Miscellaneous Fungal Diseases

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As for other types of disease, fungal infections probably are

more common causes of disease in wild birds than is currently recognized. Also, the similarity in gross lesions produced by some fungi mask the detection of less common

fungi as disease agents. Numerous types of disease-causing

fungi in addition to  Aspergillus fumigatus and Candida

albicans have been isolated from birds; most isolations have

been from poultry and wild birds being maintained in captivity. Enhanced disease surveillance that is often associated

with privately owned birds and greater opportunity to detect

disease in confined birds are reasons for these findings rather

than any known differences in the occurrence of fungal diseases in free-ranging and captive birds. Many of the reported

infections appear to have been opportunistic invasions by

the fungi involved. The important points are that many fungi

are capable of causing disease in birds but their collective

impacts do not rival A. fumigatus as a single cause of disease

in wild birds. Nevertheless, it is important to be aware of the

diversity of pathogenic or disease causing fungi

Infectious diseases caused by fungi have been grouped

into categories that represent their involvement within the

.host

Trichophyton gallinae is the primary cause of ringworm,

or fowl favus, in birds, and has been reported in poultry and

several species of wild birds in addition to companion animals, humans, and other mammalian species. T. gallinae is

widely distributed geographically, and infection by this fungus is a striking example of a cutaneous mycos(Fig15

Ringworm in birds is highly contagious, and it is transmitted

by direct bird-to-bird contact or by contact with a contaminated environment. The fungus can remain viable at room

temperature in infected scales or skin lesions that slough from

the body for up to 1 year. Microsporum gallinae is another

widely distributed fungus that is a significant cause of ringworm in birds and mammals

Dactylaria gallopova causes a subcutaneous mycosis reported for poultry. This fungus is found in warm habitats

such as hot springs and thermal soils. The fungi generally

enter the body at a traumatized or injured site and may then

invade other sites following fungal establishment and growth

D. gallopova is not contagious, but it can invade the brain

following its spread from the site of infection. Death is the

outcome when the brain is invaded

Aspergillus niger is another fungus within the genus Aspergillus that has caused bird deaths

As noted in the Introduction of this Section, disease due

to infection of tissues is only one aspect of the potential impacts of fungi. The added issues of mycotoxins (see Section

6, Biotoxins), allergic responses, and other aspects of fungal

diseases make fungi an important area for consideration in

the management and stewardship of free-ranging bird populations