L6 Poultry endoparasites

Histomonas meleagridis

Histomonosis, Blackhead disease

Heterakis gallinarum

• Hosts: chickens, turkeys, geese, ducks, pheasants, grouse, partridge, quail etc.

• Location: caeca;

Heterakis gallinarum

Morphology/life cycle

Anterior end

Mouth provided with three lips;

Oesophagus ends in a well-developed bulb;

Posterior end

• Male

- precloacal sucker

• Female

- Long, narrow and pointed.

Heterakis gallinarum

Posterior end FEMALE

Heterakis gallinarum

eggs

Eggs (resemble Ascaridia eggs)

Shape: elliptical, lateral sides almost parallel;

Brown, thick and smooth shell, one cell inside.

Eggs may survive for long time in the environment

Heterakis gallinarum

Life cycle

• Infected birds shed in the environment eggs;

• In the environment eggs get embrionated in 2-3 weeks

Infection of the birds:• Ingestion of embrionated eggs;

• Ingestion of earthworms

Heterakis gallinarum

Epidemiology

• Worldwide distribution;

• Present in outdoor and indoor systems

• Eggs may survive for long time in the environment

• Earthworms (paratenic hosts) may survive for several years in the environment;

Heterakis gallinarum

PATH

• Non-pathogenic/low pathogenicity: inflammation and thickening of the wall of caeca, nodules in the mucosa;

• Important because it is a vector for Histomonas meleagridis.

Heterakis gallinarum

Diagnosis

• Finding eggs in the faeces (floatation methods);

• Eggs look like eggs of Ascaridia galli!!• Postmortem examination of caeca

Heterakis gallinarum

Treatment

• Imidazothiazoles

• Levamisole :water

• Benzimidazoles

• Flubendazole: food

Heterakis gallinarum

Control

• In the outdoor systems: difficult because of the resistance of the eggs and presence of earthworms;

• Control required when histomonosis is a problem in turkeys;

Heterakis isolonche

• Location: caeca of pheasants

• Larval stages invade the mucosa of the caeca where they develop

to adults in nodules;

• Diarrhoea, weight depression, death (sometimes >50%).

Histomonas meleagridis

Histomonosis (Blackhead disease, Entero-hepatitis)

Hosts: many galliform birds

Severely affected: turkeys chickens

• Location: commonly in caeca and liver

Histomonas meleagridis: Morphology

Pleomorphic: its appearance depends on location;

• Caecal lumen form

• Tissue form (wall of caeca/liver)

• A cyst-like form has been described recently in cultures;

• A 3 μm form exists in the eggs of H. gallinarum;

Histomonas meleagridis: Life cycle 1

I) Transmission via Heterakis gallinarum

Enables transmission from one farm to another farm!

• Heterakis gallinarum acts as a vector for H. meleagridis;

In the caeca of the bird host Histomonas meleagridis infects Heterakis gallinarum => ovaries of the female => become incorporated in the eggs;

Within the eggs the histomonads may survive for up to 2-3 years;

Histomonas meleagridis: Life cycle 2

Infection of the birds:

a) Ingestion of embrionated eggs of Heterakis gallinarum that contain Histomonas meleagridis;

b) Ingestion of earthworms that contain larvae of Heterakis gallinarum infected with Histomonas meleagridis;

In the caeca of the host the histomonads multiply (binary fission) and in 2-3 days enter the bloodstream and reach the liver;

Histomonas meleagridis: Life cycle 3

II) Transmission by direct contact

Enables transmission from one bird to another bird

Via cloacal drinking;

After ingestion of the histomonads from environment:

Histomonas meleagridis: HOSTS

Hosts: galliform birds

Severe disease: turkey

Mild disease: chicken

• Age affected: chickens 4-6 weeks of age are most susceptible while turkeys of any age are susceptible;

Histomonas meleagridis: Epidemiology

Chickens often remain carriers => source of infection for turkeys => do not rear chickens with turkeys;

• The role of Heterakis gallinarum and earthworms as vectors explain the long period the disease might persist in affected farms;

