Noble Desk

External parasites of poultry are observed in most poultry producing country especially in the tropical region. They are mainly a problem in the laying flock than in the broiler flock because they are kept for longer periods where the parasites are allowed to complete their life cycle. Economic losses due to external parasites include unthriftiness, reduced egg production and anaemia. The parasite are of importance in poultry because they transmit a number of diseases such as fowl cholera, Borrelia anserine, Newcastle disease, fowl pox and also serve as vectors of different diseases such as eggs of Heterakis gallinarum which carry Histomonas meleagridis.
The ectoparasites of importance include;
Ticks such as Argas persicus
Mites such as Dermanyssus gallinae, Cnemidocoptes mutans and Ornithonyssus sylvarum.
Flea such as Echidnophaga gallinacean(stick tight flea)
Louse such as Menchanthus stramineus(chicken body louse) and Menopon gallinae(shaft/feather louse).

TICKS(Argas persicus)
This tick is found worldwide in tropical and subtropical countries. All stages are found hiding in cracks and crevices in the poultry house during the day. Adults feed on the host for 2-7 days(day and night). The importance of Argas persicus in poultry is in the transmission of Borrelia anserine, the causative agent of spirochaetosis.
Clinical signs: Anaemia, weight loss, depression, paralysis, drop in egg production.
Post-mortem lesion: Red spots on the skin where the ticks feed.
Diagnosis: Based on history, clinical signs and post-mortem lesion.
Treatment: Clean poultry houses regularly and cover cracks and crevices.
Use acaricide sprays routinely in the poultry house.

MITES
Dermanyssus gallinae(Red mites)
They affect domestic poultry, pigeons, canaries and wild birds. The red mites hide during the day under the poultry litter, cracks,crevices and at night, they feed on the susceptible host.
Transmission is by contact with infected birds, animals or inanimate object.
Clinical signs: weight loss, reduced egg production and unthriftiness.
Diagnosis: Based on history and clinical signs.
Treatment/control
Use acaricide solution on the litter, cracks and crevices.
Dust the birds with acaricide powder.
Ornithonyssus sylvarum
They affect chickens and turkeys severely. They are obligate blood sucking parasites that complete their lifecycle on the host. The infestation originates from the vent to the tail, back and legs of birds. The feathers are soiled with the mite eggs, skin, dried blood and excrement.
Clinical signs: weight loss, reduced egg production and depression.
Diagnosis: Based on history and clinical signs.
Treatment/control
Use acaricide solution on the litter, cracks and crevices.
Dust the birds with acaricide powder.

Cnemidocoptes mutans(scaley leg mites)
This is a small spherical sarcoptic mite that tunnels into the tissues under the scale of the skin.
Clinical signs: irritation, exudation leading to thickening encrusted legs. They may also attack the comb and wattle. Transmission is by contact.
Treatment
By topical application of acaricide solution on the affected legs and poultry houses
Cnemidocoptes gallinae(Depluming mites)
This is found in the epidermis at the base of the feathers shafts and cause intense irritation and feather pulling in chickens, pigeons and geese.
Treatment
Topical application of acaricide solution.

FLEAS(Echidnophaga gallinae)
This is also known as stick tight flea. The adult flea attaches mainly to the skin of the head for days and releases the eggs in the poultry litter. The flea affects cchickens, turkeys, pigeons, pheasants and quails.
Clinical signs: irritation, blood loss leading to anaemia and death.
Treatment
Remove infested litter
Use acaricide solution on the litter to kill innate fleas.
Topical application of acaricide solution on the head of the birds.

POULTRY LOUSE/LICE
The chicken body louse(Menchantus stramineus) and shaft louse/feather louse(Menopon gallinae) are commonly found in layer and breeder flocks. They are yellowish and approximately 1/16 inch long. They feed on dry skin and feathers with the entire life cycle on the host. These lice gum their eggs on the feathers of the host and eggs hatch into nymph then to adulthood. They cause severe irritation on the host, reduced appetite and in laying flock , reduced egg production.
Treatment
Remove infested litter
Use acaricide solution on the litter to kill innate fleas.
Topical application of acaricide solution on the head of the birds.

