CAPE TOWN, South Africa (AP) _ An ailing child plucked from an Atlantic island by a cargo ship arrived Saturday in South Africa, where medical experts will test her siblings to find a bone marrow match.

Danni Clifford, a dark-haired, slender six-year-old, was carried down the gangplank of the Nomzi just before dawn, ending her four-day journey on the cargo ship.

The children, their grandmother and a nurse made the 2,170-mile journey from their home on the remote island of St. Helena, a British protectorate northwest of Cape Town with no airport. Danni needs emergency treatment for a rare and potentially fatal blood disorder.

Her illness might be curable with a bone marrow transplant from her brother Rhys, 8, or sister Terri, 9, who also made the voyage.

``We are keeping our fingers crossed,'' said Ursula Johnson, the children's grandmother.

Upon arrival, the girl looked first puzzled, then pleased, at the group of journalists who met her. She nodded her head when asked if she was feeling fine. She was then rushed by ambulance to a private clinic, where doctors will perform tests to confirm her diagnosis.

A week ago, Danni collapsed at her island home and was provisionally diagnosed with aplastic anemia, a life-threatening condition where the bones no longer contain enough marrow to make the blood required.

The Nomzi, part of a seven-ship fleet that provides weekly container service between North America and South Africa, made an emergency 360-mile, 18-hour detour to collect the children on Tuesday after a call for help.

The captain, Peter Wierling, said the child had to be transported over breaking waves to board the ship. Danni was kept in isolation to protect her from infection.

``Sometimes she (felt) not so good, the next day she was doing fine,'' Wierling said.

John and Cherie Clifford, the girl's parents, arrived Saturday by air from the Falklands Islands, where they are doing contract work.

``The patient is comfortable and her parents are with her,'' said a nurse at the Constantiaberg Medi-Clinic on the condition of anonymity.

Dr. Gayle Sherman, a Johannesburg-based blood expert, said people suffering from the condition had a good chance of survival if a suitable blood marrow donor could be found. She said Danni's siblings each had a one-in-four chance of providing a blood marrow match. However, complications could occur.

``There is a risk of infection or bleeding and the donor marrow might be rejected,'' Sherman said.

If a suitable donor cannot be found, mortality rates were high.

Patients suffering from aplastic anemia are usually given chemotherapy to destroy the cells causing the condition before they are given a transplant.

A volcanic island with 5,500 residents, St. Helena was where France's Napoleon was placed in exile from 1815 to 1821.