Echinuriasis (Acuariasis) in Waterfowl (Parasitic Disease)

General information on Susceptibility / Transmission

WATERFOWL

Susceptibility: Seen in ducks and swans, more rarely in geese. Mainly a clinical disease of juveniles, especially cygnets. Late-hatched birds are particularly susceptible.

Stress (e.g. from high stocking densities, severe winter weather, reduced food availability) may be an important factor in the development of clinical disease.

Transmission: through ingestion of intermediate host, particularly Daphnia (water flea). Species which dabble at or near the water surface are most likely to ingest Daphnia.

Transmission is greatest when there is a combination of shallow water, numerous zooplankton (particularly Daphnia) and high waterfowl population densities (passing eggs to be ingested by the intermediate host).

Eggs do not overwinter in the environment; adults are the source of infection each year.

(J7.30.w2, J7.43.w1, J8.17.w1, P5.29.w3, B11.39.w7, B12.55.w1, B15, B18, B36.35.w35, B37.x.w1, B48.20.w20).

Infectious/Non-Infectious Agent associated with the Disease
Nematode worms Echinuria (Acuaria) uncinata, Echinuria (Acuaria) spp.
Infective "Taxa"	Echinuria uncinata Echinuria spp.
Non-infective agents	--
Physical agents	-- Indirect / Secondary

References
Disease Author	Debra Bourne

Major References / Reviews
Code and Title List	B9.6.w1, B10.26.w11, B12.55.w1, B13.46.w1, B14, B15, B16.19.w1, B18, B24, B36.35.w35, B37.x.w1, B48.20.w20 J7.30.w2, J7.43.w1, J8.17.w1 P5.29.w3 N1.80.w1
Other References
Code and Title List	B91 J1.11.w5, J1.16.w8, J1.17.w6, J1.22.w4 J4.99.w1 J7.5.w1, J7.6.w1, J7.7.w1, J7.30.w2, J7.33.w2, J7.33.w3, J7.43.w1, J7.43.w2

Detailed Clinical and Pathological Characteristics
General	WATERFOWL	Inappetance, listlessness, stunting and deaths, due to lesions of the proventriculus.
Clinical Characteristics	WATERFOWLb	Listlessness, partial and later total anorexia, anaemia, diarrhoea, weight loss, stunting, emaciation, ruffled feathers, death from starvation and anaemia. Sudden death also reported. Emaciation and weakness may precede anorexia. (J7.43.w1, J8.17.w1, P5.29.w3, B9.6.w1, B10.26.w11, B11.39.w7, B13.46.w1, B14, B15, B16.19.w1, B18, B24, B36.35.w35, B37.x.w1, B48.20.w20).
Incubation	WATERFOWL	Granuloma formation may require fifty days (P5.29.w3); death recorded in ducklings as young as 12-14 days old.
Mortality / Morbidity	WATERFOWL	Variable morbidity; infection may be common in waterfowl on shallow, slow-moving waters. Mortality can be high, particularly in juveniles (B14, B15, B18, B37.x.w1).
Pathology	WATERFOWL	Proventriculus - Ulceration of glandular tissue of the proventriculus at the junction with the gizzard; damage may be severe. Fibrous nodules are formed in the proventriculus and at the proventriculus-gizzard junction, containing worms; masses may become sufficiently large to block the lumen. Cellular infiltration. . Hypertrophy of mucosal glands and excess mucus production; severe distortion of glands and atrophy of glandular epithelium has also been reported. Numbers of parasites may reach 200, but 30-40 is more usual. Ulceration of proventriculus with Echinuria parva (B15) Clinical pathology: High fibrinogen, increased white blood cell count and normochromic microcytic anaemia may be noted. (J7.30.w2, B11.39.w7, B12.55.w1, B13.46.w1, B14, B16.19.w1, B18, B24, B37.x.w1, B36.35.w35, B48.20.w20, J7.43.w1, P5.29.w3).

General Information on Investigation / Diagnosis
WATERFOWL	Infection shown by examination of faeces for eggs: small, (46 x 25 µm), ellipsoidal, thick shelled, embryonated with single larva. Detection and identification of nematodes within proventricular lesions (P5.29.w3, B11.39.w7, B14, B15, B16.19.w1, B37.x.w1).
Related Techniques	Physical Examination - General Necropsy - General Chapter 2 - B36 Field Manual of Wildlife Diseases - Specimen Collection and Preservation Chapter 3 - B36 Field Manual of Wildlife Diseases - Specimen shipment Appendix A - B36 Field Manual of Wildlife Diseases - Sample specimen history form

Specific Medical Treatment
WATERFOWL	Anthelmintics. Ivermectin 200µg/kg, oral or subcutaneous, fenbendazole 20mg/kg, oral; mebendazole 5-15mg/kg for two days, tetramisole 25-50mg/kg oral thiabendazole 200-500mg/kg. N.B. these may kill the parasites, but will not reverse the damage already done to the proventriculus (J7.30.w2, J7.43.w1, J8.17.w1, B11.39.w7, B13.16.w1, B16.19.w1, B37.x.w1). Ivermectin was described as effective (P5.29.w3). Piperazine compouns 45-200mg/kg body weight single dose (B10.26.w3).
Related Techniques	Treatment and Care - General

Disease Summary
WATERFOWL	Nematode worm infection causing dysfunction of the proventriculus; carried by the water-flea Daphnia.

Similar Diseases (Differential Diagnosis)
WATERFOWL	Gizzard worm infection (Gizzard Worm Infection), acanthocephaliasis (thorny-headed worm) (Acanthocephala Infection) (B14, B37.x.w1).

General Nursing and Surgical Techniques
WATERFOWL	--
Related Techniques	--

Preventative Measures
Vaccination	WATERFOWL	--
Prophylactic Treatment	WATERFOWL	Regular dosing with anthelmintics: ivermectin (subcutaneous injection), fenbendazole (oral drench), piperazine, or mebendazole (in feed) may all be used (J7.43.w1, B10.26.w11, B15, B37.x.w1). For information on routine parasite control see Preventative Medicine for Birds - Parasite screening and Routine Control Measures.
Related Techniques	Treatment and Care - General Preventative Medicine for Birds - General

Environmental and Population Control Measures
General Environment Changes, Cleaning and Disinfection	WATERFOWL	Reduce Daphnia levels by draining stagnant ponds, ensuring water has a good flow-through rate, by the use of pumps if necessary, and if feasible using well-water rather than surface water; avoid bringing in duckweed (Lemna) from stagnant ponds, as this may introduce infected Daphnia (J7.7.w1, J7.43.w1, J8.17.w1, N1.80.w1, B9.6.w1, B10.26.w11, B11.39.w7, B13.46.w1, B15, B18, B24, B36.35.w35, B37.x.w1). Water from a well rather than a surface stream may be preferable, particularly for juveniles (J7.7.w1).
Population Control Measures	WATERFOWL	Exclude wild waterfowl from breeding areas if possible (B24). Raise juveniles separate from adults (B12.55.w1).
Isolation, Quarantine and Screening	WATERFOWL	--
Related Techniques	Preventative Medicine for Birds - General Environmental and Population Management - General