[Influenza and influenza-like acute respiratory diseases in Slovakia in the 1999-2000 season].

BACKGROUND

Acute respiratory infections (ARI) represent the most frequent cause of morbidity. Their epidemic outbreaks become a severe problem not only in healthcare, but also in economical and social spheres.

OBJECTIVE

Presentation of epidemiological and virologic characteristics of the 1999-2000 influenza season in Slovakia; their comparison with the same Influenza season in other European countries, as well as with the situation during the preceding season in Slovakia.

METHODS

The epidemiological analysis of Influenza and influenza-like diseases is based on the duty of attending physicians to report the number of new cases, complications, cases of working inability due to disease, and death cases. The reports are required on a compulsory weekly basis, and the reported cases are structured into 4 age groups. The laboratory diagnosis is based on virus isolation, rapid detection of antigen and serological tests.

RESULTS

The outbreak of Influenza spread through Slovakia during the period between the 4th and 8th calendar weeks with its peak appearing during the 6th calendar week, when its incidence reached 2821 cases/100,000. The age group mostly afflicted by morbidity during the entire investigated season were children at the age of 0-5, while during the outbreak, the highest morbidity was reported among school children at the age of 6-14. The epidemic broke out on the entire territory of the Slovak Republic at the same time. 5 death cases were reported. Complicated cases were reported in 6.1% of the diseased. 34.1% of the group at the age from 15 to 59 were reported to be unable to work due to disease. 25 isolates of influenza virus were obtained from 505 nasopharyngeal swabs. 2 strains were found to be atigenetically similar to the vaccine strain A(H3N2)/Sydney 5/97 and A(H3N2)/Moscow 10/99. Regarding ARI aetiology, influenza viruses were serologically confirmed in 1356 samples; out of which type A(H3N2) was confirmed in 930 cases, A(H1N1) in 143 cases, type B in 283 cases; adenoviruses were detected in 467 samples; RS viruses in 779 samples; and Mycoplasma pneumoniae in 859 samples. Mixed infection caused by two viruses was diagnosed in 27 cases.

DISCUSSION

The outbreak which hit Slovakia in the 1999/2000 season was a part of the European epidemic wave. As to its extent, it was a mild epidemic outbreak. It was significantly low as to its incidence among children. During autumn months, ARI aetiology was dominated by M. pneumoniae, viruses of type A(H3N2) prevailed.

CONCLUSION

The identification of strains isolated during the investigated season confirmed that strains of influenza virus similar to strain A(H3N2)/Sydney 5/97 which is contained within the vaccine which has been assessed for this season, circulated in Slovakia during the past two subsequent seasons. Similar experience was reported from the majority of European countries involved in the international WHO programme of influenza Surveillance. These facts explain the mild extent of the investigated epidemic outbreak. (Tab. 5, Fig. 7, Ref. 8.)