[Malaria: under-notification and risk assessment for travelers to the tropics].

OBJECTIVE

To define the risk of contracting malaria for travellers to malaria-endemic areas and to calculate the under-notification under the current notification system.

DESIGN

Retrospective epidemiological analysis.

SETTING

Agricultural University Wageningen, The Netherlands.

METHODS

Risks of contracting malaria were estimated by calculating the incidence per 100,000 travellers. This incidence was found using an estimated under-notification calculated on the basis of data from the "SIG Zorginformatie' (hospital cases) and the Medical Health Inspectorate (notified cases).

RESULTS

The average under-notification in the Netherlands was at least 59% in the period January 1988 to June 1993 inclusive and increased by 10% each year. Judging by this estimation at least 3170 travellers returned to the Netherlands with malaria in this period. The risk in Africa appeared to be decreasing. In Asia the malaria incidence increased slightly in recent years while no trend was found for America. The imported malaria was mainly caused by Plasmodium falciparum.

CONCLUSION

In order to improve the malaria notification system in the Netherlands a notification obligation for all microbiological laboratories should be introduced as almost all malaria is diagnosed there.