Medical tests have determined that a 7-year-old American girl who died last Sunday in Okinawa had contracted a rare parasitic infection, doctors at the University of the Ryukyus said Saturday.

Bliss Scott, a first-grader at Stearley Heights Elementary School on Kadena Air Base, died of meningo-encephalitis, an infection of the brain and its covering that has symptoms of both meningitis and encephalitis. It was caused by a rare parasite transmitted by snails and slugs, according to the Stars and Stripes.

The U.S. military's semiofficial daily said tests conducted by the university showed the girl had contracted a parasite called rat lung worm.

The doctors said that Scott suffered from severe headaches and that blood serum tests suggested she had contracted the parasite angiostrongylus cantonensis.

One or two cases of the disease are reported annually in Okinawa, but it is the first death linked to the parasite.

Nine people have contracted the parasite this year, according to the university.

The parasite grows in the body of mollusks such as snails, which get it from eating the feces of infected mice. People can contract the parasite by touching the snails.

Yoshiya Sato, a professor of parasitology at the university, said the disease is carried by an African snail brought to Okinawa as a food source by the Japanese government during World War II, according to the Stripes.

Cases of the infection have also been reported in Southeast Asian areas as well as Taiwan and Pacific island nations.