The message dated Tuesday urges visitors and U.S. citizens living on the island to avoid street food and under- or uncooked dishes such as ceviche.
The Pan American Health Organization says an Italian, two Venezuelans and two Chileans who travelled to Cuba contracted cholera in late July and early August.
Cuban authorities acknowledged a rare outbreak last summer after many years when the waterborne disease was not present on the island.
This January the government announced 51 new cases in the capital, but there has been nothing official since then.
Cholera can kill quickly through severe dehydration but is treatable if detected in time.