Chapter 8 Metazoan Parasites

 

 

 

                  

8.1 Helminths:

The helminths may be classified as the round worms or the nematodes; the tapeworms or the cestodes; the flukes or the trematodes; and the thorny headed worms or the Acanthocephala.

a. Nematode Infestation.

8.1.1 Nematode of the eye.

• l) Scientific name: Oxyspirura mansoni, Filaria mansoni.
• 2) The worm is found beneath the nicitiating membrane, conjunctival sacs and naso-acrimal ducts.
• 3) Life cycle.

The eggs 0f the mature female worm are deposited in the eyes of the bird host. They are then washed down the tear duct, swallowed, and passed to the exterior in the droppings.

The cockroach ingests the nematode eggs, within approximately 50 days, the cockroach contains in its body cavity mature larvae in a cyst.

Infected cockroach swallowed by chicken, the infective larva is freed in the crop of the bird host, passed up the esophagus the mouth and through the nasal-lacrimal duct to the eyes.

• 4) Species parasitized - Many.
• 5). Pathology: Ophthalmia.
• 6). Treatment:

Put a few drops of 5% creolin in the eye or irrigate immediately followed with a drop of 10% argyrol.

8.1.2 Nematodes of the respiratory tract.

1. Syngamous trachea:

Gape-worm, red worm, forked worm.

l) Description:

Red worm, the color more pronounce in female. Male permanently attached in copula to female forming a Y.

2) Life History.

The female tapeworm deposits its eggs into the lumen of the trachea. The eggs reach the mouth cavity, are swallowed, and pass to the outside in the droppings.

Following a period of approximately 8-18 days under optimum conditions, these eggs become embryonated. Soon after embronation, some of the eggs may hatch the larvae living free in the soil.

Larvae penetrate the intestinal wall, enter the body cavity and finally invade the body musculature in which they encyst for an indefinite period. Snails also can transmit this worm. Either the eggs containing the embryos, or the young worms already hatched may be eaten by fowls.

After being taken into the digestive tract of the bird, the young worms migrate to the lungs and thence to the trachea, where they mature within seven to ten days.

3) Pathology:

In young birds, under 8 weeks of age, the activities of the worms cause inflammation of the trachea with accumulation of considerable amount of mucus. The resultant interference with respiration causes the affected birds to stretch the neck and the "gape" with open mouth for air.

The birds sneeze, cough, and frequently shake their heads in an effort to expel the worms and mucus from the windpipe.

4) Prevention:

• Frequent removal of litter to prevent accumulation of worm eggs and larvae.
• Keep intermediate hosts out of the reach of chicken flocks.

5) Treatment:

Unsatisfactory.

8.1.3 Nematodes of the Alimentary Tract.

8.1.3.1 Crop Nematodes

At least three species of nematodes.

8.1.3.1.1 Capillaria annulata

Worm long thread like, occurs naturally in the bobwhite, quail, domestic chicken, and turkey, pheasant. Earthworms as intermediate host. The habit of burrowing into the crop mucosa causes a thickening of the crop wall and an enlargement of the glands, and a slight or severe inflammation of the crop and esophageal walls. In pheasants, quail, and other gallinaceous game birds, infestations with this Farasite often prove fatal. Symptoms are principally malnutrition and emaciation, associated with severe anemia.

8.1.3.1.2 Ca]pillaria contorta.

• Simple life cycle.
• Hosts. Ducks, turkey, pheasant, quail and ruffled grouse.
• Life History:

  Eggs are deposited in tunnels in the crop mucosa and escape into the lumen of crop and esophagus with sloughed mucosa. They are found abundantly in droppings of susceptible avian hosts in from 1 to 2 months after feeding embryonated eggs. 

• Pathology:

  In heavy infestations, there is marked thickening and inflammation with a flocculent exudate covering the mucosa and with more or less sloughing of the mucosa.

8.1.3.1.3 Gongylonema inguvicola or gullet worm.

Species

chicken, turkey and quail.

Life History:

Unknown.

Pathology:

Local lesion of burrowing.

Symptoms:

Birds heavily infested with capillaria worms show unthriftiness, weakness, diarrhea, listlessness and loss of weight. They sit huddled on the ground, the feathers are ruffled, the vent is soil, and the visible mucous membranes are pale.

Prevention:

Hygiene Improvement.

Treatment:

Carbon tetrachloride administered in Icc dose has been found to be effective. To obtain the best results the treatment should be repeated in 7-10 days

8.1.3.2 Stomach. Proventriculus

8.1.3.2.1 Tetramere Americana

The female of this species occurs in the glandular stomach of chickens and bobwhite quail. At necropsy, these bright red worms are often observed them through the wall of the unopened proventriculus. The male of this species resembles other nematodes in shape (pea shap).

