Testing and detection trends of Chlamydia trachomatis and Neisseria gonorrhoeae in Waikato, New Zealand: 1998-2006.

AIM: To examine influences on testing and detection trends of Chlamydia trachomatis and Neisseria gonorrhoeae in the Waikato, 1998-2006.

METHODS

Testing data for Chlamydia trachomatis and Neisseria gonorrhoeae undertaken within the Waikato District Health Board was collated from 1998 to 2006. National or local issues and interventions felt likely to be influential were identified.

RESULTS

Annual testing for Chlamydia trachomatis rose from approximately 18,000 tests in 1998 to 23,338 tests in 2002 and remained around this level for the rest of the period. Percent positive tests rose from 7.7% in 1999 to 11.3% in 2005, before a decline to 9.6% in 2006. Annual testing for Neisseria gonorrhoeae doubled over the study period with a peak of 52,199 tests in 2005 that coincided with a nationwide safer sex media campaign. From 1999-2004, about 0.4% of Neisseria gonorrhoeae tests were positive, with a peak of 0.9% in 2006, whilst fewer percent positive tests were noted during increased testing in 2005. For both conditions, fluctuations were noted in the volume of tests and positive tests by quarter but it was not possible to establish causality for these changes.

CONCLUSION

High levels of testing and detection of sexually transmitted infections are evident in the Waikato. Testing rates amongst those most at-risk are unknown. Rising numbers of gonococcal infections in recent years suggest ongoing sexual risk-taking behaviour. This study augments calls for laboratory surveillance to be upgraded, with more detailed information on all tests, not just cases, to improve data interpretation and facilitate appropriate public health action.