Aspergillosis – Emu Health

Scientific name

Aspergilla flavus


Aspergillosis is a disease caused by a fungus from the genus Aspergilla.

Aspergilla has the potential to infect a wide range of mammalian, avian and reptilian species, including humans, and is probably the most common fungal infection affecting birds.

The most common species of Aspergilla that causes diseases in birds are A. fumigatus, A. flavus and A. niger. Numerous other species of Aspergilla are present in the environment but they rarely appear as a cause of the disease.

A. flavus is a cause of aspergillosis in emus in Queensland.

How the disease occurs

Aspergilla is widespread throughout the environment. Where conditions are suitable, it grows and multiplies to give a localised high concentration of the fungus.

Favourable conditions include:

  • warm, moist areas, e.g. in litter around waterers and some types of deep litter
  • mouldy or rotting areas, e.g. spoiled or damp feed and rotting vegetation.

As with other fungi, Aspergilla has a growing phase where hyphae (the appearance of white strands/lumps) grow. This is followed by the production of spores, which are resistant to environmental conditions and are very small, enabling them to be easily transported by wind and in dust particles. Favourable conditions can produce large numbers of spores.

Birds usually become infected when they inhale the spores. The infection is not transferred from bird to bird. A bird’s immune system can control the infection if they have inhaled only a relatively small number of spores. Infection results if the immune system is deficient, such as in very young chicks where the immune system is still developing, or in birds that have been stressed by other disease problems, overcrowding, or insufficient food and water. Infection can also result in normal birds if they inhale a massive numbers of spores and their immune system is overwhelmed.

In Queensland, aspergillosis has been found in young chicks and caused deaths in the 3-8 week age group. There appears to be a strong association between infection and the presence of dust from litter in the atmosphere of the brooder shed. This dust can be raised when the litter is shovelled out or raked over, and even the passage of older chicks raises dust from the litter.

Clinical signs

In Queensland, the disease in emus is a rapidly progressing respiratory condition that continues to worsen until the chick dies.

The chicks appear to get infected in the brooder house very early in life. Initially, there are no signs, but then affected chicks will gradually appear unthrifty and less active than other chicks in the group. They will show signs of gasping and respiratory distress if forced to exercise. In the final stages, the chick is obviously depressed, doesn’t move much and shows laboured respiration, which is an exaggerated movement of the ribs and chest in and out with each breath, possibly combined with open-mouthed breathing. This is the terminal stage and the chick usually dies soon after.

These signs are caused by spores hatching and growing in the lungs. Firm, round, white nodules form in the lung tissue and grow steadily. As they grow they occupy lung space and disrupt the lung’s normal functioning. This reduces the oxygen supply to the chick to the point where it can no longer survive. These nodules may also be found in other sites, including the air sacs attached to the rib cage, liver and abdominal cavity.

Reports from the ostrich industry indicate that, as well as causing problems in chicks, aspergillosis can also infect the air sacs of older birds, causing a chronic, debilitating disease.


This is usually done by a post-mortem of suspect birds, with specimens sent to a veterinary laboratory for confirmation.


There is no known effective treatment for clinically sick birds. The ostrich industry has attempted a range of treatments but has not yet found a successful treatment regimen.


At this stage, prevention is the only effective method of controlling aspergillosis in emus.

Prevention should be aimed at three broad areas:

  • Removal or control of favourable areas for fungal growth. This would include removing wet litter, not using damp or mouldy straw or hay as litter or food, not using and removing spoiled grain, and regular provision of fresh non-dusty litter
  • Dust control in brooder sheds. This is an important area, as dust in the air of brooder sheds is closely related to infection of young chicks. As dust is most likely to be raised when litter is removed or raked over, lightly damping down the litter may prevent dust being raised when moved. Good quality litter also helps. A coarse litter of wood chips or pine wood shavings appears to work well. Litter that is already dusty may only contribute to the problem
  • Hygiene. This can prevent aspergilla numbers building up to a point where problems occur. Attention needs to be paid to hygiene in all stages to the end of the brooder stage. Eggs should be fumigated and/or washed in a recognised egg sanitiser and used according to directions. The cold storage room, incubator and hatcher should be fumigated or cleaned regularly with a recognised disinfectant active against fungi. The brooder house should be cleaned and disinfected before the hatching season begins. If individual pens are cleaned out during the breeding season, they should be disinfected each time as well. Disinfectants that are active against aspergilla include those containing gluteraldehyde as an active constituent, Virkon ® S.

The above areas will also control other diseases that may cause problems during incubation, hatching and brooding.