Intermediate host is grasshopper or cockroach.

8.1.3.3 Gizzard. 

8.1.3.3.1 Chilospirura hamulosa

in chickens and turkeys. Cheilospirura spinosa in ruffled grouse and quail. Amidostomun anseri-s in domesticated ducks and geese. CTrichostrongylidae).

8.1.3.4 Intestinal tract.

8.1.3.4.1 Ascardia galli.

Synonyms:

Ascaris galli. large roundworm.

Description:

Worms large, thick, yellowish-white. Head with three large lips. It is one of the most common nematode parasites of chickens in the U.S. Occasionally it occurs in turkeys, but no serious pathologic effects.

Life History:

Simple and direct. The infective eggs which are swallowed by the susceptible host hatch either in the proventriculus or in the duodenum.

The eggs are deposited by the female worm in the intestinal contents and are subsequently passed to the outside in the droppings of the bird. When first passed out the eggs are not infective, but under favorable conditions of warmth and moisture they embryonated and become infective in 10-16 days. If the embryonated eggs are eaten by a susceptible fowl the larvae is liberated. In a few days the young worm penetrate the lining of the bawel and undergo further development, after they emerge into the intestinal canal and continue their growth. A period of 50-60 days is required for the young worms to attain maturity.

Susceptibility:

The damage done to fowls by infestation with Ascardia gali is greater in young birds.

Symptoms:

General unthriftiness as manifested by variable appetite, emaciation, retarded growth and weakness is commonly observed in young parasitized birds.

Prevention:

General measures of sanitation, designed to prevent development of the eggs and their subsequent ingestation are the most effective means of controlling the spread of roundworm infestation.

Treatment:

Peperzine hydrochloride in water of feed at 5 weeks of age and as needed thereafter.

8.1.3.4.2 Heterakis gallinae, the cecal worm.

Common inhabitant of the ceca of chickens, turkeys, guinoas. ducks, geese, pea-fowls, partridges, grouse and quail. The worn is small, being 1/3 to 1/2 inch in length and is greyish-white in color. The parasite is frequently found in great number and may produce severe inflammation of the cesa, particularly in young birds. More important is its role of transmission of blackhead disease.

Life history:

Direct life cycle.

The eggs deposited in the ceca by the female worms are voided with the droppings of the bird. Under conditions of sufficient warmth and moisture the eggs embryonate and become infectious in 7-10 days.

Upon being swallowed by a susceptible fowl, the young worms are freed from their shells and penetrate the lining of the ceca. About 65 days are required for the entire cycle.

Symptoms:

General unthriftiness and in young chicks death may result from heavy infestation.

Treatment:

Phenothiazine or peperazine.

8.1.3.4.3 Capillaria obsignata.

Description:

Worms hair like. This hairworm occurs in the small intestine of the domestic and wild pigeon, chicken, and turkey in the U.S.

Life History:

Direct life cycle.

The freshly deposited eggs are unsegmented and require from 6-8 days to develop completely from embryos. The embryos do not escape from the eggs until after they have been swallowed by a susceptible host, the larvae enter the mucosa of the duodenum and apparently complete their development there.

Pathology:

Death resulted from heavy infestation.

Treatment:

Hygromycin, high level of Vitamin A.

8.1.4 Cestode Infestation.

1. General morphology and characters,

• l) Tapeworms are flat, white, segmented, ribbon like parasites.
• 2) A complete tapeworm consists of:
  • The head or scolex.
  • The neck or growth zone

    The segments, collectively the segments are called strobila, and each segment is a proglottid.

• 3) All tapeworms parasites are in the digestive tract.
• 4) In the case of every tapeworm of poultry in which the life cycle is known, an invertebrate intermediate host, such as beetle, fly, snail, slug orcrustacean is necessary for the completion of the life cycle.
• 5) Intermediate host ingested free eggs or egg-bearing segments voided by the infested birds. Following ingestion, the eggs hatched in the digestive tract, the larvae, penetrates the intestinal wall, enter the body cavity, and transformed into cysticeroids in about 3 weeks.
• 6) Poultry became infected with tapeworms by swallowing infected intermediate host. Cysticercoids are liberated by the digestive juice of the host, the scolex evaginates and becomes attached to the hosts' intestinal wall. New proglottids begin to form immediately, and within approximately 3 weeks a mature tapeworm is formed.
• 7) Symptoms and gross pathology.

