The strain of Ebola virus that infected two monkeys brought recently from the Philippines to a Texas primate center is virtually identical to the one that killed more than a dozen animals but caused no human disease in an outbreak outside Washington seven years ago.

Named "Ebola-Reston" after the Virginia suburb where the first cases were found, the virus behaves quite differently from the African strain of Ebola, which readily infects people and has a mortality rate between 50 percent and 80 percent. There is no treatment for the infection. Eight people at the remote animal quarantine unit in Texas have had contact with the two infected animals.

"We cannot say with absolute certainty that it is harmless to people. We need to watch things closely and move quickly if there is any sign of illness {in the exposed employees}," said Bob Howard, a spokesman for the Centers for Disease Control and Prevention (CDC), the federal agency that was invited Monday to help the Texas Department of Health investigate the outbreak.

Ebola virus infection was confirmed last weekend, when scientists at the CDC isolated and characterized the virus in blood and tissue samples from two monkeys. Preliminary tests show that the virus's genetic sequence is "much more than 90 percent" identical with the Reston strain, said Stephen Ostroff, an epidemiologist at the CDC's National Center for Infectious Diseases.

One animal died March 30, seven days after it arrived in the United States. A second animal became ill last week and was killed and autopsied.

The two animals were part of a shipment of 100 macaque monkeys sent to HRP Inc., which supplies animals for scientific research to laboratories around the United States. The company's primate breeding facility, the Texas Primate Center, is about 50 miles west of Corpus Christi. The center is eight miles outside the town of Alice (pop. 19,788), on a farm road and surrounded by a chain-link fence.

Four animal handlers tested positive for infection with Ebola, but did not become ill, during the 1989 outbreak at a primate center in Reston. Researchers have also found evidence of symptomless infection with the Ebola-Reston strain among Filipinos working with the animals, which are caught or bred for shipment to laboratories around the world.

The two veterinarians, five animal handlers and one laboratory technician who had contact with the infected Texas monkeys are working and returning home at night, said Ben Barnett, an epidemiologist with the Texas Health Department. Their temperatures are being taken every day, and they have been instructed to report any symptoms of illness immediately.

The monkeys were supplied by a firm named Ferlite, which is one of three large primate exporters in Manila. Ferlite also supplied the animals in the 1989 Reston outbreak, which was chronicled in the best-selling book "The Hot Zone," and those in a small outbreak that occurred several months later at the Texas Primate Center.

Ferlite reportedly exports about 1,500 animals a year. It could not be learned yesterday whether the animals primarily are bred in captivity or are caught in the wild. The latter are believed to be at greater risk of introducing Ebola virus into laboratory animal populations.

HRP's parent company, Hazleton Research Products Inc., of Denver, Pa., is owned by Corning Inc. of Corning, N.Y. Asked why the company has continued to use Ferlite as a supplier, Corning spokesman Paul A. Rogoski said, "As we understand it . . . every time one of these situations has occurred, the supplier has been found blameless. . . . As far as we know, they're still regarded as a reputable supplier."

The recent shipment of animals was flown from Manila to Houston, with stops in Hong Kong and Rome. Public health agencies in the United States have alerted officials in those cities so that people who might have had contact with the animals could be monitored for illness.

Officials said last night that two other animals, residing in adjacent one-animal cages, have stopped eating and are being watched closely for illness. The symptoms of Ebola infection often include high fever, confused behavior, rash, pneumonia and bleeding from bodily orifices.

Studies of the Reston cases strongly suggested that monkeys can acquire the infection by microscopic droplets spread by coughing or breathing. In contrast, human victims of the deadly African outbreaks almost always acquired the virus through direct contact with infected body fluids, usually blood. Researchers are not certain the African virus ever infects people through the respiratory route alone.

The two dead monkeys and the two that are not eating were in a room containing 50 animals -- half the original shipment. This suggests a respiratory route of transmission may have occurred. However, all the animals were shipped together during their flight from Manila. The natural history of the disease is not completely understood, but the period between initial infection and the onset of illness appears to be six to 12 days.

All of the animals are in the 31-day period of strict quarantine required of all imported primates. The animals are kept in structures resembling miniature silos, about eight feet tall. The recently arrived macaques have had no contact with the approximately 5,000 other animals at the primate center.

Both CDC and Texas officials said HRP Inc. followed quarantine procedures correctly and immediately informed public health officials of illness in the newly arrived animals. Brown reported from Washington, Suplee from Texas. CAPTION: A worker in protective gear carries a bag of feed at Texas Primate Center near Alice, where two monkeys were found to have ebola virus.