27.07.2006

Hugo perished of Aspergillosis

On Monday the 24th of July the remaining stork chick (Hugo) died of aspergillosis. He was about 57 days old. The stork was examined at the Institute for Fowl Diseases at the Freie Universitaet (FU) in Berlin. The nutritional condition of the bird poor. A profound affection of mould fungi was detected in the air bags. The diagnosis was Aspergillosis.
  
On July 3rd a blood sample had been taken. Neither abnormalities nor avian flu were found.

The mould fungi come from the nest material. Ten samples of nest material of the eyrie and from the region were tested. Comparatively high concentrations of thermotolerant aspergilli, in particular aspergillosis fumigatus were found in foliage/grass cuttings as well as in remnants of compost. During the decomposition of such materials heat is generated which promote the growth of thermo-tolerant mould fungi to which the aspergillosis agent "a. fumigatus" and "a. niger" belong. Then, during the conversion of this or natural processes the agents are carried aerogenly into the environment. With this the agents can be imported into the eyrie or the birds are directly exposed to them. In addition, the inclusion of contaminated nest material, and here all tested materials are a part of the question, can lead to the proliferation in the eyrie of the aspergilli which primarily function as saprophytes (saprophyte = a plant living off other decaying plant materials). This can be further promoted by the release of warmth of the animals while brooding.

To what extent the fungi, which have led to the infection of the birds, have originated in the nest material or the region, is unclear at the moment. To throw more light
onto the interrelationship, an agent typing would have to be conducted during which the infection agents from the lungs and air sacks of the infected birds are compared
to the same species of fungi from the nest material of the eyrie where the infection occurred, and with isolated samples from the area of the eyrie.

A further problem could be the production of mycotoxin by the mould fungi found within the material of the eyrie. For example, a. fumigatus can produce gliotoxin which
accumulates in the nest material and is possibly absorbed by the birds. Through this, the immune system of birds is weakened and the risk of an infection and subsequent illness of aspegillosis to the animals is increased. A closer estimate of these problems can only be reached through a focused examination of the nest material.

First conclusion:

• Hugo was infected by mould fungi. Although he developed well in the beginning and reached 57 days of age, the extremely favourable climactic conditions allowed the agent spread that he had no chance to survive. A cure was impossible.
• We will remove the nest material completely in fall, and place a willow basket base onto the steel base. The compost and waste heaps which are heavily contaminated with aspergillus (there are three from which the storks collect nest material)we will try to get rid of.
• Further examinations to find the causes and to draw final conclusion for the protection of storks are necessary

Winfried Boehmer
NABU-Project Leader

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