Diseases / List of Toxic Diseases / Disease description:

Aflatoxicosis (Mycotoxicosis) in Waterfowl, Cranes and Lagomorphs

INFORMATION AVAILABLE

GENERAL INFORMATION

CLINICAL CHARACTERISTICS & PATHOLOGY

INVESTIGATION & DIAGNOSIS

TREATMENT & CONTROL

SUSCEPTIBILITY & TRANSMISSION

ENVIRONMENT & GEOGRAPHY

 

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General and References

Disease Summary

WATERFOWL Aflatoxins in feed may result in sudden death, general signs, reduced growth and immunosuppression, depending on dose.

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Alternative Names (Synonyms)

  • Turkey X Disease
  • Groundnut Poisoning

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Disease Type

 Toxic

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Infectious/Non-Infectious Agent associated with the Disease

Aflatoxins: mycotoxins (toxic metabolite of fungi), produced by Aspergillus flavus, Aspergillus parasiticus and Penicillium puberulum. These fungi may grow in peanuts (groundnuts), corn and sometimes other nuts and grains, when the temperature is greater than 70F, relative humidity greater than 70% and grain moisture content greater than 14%. Aflatoxin production requires a temperature of 24-35C and relative humidity of 80-85%. Fungal growth and toxin production is most likely to occur in improperly stored feed but also occurs on crops in fields, particularly following drought stress, insect damage or mechanical injury. Aflatoxin B1 is the toxin type most commonly found and is the most toxic; it is strongly hepatotoxic (affects the liver) and is also carcinogenic.

(B20.3.w1, B32.36.w29, B36.37.w37, J29.9.w1)

Infective "Taxa"

Non-infective agents

Physical agents

-- Indirect / Secondary

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References

Disease Author

Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Click image for main Reference Section

Referees

Sharon Redrobe BSc(Hons) BVetMed CertLAS DZooMed MRCVS, RCVS Specialist in Zoo & Wildlife Medicine (V.w92); Richard Saunders BVSc BSc CertZooMed MRCVS (V.w121)

Major References / Reviews

Code and Title List

B15, B16.19.w1, B18, B20.3.w1, B32.36.w29, B36.37.w37
J1.18.w3
J3.110.w1
J5.38.w4
J9.208.w1

Cranes:
J1
.27.w10, J40.52.w2
P62.12.w1, P87.4.w3, P87.8.w9

Lagomorphs
B602.16.w16
J13.41.w2, J29.9.w1, J213.11.w1, J500.33.w1

Other References

Code and Title List

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Clinical Characteristics and Pathology

Detailed Clinical and Pathological Characteristics

General

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WATERFOWL Sudden death, depression , liver lesions.
CRANES Chronic or fatal.
LAGOMORPHS --

Clinical Characteristics

WATERFOWL
  • Variable. May be found dead.
  • General depression and lethargy, may be found sitting, may show apparent blindness and lack of response to the external environment including to food and water, weakness, inability to fly.
  • Ataxia, convulsions and opisthotonus or wing-flapping may precede death.
  • Ducklings and goslings may show cyanosis (bill, legs and feet purple), inappetance, reduced growth, abnormal vocalization, feather-picking and lameness.
  • Chronic exposure may result in general ill health, decreased appetite and weight loss.
  • Low level chronic exposure may be immunosuppressive. Abnormal circulating lymphocytes may be found.

(J1.18.w3, J3.110.w1, B16.19.w1, B20.3.w1, B32.36.w29, B36.37.w37)

CRANES
LAGOMORPHS Reduced appetite, lethargy, decreased water intake, dull mental state, reduced weight gain. (J213.11.w1)

In angora rabbits in a number of rabbitries:

  • Anorexia, dullness and weight loss.
  • Developing jaundice.
  • Death after three to four days.

