Diseases / List of Parasitic Diseases / Disease description:

Acanthocephala Infection in Waterfowl and Cranes

INFORMATION AVAILABLE

GENERAL INFORMATION

CLINICAL CHARACTERISTICS & PATHOLOGY

INVESTIGATION & DIAGNOSIS

TREATMENT & CONTROL

SUSCEPTIBILITY & TRANSMISSION

ENVIRONMENT & GEOGRAPHY

 

Return to top of page

General and References

Disease Summary

WATERFOWL Infection with acanthocephalans (thorny-headed worms) which may result in enteritis and emaciation, sometimes peritonitis.

Return to top of page

Alternative Names (Synonyms)

  • Acanthocephaliasis
  • Thorny-headed worm infection

Return to top of page

Disease Type

 Parasitic - Thorny-headed Worms

Return to top of page

Infectious/Non-Infectious Agent associated with the Disease

Acanthocephalans (thorny-headed worms) including Filicollis anatis, Polymorphus altmani, Polymorphus obtusus, Polymorphus botulus, Polymorphus minutus. Worms attach to intestinal wall with retractile proboscis.

Infective "Taxa"

Non-infective agents

--

Physical agents

-- Indirect / Secondary

Return to top of page

References

Disease Author

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

Major References / Reviews

Code and Title List

B9.6.w1, B11.39.w7, B12.55.w1, B14, B15, B36.33.w33, B37.x.w1
J7.50.w1
J36.41.w1, J36.44.w1
V.w3, V.w11

Cranes:
B115.8.w4, P87.3.w5, P87.7.w8

Other References

Code and Title List

Waterfowl:
J1.11.w5, J1.13.w6, J1.13.w7, J1.16.w8, J1.17.w6, J1.22.w4
J14.11.w1

Cranes:
P87.1.w2

Return to top of page

Clinical Characteristics and Pathology

Detailed Clinical and Pathological Characteristics

General

   
WATERFOWL Non-specific signs of lethargy and emaciation associated with loss of nutrients to parasites and damage to intestinal wall.
CRANES May be incidental (subclinical) or result in clinical, even fatal disease.

Clinical Characteristics

   
WATERFOWL Non-specific signs: lethargy, rapid weight loss, anaemia and emaciation, stunting, death (J36.44.w1, B11.39.w7, B9.6.w1, B36.33.w33, B37.x.w1).
CRANES --

Incubation

   
WATERFOWL Generally considered to be a chronic disease (B15), but lethal infections have occurred in ducklings at just a few days old (V.w3, V.w11).
CRANES  

Mortality / Morbidity

   
WATERFOWL Sometimes epizootics; may cause high mortality (B15, B36.33.w33, B37.x.w1).
CRANES Clinical disease and mortality due to acanthocephalan infection in cranes has occurred only occasionally. (B115.8.w4)

Pathology

   
WATERFOWL Gastro-intestinal tract - Enteritis, sometimes haemorrhagic. White nodules visible on serosal surface of intestine, each containing proboscis of an acanthocephalan. Mucosal surface, intense inflammation around embedded proboscis of acanthocephalans (white-to-bright yellow/orange parasites, 0.5-1cm long), which are firmly attached to the intestinal wall. Severe granulomatous haemorrhagic enteritis with heavy infections. Parasites may penetrate gut wall and cause adhesions between loops of intestine and/or peritonitis (J7.50.w1, J36.44.w1, B11.39.w7, B12.55.w1, B14, B15, B36.33.w33, B37.x.w1).
CRANES

Return to top of page

Human Health Considerations

None (B37.x.w1).

Return to top of page

Susceptibility / Transmission

General information on Susceptibility / Transmission

 
WATERFOWL
  • Common eiders Somateria mollissima appear to be particularly susceptible, due to feeding habits (ingestion of intermediate hosts). Cygnets also appear susceptible, and sometimes domestic ducklings.
  • Eider ducklings often have concurrent renal coccidiosis (Renal Coccidiosis) and other endoparasite infections.
  • Transmission by ingestion in intermediate hosts (crustaceans), particularly fresh water shrimp Gammarus spp.