These helminthes are found in ducks, sometimes in chickens. The only species that affects both ducks and geese is Prothogonius spp which resides in the bursae of fabricius, oviducts, cloaca and rectum.
Clinical signs: diarrhea
Diagnosis: based on clinical signs,presence of eggs/flukes in faeces
Treatment: levamisole, flubendazole and piperazine.

Tapeworms are also found in poultry. The tapeworms that affect poultry include;
Raillietina spp such as Echinobotrida, Tetragona.
Davainea proglotina.
RAILLIETINA ECHINOBOTRIDA/ TETRAGONA
They are both seen on the small intestine and affects chickens, turkeys, guinea fowls and pigeons. The worm produces tuberculous lesions on the wall of the intestine.
Clinical signs include mucoid diarrhea, emaciation, necrosis of the intestinal wall and death.
Diagnosis: based on clinical signs and presence of egg and worms on the faeces of affected poultry.
Treatment
The following anthelmintics can be administered;
Piperazine.
Levamisole.
Flubendazole.
DAVAINEA PROGLOTINA
This is the smallest tapeworm found in the duodenum of chickens which penetrates deep in the intestines and produces marked enteritis and dysentery.
Diagnosis: based on clinical signs.
Treatment: piperazine, flubendazole and levamisole.

NEMATODES
They are the most common and important helminth species affecting poultry. About 50 species have been described in poultry. They include
Ascaridia gali
Heterakis gallinarum
Capillaria annulata
Capillaria longicollis
Capillaria columbae
Syngamus trachea.

ASCARIDIA GALLI
These helminth parasites are large thick yellowish white worms found in the small intestine of poultry and occasionally oviduct, esophagus, crop, gizzard, body cavity. It affects chickens, turkeys, doves, ducks, geese and guinea fowl of 1-3 month of age.
Clinical signs
They are enteritis, stunted growth, anaemia, mortality in heavy infection, adult worm out in the faeces.
Post-mortem lesions
Enteritis
Adult worm in the intestine
Diagnosis
This is based on history, clinical signs and post-mortem lesions.
Identification of the ova in the faeces of affected poultry.
Presence of adult worm in the faeces.
Treatment
The following anthelmintics can be administered;
Piperazine compounds
Flubendazole
Thiabendazole
Levamisole
Phenothiazine

HETERAKIS GALLINARUM(CAECAL WORM)
These helminthes parasites resides in the caeca of fowls, turkeys, ducks, geese, guinea fowls, pheasants and quails. The eggs of the caecal worm is important in the transmission of Histomonas meleagridis, the parasite that causes black head disease in turkeys.
Clinical signs include diarrhea and anorexia.
Post-mortem lesion
Inflammation of the caeca.
Diagnosis
There is presence of eggs in faeces( smaller, thin shelled and operculated unlike that of Ascaridia galli).
Treatment
The following anthelmintics can be used;
Piperazine compounds.
Levamisole.
Phenothiazine.
Thiabendazole
Flubendazole.
CAPILLARIA SPECIES
The species that affects poultry include
Capillaria longicollis
Capillaria columbae
Capillaria annulata.
These are hair-like helminthes with barrel-shaped eggs plugged at both ends. They reside in the entire intestinal tract and generally affect chickens, turkeys, geese,  guinea fowls, pheasants and pigeons.
Clinical signs include diarrhea, emaciation, death in very heavy ingestion.
Post-mortem lesion include large number of worms in the gastrointestinal tract.
Diagnosis : presence of barrel-shaped eggs in the faeces.
Treatment 
The following anthelmintics can be used;
Flubendazole.
Thiabendazole.
Phenothiazine.
Piperazine.
Levamisole.
SYNGAMUS TRACHEA(GAPE WORM)
These are blood sucking helminth parasites found in the trachea and lungs of pheasants, chickens, turkeys, geese, guinea fowls, quails and pea fowls. The helminthes are characteristically red with male and female permanently joined in copulation forming a Y shape.
Clinical signs include anaemia seen in pale comb and wattle, tracheitis, coughing, gapping caused by the presence of large number of worms which occludes the respiratory passage, death due to asphyxiation.
Post-mortem lesion includes red coloured helminth that are in permanent copulation in the trachea.
Diagnosis is based on history, clinical signs and post-mortem lesion and presence of eggs in the faeces.
Treatment
The following anthelmintics can be used;
Piperazine.
Phenothiazine.
Thiabendazole.
Flubendazole.
Levamisole.

