Ebola in Uganda: current and past outbreaks

Via H5N1 and other sources, there's at least one new Ebola case in Uganda:

The rare and deadly Ebola virus has killed a 12-year-old Ugandan girl and health officials said on Saturday they expected more cases.

The girl from Luwero district, 75 km (45 miles) north of the capital Kampala, died on May 6, said Anthony Mbonye, the government's commissioner for community health, in the first outbreak of the virus in Uganda in four years.

"Laboratory investigations have confirmed Ebola to be the primary cause of the illness and death. So there is one case reported but we expect other cases," he said.

Though we've known about Ebola in Africa since 1976, Ebola wasn't recognized in Uganda until a bit over 10 years ago. Now, this is the third outbreak in this amount of time. The first occurred in August of 2000; the first case died in Gulu on the 17th of September. Despite an investigation, doctors were unable to determine where or how she had contracted the disease. Her death was followed by the deaths of her husband, two children, and several other family members. This was reported to the Ministry of Health in October of that year, near the peak of the epidemic. An investigation and intervention to control the disease followed, and the epidemic was declared to be over in January of 2001. A total of 425 patients from 3 villages (Gulu, Masindi, and Mbarara) across Uganda were identified based on symptoms and/or laboratory data. 224 of them died, with a resulting mortality rate of 53%; an eerie echo of the 1976 Ebola outbreak in Sudan. Indeed, sequence analysis showed the infecting strain to be the Sudan subtype of Ebola; the first time this type had surfaced since the 1979 outbreak in Sudan. It is hypothesized that Sudanese rebels, who carried out regular attacks around Gulu, may have accidentally introduced the virus in some manner, though this has not been confirmed.

Ebola returned to Uganda in August of 2007, causing 149 illnesses and 37 deaths until the outbreak was declared over in February of 2008. This mortality (36%) was significantly lower than most Ebola outbreaks. Interestingly, when scientists tested this virus, it also reacted strangely with their assays. Therefore, they determined the entire molecular sequence of the virus, and found that it was a whole new strain of Ebola, which they named Ebola Bundibugyo.

I couldn't find any other details about the current outbreak--how she was infected, if she's actually the index case or if there were previous deaths that have not yet been confirmed. (The girl died at the hospital--previous deaths may have gone unrecognized if they had died at home). I'm sure more details will be coming in the next days and weeks. What we're left with now is the knowledge that in 11 years' time, Uganda is now on its third Ebola outbreak. These have occurred in 3 different areas of the country (Gulu is toward the north, Kampala region in the south near Lake Victoria, and Bundibugyo in the southwest, almost due west of Kampala) and with 2 different strains (thus far). This again feeds my morbid fascination with the virus--what does this mean about Ebola reservoirs in Uganda? Are these cases bat-acquired? Other wildlife? Spillover from other countries, as suggested with the 2000-1 outbreak? As always, Ebola outbreaks tend to raise more questions than they answer.

[UPDATE: via Crawford Killian, CDC says current outbreak is due to Sudan strain.]