The World Health Organisation has issued an outbreak notice after reports from five European countries of an unexpected rise in infections involving psittacosis, a respiratory disease from a bacteria known to affect birds that began in late 2023 and resulted in five deaths.
The reports were from Austria, Denmark, Germany, Sweden and the Netherlands. In most instances, people had contact with wild or domestic birds, CIDRAP reports.
Affected countries are investigating exposures and case clusters. Only one of the countries – Sweden – had a change in diagnostic testing procedures, a factor that might explain an increase in reported cases.
Psittacosis is caused by Chlamydophila psittaci bacteria, which is known to affect birds. Transmission to humans typically occurs through inhaled particles from respiratory secretions, dried faeces, or feather dust.
Infections are often mild, but patients can develop a sometimes-fatal pneumonia. The disease is treatable with prompt, appropriate antibiotics.
Many patients were exposed to birds
Austria reported 14 cases from five of its nine states in 2023 and has already reported four cases in 2024.
Denmark reported a sharp increase in cases in late 2023 through to mid-January. Of 23 cases, four were fatal; 17 people were hospitalised, including 15 who were diagnosed with pneumonia.
Germany reported five cases in December that brought its 2023 total to 14. Nearly all of them had pneumonia, including 16 who were hospitalised. None were exposed to wild birds, but five had been exposed to domestic birds like parrots, chickens, or breeding pigeons.
In the Netherlands, since late December, 21 cases had been reported. All patients were hospitalised, and one died. Thirteen patients had contact with droppings from wild or domestic birds.
Sweden reported 26 cases from November to December, double what the country typically saw over the same period over the previous five years.
Investigations found that patients often had contact with droppings from small birds, mainly via feeders, though a few may have contracted bacteria from domestic birds like hens or cockatoos.
Unlike the other countries, officials said increasing use of reverse transcription-polymerase chain reaction (RT-PCR) panels for screening may have increased detection.
The WHO added that birds that carry this disease could be crossing international borders, but that there was currently no indication of the disease being spread by humans – nationally or internationally.
CIDRAP article – Unusual rise in psittacosis infections in European countries (Open access)
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