An outbreak of psittacosis due to Chlamydophila psittaci genotype A in a veterinary teaching hospital

1 Department of Medical Microbiology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands 2 Department of Medical Microbiology and Immunology, St Antonius Hospital, Nieuwegein, The Netherlands 3 Department of Medical Microbiology and Immunology, Diakonessen Hospital, Utrecht, The Netherlands 4 Department of Infectious Diseases and Hygiene, Municipal Health Service, Utrecht, The Netherlands 5 Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Division of Avian and Exotic Animal Medicine, University of Utrecht, Utrecht, The Netherlands 6 Department of Medical Microbiology and Infection Control, VU University Medical Centre, Amsterdam, The Netherlands Correspondence Edou R. Heddema e.r.heddema{at}amc.uva.nl Received 20 April 2006 Accepted 25 July 2006 An outbreak of psittacosis in a veterinary teaching hospital was recognized in December 2004. Outbreak management was instituted to evaluate the extent of the outbreak and to determine the avian source. Real-time PCR, serologic testing and sequencing of the ompA gene of Chlamydophila psittaci were performed. Sputum samples from patients, throat-swab samples from exposed students and staff, and faecal specimens from parrots and pigeons were tested. In this outbreak, 34 % (10/29) of the tested individuals were infected. The clinical features of the infection ranged from none to sepsis with multi-organ failure requiring intensive-care-unit admission. C. psittaci genotype A was identified as the outbreak strain. Parrots, recently exposed to a group of cockatiels coming from outside the teaching facility, which were used in a practical class, appeared to be the source of the outbreak. One of the tested pigeons harboured an unrelated C. psittaci genotype B strain. The microbiological diagnosis by real-time PCR on clinical specimens allowed for rapid outbreak management; subsequent genotyping of the isolates identified the avian source. Recommendations are made to reduce the incidence and extent of future outbreaks. Abbreviations: CFT, complement fixation test; IC, internal control; MIF, microimmunofluorescence; rELISA, recombinant ELISA. The GenBank/EMBL/DDBJ accession numbers for the sequences of the ompA gene of the C. psittaci OSV outbreak strain and the unrelated C. psittaci CLV pigeon isolate are DQ230095 and DQ230096, respectively. Present address: VU University Medical Centre, Department of Medical Microbiology and Infection Control, PO Box 7057, 1007