More than 3.9 billion people, or half of the world's population, are now being called on to remain in their homes to combat COVID-19, according to an AFP tally on Thursday.

 It may be the global day for pranks but with the world under assault from the deadly coronavirus pandemic many governments on Wednesday were warning against virus-themed April Fools' jokes — some even threatening jail.

Tightened lockdowns across the planet saw nearly half of humanity told to stay at home in a bid to stem the spiraling coronavirus pandemic, as Spain recorded its deadliest day Tuesday and the United States braced for the full impact of the disease.

The new coronavirus outbreak can now be described as a pandemic, the head of the World Health Organization announced Wednesday. WHO chief Tedros Adhanom Ghebreyesus said he was troubled by the spread and severity of the outbreak, along with a lack of action taken to combat it.

Since the novel coronavirus first emerged in late December, 2019, 110,564 cases have been recorded in 100 countries and territories, killing 3,862 people, according to an AFP toll based on official sources on Monday around 1100 GMT.

The number of cases from the new coronavirus topped 100,000 worldwide as the US. battled to contain an outbreak on board a stranded cruise ship where 21 people have tested positive. The World Health Organization called the spread of the virus "deeply concerning" as a wave of countries reported their first cases of the disease.