No 20a - 2022

Ornithosis 2020-2021

Ornithosis 2020-2021

In the 2020-2021 period, a total of 52 persons became infected with ornithosis, also known as parrot fewer.

Ornithosis is caused by the zoonotic Chlamydia psittaci bacterium that transmits from birds to humans but not between humans. Read more about symptoms, treatment and prevention of ornithosis here (in Danish Language)

The number of human ornithosis cases recorded may vary from one year to the next, but in 2020-2021, the numbers recorded were very similar; 27 and 25 cases, respectively, Figure 1.


The vast majority (49) of the cases recorded in the period had become infected in Denmark, and 31 were registered as having come into contact with either domestic or wild birds. See the 2020-2021 Annual Report here.

In the period, a large nation-wide outbreak among domestic birds was detected and traced. The efforts relating to the outbreak were initiated by the index person’s admission to hospital. Read more about the monitoring and investigation of the outbreak.

No ornithosis vaccine is available, but the condition can be managed effectively by antibiotics. For more information about ornithosis and prevention in humans, please see here.

Ornithosis forms part of the national One Health strategy to counter infectious diseases. Samples from sick people as well as from birds that are suspected carriers of C. psittaci are submitted to the SSI for analysis and monitoring. Read more here about One Health activities and preparedness.

(C. Kjelsø, Department of Infectious Disease Epidemiology and Prevention, R. Føns Petersen, Ø. Angen, S. Uldum, Department of Bacteria, Parasites and Fungi, S. Kjær-Andersen, Animal Health, the Danish Veterinary and Food Administration).

18 May 2022