Previous outbreaks of Pontiac fever have invariably been associated with water droplet spread of Legionella spp. In January 2007 three workers from a horticultural nursery were admitted to hospital with non-pneumonic legionellosis. Investigations showed that a working party of ten people had been exposed to aerosolized potting mix; nine of these workers met the case definition for Pontiac fever. The presence of genetically indistinguishable Legionella longbeachae serogroup 2 was demonstrated in clinical specimens from two hospitalized workers and in the potting mix to which they had been exposed. A further seven cases were diagnosed by serological tests. This is the first documented outbreak of Pontiac fever from L. longbeachae serogroup 2 confirmed from inhalation of potting mix. Pontiac fever is likely to be under-diagnosed. We advocate the introduction of an industry standard that ensures the use of face masks when handling potting mix and attaching masks and warning labels to potting mix bags sold to the public.

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SUMMARYThis study evaluated the spatio-temporal variation of Legionella spp. in New Zealand using notification and laboratory surveillance data from 1979 to 2009 and analysed the epidemiological trends. To achieve this we focused on changing incidence rates and occurrence of different species over this time. We also examined whether demographic characteristics such as ethnicity may be related to incidence. The annual incidence rate for laboratory-proven cases was 2 . 5/100 000 and 1 . 4/100 000 for notified cases. Incidence was highest in the European population and showed large geographical variations between 21 District Health Boards. An important finding of this study is that the predominant Legionella species causing disease in New Zealand differs from that found in other developed countries, with about 30-50% of cases due to L. longbeachae and a similar percentage due to L. pneumophila for any given year. The environmental risk exposure was identified in 420 (52 %) cases, of which 58 % were attributed to contact with compost ; travel was much less significant as a risk factor (6 . 5 %). This suggests that legionellosis has a distinctive epidemiological pattern in New Zealand.

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Background: During New Zealand's first outbreak in early 2020 the Southern Region had the highest per capita SARS-CoV-2 infection rate. PCR testing was initially limited by a narrow case definition and limited laboratory capacity, so cases may have been missed. Objectives: To evaluate the Abbott SARS-CoV-2 IgG nucleocapsid assay, alongside spike-based assays, and to determine the frequency of antibodies among PCR-confirmed and probable cases, contacts, and higher risk individuals in the Southern Region of NZ. Study design: Pre-pandemic sera (n=300) were used to establish assay specificity and sera from PCR-confirmed SARS-CoV-2 patients (n=78) to establish sensitivity. For prevalence analysis, all samples (n=1214) were tested on the Abbott assay, and all PCR-confirmed cases (n=78), probable cases (n=9), and higher risk individuals with grey-zone (n=14) or positive results (n=11) were tested on four additional SARS-CoV-2 serological assays. Results: The median time from infection onset to serum collection for PCR-confirmed cases was 14 weeks (range 11-17 weeks). The Abbott assay demonstrated a specificity of 99.7% (95% CI, 98.2%-99.99%) and a sensitivity of 76.9% (95% CI, 66.0%-85.7%). Spike-based assays demonstrated superior sensitivity ranging 89.7-94.9%. Nine previously undiagnosed sero-positive individuals were identified, and all had epidemiological risk factors. Conclusions: Spike-based assays demonstrated higher sensitivity than the Abbott IgG assay, likely due to temporal differences in antibody persistence. No unexpected SARS-CoV-2 infections were found in the Southern region of NZ, supporting the elimination status of the country at the time this study was conducted.