MANILA, Dec. 11 (Xinhua) -- Hogs in four Philippine piggery farms have been found positive for Ebola Reston virus, officials said on Thursday.

    As of Wednesday evening, Ebola Reston cases were confirmed in four farms in Luzon, the northern Philippines, after six out of 28hogs tested positive for the virus.

    Arthur Yap, Secretary of the Department of Agriculture, allayed fears that the disease will be transferred to humans from infected hogs, Philippine TV network GMA News reported.

    There has been no documented case on the virus being transmitted from hogs to humans, said the agriculture chief.

    "This is an animal health problem and not a human issue," Yap said.

    Yap added that most of the hog samples that were tested on Wednesday yielded negative results.

    Meanwhile, he advised the public that pork meat should be properly cleaned and thoroughly cooked before they are eaten.

    "The WHO (World Health Organization) said that the meat should be thoroughly cooked because the heat could kill the virus. The meat should likewise be properly handled and washed," Yap said.

    On Thursday, the Bureau of Animal Industry set up "hog checkpoints" to prevent the transport of pigs from four piggery farms in Luzon for slaughter or breeding.

    Soledad Agbayani, president of the Philippine Association of Hog Farmers, likewise said the Ebola Reston virus was not harmful to humans.

    "The virus is not harmful to humans but to be sure, make sure the meat you eat is not 'double dead'," Agbayani told a local radio.

    Meanwhile, the Department of Agriculture has issued a ban on pork exports to other countries.

    The government was planning to export choice pork cuts to Singapore early next year.

    Ebola-Reston, a sub-type of the Ebola, was first discovered in 1989 from crab-eating macaques originating in the Philippines. Reportedly, it is non-pathogenic to humans and is only mildly fatal to monkeys.