Fungal Diseases of Poultry

1. Avian . 2. . 3. Favus. 4. Dactylariosis. Brooder pneumonia, mycotic pneumonia, pneumomycosis, Bronchomycosis Definition:

⚫ An infectious disease ⚫ Mainly of respiratory tract of birds ⚫ Characterized by ⚫ Acute miliary of the lungs in young birds ⚫ Chronic air sac infection in adults ⚫ Respiratory distress, central nervous dysfunction, sleepiness, inappetance emaciation, conjunctivitis and cloudy eyes can be seen Etiology

⚫ Many species of genus which is composed of approximately 600 species. ⚫ Mainly Aspergillus fumigatus. Other species like A. flavus, A. nidulans, A. glaucus, A. niger, and A. candidus ⚫ Family Moniliaceae ⚫ Characteristics: ⚫ Commonly occur in decaying vegetative matter, soil & feed grains ⚫ The fungi grow on sabaroud dextrose agar media with antibiotics at room temperature 37C. Colonies are green to bluish green at first and darken with age to appear almost black.

Sabouraud dextrose agar ⚫ Aspergillus species are common in the environment. Spores often become airborne in dry windy weather spreading from one location to another. Spores can enter an individual and develop in the respiratory system, lungs, eyes, and ears. ⚫ A. Fumigatus has a toxin which is hemotoxic, neurotoxic, and histotoxic. ⚫ Aspergillosis can be fatal, especially to those with immunodeficiency. its opportunistic pathogen. ASPERGILLUS

This micrograph depicts the histologic features of aspergillus including the presence of conidial heads

Susceptibility:

⚫ Species: all species of birds probably are susceptible. The disease develops in the brooder stage in chicks, quails, pheasants, turkeys, pigeons, parrots, etc... ⚫ Age: chicks below 10 days of age but may affect birds up to the age of 10 weeks. Chicks below 3 days of age are highly susceptible. Transmission

⚫ Air borne disease: Inhalation of conidia (spores) from contaminated feed, fecal material, and soil. ⚫ Egg borne disease: Aspergillus can also infect the developing embryo by penetrating the egg while the embryo is developing. Infected eggs may develop a slightly greenish tint when candled. ⚫ Contaminated incubators & hatchers ⚫ Egg shell contamination ⚫ The disease is not contagious and does not spread from one bird to another. Clinical signs ⚫ There are two forms of aspergillosis: Acute aspergillosis: ⚫ This typically occurs in very young birds and may be associated with considerable losses. Chronic aspergillosis: ⚫ Occur in adult birds, the affected birds may survive for long periods in a gradually declining state. General signs: ⚫ Depression, inappetence, dropping of the wings, retardation of the growth, emaciation, diarrhea in the later stage ⚫ Respiratory signs (pulmonary aspergillosis) ⚫ Dyspnea, gasping, accelerated breathing, serous nasal and ocular discharge. ⚫ May coughing, sneezing, gurgling, or noises only if complicated with IB or ILT. ⚫ Nervous signs: ⚫ Occur when the fungi and its toxin reach the brain. ⚫ Torticollis, incoordination of movement, convulsions. ⚫ Occur in young birds (turkey poults, chicks, ducklings, and gooslings. ⚫ Eye infection: ⚫ Usually unilateral, characterized by yellow cheesy exudates beneath membrane causing bulging of the eyelids in turkey poults and chicks. ⚫ May ulceration of the cornea which leads to blindness in older birds. ⚫ Cutaneous aspergillosis (dermatitis): Necrotic or granulomatous dermatitis in any part of the body and the feathers are dry and easily broken. ⚫ Ostemycosis: partial paralysis in young chickens due to deformation of the vertebrate caused by A. fumigatus. ⚫ In laying flocks: Temporary lower in egg production Dyspnea, gasping & accelerated breathing post mortem lesions

⚫ Small white caseous nodules (approx. 1 mm diameter) scattered throughout lung tissue ⚫ Caseous plaques on thickened air sacs that become larger & numerous in advanced cases ⚫ Visible greenish gray growth may also be observed on air sacs due to sporulation of organism. ⚫ Yellowish-green or whitish, caseous (cheesy) nodules and/or green, fur-like down in mouth, palate, trachea, syrinx, viscera, brain and eyes Clinical signs and lesions

Aspergillosis of eggs air sacculitis Clinical signs and lesions

meningo- encephalitis pneumonia

uveitis arthritis lungs, showing large and extensive caseous nodules. granular appearance

lungs, showing large and extensive caseous nodules. Caseous nodules in the air sac.

