By Carlos H. Conde
International Herald Tribune
Published: January 23, 2009
MANILA: A worker at a pig farm in the Philippines was infected with the Ebola Reston virus, the first known case of the virus jumping between pigs and humans, officials said on Friday.
Tests by health experts from the Philippines, the World Health Organization and the U.S. Centers for Disease Control and Prevention found that the worker had developed antibodies to the virus.
Unlike the highly virulent strains of Ebola found in Africa that induce hemorrhagic fever, Ebola Reston is thought to pose little serious health risk to humans but has proved fatal to monkeys and pigs.
Although the worker, whose identity, gender and age the officials withheld, has not shown any symptoms of illness over the past 12 months, health officials are not taking chances. They plan more thorough monitoring of the two farms where the disease was first detected among pigs in December.
“We emphasize, however, that this finding presents a negligible risk to human health,” Francisco Duque 3rd, the Philippine health secretary, said at a news briefing on Friday.
Duque said tests are still being done on blood samples from 50 workers exposed to the infected pigs at the farms in the provinces of Bulacan and Pangasinan, north of Manila, to determine the extent of the outbreak, although initial tests yielded only the one positive result. Further results could become available next week, he said.
Before it appeared in pigs, the Ebola Reston virus had been confined to monkeys. It was first detected in 1989 in Reston, Virginia, in the United States, among monkeys from the Philippines. Since then, at least two more outbreaks in monkeys were reported.
Dr. Julie Hall, an expert on communicable diseases with the World Health Organization, said Ebola has five different strains, with three “associated with high mortality rates in humans.”
Hall said that since 1989 antibodies to Ebola Reston had been found in 25 other people from various countries who had been in close contact with monkeys. None of them, she said, developed any significant illnesses from the virus.
Nevertheless, Duque said health experts from at least four international agencies had agreed to conduct a 10-day test mission in the Philippines “considering the potential implications for animal and human health and welfare.”
Officials said this underscores the fact that little is know about Ebola Reston and its ability to jump between species.
Duque, responding to a reporter’s question, did not dismiss the possibility that the farm worker had infected the pigs rather than the reverse.
“We can’t say for sure that it is not dangerous to man,” Lo Wing-lok, an infectious diseases expert in Hong Kong, told Reuters. “Viruses jumping across species is always worrying,” he said.
