Chris Brown tweets Ebola virus theory

Chris Brown has said he thinks the ebola virus is a "form of population control".

The singer published his thoughts on Twitter about the epidemic, which has killed more than 4,000 people, the majority of them in West Africa.

He wrote: "I don't know ... But I think this Ebola epidemic is a form of population control.  S*** is getting crazy bruh."

Brown tweeted minutes later: "Let me shut my black a** up!"

The US started screening people travelling from Liberia, Sierra Leone and Guinea to its busiest international airports on Saturday to limit the spread of the disease.

An exercise also took place in the UK over the weekend to ensure emergency authorities were prepared for the possible spread of ebola.

The World Health Organisation has called the outbreak "the most severe, acute health emergency seen in modern times".

Ebola is transferred from person to person through contact with the blood or secretions of other bodily fluids of infected people.

There is currently no vaccine.