Aspergillosis

Aspergillosis

Introduction

Aspergillosis is also known as Brooder Pnuemonia, and is  fungal infectious disease, caused by Aspergillus fumigatus, in which the typical sign is gasping for breath, especially in young chicks, though other kinds of mold may occasionally also cause it. Birds are exposed to Aspergillosis through moldy feed, wet and moldy bedding, rotting wood, or exposure to other places mold may grow. Symptoms of Aspergillosis  are gasping, sleepiness, loss of appetite, weight loss, paralysis and sometimes convulsions and death. There is no treatment available for controlling  Aspergillosis, but keeping your poultry area clean and mold free will prevent exposure. Sometimes the same organism causes eye lesions or chronic lesions in older birds. The fungus can infect plant material and many species of animals including birds and man. Occasionally similar lesions are produced by other species of Aspergillus or even other fungi such as Penicillium, Absidia etc.

It affects chickens, turkeys, ducks, penguins, game birds, waterfowl, etc, worldwide. The infection has an incubation period of 2-5 days. Morbidity is usually low, but may be as high as 12%. Mortality among young affected birds is 5-50%. Transmission is by inhalation exposure to an environment with a high spore count; there is usually little bird-to-bird transmission. Spores are highly resistant to disinfectants.

Other Names

brooder pneumonia, aspergillus

Organism or Mechanism

 Aspergillus fumigatus , A. flavus, A. niger, A. glaucus, and A. terreus fungal spores.

Signs

• Acute form:
  • Inappetance.
  • Weakness.
  • Silent gasping.
  • Rapid breathing.
  • Thirst.
  • Drowsiness.
  • Nervous signs (rare).
• Chronic Forms:
• Ocular discharge (ocular form only).
• Wasting.

Additional Information on the Symptoms:

• Because almost any organ of the avian body may be affected by aspergillosis, the symptoms are extremely varied. They may be respiratory, digestive or nervous and occur in birds of all ages.
• Acute aspergillosis -This typically occurs in very young birds and may be associated with considerable losses. Watkins (1940), for instance, estimated that 10% of all deaths in chicks under 14 days old were caused by this disease. Typically there is loss of appetite, increased respiration, a rise in temperature, listlessness, foetid diarrhoea and rapid loss of condition. Convulsions sometimes occur and affected birds often die within 24-48 hours of the onset of symptoms. Epidemic outbreaks in young birds frequently have a very high death rate before control measures can be taken. Similar symptoms may occur in pullorum disease (Salmonella pullorum), from which this form of aspergillosis must be distinguished.
• Chronic aspergillosis -The onset of this form is insidious and the affected birds may survive for long periods in a gradually declining state. The symptoms of the acute disease are often present in a milder form together with anaemia, yellowing of the faeces and the presence of a respiratory rattle. The chronic disease generally occurs sporadically and is the usual form in adult birds.

Post-mortem lesions

• Yellow to grey nodules or plaques in lungs, air sacs, trachea, plaques in peritoneal cavity, may have greenish surface.
• Conjunctivitis/keratitis.
• Brain lesions may be seen in some birds with nervous signs.

Egg Infection

Aspergillus fumigatus can readily attack both fresh and incubating eggs once it has gained entry through the shell. Infection does not seem to occur in the oviduct but results from the external contamination of the shell after laying. Penetration occurs through the pores of the shell and the fungus grows well on the shell membranes, killing the embryo if present and occasionally penetrating into the white. Eventually conidiophores and spores are formed in the air-space and affected eggs can be detected by candling. On breaking open the air-space the greenish felt of hyphae and spores is seen.


The chief fungus reported from eggs in incubation is A.fumigatus but several others have been obtained from stored eggs. Of these probably Cladosporium herbarum is the most important in causing the "black spot" discoloration reported by Weston & Halnan (1927). Lucet (1897) demonstrated that clean eggs cannot be infected by direct application of the spores of A.fumigatus and that it was necessary to put a thin layer of butter or other grease on the shell before infection would take place. Hence he concluded that dirty eggs were more liable to infection than clean, and cited an outbreak of egg infection in ducks in which the nests were heavily contaminated with A.fumigatus.

Diagnosis

This is usually based on the signs and lesions and microscopic examination for the fungus, preferably after digestion in 10% potassium hydroxide. It may be confirmed by isolation of the fungus, typically by putting small pieces of affected tissue on Sabouraud agar. Growth occurs in 24-48 hours and colonies are powdery green/blue in appearance. Differentiate from excessive exposure to formalin or vaccinal reactions in day olds and from heat stress in older birds.

Prevention

 • Dry, good quality litter and feed and hygiene. Avoid conditions that promote fungal growth such as wet litter or moldy feeds

 • Clean and disinfect equipment and air ducts regularly

 • Frequently move feed troughs and water dispensers

 • Thiabendazole or Nystatin has been used in feed.
 • To keep the hatchery free of Aspergillus the following measures can be followed (more...)

Fig 1. 'Furry' airsacculitis in aspergillosis of an adult duck. The powdery surface is dark green in colour.

Fig 2. Aspergillosis fungal infection in Hatching Eggs

Management Treatments

 • Provide dry, deep bedding

 • Cull diseased birds

 • Good sanitation and careful control of feeding stuffs and litter remain the best methods of prevention in domestic birds.

• By far the most effective method of control is by removing the source of infection, i.e. the mouldy litter or food; this should be burned and the premises adequately cleaned out, perhaps using a fungicidal solution. Another method of prevention is described by Urbain & Guillot (1938), who regularly fed the penguins in the Paris zoo with 5-6 mg. of potassium iodide daily for eight consecutive days in each month. Each dose being inserted into a fish. By this technique they found that the incidence of aspergillosis in these birds was greatly reduced. 

Physical Treatments

• Oxine (2% chlorine dioxide) non-activated fogged in brooder 

• Environmental spraying with effective antifungal antiseptic may help reduce challenge. 

• Amphotericin B and Nystatin have been used in high-value birds.

• The treatment of avian aspergillosis is influenced by the lack of clinical diagnosis, for the symptoms are not specific and generally the peak of mortality has been passed before any therapeutic measures can be instituted. Because of this reports of successful treatment or even spontaneous recovery are doubtful.
• Various methods have been used in the direct treatment of individual birds. They include the inhalation of tar vapours (Otte, 1928), chlorine or sulphur dust, but so far no information is available concerning the use of iodide therapy which has been successfully employed in the experimental disease in rabbits and also in human cases.

Nutritional Treatments

 Herbal Treatments

• Garlic Cloves - Give 2 tsp. of ground raw garlic mixed with vinegar 2X daily in 1/2 tsp. Doses.

A popular and economical natural anti-fungal remedy for Aspergillus and other fungal infections is raw garlic cloves. Garlic was used as an antimicrobial, blood cleanser and general health tonic as far back as ancient Greek and Chinese times, according to "The Essential Book of Herbal Medicine." The strong anti-fungal properties of garlic are mainly related to a compound called allicin, which destroys a wide spectrum of mold, fungus and other potential pathogens throughout the body, although it seems to safeguard the beneficial bacteria of the intestinal tract, as cited in "Biochemistry of Human Nutrition." Garlic is eaten raw or consumed as non-odorous capsules and is able to travel to the infected areas via the bloodstream.

• Grapefruit seed extract

Grapefruit seed extract is effective at inhibiting a range of fungal strains including: Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, 

 Homeopathic Treatments for Aspergillosis in chicken

• Ant. Tartrate 30C once daily X 3 days

• Drosera rotundfolia 30C once daily X 3 days

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