jeudi 20 décembre 2007
1] Netherlands : (Gelderland), bird show Date : Thu 13 Dec 2007 Source : Eurosurveillance weekly release, 2007 12(12) [edited]
On 14 Nov 2007, a general practitioner in the Nijmegen region of the Netherlands called the Municipal Health Service (MHS). He reported 3 patients complaining of high fever, vomiting, diarrhoea, and headache, all of whom had visited a bird show in the rural town of Weurt (village of Beuningen). The bird show, organised by the local bird society, took place between 31 Oct and 4 Nov . The birds arrived on 31 Oct  at the show’s premises and were inspected for the contest on 1 Nov. In the following days, the show was open to the public. According to the organisation committee, about 200 people, mainly members of bird societies in the region of Nijmegen and their families, visited the show.
On 15 Nov , it became clear that at least 18 people, all connected to the local bird association, had become ill with the symptoms mentioned above after visiting the show ; 7 of them were hospitalised. On 16 Nov, one of 2 sputum samples and one of 6 throat swabs that had been taken from 6 of the hospitalised patients tested positive for _Chlamydophila psittaci_ in real-time PCR (polymerase chain reaction). The 2 positive samples stemmed from 2 different patients.
In a nearby village, a bird show scheduled for the weekend of 17-18 Nov  was cancelled as a precautionary measure.
In close cooperation with the local bird society, the MHS actively traced visitors who fell ill after attending the bird show. Based on clinical presentation, date of illness onset, and the common exposure of these patients at the bird show, a cluster of _C. psittaci_ infections was suspected. For further case finding, the following case definition was used : a person who visited the bird show on any day between 31 Oct and 4 Nov  and developed, 5 days or more after attending the show, at least 2 of the following symptoms : fever of over 39 deg C (102.2 deg F), headache, muscular pain (shoulder, neck), coughing, shortness of breath, cold shivers or sweating, and gastrointestinal symptoms (abdominal pain, nausea, vomiting, diarrhoea).
Regional general practitioners and specialists were informed about this cluster of probable psittacosis. They were advised to perform laboratory diagnosis (throats swab and serology) and to start treatment (200 mg doxycycline for 10 days) in patients that matched the case definition.
People who had visited the show were informed of the outbreak in a letter that recommended timely consultation of a physician if they had developed symptoms. In cooperation with the Food and Consumer Product Safety Authority (VWA), source and contact tracing of the birds was launched. Faecal samples of all birds that were exhibited at the bird show were taken and tested for _C. psittaci_.
By 30 Nov , 25 cases had been registered. Figure 1 [available at the source URL] shows the epidemic curve of this outbreak to date.
Among people who had prolonged contact with the birds, such as the organisers of the show, jury members, or members of the society (referred to as ’members’ in the figure), the attack rate was higher (39 percent [19/49]) than among persons who only visited the show (estimated attack rate 3 percent [6/150] ; referred to as ’visitors’ in the figure). So far, 3 (12 percent) of the 25 reported cases have been laboratory-confirmed by RT-PCR (reverse transcriptase polymerase chain reaction). Serological confirmation of _C. psittaci_ infections by ELISA enzyme-linked immunosorbent assay IgM or IgG are pending.
The VWA took samples of all birds that were exhibited during the show (parakeets, finches, canaries, and several other types of bird). A total of 74 pooled samples were taken from approximately 300 birds. _C. psittaci_ was detected by RT-PCR in the birds of one owner, who was one of the 7 hospitalised patients. The test results of the birds of a second owner, who was not ill, were unclear. Faecal samples of other birds were negative for _C. psittaci_. The VWA informed the owners of the infected and possibly infected birds of the test results on 23 Nov . Birds that may have carried the bacteria are now being individually sampled and subsequently treated with doxycycline.
In the Netherlands, between 30 and 70 cases of psittacosis are notified annually. If left untreated, psittacosis can have serious complications, such as severe pneumonia. People may become infected after contact with infected birds as a result of their occupation (for example, pet shop employees, bird breeders, poultry slaughterhouse workers), hobby, or incidental contact. Most cases of psittacosis are sporadic, and outbreaks are rarely reported [1-5]. A paper on a large outbreak of psittacosis in a veterinary teaching hospital in the Netherlands has recently been published .
Surprisingly, the faecal samples of only a few birds were positive in the current outbreak. This could have been caused by intermittent shedding of _C. psittaci_. Furthermore, it has been shown that birds shed more bacteria during stress . Increased shedding might thus have occurred because of the stressful situation during the bird show.
Genotyping of the _C. psittaci_ cultivated from human cases and birds will be performed. A retrospective cohort study has been launched. All visitors to the bird show have been invited for serological screening and to complete a questionnaire in order to get a better estimate of the attack rate and help clarify possible risk factors associated with infection.