Acute gastrointestinal illness in New Zealand: information from a survey of community and hospital laboratories

Abstract

Aim: To describe and quantify laboratory testing of faecal samples for enteric pathogens as a component of the reporting pyramid of acute gastrointestinal illness (AGI) in New Zealand.

Method: Postal survey of community and hospital laboratories throughout New Zealand conducted in mid-2006, requesting data from the 2005 calendar year.

Results: Of the 47 laboratories eligible for the survey, responses were received from 35 (74%, 16 hospital laboratories, 12 community laboratories, five hospital and community laboratories, and two Public Health Laboratories). Based on survey data and extrapolation it was estimated that approximately 250,000 faecal samples were received by New Zealand laboratories in 2005. The majority of these (77%) were requested by primary healthcare providers on people in the community. Routine testing of these samples would include bacteria (Salmonella, Shigella, Campylobacter, Yersinia) and parasites (Cryptosporidium, Giardia) and (depending principally on the age of the patient) rotavirus. Testing for other pathogens was comparatively infrequent. The frequency of detection of a pathogen in community samples was estimated as approximately 20%.

Conclusion: The positivity rate of 20% for faecal samples from people in the community is consistent with overseas results. Although there was considerable variation in the testing methods employed by the laboratories the methods were considered appropriate based on consultation with ESR Public Health and Reference Laboratory staff. These data on the number and type of samples, and positivity rate , will assist in the determination of a reporting pyramid for AGI in New Zealand.