Giardia infection in Auckland and New Zealand: trends and international comparison.
OBJECTIVE
To describe the epidemiological pattern of Giardia infection in the Auckland region and compare it with national and international patterns of Giardia infection.


METHODS
Anonymised giardiasis notification data from the Auckland District Health Board for the period July 1996 to June 2000 were analysed by person, place and time. Infection rates and relative risks were calculated and compared with national and international information.


RESULTS
Auckland had a significantly higher rate of Giardia infection than New Zealand as a whole. Infection rates, which peaked during February-May, were significantly higher in Pakeha/Europeans and Asian/others, compared with Maori/Pacificans. Adjusted notification rates were higher for residents of North Shore and Auckland cities than for other areas of Auckland. The crude regional and national notification rates were almost six times the rate of laboratory identification of positive isolates in the UK and four times US reported rates.


CONCLUSIONS
The higher rates of giardiasis observed in Auckland and New Zealand, in comparison with other developed countries, may be related to environmental or social factors. Missing ethnicity information precludes clear interpretation of variations in notification rate by ethnic group and suggests a need for improvement in data collection. There are opportunities to investigate the influence of risk factors on seasonal changes in notification rates both locally and nationally.
Hoque
M Ekramul
ME
New Zealand Environmental and Occupational Health Research Centre, Division of Community Health, The University of Auckland. e.hoque@auckland.ac.nz
Hope
Virginia T
VT
Scragg
Robert
R
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D005873:Giardiasis / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D011159:Population Surveillance; D012307:Risk Factors; D012621:Seasons; D017678:Sex Distribution