An outbreak of the deadly Ebola virus has raged in Africa for over a year. Despite heroic efforts by health care workers, the disease continues to claim lives and there are fears that it could now spread more widely. Suspicions, uncertainties and opportunism are hindering efforts to combat this horrific disease. The world must do more to combat this outbreak and prevent future ones.

Last Sunday, a Japanese woman who recently returned from a visit to Congo tested negative for Ebola infection — which was suspected when she suffered from high fever upon her return. The government here is stepping up efforts to contain infections at the border.

Over a year ago, Ebola appeared in eastern Congo, the 10th outbreak in that country. Health officials and workers responded quickly, identifying and isolating infected individuals, raising consciousness of the disease among local communities and promoting vaccination efforts. Nonetheless, it is officially estimated that 2,700 people have been infected with the virus, and about 1,800 have died; nearly 150 of the infected have been health care workers. While this is an order of magnitude less than the outbreak that killed more than 11,000 people in west Africa between 2014 and 2016, it is the second worst the world has ever witnessed.

Last month, the World Health Organization declared the outbreak to be a “public health emergency of international concern,” a designation that has only been used four times before and which the committee of 10 scientists who make the call had declined to issue in three previous meetings.

Their change of heart followed reports that a case had been detected in Goma, a city of over 1 million people that straddles the Congo-Rwanda border. Between 40,000 and 70,000 people cross the border daily, prompting fears that it will now spread to Rwanda. Rwanda then closed its border with Congo, which threatens an economic disaster.

That action may even be too late. Containing the disease requires the rigorous tracking of contacts with infected individuals. As one WHO official explained: “Ebola is like water. If you don’t build a perfect dam, even a small hole can lead to a flood of new cases.” While teams have been doing that since the outbreak began, some cases have slipped through the cracks: One individual got to Dubai and another to China before being tested for the virus.

Cases of Ebola have been identified in Uganda, which has suffered multiple outbreaks before. Fortunately, that history means that Uganda is better prepared to deal with the disease and the country’s health officials have caught “active cases” and identified target communities for vaccination. The WHO said that nearly 600 fishmongers in Uganda might be targeted for vaccination, but no confirmed case could be traced to that incident.

Fortunately, there is a vaccine that appears to be working. Millions of individuals have been checked and given doses. But handling the vaccine presents big challenges: It has to be stored at subzero temperatures, which makes it difficult to get to remote locations.

Those efforts are also complicated by regional politics. Congo is riven by violence, and the areas where the most recent outbreak occurred have been plagued by ethnic conflict. Decades-long struggles have been amplified by refugees from neighboring Rwanda, who fled their own ethnic violence. Fighting impedes the ability of health officials to intervene, but there are also fears that, because they are foreigners, the workers are soldiers in the conflict, using the disease — or the vaccinations — as weapons. When individuals are sickened by Ebola and die, locals confuse cause and effect, blaming health care teams for spreading the disease, rather than containing it. There have been nearly 200 attacks on health workers since January, and seven have been killed.

This outbreak may seem remote from Japan, but health officials here are worried about the possibility of infection as the number of visitors skyrockets and the country prepares for next year’s Summer Olympic Games. It has been announced that Japan will for the first time import strains of Ebola — as well as four other deadly viruses, Lassa, South American, Crimean-Congo and Marburg — to develop diagnostic kits.

Imports and sales of these viruses are banned, so the government will obtain them under a special arrangement and store them for research at the National Institute of Infectious Diseases in Musashimurayama, western Tokyo. Currently, the NIID has Japan’s only biosafety level-4 research facility, the most secure type of laboratory. Officials at the Health, Labor and Welfare Ministry have held meetings with residents and invited them to the facility to explain the planned studies.

Those efforts can promote innovation and diagnostics to identify and treat the disease, but only in the future. Africa needs money and attention now to combat the current outbreak. Every day it continues, the risk of an epidemic increase. It has already been a year, a fact that should trigger more concern than confidence.