(B9.6.w1, B11.39.w7, B15, B36.33.w33, B37.x.w1)

CRANES Captive chicks have died due to peritonitis associated with intestinal perforation, but the significance of infection in older cranes, and in wild cranes, is unknown. (B115.8.w4, P87.1.w2)

Return to top of page

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

Waterfowl

Disease has been reported in:

  • Common eiders Somateria mollissima, cygnets, domestic ducklings (B15, B36.33.w33).
  • Mute swans Cygnus olor in Scotland (J7.50.w1, J36.41.w1, J36.44.w1).
  • Blue duck Hymenolaimus malacorhynchus ducklings in a collection in the UK - fatal infection at only a few days old (V.w3, V.w11).

Infection has also been reported in:

  • Wild Trumpeter swan Cygnus buccinator in Canada, with concurrent gizzard worm, intestinal fluke and cestode infection (J14.11.w1).
  • Wild Black-bellied whistling-ducks Dendrocygna autumnalis in southern Texas, USA (J1.11.w5).
  • Wild Cinnamon teal Anas cyanoptera in southwest Texas, USA (J1.13.w6).
  • Wild Northern shovelers Anas clypeata in southwest Texas (J1.13.w7).
  • Wild Mallard Anas platyrhynchos, American wigeon Anas americana, Green-winged teal Anas crecca and Blue-winged teal Anas discors in Oklahoma, USA (J1.16.w8).
  • Wild Green-winged teal Anas crecca in southwest Texas, USA (J1.17.w6).
  • Wild Mexican duck Anas platyrhynchos diazi (J1.22.w4).
  • A few acanthocephalans were noted at necropsy in some Grus americana - Whooping crane chicks. (P87.3.w5)
Cranes

Host Species List

Waterfowl

Cranes

Return to top of page

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

Disease has been reported in:

Infection has also been reported in:

  • Wild Trumpeter swan Cygnus buccinator in Canada, with concurrent gizzard worm, intestinal fluke and cestode infection (J14.11.w1).
  • Wild Black-bellied whistling-ducks Dendrocygna autumnalis in southern Texas, USA (J1.11.w5).
  • Wild Cinnamon teal Anas cyanoptera in southwest Texas, USA (J1.13.w6).
  • Wild Northern shovelers Anas clypeata in southwest Texas, USA (J1.13.w7).
  • Wild Mallard Anas platyrhynchos, American wigeon Anas americana, Green-winged teal Anas crecca and Blue-winged teal Anas discors in Oklahoma, USA (J1.16.w8).
  • Wild Green-winged teal Anas crecca in southwest Texas, USA (J1.17.w6).
  • Wild Mexican duck Anas platyrhynchos diazi (J1.22.w4).

Host Species List

Waterfowl

Cranes

Return to top of page

Environment/Geography

General Information on Environmental Factors/Events and Seasonality

Epizootics are usually associated with stresses such as food shortage, stress of migration or breeding (particularly female eiders while or just after brooding, versus in males and immatures in late winter/early spring). May be common in certain localized geographical areas (B14, B15, B36.33.w33).

Return to top of page

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

Worldwide (B36.33.w33).

Return to top of page

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

--

Return to top of page

General Investigation / Diagnosis

General Information on Investigation / Diagnosis

  • Detection of eggs in the faeces (live birds) and detection of worms found attached to the inside of the intestines at post mortem examination. (B591.15.w15)
    • Detection of eggs confirms infection; necropsy is required to confirm that the parasite was the cause of disease. (B36.33.w33 - full text included)
    • The eggs have characteristic multiple (outer, middle and inner) membranes enclosing a spined acanthor; characteristics of the eggs allow identification to genus level. (B591.15.w15)
    • At necropsy, needles or insect pins are used to remove the attaching proboscides of the acanthocephalans from the intestinal wall, with care not to puncture the parasite. Placing the parasites in tap water for 24 hours promotes full evagination of the proboscis, which is needed for identification (if it still does not evert, the worms can be placed in distilled water for a further 24 hours). The worms are then fixed in an ethanol:formalin:acetic acid mixture at a 85:10:5 ratio for 24 hours, after which they can be stored in 70% ethanol while awaiting identification. (B591.15.w15)
    • Formalin-fixed intestines do not allow identification of the parasites to species level, but identification to genus level is still possible, as well as assessment of the size of the worm burden and the response of the tissues to the parasites. (B36.33.w33 - full text included)
WATERFOWL Fecal examination can show presence of infection (spindle-shaped eggs, containing embryo with rostral circlet of hooks). Post mortem examination is necessary to show acanthocephalan infection (cylindrical, non-segmented, often bright yellow/orange) as the cause of death or a contributory factor, based on the number of parasites present (more than 100 P. botulus may be considered a heavy infection; numbers may reach 1-2000) and degree of intestinal damage associated (B11.39.w7, B12.55.w1, B14, B15, B36.33.w33 - full text included, B37.x.w1).

