The Epidemiologic Surveillance System of Navarra includes the notification of 34 communicable diseases, to which are added epidemic outbreaks of any aetiology and cause. Every doctor who suspects, or diagnoses, any of the processes carries out reporting to the system on a weekly basis. In 2001, under the heading of diseases of respiratory transmission, 7,779 cases of Flu were reported (EI: 0.20), with the particular circumstance that the winter epidemic peak did not occur; 48% of total annual cases were reported in the first 12 weeks of the year, with a maximum in week 4 when only 449 cases were reported. 10 cases of Meningococcal Disease were reported to the system (EI: 0.59), a figure that is considered to be an historical minimum. Nine cases were confirmed microbiologically and all appeared in a sporadic way. With respect to the causative serogroup, on 6 occasions Neisseria meningitidis serogroup B was isolated and in the 3 remaining cases serogroup C was isolated. By age groups, 3 cases were declared in infants of less than 2 years of age (Rate: 34.6 cases per 100,000), 2 cases in children between 2 and 5 years (11.0 cases per 100,000), 4 cases in the age group of 6 to 10 years (Rate: 4.7 per 100,000) and the remaining case in the age group of persons aged 20 years or over (0.24 per 100,000). 42 cases of Legionellosis were declared in 2001, all under the clinical form of pneumonia. Twenty-five of them were presented in a context of outbreak; three community outbreaks and one with a nosocomial origin, which affected 19 persons. Similarly, there was a notable increase in the declaration of cases of Hepatitis A, with 33 cases (EI: 2.06), brucellosis, with 9 cases (EI: 0.81) and above all parotiditis, with 267 notified cases (EI: 8.34).