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.
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
Infestation in Poultry
(mainly in young birds)
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
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.
male and female in permanent copulation.
in the trachea of a pheasant
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
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.
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
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
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 Capillariaannulata and Capillariacontorta.
Capillary Worm (Capillaria obsignata)
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'sDisease, especially in young
An affected flock suffering from any
of the above parasites will need treating immediately with Flubendazole which
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
Farm, Fontwell Avenue, Eastergate, Chichester, West Sussex, PO20