(J500.33.w1)

In New Zealand white rabbits experimentally exposed:

  • Anorexia, reduced weight gain and emaciation, lethargy, dehydration, jaundice and death. (J13.41.w2)
  • Clinical pathology: decreased total protein, while serum bilirubin concentration, blood clotting time, ALT and AST increased. (J13.41.w2)

Incubation

WATERFOWL Variable, acute to chronic (B32.36.w29).
CRANES --
LAGOMORPHS Signs of toxicosis after 14 days in rabbits given 0.05 or 0.0625 mg/kg aflatoxin B1 in feed, and severe signs and deaths after 24 days. (J13.41.w2)

Mortality / Morbidity

WATERFOWL Uncommon, sporadic. Few reports in wild waterfowl. Not all birds in a flock may be affected (J3.110.w1, B36 37.w37).
CRANES  
LAGOMORPHS
  • Higher mortality in weaners than in adults. (J500.33.w1)
  • Mortality depends on dose: with exposure to low doses of aflatoxin, no mortality may be seen, but with increased mortality with higher doses. (J13.41.w2)

Pathology

WATERFOWL ACUTE TOXICITY

Gross Pathology: (There may be minimal gross pathological findings.)

  • Liver - enlarged, swollen, pale. May be multiple focal haemorrhages or diffuse haemorrhage of much of the liver.
  • Gastro-intestinal tract - Mucosal inflammation and haemorrhage - intestines may appear red-black along much of their length. May be food such as corn or peanuts in the oesophagus, proventriculus and/or gizzard.
  • General - haemorrhages and excess fluid in many organs, e.g. pericardial.
  • Kidneys - variable discolouration from dark brown to tan or pale; sometimes enlarged.

Histopathology:

  • Liver - acute hepatocellular degeneration or necrosis, biliary proliferation. N.B. proliferation of bile ducts may be seen from as soon as two days after exposure to aflatoxin.

CHRONIC TOXICITY:

Gross Pathology:

  • Liver - atrophied, firm, pale yellow-brown. Gall bladder may be swollen and contain inspissated bile or have ruptured with bile salts found over the liver.
  • Heart - may be flabby with dilated ventricles. May be hydropericardium.
    May be ascites.

Histopathology:

  • Liver - fatty degeneration of hepatocytes, infiltration of connective tissue around groups of cells, sometimes as a solid mass with mononuclear cells and proliferating bile ducts.
  • Kidney, pancreas - may be vascular lesions and degenerative lesions.

NEOPLASTIC SYNDROME:

  • Liver - hepatic carcinomas may be found following long term low-level ingestion of aflatoxin.

(J1.18.w3, J3.110.w1, J9.208.w1, B15, B16.19.w1, B32.36.w29, B36.37.w37).

CRANES --
LAGOMORPHS Gross:

In an outbreak in angora rabbits: 

  • Hepatic: 
    • Moderate to severe liver congestion, with icterus. Difficult to cut. 
    • Distended gall bladder, filled with inspissated bile. (J500.33.w1)

In experimentally exposed New Zealand White rabbits:

  • General: jaundice. (J13.41.w2)
  • Hepatic: liver yellow to orange. (J13.41.w2)
  • GIT: in the jejunum, traces of fresh blood in one individual. (J13.41.w2)

Histopathology:

  • Hepatic: focal necrosis, sinusoids dilated and engorged, biliary hyperplasia, periportal fibrosis and mononuclear cell inflammatory infiltration. (J213.11.w1)
  • Cardiac: myocardial degeneration. (J213.11.w1)
  • Renal: tubular degeneration, mononuclear cell inflammatory infiltrate. (J213.11.w1)

In an outbreak in angora rabbits: (J500.33.w1)

  • Hepatic:
    • Hepatocellular degeneration, sinusoids dilated and engorged. Mild to severe periportal fibrosis of bile ducts. Also focal areas of pseudolobulation and foci of regeneration. (J500.33.w1)

In experimentally exposed New Zealand White rabbits:

  • Hepatic:
    • Hepatocytes showed increased eosinophilia of cytoplasm, and reduced cytoplasmic granularity. (J13.41.w2)
    • In some rabbits, mild karyomegaly and increase in binucleate hepatocytes. (J13.41.w2)
    • In biliary canaliculi, bile stasis. (J13.41.w2)
    • In portal triads, increased cells with very little cytoplasm and fusiform nuclei. (J13.41.w2)

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Human Health Considerations

No known health risk from handling sick or dead birds, but waterfowl dying from acute aflatoxicosis should not be eaten (B36.37.w37).