  In heavy tapeworm infestations, a more or less extensive catarrhal enteritis and diarrhea may result. Emaciation, listlessness and loss of appetite are the common symptoms.

• 8) Method of control involves, the proper disposal of poultry manure containing the eggs of tapeworms so that the intermediate hosts cannot become infected with the larval stages of these parasites. Keeping the intermediate hosts out of the chicken house is another method to control tapeworm infection.
• 9) Treatment:

  Hexachlorophene (2,2' - dihydroxy -3, 3', 5, 5' hexachloro diphenylemethane), Dibutyltin dilaurate and dibutyltin oxide are effective.

2. Common poultry tapeworms.

1) Amoebotaenia sphenoides .

• Intermediate host - earthworms
• Region- Duodenum. 

2) Choanotaenia infundibulum.

Characteristics:

Rostellum armed with a single row of relatively few and very large hooks.

Intermediate hosts:

House flies, grasshoppers and several species of beetles.

Region:

Jejunum.

3) Davainea proglottina.

Characteristics:

Mature worms attain a length of a-out 4 mm, The strobila consists of from 2-5 segments.

Intermediate host:

Snails and slugs.

Region:

Duodenum.

4) Raillietina cesticellus.

One of the most common species of cestode occuring in poultry.

Characteristics:

Broad and flattened rostellum with two rows of hooks near its base. .

Intermediate host:

Ground beetles and dung beetles.

Region:

Jejunum.

5) Raillietina echinobothrida.

Characteristics:

Uterus ultimately forming egg capsules, each capsule usually containing a single egg.

Intermediate host:

Ants.

Region:

Ileum.

Pathology:

Formation of tubercles on the intestinal wall of infected birds.

6) Raillietina tetragona.

Characteristics:

Uterus eventually breaking up into egg capsules, 6-12 eggs in each capsules.

Intermediate host:

Ants.

Region:

Ileum.

7) Hymenolepis carioca.

Characteristics:

Segments 3-5 times broader than long. Testes 3 in numbers, usually in a more or less straight row across the segment. It is one of the most common tapeworms of the duodenum of chickens and turkeys.

Intermediate host:

Stable flies, dung beetles.

3. Poultry trematodes.

In comparison with the nematodes of poultry, the flukes are of much less importance.

l) Prosthogonimus macrochis .

Testes oval, opposite each other and about unthread of body length from posterior end.

This fluke occurs in the bursa of Frabricii and oviduct of the duck, chicken and other birds in the U.S.; it is particularly common in the lake region of Michigan and Minnesota.

Life History

Embryonated eggs produced by the fluke leave the host by way of the cloacal opening, and if they reach a lake inhabited by Amnicola limosa (snail), sporocysts and cercaria develop, (sporocyst, found in the liver of the snail). There being no media stage. The cercaria swims away from the snail host and drawn into the anal opening of a suitable species of dragonfly by the breathing movement. Metacercaria thus formed makes its way to the muscle of the dragonfly. Ingestion of the dragonfly by poultry makes the cycle possible.

Pathology:

Powl lose their normal activity and appetite and there is a pronounced dropping off in egg production. The eggs that are produced frequently have very thin shells or no shells. Adhesive peritonitis might result. Parasite may be found in oviduct or eggs.

Treatment: CC14 

8.2 External Parasites.

Many kinds and varieties of external parasites are known to infest poultry. The list includes lice, mites, ticks, fleas, flies and other less important forms. The total loss for which they are responsible is enormous, and they present an important practical problem where ever fowls are kept.

8.2.1 Classification.

Phylum Arthropoda

Jointed limbed animals without a vertebral column. Class insecta - with antennae, such as lice, "bedbugs" fleas, beetles, flies and gnats. Of these only the last three have wings. The insect body is divided into head, thorax and abdomen. Legs and wings are attached to the thorax. Insects are further distinguished by having three pairs of legs in the adult stage.

Class Arachnida.

Not having antennae of which many of the mites and all of the ticks are parasites. The arachnid body consists of a combined head and thorax (cephalo-thorax) not usually marked off from the unsegmented abdomen. The legs of arachnids are attached to the cephalothorax. There are typically 4 pairs of legs in the adult and the nymphs stages, whereas the larval arachnid is provided with only three pairs.

8.2.2 Lice

1. General Consideration.

The lice affecting poultry belong to the Ordes Mallophaga, chewing lice or bird lice. Over 2000 species of Mallophaga have been described, and nearly all of these are found exclusively on birds.