Turkey farms are not contaminated with Heterakis gallinarum => outbreaks occur after introduction of the eggs of the caecal worm H. gallinarum from chickens farms;

• Once the infection is established in a flock it spreads rapidly without the need of vectors: cloacal drinking and ingestion of histomonads;

HIstomonas meleagridis: Pathogensis/Pathology

• Host species: turkey,

• Intestinal flora: lesions can not be produced in germ-free turkey

H. meleagridis: Pathogensis CAECA PATH

Multiplication of the histomonads in the caecal wall and the

liver => necrosis;

After tissue invasion => caecal walls become thickened and

hyperemic => necrosis develops;

Caeca become distended with a caseous/cheesy core made up of concentric layers;

Ulcers=>perforation of the caeca=> generalized peritonitis;

LIVER PATHOLOGY

Areas of depressed necrosis that grow up to 1 cm in diameter and are surrounded by a raised ring;

H. meleagridis: Clinical signs TURKEYS

Yellow faeces, drowsiness, dropping of the wings, closed eyes, head down close to the body or tucked under a wing, anorexia

Emaciation and death in high percentage

H. meleagridis: Clinical signs CHICKENS

Rarely yellow faeeces (the liver is not affected) but the chickens may shed bloody faeces and caseous caecal cores (pathology resembles caecal coccidiosis);

Histomonas meleagridis: Diagnosis

I. Clinical signs & history/Gross appearance of the lesions

II. Confirmation

- Identification of the histomonads in the caecal fluids or

mucosal scrapings

- Cultivation

- Histopathology, inc

- PCR

Histomomas meleagridis: Treatment

5-Nitroimidazoles

For use only in breeder game birds!!

Do not use in birds intended for human consumption!!

Do not medicate birds laying eggs for human consumption!!

Nitroimidazole products have been prohibited for use in food animals in EU, USA and Australia.

Histomonas meleagridis: Prevention

Do not grow chickens and turkeys together

Do not use chickens sheds for turkeys

House flocks in concrete or wire floored pens;

Hygiene, cleaning and disinfection of the floors, feeders,

drinkers etc before restocking, quarantine new birds;

Syngamus trachea

Location: tracheaHosts: turkey, fowl, pheasants etc

Adult worms

Female worm and male always coupled => couple has the shape of letter ‘Y’;

Red colour (when fresh); feed on blood (Buccal capsule is cup shaped, no leaf- crowns)

Eggs

ellipsoidal shape;

• An operculum at each pole;

• Relatively thick shell;•

Morula stage;

Syngamus trachea: Life cycle

• Eggs coughed up, swallowed => in the environment

with faeces;

• L1-L3 within egg =>some L3s might hatch;

• Infection of the host by ingestion of:

- Eggs with L3

- Free L3

- Paratenic host containing L3

Syngamus trachea: Epidemiology

• Hosts: turkey, chicken, pheasant, goose, guinea fowl, peafowl, emu, quail etc;

• Birds of all ages are susceptible to infection but generally young birds suffer severe disease, especially turkey poults, baby chicks and pheasant chicks;

• Common in outdoor systems;

• Infections occur seasonally

Syngamus trachea Sources of infection

Young birds and adult birds with inapparent infections;

Earthworms: larvae may persists for 4 years => the ground remains

contaminated for long time

Wild birds

Syngamus trachea: Pathogensis/pathology

• Caused by larvae while migrating in the lungs and adults in the trachea;

II. Adult worms:

Feed on blood (males) and tissue (females)

Grow rapidly

Cause

- Haemorrhagic inflammation and excess mucus

- Males are deeply embedded into the wall of trachea => nodules;

Block the lumen of the trachea => suffocation => death

Syngamus trachea: Clinical signs

• Suffocation => birds gasp for air and stand “gaping”;

Coughing, dispnoea, shaking of the head, extending of the neck etc;

Death in 2-3 days;

Syngamus trachea: Diagnosis Live birds

Clinical signs;

