Legionellosis in Italy and COVID-19 pandemic: results of the Italian National Surveillance System for legionellosis for the year 2020

ABSTRACT

Introduction: 2020 will be remembered as the year of the COVID-19 pandemic, which caused 2,107,166 cases and 74,159 deaths in Italy as of December 31st. At the same time, protective measures against COVID-19 have proved to be effective for other infectious pathogens, since we noticed the absence or reduction of some infectious diseases, such as measles and seasonal flu. Legionellosis may also have been affected by these measures. Legionellosis is a form of interstitial pneumonia subject to mandatory reporting and laboratory tests are required to confirm the diagnosis. This article summarises the results of the Italian National Surveillance System (INSS) for legionellosis, coordinated and managed by the Istituto Superiore di Sanita (ISS), for the year 2020. Furthermore, this report shows the microbiological surveillance data from the National Reference Laboratory for Legionellosis of the ISS. Materials and methods: The surveillance forms, filled in by the doctors who diagnose legionellosis, are analyzed by the NSS for possible sources of infection, clinical picture and etiological assessment. In parallel with the INSS there is a European Surveillance System for travel-associated Legionnaires' disease, the European Legionnaires' Disease Surveillance Network (ELDSNet).