2. Description.

• l) Having chewing mouthparts.
• 2) 3 pairs of legs.
• 3) Brown to blue or gray in color.
• 4) 3 body parts.
• 5) Flattened insects.
• 6) Fairly host specific.
• 7) They are not blood sucking parasites but have cutting mouth parts with which they feed upon bits of feathers or scales from the skin. In this way, and also by their sharp claws and spiny structure, they cause considerable irritation and annoyance to the fowls on which they live.

3. Life cycle:

• l) They are permanent parasites, the entire life cycle including the egg stage being spent on the body of the host.
• 2) Can live a short time off host, most of the time they are host specific.
• 3) Lay eggs at the base of feathers, and hatch in about 7-10 days. Complete life cycle is about 2-3 weeks.

4. Symptoms:

• 1) Able to find lice in the vent, skin areas of a bird.
• 2) Severe infestation would cut the egg production.

5. Common species of chicken lice.

• l) Menacanthus stramineus - body louse.
• 2) Menopon gallinae - chicken shaft louse small body louse.
• 3) Gonicotes hologaster - chicken pluff louse.
• 4) Goniodes gigas - large chicken body louse.
• 5) Cuclotogaster heterographus - chicken head louse cause big trouble in young chicks or poults.
• 6) Liperurus caponis - chicken wing louse.
• 7) Mencanthus cosnutus - chicken body louse.

6. Treatment and Control.

• l) Greasing - ointment is not satisfactory.
• 2) See Circular A-2, Cooperative Extensive Service, Auburn University. Control external poultry pests.

8.2.3 Mites

There are about twenty species of mites which are known to infest domestic poultry, but only a few of them are sufficiently injurious to be of economic importance. They belong to the family Acarina of the class Arachnids.

1. Chicken mite, red mite or rooster mite. 

Dermanyssus gallinae.

• Common parasites of general farms.
• Not very common on commercial poultry farms.

l) Descriptions:

Four pairs of legs. One part to the body, round.

Although actually gray in color, these mites usually appear red because they so often contain blood of fowls on which they have been feeding.

They are intermittent parasites, hiding in cracks and crevices during the day and coming out to feed on the fowls at night.

2) Symptoms:

Because of the feeding habits of the mites, and infestation may easily become severe before the flock owner is aware of their presence. Their presence is easily determined by examine the ends and undersides of the roosts at the points of support and by careful inspection of any cracks or cry vices in the roosts or -oost supports.

In severe infestations a characteristic odor is quite apparent.

2. Northern fowl or Northern feather mite, Ornithonyssus sylviarum.

• l) It occurs mostly in temperate as well as in subtropical areas.
• 2) It has been reported from 22 species of birds and accidentally on man.
• 3) It resembles the common red mite, but differs from it in that it occurs both on birds and on their surroundings more or less continuously, even during the day time.
• 4) It lives and reproduces on the fowl and gets its food by sucking blood from the host. The eggs are deposited and hatched among feathers and the young mites complete their development without leaving the fowl.
• 5) The mites are most commonly found about the base of the tail and around the vent, and the egg masses commonly occur in the same regions.

3. Tropical feather mite, Ornithonyssus bursa.

• l) Not common in the U.S., more common in tropical area
• 2) Closely related to the northern fowl mite.

4. Differential diagnosis of red mites, northern mites and tropical mites. 

•  
• 2) Black
• Smaller
• + - - to +
• excellent
• Better

5. Scaly leg mites, Knemidocoptes mutans.

• l) A very small itch mite, less than 1/50 inch across, which burrows under the scale on the shanks.
• 2) The mites are almost spherical in shape, short legged. Adult larger in females.
• 3) The severe irritation which is set up by the activities of the mites results in accumulation of grayish, dry debris under the scales, the scales being loosened and lifted until the shanks appear to be greatly enlarged.
• 4) The entire life cycle is spent upon the host. Eggs are laid in the channels formed as the mites burrow in the skin. The young mites pass through a simple metamorphosis and soon start burrows of their own.
• 5) Treatment:

  Soak the shank in soapy water with the aid of a hand brush. Allow them to dry, then apply oil of caraway 1 part to petrolatum (Vaseline) 5 parts.

• 6) Not common.

6.. The depluming mite, Knemduming lscvis var. gallinae.

• l) Resembles the scaly-leg mite in general structure although it is smaller.
• 2) They live at the base of the feathers, where they produce the condition known as "deplubing scabies". The intense irritation induced by the mites causes the affected birds to pull out its own feathers.
• 3) Not common.
• 4) Treatment similar to scaly leg mite.

