With Italy in lockdown as the country attempts to deal with the COVID-19 pandemic, Ronaldo insisted the protection of human life must be the main focus at a time of huge disruption to the sporting calendar.
Ronaldo's Juve team-mate Rugani is in isolation after it was announced he had tested positive, with the number of confirmed global cases now more than 132,000.
Rugani was in the Portugal international's thoughts as he posted on social media to discuss the recent developments surrounding coronavirus.
Ronaldo's post came on a day where the Premier League and Bundesliga became the latest leagues to postpone matches amid a host of other cancellations across the world, with the UEFA Champions League and UEFA Europa League also off next week.
"The world is going through a very difficult moment which demands the utmost care and attention from all of us," Ronaldo, 35, wrote while also posting a World Health Organization (WHO) link containing information on the virus.
"I speak to you today not as a football player but as a son, father, a human being concerned with the latest developments that are affecting the whole world.
"It is important we all follow the advice of the WHO and the governing bodies on how we handle this current situation. Protecting human life must come above any other interests.
"I would like to send my thoughts to everyone who has lost someone close to them, my solidarity to those who are fighting the virus like my team-mate Daniele Rugani, and my continued support to the amazing health professionals putting their own lives at risk to help save others."