Weight Loss

Source: Amelia Hill

Feeding Behaviour

Categories of Renal Compromised Koalas

LOW DEPENDENCY

CARE Mild dehydration

+1 protein

No sediment

USG 1.040

Attitude is becoming altered. Still

bright, alert and responsive

Ears and head are up – in a normal

sitting and sleeping position

Normal capillary refill

Reduced eating and decreased

faecal output (<100 pellets per day)

Low gut fill

Minimal treatment

supplementary feeding,

ongoing drug and short

term fluid therapy

HIGH DEPENDENCY

CARE Moderately dehydrated

+2 protein

≥+1 sediment

SG 1.030

Depressed but responsive to noise

and movement

Tires quickly and appears lethargic

Ears starting to droop but sitting

and sleeping in a normal position

Normal capillary refill or may

becoming pale

Minimal eating

Poor gut fill

Minimal faecal output, possible

dry

Long term treatment

Drug and fluid therapy for

life of the koala, without

which the disease will

advance

END STAGE RENAL

FAILURE Severely dehydrated

+4 protein

≥+4 sediment

USG 1.020

Non responsive to touch, noise. May

be in a semi-coma

Curled in ball; minimal response to

handling

Blueish grey or red gums

Not eating

No gut fill – high probability of

torsion if tube feed

Almost no faecal output; Gut has

likely gone into ileus

May be grinding teeth

Emaciated

Euthanasia

Due to advanced

stages of disease no

drug or fluid therapy

will alter reverse the

damage

Cleland Koalas and Oxalate Nephrosis

Ongoing Assessment

Gut fill

Demeanour

Behavioural assessment

Faecal output

Sedimentation in enclosure

Feeding behaviour and amount

Mouth, gum and chin colour

Weight

Urine analysis (when required)

Mrs B

• Showed no signs of kidney

dysfunction until she was 8

years old

• She had a 6 month old joey

when she showed her first

symptoms:

• Drinking

• USG 1.030

• Oxalate crystals in urine

Issac

• Orphan from a severe weather

event and was handraised

from 385gms

• His first symptoms appeared

when he was 800gms:

• Flat in attitude

• Reduce faecal output

• Thirsty

• USG 1.020 (was also

receiving a bottle)

• Oxalate crystals in urine.

Management of Renal

Compromised Koalas

• Administered upon

diagnosis of kidney

dysfunction

• Patient remains on

this treatment for

their lifetime to

assist with

management

Management of Acute Renal Episodes

Mrs B High Dependency

Patient

- Now 10 years old

- Maintained on B6 and

Vivitonin

- Fluid therapy when required

- Isolated if lost more than

1kg

- Gum consumption and

faecal output monitored

- Anabolic steroid used to

stimulate appetite

- Gum Smoothie when

weight has dropped and

faecal output low.

“Gum Smoothie” Recipe

- Critical Care

- Divetelact

- Soaked MATURE leaves

- Blended to a ‘chunky sand’

texture

Issac Low Dependency

Patient

• Now 7 years old

• Stable on B6 and

Vivitonin

Koalas and Stress

Triggers that can lead to

Stress in Koalas Wild koalas coming into captivity

Illness

Capture and Restraint

Release back to the wild

Competition for habitat

Separation anxiety from carer

Over handling

Intense treatment

Unfamiliar noise

Changes in feeding routine

Breeding

Incorrect housing

Travel

Abnormal gut activity

Medical Procedures

Exposure to unfamiliar animals

Change in living conditions

Seasonal preferences

Amount and quality of feed

Supplementary feeding

Housing with multiple koalas

Human contact time with the koala

Temperature change

Drought

Cleland's Collection

• 60% of the population have been diagnosed with oxalate nephrosis

• Most are in the low-dependency category and are maintained on B6 and Vivitonin as part of their treatment plan

• 5% are in the high-dependency category and are considered to be chronic kidney candidates which will involve high-dependency treatment throughout periods of their life.

Captive vs Wild

Treatment

• Once diagnosed with Oxalate

Nephrosis the individual will

require long-term, ongoing

treatment to help maintain their

kidney function.

• This is NOT a viable option for a

wild koala and unfortunately

once diagnosed the disease will

inevitably progress.

Further

research and

options for

clinical testing

are underway!

Thank You

Any

Questions?