Parasitic Worm Control in Poultry

Information and Treatment


Roundworms and Gapeworms

The two main types of poultry worms are Roundworms and Gapeworms. Roundworms are round & smooth and  the tapeworm segmented.
Birds suffering from a heavy infestation of roundworms, when treated, will excrete bundles of dead worms not unlike 'shredded wheat'.
These two types also differ from one another in the spread from bird to bird.




Roundworms produce eggs which are laid in the bird's intestines and pass out through the faeces.
They then undergo a maturation process lasting a week or more, after which they may be picked up
by another bird, hatch in the intestine and here develop to a mature worm up  to 12cm in length.

The Signs of Roundworm Infestation in Poultry

 Loss of condition     Poor growth    •  Listlessness    Diarrhoea     Wasting, (mainly in young birds)

Roundworms in intestine



Gapes is a condition caused by the pathogenic nematode roundworm Syngamus trachea and is most likely to be seen in free-range systems where chickens may
be kept together with infected pheasants, or on infected pasture. The condition, which is common in both wild and domestic birds, results in paralysis and physical
blockage of the respiratory tract, leading to difficulty in breathing. Infected birds respond with outstretched necks and open mouths. The disease is called 'gapes'
from the characteristic gaping mouth of an afflicted bird. The disease can occur sporadically and can result in severe loss of condition and high rates of mortality.

The life cycle of the nematode most frequently involves the earthworm, although it can be more direct. In the earthworm, infections can persist for long periods
and soils can become heavily infected for many years. Infective larvae may live as long as several years in infected intermediate hosts. There is evidence
that the passage of the larvae through earthworms renders them more highly infective to chickens. Game and wild birds provide a reservoir for the parasite.

The worms are bright red, with the male measuring 2 to 6mm and the female 5 to 20mm. The male becomes firmly attached to the tracheal wall and is in
almost permanent copulation with the females, forming an easily distinguishable Y-shape. Eggs produced by the female worm are carried by the mucus of
the trachea to the pharynx where they are swallowed and eventually passed out of the bird in faeces. Under optimal temperature and humidity levels, the egg
undergoes a third stage, moulting to produce an infective larva. Eggs containing larvae have been reported to survive on pasture and up to 9 months in soil.

Syngamus trachea (gapeworm)
male and female in permanent copulation.

Syngamus trachea (gapeworm)
in the trachea of a pheasant

Syngamus trachea (gapeworm)
Adult worms in the trachea of a turkey.

Eggs on pasture may undergo three different courses of development. The infective larvae may remain in the eggs and become ingested by birds in this form. Alternatively, the larvae may hatch from the eggs on about the ninth day of incubation. In this form the larvae are easily killed by desiccation from sunlight, or they may survive for many weeks in shaded areas. A third course of development may be ingestion by a facultative intermediate hosts, such as earthworms, slugs, snails or house flies. The larvae can penetrate the intestinal walls of the invertebrate hosts and remain there for long periods. The larvae may remain viable in slugs and snails for more than a year, and up to 4 years in earthworms. Since an invertebrate host may accumulate many larvae, ingestion of a single intermediate host by a single bird may result in a severe infection.

After ingestion of the worm larva (either in the form of an intermediate host or as a free egg), the larva migrates  in the bird from the bowel to
the lungs via the blood stream. Larvae undergo a fourth stage moult at about the third day after ingestion, and undergo a fifth larval stage in the
bronchi of the lungs on the fifth day of infection. Copulation starts at this time. By the seventh day of infection the parasite is found in the trachea.
They reach sexual maturity twelve days after this and eggs can be found in poultry faeces 18 to 20 days after infection.

Although gapeworms are only rarely found in mature layers, the parasites can survive in poultry birds for long periods. They are more often found in adult turkeys.

Gape worms are not commonly seen in poultry reared on impervious floors. Only chicks up to 8 weeks of age are susceptible.
Since most commercial enterprises  now rear chicks in systems where they are not in constant contact with their droppings and
not ingesting earthworms, the incidence of gapes is not widespread. The disease can however be found in turkeys kept on dirt floors.


Hairworm / Threadworm

The Capillaria species of nematode, or roundworm, are intestinal worms that can cause severe symptoms such as diarrhoea,
weakness, weight loss and a drop in egg production. The condition is sometimes referred to as
capillariasis. There are several species
of Capillaria, and they cause paralysis of different parts of the alimentary  tract, including the crop, oesophagus and the intestinal tract.
Commonly, the Capillaria species are referred to as the threadworm or hairworm, and they can be highly pathogenic, causing severe disease.

The Capillaria are a small species of worms, and some tend to be restricted to free-range birds, as the intermediate host is the earthworm.
Others have a more direct life cycle. Capillaria bursata is found only in chickens and its life cycle is dependent on the earthworm as an
intermediate host. Capillaria caudinflata has a similar life cycle and can be found in a number of domestic poultry species. Capillaria obsignata
can be a problem in deep-litter systems. This worm does not have an intermediate host  and can be found in a number of poultry species.

The main site of infection of Capillaria bursata, Capillaria caudinflata and Capillaria obsignata is the small intestine.

Capillaria anatis is a parasite of the caecum and is found mainly in ducks.

The main species afflicting turkeys and game birds are Capillaria annulata and Capillaria contorta.

Capillary Worm

Capillary Worm (Capillaria obsignata)

Capillary Worm

Capillaria obsignata has a direct development. Freshly deposited eggs require 6 to 8 days to develop completely formed embryos. The eggs remain infective
for a period of up to 14 days. Following the ingestion of the worm eggs from the pasture, the embryo escapes from the egg and completes its development
in the duodenum of  the host bird. Birds infected with Capillaria obsignata spend much of their time apart from the rest of the flock, huddled on the ground
or corner of the house. They develop diarrhoea and the feathers are ruffled. These first clinical symptoms are noted at approximately 12 days after infection. 

Capillaria annulata occurs in the crop and oesophagus. These worms are long and thread-like. The developmental cycle involves the earthworm. Eggs passed in
bird faeces develop slowly to produce larvae which are infective to earthworms. At normal temperatures, this can take 3 to 4 weeks. The infective stage in the
earthworm is reached  2 to 3 weeks after ingestion. The worm develops to maturity in a bird approximately 1 to 2 months after the earthworm has been ingested.

Capillaria contorta, which occurs in the oesophagus, crop and mouth of a number of bird species, has a direct life-cycle.
Eggs become infective to birds 4 to 6 weeks after they have been passed in faeces.

Poor drainage and ventilation and the feeding of birds off the ground have been associated with infections of Capillaria species.
The nematode eggs are markedly resistant  to adverse conditions and they may survive on pasture or in deep-litter houses for a
considerable period. The larval stages of those that pass through the earthworm probably survive as long as the earthworms survive.

Capillaria caudinflata, which occurs in the small intestine, also has the earthworm as a secondary host.

Like many other stresses, these worms can cause an outbreak of Marek's Disease, especially in young growing birds.



An affected flock suffering from any of the above parasites will need treating immediately with Flubendazole which is a anthelmintic
belonging to a group of chemical compounds called benzimidazole carbamates which are effective in controlling intestinal parasites.
Flubendazole is  available in a powdered pre-mix form, or ready mixed into poultry feed.

To Buy Poultry Wormers Containing Flubendazole
Click Here



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