[neverdem]

The CDC found in the repeat testing that the man had Marburg hemorrhagic fever, and sent Lutheran Hospital its findings at the end of last month.

The CDC tested for specific immunoglobulins known as IgG antibodies found in survivors of Marberg infections. IgG antibodies confer long term immunity. IgG antibodies are not a significant part of a vertebrate's initial immune response. They are not usually detected for a number of weeks after initial infection in humans, IIRC.

Lutheran Hospital officials said that when the patient first came in, the medical staff "followed the protocols for dealing with an unknown infection, including contact isolation (gown and glove) and testing for a number of infectious, with some of the tests being performed at the CDC."

It was not clear Friday why the initial CDC tests did not reveal the virus.

IMHO, initial tests lack the specificity of IgG antibodies. It was too soon to test for IgG antibodies. Any corrections or updates to my knowledge of microbiology and immunology are always appreciated.

[ga medic]

The diagnostics for filoviruses follow a process. The first diagnosis is made by clinical assessment, which is basically a physician properly identifying the symptoms of the patient with those of the virus (EBOV & MARV), and determining that the patient has traveled to a location where contact with these viruses could occur.

Bodily fluids can be examined and the virus or inclusion bodies can be identified in patients having relatively high viremia. These early results are not always accurate because results can be difficult to read. Once the virus has been observed it can be cultured, which requires 3-10 days.

Immunoassay tests such as ELISA and PCR (there are several) can be used to identify IgG and IgM antibodies, as you said. These tests can be conducted in a matter of hours and can be used to confirm the initial observations. However, they are dependent on a sufficient immune response, which may not always occur. In the very virulent strains, the patient will often die, before a significant immune response occurs.

My guess is that there was more than one diagnostic measure used to confirm the initial diagnosis. While one test might might not have provided conclusive evidence, the addition of other results might create a definitive diagnosis.

Sounds like the medical community and CDC did a good job on this one.

[vetvetdoug]

Interesting. The Marburg Virus was one of the reasons the USAF stopped buying primates directly from Africa. I always worried about it when I was using Green Monkey kidney cells to grow my viruses in vitro.

[MarMema]

IMHO, initial tests lack the specificity of IgG antibodies. It was too soon to test for IgG antibodies. Any corrections or updates to my knowledge of microbiology and immunology are always appreciated.

You are exactly correct. IGM is the first responder.