On Sunday, Rocco Casalino, the spokesman for Conte, and Giovanni Grasso, the spokesman for Mattarella, said they were suffering from mild symptoms and it was unlikely that they had infected the Prime Minister and President, reports Xinhua news agency
Casalino, 48, said he had not seen Conte in person since October 22, while Grasso, 58, said he has had no recent contact with President Mattarella.
Casalino said on Sunday he discovered he was infected after a positive test late Saturday.
He said he had previously tested negative on October 21, the day after he last saw Conte in person, adding that every time he always paid attention to health rules with the Prime Minister, including the use of face masks and social distancing.
Casalino said he was in self-isolation along with his partner, who had also tested positive for Covid-19.
For his part, Grasso said he had a high fever on October 23. He took a test the next day and received the results showing he had been infected on Sunday.
Grasso said he had previously tested negative on October 21.
Grasso said he was in self-isolation at home, away from his wife and son, who, according to media reports, are not infected.
Neither Conte nor Mattarella had made any official comment about the developments, and news reports said that having the two spokesmen under self-isolation would not have an impact on the schedules of the two leaders.
Xinhua confirmed the information about Casalino through a senior deputy in Conte's press office.
Grasso announced the news of his infection via social media followed up by a phone call carried by Italian state broadcaster RAI.
The developments came the same day when Italy passed a new grim milestone, with 21,273 new coronavirus infections reported in the past 24 hours.
That is higher than the previous high of 19,644 recorded a day earlier, and more than three times higher than the 6,554 infections recorded on March 21, the high point from the first wave of the pandemic.
On Sunday, the Ministry of Health also recorded 128 deaths down from 151 a day earlier.
Italy's overall caseload has increased to 525,782, while the death toll stood at 37,338.