A health worker wearing a protective suit conducts an Ebola prevention drill at the port in Monrovia in Liberia on Aug. 29. (Dominique Faget/AFP/Getty Images)

The death toll in the worst Ebola outbreak in history has climbed to at least 2,296 in West Africa, the World Health Organization announced Tuesday. The new figures are current through Saturday and showed a staggering spike of nearly 200 new deaths recorded in one day, according to WHO data.

West Africa now has 4,293 total cases of confirmed, probable and suspected Ebola infections, according to the WHO -- a number that could rise as high as 20,000, the organization has warned.

The Nigerian Ministry of Health announced this week that nearly 500 people are under surveillance for Ebola in the oil city of Port Harcourt, and the death tolls continue to rise in Sierra Leone and Guinea.

But Liberia has been hardest hit by the virus: The Ebola-ravaged country is home to more than half of the epidemic's deaths (1,224) and nearly half of all cases (2,046). On Monday, the WHO declared that cases are "increasing exponentially" in the country, where "the demands of the Ebola outbreak have completely outstripped the government's and partners' capacity to respond."

As The Washington Post’s Brady Dennis explained:

In Liberia’s capital of Monrovia, taxis filled with families crisscross the city, searching in vain for a facility with space to treat loved ones infected with the Ebola virus. Children orphaned by the disease and shunned by other relatives have nowhere to go. The government’s main hospital is plagued by floods and electrical fires, and several employees have succumbed to Ebola.

"As soon as a new Ebola treatment facility is opened, it immediately fills to overflowing with patients, pointing to a large but previously invisible caseload,” the WHO wrote. “When patients are turned away at Ebola treatment centers, they have no choice but to return to their communities and homes, where they inevitably infect others.”

The country has become so overwhelmed that only 31 percent of Ebola cases in Liberia have been lab-confirmed through blood tests, the WHO said. Another 47 percent of Liberia's cases have been deemed "probable," which means they've been evaluated by a clinician, according to WHO. Probable cases also include people who have died, were suspected to have had Ebola and had a link to someone with a confirmed case.

In Sierra Leone, 91 percent of Ebola cases have been confirmed by a lab. In Guinea, labs confirmed 77 percent of all cases. Just three percent of Sierra Leone's cases and 19 percent of Guinea's have been deemed probable.

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There are a number of reasons that explain why so many Liberian cases aren't confirmed by labs, WHO spokesman Daniel Epstein said Tuesday. Among them: the sheer volume of cases in that country (2,046 as of Saturday), poor infrastructure and the limited number of Ebola labs and staff throughout West Africa.

Also, the virus is much more widespread in Liberia, with confirmed cases in 14 out of 15 counties. "Whereas in Sierra Leone, it's more geographically limited," Epstein said.

While confirming cases is useful for epidemiology and tracing the virus’s spread, he added, it doesn't necessarily result in a difference in care.

“What happens in the field, from what I've seen and heard, people treat and medical staff treat probable and confirmed cases the same,” Epstein said.