7. Red, bugs, Chiggers, Eutrombicular alfreddugesi.

• l) A chigger is the six-legged larval stage of a mite that may infest the skin surface of various birds hosts as well as mammals, including man. The adults are not parasitic.
• 2) The adults breed on: the ground especially along fence rows or in undisturbed wooded or brushy areas.
• 3) The larvae attach to the skin, often in groups, by means of their mouthparts, and injected a highly irritant substance in to the wound
• 4). There follows a liquefaction of the skin which provides the larval chigger with food. Itching vesticles or even abscess may form at the point of attachment, surrounded by a zone of hypermia and edema. 

8.2.4 Ticks.

Class: Arachnida.

Order: Acarina

The ticks constitute a blood-sucking super-family, namely Ixodoides. They are distinguished by the mites by being usually larger and by the presence of a pair of respiratory openings. One on each side of the leathery abdomen, these openings, called spiracles or stigmal plates are situated either between the boxes of the last two pairs o£ legs (family Argasidae) or posterior to the last pair (family Ixosiae).

1. The fowl tick, Argas persicus.

l) General consideration:

• The most important tick parasite of birds.
• Fowls often being killed by it. It is a powerful bloodsucker.
• 2) The chickens appears to be the favorite host, but turkeys, geese, duck, pigeon, guineas and ostriches are all subject to attack.
• 3) Life cycle: A typical tick life cycle includes the eggs, the larva (seed tick), the nymph, and the adult stages. After engaging with blood, the female tick drops from the host to hide in soil, humus, litter, tree bark, or crevices during the pre-ovulation and egglaying periods;' Following this the female tick dies (the male previously had died following copulation). After an incubation period, the minute six-legged larvae (seed ticks) emerge from the egg shells and await contact with a suitable host. Feeding on blood is followed by molding of the larval skin and emergence of the eight legged nymphs that resemble the adults except for maturity of the reproductive organs. One or more additional molts follow before the adult female and male ticks fully develop.
• 4) Ticks can live outside a host for 21/2 years.
• 5) Disease caused by ticks may be of the three general types.

Loss of host blood. Loss of egg, meat production. Transmitters of other parasites, such as those of avian spirohaetosis,tularemia, babesiosis, anaplasmosis, dirofilariasis, encephalomyelitis, and certain rickettsial diseases. e. Fleas.

Fleas are very adaptable blood sucking insects and may attack various host species, especially those closely related. Class Insecta.

2. The sticktight flea, Echinophaga gallinacea.

• l) The flea attached themselves to the comb, face earlobes and wattles, and remain attached by their mouthparts for 4 to 19 days. They tend to be found in clusters.
• 2) They may be recognized as brown to black, laterally flattened insecta having the ability to run rapidly along the skin and to propel themselves in the open by leaping.
• 3) Female fleas deposit several eggs per day which rool off the host into surrounding litter where they incubate. Dampness is essential for further development.
• 4) Within one or several weeks, average about 6-8 days, the eggs hatched, liberating tiny maggot-like larva that feed partly on organic matter found in dust and litter, but their principle food is flea feces. After the larvae have grown and shed their skins, usually twice in a period varying from one to several weeks, they proceed to spin silk cocoons. In 1 week to months, pupae transform to white then to yellow the brown fleas. Emerging from the pupal cocoon, the young flea seeks a host, suck blood, and reach maturity in a few days.

8.2.6 Mosquitoes, Order Diptera.

• Common chicken house mosquitoes belong to culex quinquefaciatus.
• Culex tarsails. Fowl pox virus is transmitted by Aedes Stimulans .
• A . aegypti, A. vexam. Mosquitoes belong to the genera Culex,,
• An&endash;opheles and Aedes. 

8.2.7 Flies and Gnats.

Order: Diptera.

• 1. Blackflies, turkey gnats, buffalo gnats, belong to the fly family Simuliidae, Blood suckers, transmit leucocytozoon. Black flies are tiny, hump-backed, two winged flies. They breed in running or slowly moving water from which they may travel miles in search of blood. Eggs are laid on solid objects at the egg of water. The larvae emerge in 5-30 days and enter the water, attaching to stones or other objects. After about 3-10 weeks, during which the larvae molt six times, the pupal stage is reached. This stage too, occurs under water, lasting from a few days to a month. The adult flies emerge during warm weather. Hibernation occurs in the egg or larval stage. Stimulium occidentale could transmit Leucocytozoon smithi to turkey.
• 2. Musca domestica, the common house fly. Intermediate host Raillietina cesticillus and Choanotaenia infundibulum.