title: Comparison of an indirect fluorescent antibody test with Western blot for the detection of serum antibodies against Encephalitozoon cuniculi in cats.
abstract: Current clinical research indicates that Encephalitozoon (E.) cuniculi infections in cats may be underdiagnosed, especially in animals with typical ocular signs (cataract/anterior uveitis). Although molecular detection of the pathogen in tissue appears promising, serology remains the major diagnostic tool in the living animal. While serological tests are established for the main host of E. cuniculi, the rabbit, the routine serological diagnosis for cats still needs validation. The aim of the study was to evaluate the consistency of indirect fluorescence antibody test (IFAT) and Western blot (WB) for the detection of IgG antibodies against E. cuniculi in the serum of 84 cats. In addition, PCR of liquefied lens material or intraocular fluid was performed in those of the cats with a suspected ocular E. cuniculi infection. Twenty-one cats with positive PCR results were considered as a positive reference group. Results obtained by IFAT and WB corresponded in 83/84 serum samples, indicating a very good correlation between both serological methods. Using WB as the standard reference, sensitivity and specificity for the detection of antibodies against E. cuniculi by the IFAT were 97.6 and 100%, respectively. The positive and negative predictive values for the IFAT were 100 and 97.7%, respectively. The accuracy (correct classified proportion) for the detection of IgG antibodies against E. cuniculi in cats was 98.8%. The comparison of both serological methods with the PCR results also revealed a good agreement as 20 out of 21 PCR-positive samples were seropositive both in IFAT and WB. Both tests can be considered as equally reliable assays to detect IgG antibodies against E. cuniculi in cats. As the IFAT is quicker and easier to perform, it is recommended for routine use in the diagnosis of feline encephalitozoonosis.
authors.affiliation: Clinical Department of Small Animals and Horses, Clinic of Internal Medicine and Infectious Diseases, University of Veterinary Medicine Vienna, Veterinärplatz 1, 1210, Vienna, Austria, frank.kuenzel@vetmeduni.ac.at.
authors.forename: Frank
authors.initials: F
authors.lastname: Künzel
authors.forename: Roman
authors.initials: R
authors.lastname: Peschke
authors.forename: Alexander
authors.initials: A
authors.lastname: Tichy
authors.forename: Anja
authors.initials: A
authors.lastname: Joachim
mesh_terms: D000818:Animals; D000908:Antibodies, Fungal / Q000097:blood*; D015153:Blotting, Western / Q000592:standards / Q000662:veterinary*; D016022:Case-Control Studies; D002371:Cat Diseases / Q000175:diagnosis* / Q000276:immunology / Q000469:parasitology; D002415:Cats; D004285:Dogs; D009670:Encephalitozoon cuniculi / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D016890:Encephalitozoonosis / Q000175:diagnosis / Q000276:immunology / Q000662:veterinary*; D019084:Fluorescent Antibody Technique, Indirect / Q000592:standards / Q000662:veterinary*; D007074:Immunoglobulin G / Q000097:blood; D061985:Madin Darby Canine Kidney Cells; D011817:Rabbits; D012680:Sensitivity and Specificity
chemical_list: D000908:Antibodies, Fungal; D007074:Immunoglobulin G