Multiple nodules in the liver

DIAGNOSIS

⚫ Necropsy findings ⚫ Isolation & identification of organism ⚫ Sample sites: Caseous nodule in lung or air sac ⚫ Isolation of culture in 48 hours on Sabouraud dextrose agar is diagnostic ⚫ Direct microscopy: Small portion of nodule is teased in 20% KOH on a slide & is covered with cover slip. (hyphae, mycelia, conidophores) Stain colony with lactophenol cotton blue to see conidophores ⚫ Serologic tests are of limited use ⚫ Monitoring of hatchery, feed, litter & premises to find out source of infection Hyphae of Aspergillus fumigatus Differential diagnosis

⚫ Pullorum disease: Lesions of brooder pneumonia are confined to respiratory system while pullorum disease lesions occur also in abdominal organs ⚫ CRD, ND & IB: Gasping & breathing is rapid in brooder pneumonia but no respiratory sounds. ⚫ MD & LL: In Aspergillosis nodules in the lungs and fungal fur-like down in the air sacs are diagnostic, which is not seen in MD & LL Prevention:

⚫ Hatchery sanitation: Regular fumigation of eggs An aerosol of thiabenidazole can be placed in the hatchery to kill Formalin fumigation is an effective method to kill Aspergillus in the environment ⚫ Feed & litter should be kept dry. ⚫ Access to moldy litter & feed should be avoided. ⚫ Daily cleaning & disinfection of feed and water utensils. ⚫ Proper ventilation ⚫ Overcrowding should be avoided. ⚫ Chlorine, and/or copper sulphate can be added to the water to help reduce the spread of the organism Control:

⚫ It is usually an infection of individual birds rather than a flock problem ⚫ Sacrifice the affected birds ⚫ Spray pens with 1% CuSo4 solution ⚫ 1: 12000 aqueous solution of CuSO4 in drinking water. ⚫ Hygienic disposal of dead birds. ⚫ Options for the treatment of aspergillosis are limited, the drugs used include: nystatin, mycostatin, and amphotericin B Treatment

No treatment ! Thrush / candidiasis/ crop / moniliasis

⚫ ⚫ Disease of upper GIT tract. ⚫ Characterized by whitish thickened areas of the crop and proventriculus, erosions in the gizzard. ⚫ Crop is thickened by a soft ,yellow white irregular false (pseudo) membrane (curd like appearance ) ⚫ Mouth & esophagus show ulcer like patches. ⚫ Nystatin / Gentian violet drops Definition:

⚫ Candidiasis is a mycotic disease primarily affects the upper digestive tract of all birds mainly chicken and turkeys, characterized by whitish thickened areas of the crop and proventriculus, erosions in the gizzard, and inflammation of the vent area. Susceptibility:

⚫ Species: Candidiasis is usually seen in chickens and turkeys but also occurs in pigeons, pheasant, quails, geese as well as other domestic animals and mammals. Ages: Poultry of all ages are susceptible to the effects of this organism. young ages tend to be more susceptible than adult birds and infection is more common in birds under than 3 weeks of age. Etiology:

⚫ It is caused by -like fungus (Candida albicans) appear as round to oval budding . ⚫ Candida albicans grows on saboraud’s dextrose agar with chloramphenicol and cycloheximde at room temperature. Or at 37c and after 1-2 days produce creamlike colony can be isolated from digestive tract of many normal birds. ⚫ Apparently it acts as a facultative pathogen.

Predisposing factors and Mode of transmission:

⚫ Candida albicans is present in the normal digestive tract of many birds and mammals. When the birds become debilitated or the normal flora is altered, the fungus can invade the mucosa and produce lesions. ⚫ Common predisposing factors causes include parasitism, nutritional deficiency, infectious diseases, lack of good sanitation and overtreatment with antibiotics or other medications. ⚫ Moniliasis is transmitted by ingestion of the causative organism in infected feed, water or environment. ⚫ Unsanitary and unclean water troughs are an excellent reservoir of the Candida organism. Clinical signs:

⚫ This disease produces no specific symptoms. ⚫ General signs: Young birds become listless, pale, show ruffled feat and appear unthrifty. ⚫ Affected caged layer hens become obese and anemic. ⚫ Some birds exhibit a vent inflammation that resembles diarrhea. Gross lesions

