India, June 22 -- The Ebola outbreak in eastern Congo has now reached 1,003 confirmed cases, including 254 deaths, according to the Democratic Republic of the Congo's Ministry of Health.

Since the outbreak was declared on May 15, about 100 people have recovered, while at least 365 patients remain hospitalized or in isolation, the Associated Press reports. The outbreak is centered in Ituri province and is caused by the rare Bundibugyo strain of Ebola, for which there is currently no approved vaccine or specific treatment.

Health authorities warn that the actual number of infections could be much higher, as many cases may be going undetected. Officials have traced only about 55% of people who may have been exposed to the virus, leaving sign...