AR-News: Researchers watch another monkey-to-human virus

[סמדר]

From: Primfocus 


Researchers watch another monkey-to-human virus
By MARILYNN MARCHIONE
mmarchione at journalsentinel.com
Posted: Feb. 15, 2004
http://www.jsonline.com/alive/news/feb04/207473.asp

San Francisco - Could it become the next AIDS or SARS, another deadly alphabet soup disease that jumped from animals to people?

It doesn't seem likely, but health officials are keeping a close watch on SFV, a monkey virus that has now been found in a surprisingly high number of zoo workers and animal researchers.

It shares one troubling characteristic of HIV, the virus that causes AIDS: permanence. It is a retrovirus, a germ that stitches itself into a person's DNA and stays there for good.

"Any time you identify a zoonotic transfer of a retrovirus it raises a lot of concern," said Walid Heneine, a virus researcher at the Centers for Disease Control and Prevention.

So far, no humans have gotten ill from SFV. And the virus doesn't make monkeys or apes sick, but neither does SIV, or simian immunodeficiency virus.

"When it crossed to people, it became HIV and caused pandemics," Heneine said of SIV.

Whether SFV can do the same is not known. It takes roughly seven years for HIV to develop into AIDS. And it took 50 years for the AIDS epidemic to be recognized after the virus first crossed into humans.

"We just have to do the research to find out," he said. "We don't want to be alarming here, but we have to be aware of the implications of these findings."

He reported results from the simian virus study at last week's 11th Annual Retrovirus Conference, the chief U.S. scientific meeting on AIDS, and will publish them in the March issue of the Journal of Virology.

The Food and Drug Administration has been monitoring the research and is concerned about the potential risk to the blood supply. Half of the lab workers with SFV were regular donors and have now been told not to give blood.

SFV stands for simian foamy virus, named because it causes cells to clump together and look like foamy bubbles on microscope slides. It's common in a wide variety of apes and monkeys.

Simian virus gets more study
The CDC started researching its prevalence in humans in the early 1990s, when a researcher at a primate lab was accidentally stuck with a needle while trying to deliberately infect a primate with SIV for an AIDS study.

Officials tested the worker to see whether he had contracted SIV and found he had SFV.

"It made us pause and think, 'How common are these?' " Heneine said.

By 1998, four human cases had been identified and reported in a medical journal. The FDA's Blood Products Advisory Committee met in December 2001 and decided transmission through the blood supply hadn't been shown, but wanted to continue to monitor the situation, Heneine said.

The CDC enrolled workers from 15 primate research centers and zoos around the country in a study to look for SFV and other simian viruses. Of the 417 animal handlers tested so far, 12 men and two women - 3.35% of the sample - were found to have SFV, far more than had been expected.

Genetic analyses showed they acquired the germ from African green monkeys, baboons and chimpanzees.

Wives of six of the workers have been tested and do not show the virus, suggesting it's not easily transmitted through sex.

Although the lab workers with the virus are healthy and show no signs of illness, there are signs of abnormalities in certain blood cells.

Lab workers at Wisconsin's primate center were not involved in the research.

Many unknowns
"Nobody in our group has been tested," said Thomas Friedrich, head of viruses at the HIV primate lab at the University of Wisconsin-Madison. He doesn't consider SFV a threat now because it's not known to cause disease.

"But you really never know," he said. "When viruses cross the species barrier, they can be more or less pathogenic. Often they're more pathogenic. HIV is a prime example."

The lab worker study also looked for another STLV, simian T-lymphotropic virus, the primate version of HTLV, a virus that causes leukemia, lymphoma and a variety of neurological diseases in people. None of the lab workers in this study had it, but it's been found in humans before and causes disease in about 5% of cases, Heneine said.

His study did find one worker with SIV. The worker is well, but Heneine cautioned that that doesn't mean SIV isn't harmful to humans.

"That particular strain in that particular person didn't cause disease. I'm not sure how much we can generalize," he said.

Mario Stevenson, vice chair of the conference and an AIDS expert from the University of Massachusetts Medical Center in Worcester, said that recent history has been "a rude awakening" about extremely small changes in animal viruses that can make them deadly to humans, such as SARS and HIV.

"Conditions for similar transmission are ever-present and ever-threatening," he said.

The study is continuing, and the CDC is trying to enroll more zoos and primate research centers. The CDC also soon will publish data from another study with Johns Hopkins University researchers on 1,100 animal hunters in Cameroon. About 1% of them tested positive for SFV, Heneine said. This is the first direct evidence that simian retroviruses can be spread through hunting and butchering, the way scientists think SIV first infected people.




>From the Feb. 16, 2004 editions of the Milwaukee Journal Sentinel
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.envirolink.org/pipermail/ar-news/attachments/20040218/8eaa203c/attachment.html