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Susceptibility / Transmission

General information on Susceptibility / Transmission

WATERFOWL Transmission:
  • Ingestion of foods which have been contaminated with fungi and in which toxins have been produced.

Susceptibility:

  • Susceptibility is affected by species, breed or strain and age of birds affected, as well as toxin type, dose and whether exposure is acute or chronic. Ducklings are considered highly susceptible.
  • The LD50 for day-old domestic ducklings (Anas platyrhynchos domesticus) was 360 parts per billion in one study. A nine-day feeding trial with up to 33 parts per billion (ppb) aflatoxin in feed given to six-week-old mallard ducklings Anas platyrhynchos had no apparent effect, while 14-16 months of 30 ppb in the diet fed to ducks resulted in liver neoplasia.

(J3.75.w2, J5.38.w4, B18, B36.37.w37).

CRANES Transmission
  • In thirty Grus canadensis - Sandhill cranes in the Aransas National Wildlife Refuge area, southeast Texas, USA, 1979, toxins were presumed to be from mouldy corn (maize). (J40.52.w2)

Susceptibility

  • Cranes are susceptible. (J40.52.w2)
  • The risk of aflatoxicosis in cranes is affected by the availability of corn (maize), how important this is in the diet, and the concentration of aflatoxin B1 in the corn. (J1.27.w10)
  • There is a risk of long-term low-level exposure causing subacute effects such as reduced growth rate and immunosuppression (leading to increased susceptibility to disease and predation) or chronic exposure leading to tumour developments. (J1.27.w10)
LAGOMORPHS
  • Rabbits are very susceptible to aflatoxicosis, with a very low LD50. (B602.16.w16, J13.41.w2)
    • Clinical signs may be seen with exposure at as low as 2 ppm in feed. (J213.11.w1)
    • Clinical signs and mortality may be seen with levels of aflatoxin B1as low as 100 ppm in feed. (B602.16.w16)
  • Individual variability is seen in susceptibility. (J13.41.w2)
  • Juveniles are more susceptible than adults. (J213.11.w1)

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Disease has been reported in either the wild or in captivity in:

Waterfowl
  • Snow geese Anser caerulescens, mallard Anas platyrhynchos and other waterfowl (J1.18.w3).
  • Domestic geese (J3.110.w1).
  • Khaki Campbell ducklings Anas platyrhynchos domesticus with hepatic tumours following long-term (14 months) feeding of low-level groundnut meal containing aflatoxin (J9.208.w1).
  • Canada goose Branta canadensis, snow goose Anser caerulescens, mallard Anas platyrhynchos, American black duck Anas rubripes, lesser scaup Aythya affinis, gadwall Anas strepera, green-winged (common) teal Anas crecca (also Sandhill cranes Grus canadensis) (B36.37.w37).
  • Domestic ducks Anas platyrhynchos domesticus (B32.36.w29).
Cranes
Lagomorphs
  • Experimental in domestic rabbits. (J13.41.w2)
  • An outbreak was reported in Angora rabbits in India. (J500.33.w1)

Host Species List

WATERFOWL 

CRANES

 

LAGOMORPHS

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Disease has been specifically reported in Free-ranging populations of:

