Equine Toxoplasma gondii

Equine Toxoplasma gondii

Toxoplasma gondii, an obligate intracellular parasite, is an important pathogen of warm-blooded animals, including horses. Clinical signs includes fever, ataxia, retinal degeneration and encephalomyelitis, and abortion or stillbirth in pregnant equids.


Results Interpretation

Studies performed at UC Davis have shown that at a titer cutoff of 320, horses with clinical signs compatible with EPM had 3.55 times the odds of seropositive T. gondii tests compared to those without clinical signs. In other species, increased infection rates are noted later in the calendar year (late summer and autumn), potentially due to peak periods of T. gondii oocyst shedding in domestic kittens and cats. When restricted to the autumn season, at a titer cutoff of 320, an EPM suspect horse had 6.4 times the odds of testing seropositive to T. gondii when compared to non-neurologic horses. The association between high T. gondii titers and clinical signs of EPM is potentially reflective of toxoplasmosis in horses. (1)

While future studies investigating the relationship between T. gondii and neurological signs compatible with EPM are necessary, the UC Davis VMTH Clinical Diagnostic Laboratories are proud to offer Toxoplasma gondii IFA testing to our veterinary clients to assist in clinical diagnostics.

It is recommended to have a concurrent fluid analysis performed on CSF at the time of ToxoFluor™ testing to rule out blood contamination.


Effective for samples received by the lab July 1, 2021 - June 30, 2022


  • ToxoFluor™ - $68/sample*
  • CSF Fluid Analysis - $87/sample*
  • *Prices subject to change without notice.  Updated 6/29/2021

Include the following information with each submission:

  • Check the test(s) requested on the sample submission form. ***Please note: If no tests are selected, an IFAT panel (SarcoFluor™ and NeoFluor™) will be run***
  • Number and type of samples included in submission
  • Sample collection date
  • Patient name, breed, sex, and age
  • Patient’s owner name and address
  • Clinic/hospital name and complete mailing address
  • Veterinarian’s name
  • Phone number, fax number and email
  • Pertinent clinical history

Sample Processing & Shipping

  • Blood Processing: Spin and separate serum from red cells. Place serum in a new, clean tube. Serum separator tubes are not recommended, as the separator becomes dislodged during shipping, allowing red cells and serum to mix. A handling fee will be assessed for unprocessed or improperly processed blood samples.
  • CSF processing: Collect CSF in a clean red top tube. DO NOT spin CSF samples. If submitting samples for ToxoFluor™ AND CSF Fluid analysis, please provide at least 2mL CSF.
  • If testing is delayed longer than 5 days, it is recommended to freeze the serum samples at -20°C or below. DO NOT freeze CSF samples -- submit as soon as possible.
  • Send all samples with a cold pack / ice pack.
  • Ship overnight by FedEx (do not use USPS), Monday-Thursday only. Do not ship on Fridays, weekends or national holidays.
  • Our FedEx Reduced Price Shipping Program is available for for veterinarians and veterinary clinics. FedEx is the preferred shipping method for overnight delivery. Please do not ship using USPS; USPS mail is delivered to a central campus location before being distributed to our labs, delaying transit time of sensitive laboratory samples.
  • Ship to:
    UC Davis VMTH
    Central Laboratory Receiving, Rm 1033

    1 Garrod Drive
    Davis, CA  95616-8747

Turnaround times

  • ToxoFluor™ - 4-6 business days from date of sample receipt.
  • CSF fluid analysis - 2 business days from date of sample receipt.
  • Samples can be run “STAT,” for an additional fee; turnaround time for STAT samples is 3 business days from date of sample receipt for ToxoFluor™.
  • All turnaround times assume there are no complications with testing; should complications occur, turnaround times may be delayed
  • For information on equine medical care or medical treatments, please contact the veterinary hospital's Large Animal Clinic at (530) 752-1393.

Biological samples submitted to the VMTH Clinical Diagnostic Laboratories may be used for VMTH teaching and research purposes consistent with the mission of the University.

ToxoFluor™ testing references

"Toxoplasma gondii seroprevalence and association with equine protozoal myeloencephalitis: A case controlled study of California horses.” James KE, Smith WA, Packham AE, Conrad PA, Pusterla N. Vet J. 2017 Jun;224:38-43.  doi: 10.1016/j.tvjl.2017.05.008.