Measles is an extremely contagious infectious disease; it is directly transmitted by a single-strand RNA virus,
member of the Morbillivirus genus in the family Paramyxoviridae and can afflict the respiratory sistem.
It is mainly spread by direct contact with airborne respiratory droplets,
and is transmitted normally from 4 days before to 4 days after the onset of rash,
with an incubation period of 10–14 days.
Before the introduction of an effective measles vaccine,
virtually everyone experienced measles during childhood.
The global rate of morbidity and mortality has started to decrease since 1963 thanks to vaccination strategies.
Despite the availability of an effective vaccine,
in Italy,
in other European countries (mainly Romania,
Greece and France) and in the United States,
there has recently been a reappearance of Measles.
Sub-optimal vaccination coverage (<95%),
especially among those born in the 80s and 90s,
strongly contributed to the re-emergence of this pathology.
Italy is one of the fourteen WHO European Region Member States where measles remains endemic.
As Based on the available data from regional health authority,
the proportion of children being vaccinated for MMR/MMRV has progressively fallen in recent years: anti-vaccination campaigns determined an unexpected recurrence of measles,
an infectious disease with more serious clinical presentation in subjects <5 and >20 years old or immunocompromised.
Pulmonary complications,
among the most common (incidence reported between 3 and 57%),
can be lethal (mortality between 1 and 36%); therefore,
it is necessary to consider a possible pulmonary involvement in every patient presenting respiratory symptoms.
Viruses can determine several pathologic forms of respiratory infection,
such as bronchitis,
laryngotracheobronchitis,
bronchiolitis,
and pneumonia; pneumonia can be caused by the virus itself or by bacterial superinfection.
Various histopathologic patterns of lung injury have been described in viral pneumonia,
more often nonspecific. Most respiratory viruses produce cytopathic effects,
wit epithelial necrosis,
fibrinous exudates and alveolar damage,
which can be hemorrhagic.
Histologically measles virus pneumonia is characterized by presence od multinucleated giant cells in the alveolar air spaces and within the bronchiolar and tracheobronchial epithelium.
The radiological findings reflect the these histopathologic features,
and are dependent on underlying risk factors such as very young and old age,
malnutrition,
and immunologic disorders.
Other possible complications are otitis media and those related to the nervous system (encephalitis and sub-acute sclerosing panencephalitis).