⚫ Are mostly confined to the crop, proventriculus and gizzard. ⚫ Crop shows characteristic lesions; sometimes oesophagus and proventriculus : Mucosa of the crop gives “Turkish towel-like” appearance or it may produce round, raised ulcers. ⚫ Erosion of the lining of the proventriculus and gizzard is commonly observed, as well as an inflammation of the intestines. Curd like appearance 22-Candidiasis Diagnosis:

⚫ Is based on history and typical lesions in the flock. ⚫ Confirmation of the condition is by isolation and laboratory identification of the C. albicans organism. ⚫ By embryo inoculation test: Isolated C. albicans is inoculated into chorioallantoic membrane of the chicken embryo. one hundred thousand Candida organisms in 0.1 ml of distilled water produce lesions within 48 hrs. and 50 per cent of the embryos may die between 40 and 72 hrs. Prevention:

⚫ Avoid predisposing factors especially long administration of drugs. ⚫ Cleanliness, proper managemental care and adequate vitamin A supplement are essential for prevention of the disease ⚫ Continous use of mold inhibitors in the feed. ⚫ Proper feed handling and storage. ⚫ Daily cleaning and sanitizing of the watering system and periodic stirring and/or replacement of wet litter areas to prevent caking. Treatment:

⚫ Treatment of the flock with an antimycotic drug will control the infection. ⚫ Administration of 71-125 mg nystatin/kg of feed helps in preventing further spread of the disease and 200 g mycostatin/ton of feed completely destroys the contaminating fungus in the crop. ⚫ Gentian violet given in dose of 8 mg/kg feed also controls the disease. ⚫ Amphotericin B. ⚫ Copper sulphate 1:2000 to flush GIT during the course of outbreaks ⚫ Lesions in the mouth can be treated by local application o a suitable antiseptic. Favus (chicken ringworm) , Avian ring worm, . Definition:

⚫ Favus is an economically less important fungus disease which occurs sporadically. It is caused by . Cause:

⚫ Microsporum gallinae. ⚫ Cultured on Saboraud ’s dextrose agar and the Colonies usually will develop in 1-2 weeks at 27°C, or about 4 weeks at 20°C. Initially, colonies are white and velvety and become tinged with pink as the culture ages. The colony reverse is initially yellowish and gradually changes to red. Predisposing factors

⚫ Wounds in comb and wattles. Spread

⚫ Spread Infection spreads from one bird to another by direct and indirect contact through detached scales contaminating the fomites. Susceptibility:

⚫ Favus affects mainly chickens and to less extent turkey, duck, quail, and canary and the birds which are kept under poor managemental conditions. ⚫ Favus can produce ringworm lesions in their human handlers (zoonotic). ⚫ It affects only adult birds because it is chronic disease which develops slowly. Symptoms and Lesions

⚫ The combs of the affected birds show deposition of thin, white, flour-like material. Slowly, this layer spreads to other unfeathered parts of the body. Later, the deposits slough off from the skin. Infected skin becomes thickened.

Diagnosis:

⚫ Signs and lesions. ⚫ Isolation of Microsporum gallinae by Skin scrapings on Saboraud’s dextrose agar: ➢ Skin scrapings placed in a drop of 10% KOH on a glass slide, which is then cover-slipped and gently heated over aflame, can be used to visualize the intact and fragmented intralesional hyphae. ⚫ Scrapings can be cultured on Saboraud's dextrose agar with ~50g/ml chloramphenicol and 0.5 mg/ml cycloheximide and incubated at or around 27°C. Colonies of M. gallinae usually will develop in 1-2 weeks at 27°C, or about 4 weeks at 20°C. ⚫ microscopic examination of the fungus through: ⚫ The skin scab is placed on glass slide in 20 % solution of potassium hydroxide and heated till the appearance of a few bubbles and then it is examined to see the fungi. Prevention:

⚫ Avoid predisposing factors. ⚫ New birds must be checked for the symptoms and lesions of the disease at the time of replacement. Control

⚫ Diseased birds should be segregated and kept in isolation. ⚫ If necessary, the diseased birds should be killed. ⚫ Care should be exercised when handling birds with favus to prevent zoonotic transmission. ⚫ Use of examining gloves with proper disposal after use is encouraged. ⚫ Thorough cleaning and disinfection of the premises with 2-3% formalin or 0.5- 1% copper sulphate or 1 % NaOH. Treatment:

⚫ Treated mildy affected birds locally after removal of scales by warm water and soap by: ➢ Sulpher ointment. ➢ Tincture iodine and glycerine 1:6 ➢ Soap and 5% phenol solution. ➢ Use recent fungal ointment. ➢ Systemic antifungal therapy may attempt in valuable birds.