Boppard, Germany  - A party of sick British pensioners were isolated Tuesday aboard a river cruise boat, the Lady Anne, after German authorities put them under quarantine on the Rhine River.

At least 37 of 110 occupants of the boat had come down with a norovirus infection and 16 were moved to area hospitals after suffering drastic loss of body fluid.

The rest were not allowed to leave the boat, in which tourists sleep and dine in luxury while sailing past mountain-top castles and towering cliffs of the Rhine Gorge.

A German disinfection team was sent aboard the anchored boat off Boppard to clean it after the captain radioed for help Monday with many patients suffering vomiting and diarrhoea. The ship's cook was one of those who fell ill.

Norovirus infections can be spread by shaking hands and touching door handles and wash basins.

Municipal health officials in nearby Simmern who said earlier that there were 42 sufferers later corrected the tally to 37. The tally of 110 aboard comprised the crew and the passengers, most of whom were over 65. (dpa)