Utah lab ready for West Nile tests

News reporters got a look Thursday at how microbiologists in the state's public health laboratory process samples from mosquitoes, birds and people in the search for West Nile virus.

It's a many-faceted task that ranges from "squishing" the bugs to coloring antibodies in human serum.

The tests, which can take several days to run, are different for humans than for mosquitoes and birds. They are also used to look for similar viruses, including the mosquito-transmitted St. Louis encephalitis viruses.

Testing is expected to be a very big deal this year. West Nile virus, which is transmitted by mosquitoes to birds, humans and horses, first reached Utah last summer. The second year has, traditionally in each state, been the worst. And though most infected people will not even show symptoms, a small percentage die, according to the Centers for Disease Control and Prevention.

That's why the state Health Department and a coalition of other agencies that includes the Division of Wildlife Resources, state Mosquito Abatement districts, local health departments, Agriculture and many others has put the emphasis this year on education and prevention.

In two sessions Thursday, the state lab, which is normally off-limits for security reasons, opened its doors to area reporters who watched as the same tests were run that will be used to detect West Nile. It's too early for the actual tests, since the mosquito types that carry West Nile are just beginning to appear.

Efforts will begin in earnest in a couple of weeks at the lab, said Barbara Jepson, director of the Bureau of Microbiology. Then a number of microbiologists will work full time for months at a time testing for the virus.

Human testing for West Nile virus is indirect, a search for the body's response to infection, using an Enzyme-Linked ImmunoSorbent Assay (ELISA) that detects antibodies produced by the body when the virus infects it. ELISA is a three-day process that includes coating a plate with a "capture antibody" and adding a patient's serum (the liquid portion of clotted blood) to it.

If the virus immunoglobulin M antibody is in the serum, it binds to the capture antibody coating; then chemicals are added that produce a colored reaction. The color hue depends on the amount of antibody in the serum. An optical reader checks the intensity of the color and generates a readout, said Annette Atkinson, microbiologist.