Story highlights So far, 455 African rhinos have been killed this year, officials say

The number surpasses last year's killings

"It is critical for the South African government to engage with consumer countries," expert says

A record number of rhinos have been killed this year in South Africa, fueled by the belief that their horns can cure cancer.

An unsubstantiated belief on their healing powers is spreading in southeast Asia, sending clients paying top dollar for traditional cures, officials said.

So far, 455 African rhinos have been killed this year, according to government officials. A total of 448 rhinos were killed last year.

"It is critical for the South African government to engage with consumer countries and to fight against international syndicates involved in illegal rhino horn trade," said Dr. Jo Shaw, rhino coordinator for the WWF in South Africa.

One of the nations linked to the trade is Vietnam and a collaboration action between the two against illegal rhino horn trade remains unsigned, according to Shaw.

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"There is also an urgent need for law enforcement actions by neighboring countries implicated as transit routes for illegal trade in rhino horn," the coordinator said.

Conservation group Save the Rhino estimates that there are 25,000 rhinos in Africa. Of those, about 21,000 live in South Africa, the group says.

"Rhino numbers continue to grow in South Africa as more rhinos are being born than are dying, even when poaching mortalities are taken into account," Shaw said. "However, we are approaching the critical tipping point where rhino numbers go into decline and would undermine conservation efforts."