History

Detection of the eggs in the faeces and worms in the trachea on necropsy;

Live birds other diagnosis

• Transillumination;

Syngamus trachea: Treatment

Imidazothiazoles

Levamisole

Benzimidazoles

Flubendazole

Syngamus trachea: CONTROL

Indoor systems;

Separate young from old birds, do not grow mixed species;

Prevent contact with wild birds;

Treat prophylactically before/in the periods the outbreaks occur;

Oxyspirura mansoni

Host: chickens, turkey, ducks;

Location: inner corner of the orbit, under the nictitating membrane => causes blindness;

Oxyspirura mansoni LIFECYCLE

Intermediate host: cockroaches

Eggs are deposited in the eye => secretions => lachrymal ducts => mouth => swallowed => passed in the faeces;

Eggs are ingested by the cockroaches => in about 50 days the larvae reach the infective stage;

Cockroaches are ingested by the birds => larvae leave the cockroaches in the crop => up to the esophagus => mouth => lachrymal ducts => eye.

Oxyspirura mansoni DETAILS

Distribution: tropical and subtropical areas;

Pathogenesis/pathology: inflammation of the eye, oedema, watery eyes, blindness;

scratching of the eye;

Diagnosis

Clinical signs;

Visualization of the parasites;

Treatment

• MLs: Ivermectin and Moxidectin, oral

Prevention

• Reduce the number of cockroaches;

Trichomonas gallinae

Trichomonosis (canker)

Trichomonas gallinae is a flagellate protozoan that occurs primarily in the upper digestive tract of columbiforms (pigeons, doves etc) but it can infect a wide range of species of birds;

Four anterior flagella and no free posterior flagellum;

Undulating membrane does not reach the posterior end of the body;

Trichomonas gallinae: Epidemiology

• Distribution: worldwide

• Hosts

•Birds, especially from the order Columbiformes (pigeons& doves) but also budgies, finches, sparrows, hawks, eagles, turkeys, chickens etc;

Location

Upper digestive tracts: mouth, pharynx, oesophagus, crop;

Trichomonas gallinae SOURCES OF INF.

• Pigeons: adults - up to 80-90% are asymptomatic carriers

=> clinical signs usually in birds younger than 1 month;

Trichomonas gallinae TRANSMISSION

Columbiforms

• Pigeon‘milk’

Galliforms: feeding/watering in/from places/containers infected by columbiforms or other wild birds

T. gallinae: Pathogenesis/Pathology

Depends on the strain and immune status of the birds

Ulcers covered by yellow membranes => caseous necrosis => build up of the caseous material that may invade the roof of the mouth and the sinuses and block the pharynx/oesophagus;

In the esophagus and crop: yellow caseous nodules that grow ‘yellow buttons’;

In the livers: abscesses, necrosis;

Trichomonas gallinae: Clinical signs

Excess of watery saliva and foul cheese-like smell;

Yellowish caseous lesions around the beak or eyes;

Yellow masses located on the floor/roof of the mouth/pharyngeal region => block the passage of the food/trachea => death from starvation or respiratory failure

Weight loss, ruffled feathers, listlessness

Trichomonas gallinae: Diagnosis

• Clinical signs

• Identification of the trichomonads

- In wet smears

- Cultures = higher sensitivity

Differential diagnosis

Vitamin A deficiency;

Infections with Candida spp, Aspergillus spp, poxvirus, Capillaria

spp.

Trichomonas gallinae: Treatment

5-Nitroimidazoles

Dimetridazole (Emtryl)

Metronidazole (Metrin)

Ronidazole

Nitroimidazole products have been prohibited for use in food animals in EU, USA and Australia

Not for use in food animals!!!

Trichomonas gallinae: Prevention

Pigeons

Prophylactic treatments of healthy adults

Treat the parents during incubation of the eggs

• Poultry

Prevent the flocks of doves/pigeons coming to feed

from feedlots of livestock;

Keep feeders and drinkers clean;

Food & water should be changed regularly;