Italy sees spike in parainfluenza virus infections

The national detection system RespiVirNet ISS has reported a significant increase in respiratory infections from parainfluenza viruses in Italy, with over 370,000 cases documented between 24 March and 7 April 2025. Human parainfluenza viruses (HPIV) are classified within the Paramyxovirus family and are distinct from traditional influenza viruses (A and B). The four main strains are as follows: HPIV-1, HPIV-2, HPIV-3 and HPIV-4. While these pathogens frequently manifest as mild infections, such as the common cold, cough, and fever, in younger or immunocompromised individuals, they can evolve into laryngotracheitis or bronchiolitis. According to experts in the field, the cause of this phenomenon is attributable to seasonal temperature changes. The prevalence of such viruses has been demonstrated to coincide with periods of climatic transition, such as spring and autumn, when immune systems may be rendered vulnerable by sudden fluctuations in temperature. Preventative measures include the adoption of several strategies, such as the utilisation of appropriate clothing (‘layers’), meticulous hand hygiene, frequent room ventilation, and a balanced diet, all of which are intended to strengthen the immune system.