[Considerable underreporting of malaria in the Netherlands; a capture-recapture analysis].

OBJECTIVE

To estimate the completeness of notification of malaria by physicians and laboratories in the Netherlands.

METHOD

Capture-recapture analysis was applied to three incomplete, partially overlapping registers of malaria cases in 1995 and 1996: a laboratory survey, the Notification Office and the hospital admission registration.

RESULTS

The average response of the 107 laboratories approached was 83.6% over both years. In 1995 and 1996 581 and 535 malaria cases respectively were microscopically diagnosed. In each year physicians officially notified 311 patients. 350 and 330 patients respectively were admitted to hospital. Capture-recapture analysis estimated the total number of new malaria cases at 933 (95% confidence interval: 849-1072) in 1995 and at 774 cases (740-821) in 1996. The estimated completeness of notification in 1995 and 1996 was therefore 33.3% and 40.2% for physicians and 62.3% and 69.1% for the laboratories.

CONCLUSION

Laboratory-based notification, introduced in the Infectious Diseases Act, can considerably increase the number of officially reported malaria cases as compared with notification by physicians. However, approximately one-third of the estimated number of cases may still go unreported.