This is an acute or chronic respiratory disease of poultry caused by Aspergillus species. The disease is characterized by dyspnea, enhanced tense and heavy breathing.
Synonyms
Brooder pneumonia, fungal pneumonia, mycotic pneumonia, pneumomycosis
Aetiology: Aspergillus fumigates
Age/host range: chickens, turkeys, ducks, penguns, game birds, waterfowls are susceptible with chicken/turkeys highly susceptible. The disease affects all ages of birds but very severe in young birds of less than 3 weeks of age.
Forms of Aspergillosis
Two forms of the disease exist in poultry. They include acute and chronic forms.
Acute form is characterized by severe outbreak in young chicks with high morbidity and mortality.
Chronic form is common in adult flock; morbidity and mortality is also high.
Transmission
By inhalation exposure to an environment with a high spore count.
Inovo: through internal and external contamination of the embryo.
Clinical signs
Clinical signs associated with acute form include
Inappetence
Weakness
Silent gasping
Rapid breathing
Thirst
Drowsiness
Torticolis(occasional)
Clinical signs associated with chronic form include
Ocular discharge
Wasting
Post-mortem lesions
Yellowish-grey nodules in lungs, air sacs, trachea and occasionally brain, peritoneal cavity may have a greenish surface.
Serous fibrinous pneumonia is seen in the trachea and bronchi
Conjunctivitis/keratitis.
Diagnosis
This is based on characteristic clinical signs and post-mortem lesions.
Isolation and recognition of the fungal cultures using appropriate media.
Treatment
An effective means of therapy for avian aspergillosis is not available.
Prevention
Good sanitation
Fumigation of poultry environment with Nystatin.
Keep poultry litter and feed dry.

This is primarily a disease of young turkeys, occasionally chickens, pheasants and game birds. The disease is caused by a protozoan parasite and characterized by lesions in the ceca and liver of poultry.
Synonyms
Histomoniasis, infectious enterohepatitis, black head disease.
Aetiology
Histomonas meleagridis , a flagellated ameboid protozoan often disseminated by the ova or egg of Heterakis gallinarium. Histomonas does not survive for long outside the ova of the caecal worm.
Age/host affected
Susceptible species are turkeys, chickens, pheasants, guinea fowls and geese. Turkeys are most vulnerable at 3-12 weeks of age while chickens at 4-6 weeks of age.
Transmission
Transmitted by ingestion of embryonated eggs of Heterakis gallinarium carrying viable histomonads.
Disseminated by ingestion of earthworms which accidentally ingest egg of Heterakis gallinarium carrying viable histomonads.
Direct transmission by ingestion of viable histomonads in fresh droppings of infected birds.
Clinical signs
Depression
Inappetence
Poor growth
Sulphur-yellow diarrhea
Cyanosis of head leads to the term black head disease especially in turkeys.
Blood in faeces(chickens).
Progressive emaciation.
Post-mortem lesions
Caeca enlargement , ulcers, caseous cores with yellow, grey or green areas.
Liver may have irregular-round indented lesions, usually grey in colour, however they may not be present in the early stages especially chickens.
Diagnosis
This is based on clinical signs and post-mortem lesions, scrapings from fresh material.
Treatment
Nitro-imidazoles(such as dimetridazole), nitrofurans(such as furazolidone, nifursol) and arsenicals(such as nitarsone) have been used to treat this disease of poultry.
Prevention
Good sanitation
Avoid mixing species
Poultry houses should be built on concrete floors
Regular deworming to help control the intermediate hosts.