Uganda Declares Ebola Outbreak Caused by Sudan Virus

Earlier this week, Uganda reported an Ebola outbreak caused by Sudan virus (SUDV). This is the first Ebola outbreak caused by SUDV since 2012, and there is no approved vaccine for the Sudan strain.

On September 20, Ugandan health officials confirmed laboratory cases of Ebola disease. As of Sunday, September 25, there were 18 confirmed and 18 likely Ebola infections from the Mubende, Kyegegwa, and Kassanda districts. The infections are spread over an area of 120 km. The suspected 36 cases include 23 reported mortalities, 5 of which occurred among confirmed cases.

The first case was confirmed on September 20 in the village of Madudu subcounty in central Uganda’s Mubende district. The case, a 24-year-old man, presented on September 11 with high-grade fever, tonic convulsions, loss of appetite, pain while swallowing, chest pain, dry cough, bleeding in the eyes, and blood-stained vomit and diarrhea.

The man visited 2 private clinics, one from September 11-13 and the other from September 13-15, but saw no improvements. He was next admitted to the Regional Referral Hospital on September 15, where he was isolated as a suspected case of viral hemorrhagic fever. On September 19, the patient’s blood samples tested positive for SUDV. He died that same day.

Preliminary investigations of community deaths due to unknown illness are now probable cases of SUDV Ebola. These cases occurred in the Madudu and Kiruma sub-counties of the Mubende district and were reported in the first 2 weeks of September.

Of all the confirmed and suspected Ebola infections, the patients are 62% female and 38% male. The average age of the patients is 26 years, and 13 cases are currently hospitalized. A total of 223 close contacts have been reported.

Sudan virus disease is severe and often fatal. Since its emergence in June 1976, there have been 7 SUDV outbreaks recorded (4 in Uganda, 3 in Sudan). Estimated fatality ratios of Sudan virus have varied from 41-100%. There are no licensed vaccines or therapeutics to treat or prevent Sudan virus disease.

The virus is spread by human-to-human transmission via direct contact or contact with the bodily fluids of a person who is sick with or has died of Sudan virus disease. The incubation period can range from 2-21 days, and infected persons are not contagious until they become symptomatic.

Training doctors have been going on strike due to a lack of resources and protective equipment. The strike began after a medical student died after caring for a baby infected with Ebola. Frontline medical workers are at high risk of death, as any drops of bodily fluid that enter the eyes or mouth may result in agonizing death. Additionally, there are reports of infected patients escaping medical facilities.

Ebola caused by Sudan virus can have a very rapid symptom onset. Symptoms may initially include fever, fatigue, muscle pain, headache, and sore throat, and subsequently, vomiting, diarrhea, rash, and impaired kidney and liver function. Internal and external bleeding are also indicative symptoms.

Sudan virus can jump to humans after close contact with the blood, organs, secretion, or other bodily fluids of an infected animal. Known vectors have included fruit bats, chimpanzees, gorillas, monkeys, forest antelope, and porcupines.

The outbreak is still small, but experts are concerned it could spread abroad. The World Health Organization (WHO) cautioned, “risk of international spread cannot be ruled out due to the active cross-border population movement.”