A previously unknown virus that killed four of the five people it struck in an outbreak in South Africa last year has been identified as part of a family of viruses humans can catch from rats.
The virus, named Lujo, is an arenavirus that over the course of nine days caused rash, fever, muscle pain, diarrhea, severe bleeding, vomiting, organ failure and death, said Nivesh Sewlall, who treated the first patient at Johannesburg’s Morningside MediClinic Hospital. He reported the findings at an infectious disease conference in San Francisco today.
Lujo appears more dangerous than other arenaviruses and related hemorrhagic fever syndromes, with the exception of Ebola and Marburg, which have similar fatality rates of about 80 percent. Although outbreaks of illness from these viruses have been sporadic and not widespread, the World Health Organization has said population growth into remote areas and urbanization have led to new diseases emerging more quickly in recent years.
“It wasn’t the outer jungle, this was suburban Lusaka,” said Sewlall, a pulmonary and critical care physician at Morningside, in an interview in San Francisco. “There are parts of Central Park that are more rural,” he said, referring to the landmark in New York.
Scientists don’t know where the pathogen came from, though humans usually catch other arenaviruses such as Lassa fever by inhaling dust contaminated with rodent droppings, according to the U.S. Centers for Disease Control and Prevention in Atlanta. Human-to-human infections may occur through contact with bodily fluids or open skin cuts, the CDC said.
The first case of Lujo virus was a critically ill tourist guide and polo player in Lusaka, Zambia, who was airlifted to Johannesburg, South Africa, for treatment in September last year, according to the CDC. The Lujo virus is named after Lusaka and Johannesburg, where it was first detected.
The first patient died, as did three health-care workers who treated her. A fifth person, a nurse who worked with Sewlall in the hospital and treated one of the secondary cases, also caught the virus but survived after a barrage of treatments including the antiviral drug ribavirin. The patient took almost a year before she was able to return to work.
After the first few cases, the hospital staff was taking extra precautions: wearing protective clothing and checking their temperatures twice a day. That didn’t stop the second nurse from catching the disease. At one point, Sewlall himself developed a fever, around midnight after caring for the dying patients.
‘Hardest Three Hours’
“It was one of the hardest three hours of my life,” waiting for the laboratory results to determine whether he, too, had caught the virus, Sewlall said. The results came back negative.
The research was presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy in San Francisco today.
There are about 20 known arenaviruses carried by rats, and only five show symptoms in humans, Sewlall said. Most arenaviruses don’t sicken their rodent hosts.
The virus was genetically identified as an entirely new arenavirus with the help of the National Institute for Communicable Diseases in South Africa and disease sleuth W. Ian Lipkin, a professor of epidemiology at Columbia University’s Mailman School of Public Health in New York. Lipkin was first to identify West Nile Virus in the U.S.