  • Snow geese Anser caerulescens, mallard Anas platyrhynchos and other waterfowl (J1.18.w3).
  • Canada goose Branta canadensis, snow goose Anser caerulescens, mallard Anas platyrhynchos, American black duck Anas rubripes, lesser scaup Aythya affinis, gadwall Anas strepera, green-winged (common) teal Anas crecca (also Sandhill cranes Grus canadensis) (B36.37.w37).
Cranes

Host Species List

WATERFOWL 

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Environment/Geography

General Information on Environmental Factors/Events and Seasonality

In wild waterfowl, aflatoxicosis is most likely to occur in autumn (fall) and winter, when birds are feeding on waste nuts and grain in fields (B15, B36.37.w37).
  • Occurrence at any time of the year may be seen in birds feeding at bird feeding stations. (B36.37.w37)

 

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Regions / Countries where the Infectious Agent or Disease has been recorded

  • The fungi which produce aflatoxins are widespread across temperate and tropical areas (B36.37.w37).
  • In rabbits: India. (J500.33.w1)

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Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

USA (J1.18.w3, B36.37.w37).

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General Investigation / Diagnosis

General Information on Investigation / Diagnosis

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WATERFOWL
  • Post mortem findings with mainly liver pathology is suggestive, particularly liver necrosis (acute) and bile duct proliferation.
  • Confirmation requires measurement of aflatoxin in food either found in the oesophagus/proventriculus/gizzard of affected birds or in food to which they had access.
  • Confirmation may be particularly difficult with chronic toxicity as the relevant contaminated feed may no longer be available.
  • Feed to be tested for aflatoxin should be frozen for transport and storage to avoid the possibility of fungal growth and toxin production during this time.

(J3.110.w1, B36.37.w37).

CRANES
LAGOMORPHS
  • Histopathological findings. (J213.11.w1)
  • Examination of feed for aflatoxin. (B602.16.w16, J213.11.w1)
    • In an outbreak in Angora rabbits, feed samples contained aflatoxin B1 at 90 - 540 g/kg feed. (J500.33.w1)
Related Techniques
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Similar Diseases (Differential Diagnosis)

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WATERFOWL --
LAGOMORPHS --

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Treatment and Control

Specific Medical Treatment

--
WATERFOWL --
CRANES --
LAGOMORPHS --
Related Techniques

 

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General Nursing and Surgical Techniques

WATERFOWL --
CRANES
  • Flush the gastro-intestinal tract with saline. (P62.12.w1)
  • General supportive care. (P62.12.w1)
LAGOMORPHS
  • Remove contaminated feed. (B602.16.w16, J500.33.w1)
  • Supportive care. (B602.16.w16, J500.33.w1)
Related Techniques

 

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Preventative Measures

Vaccination WATERFOWL --
LAGOMORPHS --
Prophylactic Treatment

WATERFOWL

--
LAGOMORPHS --
Related Techniques

 

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Environmental and Population Control Measures

General Environment Changes, Cleaning and Disinfection

WATERFOWL

  • Use high-quality feed, properly stored; avoid feeding mouldy grain, nuts or prepared feed.
  • Do not use feed with levels of aflatoxin greater than those allowable for use in human or animal feeds. (Limit of 20 part per billion for humans, young animals and dairy cattle, 100 parts per billion for mature poultry, USA).
  • Fungal growth in feed may be detected by the presence of bright greenish-yellow fluorescence under ultraviolet light (365nm).

(B18, B20.3.w1, B36.37.w37).

CRANES
  • Remove possible sources of toxin. (P62.12.w1)
  • Where fields are deliberately planted with crops to provide food for cranes, seed crops which are less likely to grow toxin-producing moulds, or root crops such as chufa, may be grown rather than maize. (J1.27.w10)
  • Ensure feed for captive birds is properly stored; use appropriate quality control and feed-testing. (P62.12.w1)
 
Population Control Measures WATERFOWL Waterfowl may be discouraged (by hazing) from using an area where contaminated feed is known to be present (B36.37.w37).
CRANES --
Isolation, Quarantine and Screening WATERFOWL --
CRANES --
Related Techniques
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