White stork suffering from avian-tuberculosis

Background information

At the end of January 2019, a crouching white stork was found, lying on the grounds of a farm in the province of Utrecht. The bird was very calm and could easily be approached. The weakened animal was placed in the scullery to recover. Although after a while the white stork seemed to get better and was able to stand again, he was found dead the next morning.

The investigation

The bird has been retrieved and investigated by the DWHC. The bird was an emaciated sub-adult male white stork (Ciconia ciconia). After investigating the animal, the white stork turned out to have several inflamed organs. The small intestine, liver, spleen, crop, and lungs were affected and the bird also had extensive pulmonary edema. These inflammations are caused by “acid-fast” bacteria.

The case of several inflammations and the detection of many acid-fast bacteria fits the clinical picture of the bacterium Mycobacterium avium. The disease caused by this bacterium is called avian-tuberculosis and is not dangerous for healthy people. However, the bacteria can establish infection in people, particularly those with immune suppression. Besides this disease, the white stork also had tapeworms in their intestines and lice in their plumage. The white stork belongs to the so-called “target species” for bird flu-surveillance and has been tested in that context for the possible presence of the bird flu virus. This white stork turned out not to be infected with avian influenza (bird flu).

Conclusion

The white stork has most probably died by implications caused by avian tuberculosis. When the animal was found, it was already dying, therefore making it possible to approach this wild bird.

More information on avian-tuberculosis can be found on: https://www.dwhc-dev.wp.hum.uu.nl/en/diseases/avian-tuberculosis/