Health officials in Uganda have confirmed the country’s first case of Ebola stemming from a massive outbreak that has been raging across the border in the Democratic Republic of the Congo since August of 2018.

The World Health Organization reported Tuesday, June 11, that the case is in a 5-year-old boy from the DRC who traveled with his family into Uganda on June 9. The boy’s case was confirmed by the Uganda Virus Institute (UVRI), and he’s receiving care in the Ebola Treatment Unit in the western Ugandan town of Bwera, which sits at the border with DRC.

Health officials have feared the spread of the virus, which has festered in DRC’s North Kivu and Ituri provinces for nearly a year. The provinces sit on the eastern side of the country, bordering South Sudan, Uganda, and Rwanda. As of June 9, the WHO reports 2,062 cases (1,968 confirmed and 94 probable), including 1,390 deaths (1,296 confirmed and 94 probable) in the outbreak. It is the second largest Ebola outbreak on record, surpassed only by the 2014 West African outbreak, which involved more than 28,000 cases and 11,000 deaths.

Violent attacks and community distrust have severely hampered outbreak responses in the volatile region. Militants have injured health responders and, in one case, killed a police officer. In February, Doctors Without Borders/Médecins Sans Frontières (MSF) suspended medical responses after two attacks that left treatment facilities partially burnt down.

With the potential for the outbreak to spread, Uganda has already vaccinated 4,700 health workers in 165 health facilities and has intensified monitoring. The experimental vaccine being used in the outbreak is 97.5% effective at preventing the viral disease, preliminary data suggests. Ebola treatment centers, like the one in Bwera, are already set up. Further, the WHO has dispatched a Rapid Response team to monitor those who had contact with the boy and help with the response.

In April, the WHO’s Emergency Committee concluded that the outbreak did not constitute a Public Health Emergency of International Concern, which would have freed more resources to address the spread of the virus. The WHO may reconsider the situation now that the virus has spread across a border.