Ascaridia // is the name of a genus of parasitic nematodes. Members of the genus are primarily intestinal parasites of birds. There are three well known species, namely, A. galli found mostly in chicken, A. dissimilis in turkeys, and A. columbae in pigeons. Lesser known species such as A. hermaphrodita, A. sergiomeirai, A. ornata, A. nicobarensis and A. platyceri are found in parrots.
Among these A. galli is the most important and most pathogenic species, responsible for 'ascaridiasis' of poultry. The eggs of these nematodes are characterized by a thick shell, smooth and ellipsoidal, and composed of three distinct layers.
The eggs of A. dissimilis is marginally bigger than A. galli and A. columbae in marginally smaller. All these ascarid eggs are very similar in appearance to Heterakis gallinarum.
Clinical signs & diagnosis
Symptoms of heavy infection include anorexia, diarrhea, stunted growth, listlessness, a change in behavior and enteritis. Heavy infections can cause a partial or total obstruction of the gastrointestinal tract. Laying hens may produce soft eggs with thin and misshapened shells.
Clinical signs are more common in young chickens less than three months old as older chicken develop some resistance to infection.
Infection may be diagnosed on clinical signs and fecal examination. Alternatively, postmortem examination should demonstrate enteritis - caused by the emergence of larvae from the mucosa. The gastrointestinal tract may also be distended in chronic cases.
Treatment & control
Ascarid eggs are resistant to desiccation, persist for a long time in the environment, and remain directly infective. Therefore, control of infection involves the prevention of contamination of feeders and drinkers with faeces (by raising them off the ground); pasture rotation and regular dosing with the above-mentioned treatments, especially in young birds.
- Yamaguti, S. (1961). Systema Helminthum. 3. The nematodes of vertebrates. Interscience Publishers, New York and London, pp. 1261
- Kajerova V, Barus V, Literak I (2004). Nematodes from the genus Ascaridia parasitizing psittaciform birds: a review and determination key Archived February 6, 2015, at the Wayback Machine.. Vet. Med. – Czech, 49 (6): 217–223.
- Griffiths HJ (1978). A Handbook of Veterinary Parasitology: Domestic Animals of North America. University of Minnesota Press, Minneapolis, Minnesota, USA, pp. 46-47.
- McMullin P (2004). A Pocket Guide to: Poultry Health and Disease. 5M Enterprises Ltd., Sheffield, UK. ISBN 0-9530150-5-X.