The Epidemiological Surveillance System of Navarra includes the notification of 33 transmissible infectious diseases, to which epidemic outbreaks of any aetiology and cause are added. Reporting to the system is carried out on a weekly basis by every doctor who suspects or diagnoses any of these processes. In our autonomous community, Diseases of Compulsory Notification (DCN) are reported to the Section for the Control of Infectious Diseases and Outbreaks of the Public Health Institute on a weekly basis by the doctors of Primary and Specialised Care. Subsequently, the information is sent to the National Epidemiology Centre where data from the autonomous communities is centralised. In 1999, under the heading of diseases of respiratory transmission, 59,159 cases of Flu were reported; 65% of total annual cases were reported in the first 9 weeks of the year, with a maximum in week 4 when 6,826 cases were reported. 18 cases of Meningococcal Disease were reported to the system. Sixteen cases were confirmed microbiologically and appeared in a sporadic way. With respect to the causative serogroup, serogroup C was isolated on 8 occasions. On 7 occasions Neisseria meningitidis serogroup B was isolated. By age groups, 4 cases were declared in infants of 2 years of age (Rate: 46.1 per 100,000), nine cases in children between 2 and 9 years of age (1.53 per 100,000) and the remaining 2 cases in persons aged 20 years or over (0.49 per 100,000). 15 cases of Legionellosis were declared in 1999, all under the clinical form of pneumonia. These were isolated cases in persons of middle or advanced age. No indication was found of prior tourist trips to areas of high prevalence. In the majority of cases the origin was considered to be in the community, while one outbreak was identified as nosocomial. Similarly, there was a notable increase in the declaration of cases of Paludism, with 16 cases (EI: 5.33) affecting travellers and immigrants.