N.B. Inspection of Gammarus spp. (intermediate hosts) may reveal the presence of the larval parasites - e.g. orange Polymorphus minutus, which is visible within the gammarids to the naked eye (V.w3).

CRANES Detection of eggs or worms, as above.
Related Techniques
WaterfowlINDEXDisInvTrCntr.gif (2325 bytes)

Return to top of page

Similar Diseases (Differential Diagnosis)

[Other parasitic infections.]
WATERFOWL Gizzard worm infection (Gizzard Worm Infection), echinuariasis (Echinuriasis (Acuariasis)) (B37.x.w1).
  • Differentiate worms found at post mortem examination (cylindrical, non-segmented, often bright yellow/orange) from cestodes (B12.55.w1).
CRANES [Other parasitic infections.]

Return to top of page

Treatment and Control

Specific Medical Treatment

  • "No satisfactory treatment for acanthocephalan infection is known." (B591.15.w15)
  • Ivermectin and fenbendazole have been used in treating mammals with acanthocephalan infections. Thiabendazole has been used in birds, however "treatment is acknowledged to be difficult and success low."  (B36.33.w33 - full text included)
WATERFOWL Treatment is impractical in wild birds. In captive birds, use of anthelmintics: ivermectin (single dose 200 g/kg body weight oral or subcutaneous), benzimidazoles such as fenbendazole (single oral dose 20 mg/kg), or levamisole (25-50 mg/kg oral or subcutaneous single dose) may be useful (B11.39.w7, B15, B36.33.w33, B37.x.w1).
CRANES No known treatment. (B115.8.w4)
Related Techniques
WaterfowlINDEXDisInvTrCntr.gif (2325 bytes)

Return to top of page

General Nursing and Surgical Techniques

--
Related Techniques

--

WaterfowlINDEXDisInvTrCntr.gif (2325 bytes)

Return to top of page

Preventative Measures

Vaccination --
Prophylactic Treatment For information on routine parasite control see Preventative Medicine for Birds - Parasite screening and Routine Control Measures
Related Techniques
WaterfowlINDEXDisInvTrCntr.gif (2325 bytes)

Return to top of page

Environmental and Population Control Measures

General Environment Changes, Cleaning and Disinfection

Keeping birds away from environments containing the intermediate hosts is the best way to prevent infection, although this is not practical for free-living birds. (B591.15.w15)

WATERFOWL Impractical for wild birds. Manage waterfowl to avoid waterfowl using water areas with large numbers of the crustaceans which act as intermediate hosts for acanthocephalans, particularly freshwater shrimp Gammarus spp, or drain infected waters (B11.39.w7, B15, B36.33.w33, B37.x.w1).
CRANES Reduce exposure of cranes to earthworms, which may act as an intermediate host for acathocephalans, e.g. by raising chicks indoors. (B115.8.w4)
Population Control Measures --
WATERFOWL
  • Keeping wild waterfowl away from areas used for breeding waterfowl is advisable, as the wild birds may introduce the parasite. (B24)
  • Keep young birds on water areas not used by other birds and therefore less likely to have large numbers of infected intermediate hosts (B15, B36.33.w33).
CRANES  
Isolation, Quarantine and Screening --
WATERFOWL --
CRANES --
Related Techniques
WaterfowlINDEXDisInvTrCntr.gif (2325 bytes)

Return to top of page