The new type of Ebola in Uganda might be less deadly than others — but that's not necessarily good news.
The World Health Organization said last week that an ongoing Ebola outbreak in Uganda was caused by a new subtype, the fifth to be detected since the virus was first identified in 1976 in Sudan and Congo. While information about the outbreak was still limited, it appeared to be killing fewer of its victims than other strains typically do.
Dr. Tom Ksiazek, chief of the special pathogens branch at the United States' Centers for Disease Control and Prevention, said Tuesday it was premature to conclude whether the new Ebola strain was milder.
If it were, its victims could be less contagious, Ksiazek said.
A less lethal version of Ebola, though, might spread unnoticed and be confused with other diseases, making it "a more difficult challenge," Asiya Odugleh-Kolev, a WHO communications expert who has worked on numerous Ebola outbreaks, said Wednesday.
Ending previous Ebola outbreaks in Africa has largely depended on Odugleh-Kolev's specialty: teaching people to spot the disease early and to reduce behaviors that could spread it. She said people might not take a less dangerous form of Ebola seriously, or fail to take the proper precautions because they think they have measles or some other disease.
Containing the virus
The new type of Ebola has so far killed at least 22 people in Uganda, including four health workers, said Dr. Sam Zaramba, director general of Uganda's health service. He also said there were 93 suspected cases. Typically, Ebola kills between 50 to 90 percent of the people it infects.
Two teams of international experts, including infection control doctors, have been sent by the CDC and the World Health Organization to help local officials contain the virus.
Ugandan officials report that some health workers have fled the outbreak's epicenter in fear and that there is a manpower shortage.
Ebola causes fever, intense weakness, muscle pain and other symptoms. In severe cases, the virus damages the kidneys and liver, and patients may bleed internally and externally. Ebola is usually spread by close contact with an infected patient, or by contact with the secretions of an infected patient.
In Uganda, WHO said the classic Ebola symptoms were not always present, and that in the current outbreak, there were more reports of vomiting than usual. That slowed diagnosis, according to Ugandan health authorities who said that the outbreak might have begun in August.
The Ebola viruses from Uganda examined so far appear to be up to 25 percent different genetically from previously known Ebola strains. Ksiazek was unsure whether this difference might be significant for patients and doctors.
"What we know from previous Ebola outbreaks is still going to apply," he said. "We now have to figure out if the mortality might be any different."
Doctors also worry that the presence of other diseases in Uganda could complicate the effort to contain Ebola. Because the symptoms for diseases like malaria and typhoid are sometimes similar to those for Ebola, doctors and nurses will need to be careful not to mix Ebola patients with other patients, which could spread the virus in health care centers.
The last outbreak of Ebola in Uganda occurred in October 2000 when 173 people died and a total of 426 people were infected in the north of the country.