The World Health Organization has warned that Ebola infections and deaths linked to the latest outbreak in the Democratic Republic of the Congo are expected to rise further as health officials continue tracing the spread of the virus.

WHO chief Tedros Adhanom Ghebreyesus said on Wednesday that there are now 600 suspected Ebola cases and 139 suspected deaths connected to the outbreak.

So far, 51 cases have been confirmed in DR Congo, where the outbreak began, while neighbouring Uganda has recorded two confirmed cases in its capital, Kampala. One of the infected travellers from DR Congo has died.

Speaking in Geneva, Ghebreyesus said the Bundibugyo strain of Ebola likely began spreading “a couple of months ago” before being detected.

Although the WHO declared the outbreak a public health emergency of international concern on Sunday, the agency stressed that the situation does not currently meet the threshold for a pandemic.

“WHO assesses the risk of the epidemic as high at the national and regional levels and low at the global level,” Ghebreyesus said after the organisation’s emergency committee reviewed the situation.

Health officials say the epicentre of the outbreak remains eastern DR Congo, particularly Ituri province, where confirmed cases have been reported in Mongwalu, Bunia, Rwampara and Nyakunde. Cases have also emerged in North Kivu province, including the cities of Goma and Butembo.

According to WHO officials, healthcare workers are among those who have died, increasing concerns over the outbreak’s severity and the risk of wider transmission.

Investigators are still trying to determine how long the virus circulated before being identified. The first known patient was reportedly a nurse in Bunia who developed symptoms and died on 24 April. Her body was later taken to Mongwalu, one of two gold-mining towns heavily affected by the outbreak.

The current outbreak marks DR Congo’s 17th Ebola outbreak, but officials say the Bundibugyo species presents unique challenges because it has not been seen for more than a decade.

Bundibugyo has previously caused only two known outbreaks and historically killed around one-third of infected patients.

There are currently no approved vaccines or specific treatments for the Bundibugyo strain, although experimental vaccines are under development. Health experts say vaccines designed for the more common Zaire strain of Ebola may offer limited protection, but this has not yet been confirmed.

The driver of a freight train involved in a deadly collision with a public bus in Bangkok has tested positive for drugs and now faces charges of reckless driving, Thai police have confirmed.

The crash occurred on Saturday afternoon at the busy Asoke-Din Daeng railway crossing when the freight train slammed into a public bus that had reportedly become stranded on the tracks.

The impact caused the bus to burst into flames, killing eight people and leaving dozens injured.

Initial investigations suggest heavy traffic prevented the bus from clearing the crossing in time. Authorities also believe the congestion stopped the manually operated railway barriers from closing properly before the train approached.

The Asoke-Din Daeng crossing is known as one of the busiest and most congested traffic points in Bangkok.

Police said both the bus driver and the railway guard responsible for lowering the barriers have also been charged in connection with the incident.

Pichet Kunadhamraks, director-general of Thailand’s rail transport department, announced that mandatory drug and alcohol testing would now be required for all train drivers and railway personnel before starting work shifts.

Authorities have not disclosed which substances were detected in the train driver’s urine test.

According to preliminary findings from the train’s black box, the emergency braking system was activated only about 100 metres (330 feet) before impact — a distance investigators say was too short to prevent the collision.

The bodies of four Italian divers who disappeared during a scuba diving accident in the Maldives have been recovered, local authorities confirmed.

One member of the group had already been found shortly after the incident, which took place last Thursday.

Officials said the four remaining victims were discovered inside a cave around 60 metres (197 feet) underwater in Vaavu Atoll during a joint recovery operation involving specially trained Finnish and Maldivian divers.

The tragedy also claimed the life of a Maldivian rescue diver who died on Saturday while taking part in the search effort.

Authorities believe the accident is the deadliest single diving incident recorded in the Maldives, a country internationally known for its tourism industry and coral island resorts.

Four of the Italian victims were linked to the University of Genoa research team. They were identified as Prof Monica Montefalcone, her daughter Giorgia Sommacal, and researchers Muriel Oddenino and Federico Gualtieri.

The fifth Italian victim was diving instructor and boat operations manager Gianluca Benedetti.

The Maldivian rescue diver who died during the operation was identified as Staff Sgt Mohamed Mahdhee.

Officials believe all four bodies recovered this week were located in the same underwater cave where military personnel had earlier discovered the first victim on the day of the accident.