# 293
The early news reports are sketchy, and so it is difficult to know what to make of all of this, but authorities in South Korea are reporting that at least one person who worked on a poultry farm where infected birds were culled has tested positive for H5N1 antibodies.
This report from Bloomberg:
Bird Flu Infects Person in South Korea Without Causing Disease
By Seonjin Cha
Jan. 11 (Bloomberg) -- South Korea said it found a new case of bird flu in a person who showed no signs of the disease.
The new asymptomatic case of the H5N1 strain of avian influenza was found after analyzing blood taken from a farm worker exposed to diseased fowl during an outbreak last month, the Korea Centers for Disease Control and Prevention said in an e-mailed statement today. It didn't give details of the person.
``There were no abnormal symptoms observed in the person, so the person isn't'' infected with disease, the agency said.
Although somewhat rare, this isn’t the first time that someone has been reported to develop antibodies to the H5N1 virus without developing the illness. During an outbreak in late 2003 and early 2004, several South Koreans reportedly developed antibodies without becoming severely ill.
We are fortunate that the South Koreans are being diligent in the follow up blood work on these workers. It is giving us greater insight into the way the virus works, and right now, we need all the information we can get.
As to exactly what this means, it is too early to tell. The reportage on this story varies just a bit, as we shall see. In the Associated Press stories, carried by USA Today, and other outlets, they state:
The Korean Centers for Disease Control and Prevention said a person, whom it didn't identify, had been infected with the deadly H5N1 strain of the virus but developed natural immunity to the disease and wasn't ill.
The Bloomberg report, cited above, gives a slightly different version. They report:
The latest case had been given Roche Holding AG's Tamiflu antiviral medicine as a precaution to prevent the disease and was vaccinated against seasonal influenza to help prevent the avian strain combining with the more infectious human form, the Korean health agency said. The person was re-tested for H5N1 10 days after the initial exposure, it said.
The center completed testing on blood samples from 26 of 85 people considered to have been exposed to the virus, it said. The remainder of results may be reported by the end of the month, the center said.
So, the question on my mind this morning is: Is this the result of natural immunity or of chemoprophylaxis?
If the Tamiflu worked as advertised, then it wouldn’t be a surprise to find that a recipient had developed antibodies to the disease post-exposure. The antiviral would have inhibited the replication of the virus, and allowed the body’s defenses to quickly destroy it, by creating the appropriate antibodies.
I’m not sure we are going to know the answer to this question anytime soon. Not without wide ranging seroprevalence studies done on populations exposed to the virus, but not given Tamiflu.
The good news in all of this is that it may show that one can be exposed, and either through natural immunity or chemoprophylaxis, that it is possible to avoid an active infection.
And that would be good news, indeed.
