Neorickettsia risticii

Background

Neorickettsia risticii (previously Ehrlichia risticiii) is a gram-negative intracellular bacterium. Neorickettsia risticii causes potomac horse fever (PHF) and is an acute enterocolitis, producing mild colic, fever, and diarrhea in horses of all ages, and abortion in pregnant mares. The enterocytes infect the small and large intestine resulting in acute colitis, a primary clinical sign of PHF. This disease occurs in spring, summer, and early fall; and is associated with pastures located near creeks or rivers. Exposure to this pathogen is believed to occur by ingestion of aquatic insects that carry N. risticii.1 The incubation period occurs for 10 to 18 days. Horses diagnosed with PHF are not contagious. Initial clinical symptoms are characterized by mild depression, anorexia, and a fever. Within 48 hrs. signs may include severe sepsis, dehydration, and abdominal discomfort. N. risticii can be diagnosed using polymerase chain reaction (PCR), a technique that confirms the presence of a pathogen by identifying nucleic acids. Currently, PCR detection of the bacterium in blood is the only diagnostic method available.2 The Fluxergy N. risticii PCR assay has been designed to target a conserved region of this bacteria and allows for rapid detection of the pathogen within close proximity of the patient.

Key Benefits

Simple workflow

No sample preparation

Automated data interpretation

Sample to result in 30 minutes

Early detection is treatable with antibiotics

Assay Specifications

Sample Type ETDA whole blood or fecal swab*
Species Equine
Storage Condition Fluxergy Card – Room temperature @ ~23° C
Fluxergy Buffers – Frozen @ -20°C
*Sample type must be specified before use. Each assay kit is sample type specific.

Kit Contents

  • 6” Rayon swab
  • Fluxergy N. risticii Buffer 1
  • Fluxergy N. risticii Buffer 2
  • Fluxergy Card

Customer supplied reagents and supplies

  • Clinical sample for testing

Sample collection method

For whole blood, collect in 1 mL in tube coated with EDTA anticoagulant. Other anticoagulants are not suitable for this assay. Store sample in refrigerator or at 4°C if not testing immediately after sample collection.

For fecal swabs, it is recommended that the head of the swab is fully coated with sample material. For optimal performance, collect feces to be tested in a sterile 2 oz specimen cup. Fully submerge the head of the swab into the sample for 5 seconds. Place stool coated swab into the swab tube. The opposite end of the tube serves as a tight-fitting cap. Store sample in refrigerator or at 4°C if not testing immediately after sample collection.

Warnings and Precautions

  • Fluxergy’s N. risticii assay is for Research Use Only (RUO). It is not intended for diagnostic use.
  • Fluxergy’s N. risticii assay is compatible only with the Fluxergy Analyzer Beta device.
  • All specimens should be handled as potentially infectious agents and according to universal safety precautions.
  • This Fluxergy N. risticii assay is compatible only for EDTA whole blood and feces. The sample type must be specified as each buffer is specially crafted for the sample.
  • Contamination of the sample and kit contents may lead to erroneous results. Use aseptic technique and a clean workspace whenever possible.
  • Store Fluxergy assay kit at recommended storage temperature and conduct assay within specified environment (e.g. temperature and humidity) for optimal performance.
  • Follow appropriate specimen collection, storage and processing for optimal performance.
  • Use Fluxergy supplied swabs, reagents, pipettes and pipette tips to conduct assay for optimal performance.

Detection of Clinical Sample

Clinical sample, specifi cally equine EDTA whole blood positive for N. risticii, was tested using the Fluxergy Analyzer Beta and N. risticii assay. Results showed amplifi cation and positive agreement with the clinical reference laboratory assay.

References

  1. Jennifer H. McQuiston et al.; Ehrlichiosis and related infections, Vet Med Today: Zoonosis Update, Volume 223, Issue 12, 15 December 2003, Pages 1750–1754.
  2. Stewart, A. J. (2016). Potomac Horse Fever. Retrieved from Merck Veterinary Manual.