An infection that has killed 3 people in South Africa worries the World Health Organization, who has put under observation 100 South Africans, who may have come in contact with the victims. A type of hemorrhagic fever might be the cause, but it seems that Ebola is out of the question.

The three victims were a Zambian tour guide and two medical people who treated her. The woman had been in South Africa for two days when she got ill, and died on September 13. Two further deaths on September 30 and October 4 involved a paramedic and a nurse who treated the woman. Clinical features common to the three patients included fever, headache, diarrhea and myalgia developing into rash and hepatic dysfunction, followed by rapid deterioration and death.

The World Health Organization’s spokesman told the press that 121 people are under observation and WHO hopes to receive further test results by Sunday. Furthermore, tests have proven negative for not only Ebola, but for Lassa fever, Rift Valley fever, Marburg fever and other main types of hemorrhagic fever.

Because hemorrhagic fever strikes so quickly and is so contagious, South African health officials set up the monitoring of 121 people in Johannesburg to make sure no one else is ill. Monitoring includes temperatures taken four times daily for the next three weeks.

The symptoms of the presumed hemorrhagic fever include nausea, external bleeding and high fever. Further testing will include even the United States. No special measures are required for passengers going to Zambia from South Africa or the other way around.