Lab procedures

Ticks are sent to us in a variety of shipping containers and conditions. Since our tests detect DNA, and DNA is very stable (not destroyed by heat or mechanical damage), we can test almost any specimen.  We’ve even managed to extract and detect DNA in specimens that are over 100 years old!

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The first thing we do when we receive your tick is to place it under the microscope to identify its species.  There are many tick species, though only a small number of the actually bite people.  Different ticks are associated with different pathogens. Occasionally, people send us things that they think are ticks, but these turn out to be other arthropods (betters, ants), seeds, or even pieces of skin from a scab.  We carefully photograph each specimen under high magnification to document what we’ve found.

deer ticks studied at UMass, Amherst

Once we know what kind of tick was sent, we begin the process of extracting its DNA.  This requires smashing the tick with a small, sterile, plastic pestle.  There are different methods for smashing ticks but having done tens of thousands over the years, we’ve found this manual method words best.

deer ticks studied at UMass, Amherst

Next we use an organic extraction protocol to extract and purify the DNA.  At this point, the sample is not visible to the naked eye. Any resemblance to a tick (and chance of infection) is long gone.

deer ticks studied at UMass, Amherst

The DNA sample is then added to a tube containing reagents and placed on the real time PCR instrument.  Results appear on a computer screen as amplification plots.  All ticks are tested for tick DNA + Borrelia burgdorferi (duplex reaction).  We test for tick DNA as a control to make sure the specimen is a tick (we occasionally are sent sesame seeds or beetles) and to make sure the DNA is of sufficient quality and quantity.  There are several other pathogens for which the tick can be tested at any time.

deer ticks studied at UMass, Amherst

After testing, all DNA samples are kept in a -20C freezer indefinitely.  Many clients return and ask us to test for other pathogen.  These ticks also provide a record of pathogens from year to year.  Ticks have hundreds of bacteria living in their guts.  At least some of these may be pathogens not yet identified.  If at some point a new disease emerged (or was identified) we could return to this molecular archive to test for that new pathogen.

 

deer ticks studied at UMass, Amherst