One of two patients being monitored by Brazilian health authorities for possible Ebola infection in Sao Paulo and Rio de Janeiro has tested negative, officials said Sunday. The possible infections have sparked further concern over the deadly virus outbreak in central Africa spreading abroad.

A 37-year-old man from the Democratic Republic of the Congo, where the outbreak has been concentrated, "exhibited symptoms such as fever, meeting the definition of a suspected case" of Ebola, the Sao Paulo state government said in a statement on Saturday.

While initial tests did not detect the Ebola virus in the patient, he is being monitored and isolated as a precautionary measure at a specialized infectious disease facility, the statement said.

The health department in Rio de Janeiro state meanwhile reported that it had activated safety protocols after a man from Uganda showed "viral symptoms such as cough, chills, and diarrhea."

The Rio city government said in an email to AFP that the patient tested positive for malaria Saturday evening and "the case remains under investigation."

Brazil's Health Minister said Sunday that the man's tests showed "negative results for Ebola," but he will stay in quarantine until the end of the investigation, AFP reported. 

The Sao Paulo government said that despite the suspected case, "the technical assessment indicates that the risk of the disease being introduced into Brazil and South America remains very low."

Some Ebola recoveries reported 

The reports from Brazil came the same day that World Health Organization chief Director-General Tedros Adhanom Ghebreyesus reported five patients in Africa had recovered from the Bundibugyo virus, a rare strain fueling the current outbreak. Bundibugyo has no approved treatment or vaccine. 

Tedros said these five cases exemplify that recovery from the illness is still possible. The WHO had said Friday that one patient recovered from the Bundibugyo virus, marking the first documented recovery of a person with a confirmed case since this outbreak began.

"Four people will be discharged today and there was one that was discharged the day before yesterday," Tedros said during the opening of a new Ebola treatment center in Bunia, the provincial capital of Ituri in eastern Congo, which is at the center of the current outbreak.

"Of course, we're still working on vaccines and treatments but that doesn't mean that people cannot recover from Ebola," he added.

At least 906 suspected cases of the virus and 223 deaths, among the suspected cases, have been reported in Congo, according to the WHO. There 134 confirmed cases and 18 deaths among the confirmed cases in Congo and neighboring Uganda, the health agency said. Uganda has confirmed nine cases and one death, the Ugandan Health Ministry said Friday.

Calls for more aid and testing 

The virus continues to spread faster than the response despite better-organized health facilities and new aid arrivals, Doctors Without Borders, or MSF, said Saturday, calling for the immediate expansion of testing, faster deployment of aid workers and sustained access for medical supplies.

The dangers faced by health workers have been heightened by anger among residents over the stringent medical protocols for handling the victims' bodies, which clash with local burial rites. Residents have launched at least three attacks against health centers.

Tedros stressed the importance of involving the community in the outbreak response during the opening of the new treatment center on Sunday.

"If you come to health facilities when you have symptoms, you can get the support and recover, so the key is to come forward as early as possible and to get the necessary support," the WHO chief said.

"We can stop this Ebola and anyone who has it can also recover. But the rule ... is this thing is everybody's business and every citizen should be involved," he added.

Attacks in Ituri by the Allied Democratic Forces, a rebel group allied with the Islamic State group, and a coalition of ethnic militias have also hindered the response.

The illness also has been reported in the Congolese provinces of North Kivu and South Kivu, south of Ituri, where the Rwanda-backed M23 rebel group controls many key cities, including Goma and Bukavu. The rebels have reported two cases.

"The final message we would like to share with the Ituri community is that there is hope," Pierre Akilimali, Incident Manager at Congo's National Institute of Public Health, said during the inauguration on Sunday.

"With the symptomatic treatment that we are currently providing, we are seeing patients recover," Akilimali added.

"We truly have hope. The virus here is not as complicated as those we have dealt with in the past, and with the support of all our partners, we believe we will be able to bring this outbreak under control as quickly as possible," said Davin Ambitapio, another doctor at the treatment center.