(CNN) - The Ebola outbreak that has infected more than 2,000 people in the Democratic Republic of Congo has now spread outside the country, the World Health Organization announced Tuesday.
A 5-year-old Congolese boy was diagnosed with the virus in Uganda, the country's Ministry of Health and WHO said.
"The child and his family entered the country through Bwera Border post and sought medical care at Kagando hospital where health workers identified Ebola as a possible cause of illness," WHO said in a statement.
The child is receiving supportive care at an Ebola treatment unit in Bwera.
The outbreak is both the second largest and second deadliest Ebola outbreak in history. More than 1,300 people have died since it began in August. The epicenter is in North Kivu and Ituri provinces, among the most populous in the nation and bordering Uganda, Rwanda and South Sudan.
As the number of cases has increased, so has the concern that the infectious disease would cross the border. An increase in the number of cases in recent weeks has been even more concerning.
"Although there have been numerous previous alerts, this is the first confirmed case in Uganda during the Ebola outbreak on-going in neighbouring Democratic Republic of the Congo," WHO said.
In anticipation that Ebola cases would be identified in Uganda, preparations have been underway. Health workers have been trained to recognize the disease, and nearly 4,700 health care workers in 165 health facilities have been vaccinated against the disease with an experimental inoculation that has been effective at preventing widespread transmission in Congo.
Uganda and WHO "have dispatched a Rapid Response Team to Kasese to start contact tracing and management of cases that are likely to occur," the international agency said.
The deadliest outbreak occurred in 2014 in West Africa, when more than 11,000 people died from Ebola.
This is the 10th outbreak in Congo since 1976.
CNN's Susan Scutti contributed to this report.
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