SAO PAULO, June 1 (Xinhua) -- Brazilian authorities on Monday ruled out a suspected Ebola case in Sao Paulo state after laboratory tests found no genetic material from the virus.

The patient, a 37-year-old man who recently arrived from the Democratic Republic of the Congo and had a recent travel history, showed symptoms including fever and diarrhea, which fall under Ebola surveillance protocols.

The patient remains in serious condition in the intensive care unit of the Emilio Ribas Institute of Infectious Diseases, a reference center in Brazil for suspected or confirmed Ebola cases.

The health department said the risk of Ebola being introduced into Brazil and South America remains very low, citing the lack of local transmission, the absence of direct flights from affected areas, and the fact that Ebola requires direct contact with bodily fluids from infected people. ■