Liberia Ebola-free, but 'can't relax yet,' WHO says

In late March, Liberia buried its last citizen killed by the Ebola outbreak in West Africa. She wasa woman in her 40s who worked as a street-food seller in the nation's capital, Monrovia.

Forty-two days later, none of the 332 people who could have contracted Ebola from her, including her daughter, tested positive.

On Saturday, May 9, the World Health Organization celebrated Liberia's 42 days without a confirmed case by declaring the nation Ebola-free.

"The outbreak of Ebola virus disease in Liberia is over," read a statement from the WHO.

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Still, Ebola-free is a complicated designation since survivors and animals can continue to carry the infectious disease.

It's believed fruit bats started the current outbreak and the WHO warns that chimpanzees, gorillas, porcupines and other animals can be infected. Their bodily fluids can pass the disease on to humans.

Ebola presents "an interesting challenge" for declaring an area free of the disease, says AllisonMcGeer,the director of infection control at Mount Sinai Hospital in Toronto,whotravelled several times to Liberia throughout the winter to work with the WHO.

It assumes that there are no undetected cases in the country, she says.It also neglectsthat survivors may infect others through their semen and amniotic or ocular fluids.

At first, doctors believed male Ebola survivors could infect others through their semen up to three months after recovery.

But therecent case of a woman who appears to have contracted the diseaseafter having unprotected sex with a survivor five months after his recovery has prompted doctors to recommend survivors avoid unprotected sex indefinitely.

Some survivors also experienced blindness after inflammation to the fluid in their eye, says McGeer, and doctors testing their eyes may be exposed to infectious materials.

It's an "open question" whether that fluid is infectious, she says. But, recently,fluid from one survivor's eye tested positive for Ebola months after his blood tested negative.

There's also concern that the few pregnant woman who recovered from Ebola will release infected amniotic fluid when they deliver.

"Part of the question is: Will those people, can those people, start another outbreak?" asks McGeer.

11,000 dead

In this current round, which isregarded as the largest and most complex outbreak since the disease first surfaced in 1976, Ebola has killed more than 11,000 people, according to the WHO. The majority of them died in Liberia, which had4,716 fatalities.

At this point, it is very likely Liberia will experience another case of Ebola, saysMargaret Harris, a WHO communications officer, adding the nation "really can't relax" until its neighbours reach the same status.

Sierra Leone and Guinea make up the bulk of the remaining 6,304 deaths. In the week of May 3, each reported nine new cases, according to the WHO.Harris expects it will take at least three months before they report zero new cases.

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For health-care experts, the big question isn't necessarily whetherLiberia will see another Ebola case, but whether thenation's fledgling health-care system can stop another full-blown outbreak.

Health-care workers in the three countrieswillneed to rebuild patient trust and continue education campaigns, says Stephen Cornish, executive director of Doctors Without Borders Canada. Some symptomatic people still prefer traditional care, and fear catching Ebola at a care centre or believe the disease is incurable.

Cornish recently returned from Sierra Leone and Guinea, where some cases are still only identified through posthumous testing because the affected person never sought help.

Officials must then work backwards to trace everyone the deceased might have infected. With people frequently crossing betweenborders, that could bring Ebola back into Liberia.

"It only takes one to set off a whole new chain," says Cornish. "So we've got tomake sure that the system itself can respond adequately to one case."

The WHO is committed to remaining in West Africa after all three nations are declared Ebola-free to strengthen their health-care systems. Preventing the next outbreak will require well trained, paid, equipped health-care workers in every town and village, Harris says.

"Nature's not going to leave this alone," she says. "We need to be a lot better at detecting and responding and preventing these sort of infectious disease outbreaks."