  Social dialogue, the foundation of our democracies, is currently threatened
by disinformation and partisanship, with their disrupting role on individual
and collective awareness and detrimental effects on decision-making processes.
Despite a great deal of attention to the news sphere itself, little is known
about the subtle interplay between the offer and the demand for information.
Still, a broader perspective on the news ecosystem, including both the
producers and the consumers of information, is needed to build new tools to
assess the health of the infosphere. Here, we combine in the same framework
news supply, as mirrored by a fairly complete Italian news database - partially
annotated for fake news, and news demand, as captured through the Google Trends
data for Italy. Our investigation focuses on the temporal and semantic
interplay of news, fake news, and searches in several domains, including the
virus SARS-CoV-2 pandemic. Two main results emerge. First, disinformation is
extremely reactive to people's interests and tends to thrive, especially when
there is a mismatch between what people are interested in and what news outlets
provide. Second, a suitably defined index can assess the level of
disinformation only based on the available volumes of news and searches.
Although our results mainly concern the Coronavirus subject, we provide hints
that the same findings can have more general applications. We contend these
results can be a powerful asset in informing campaigns against disinformation
and providing news outlets and institutions with potentially relevant
strategies.
