2017 ACVIM Forum Research Abstract Program

A 4-week course of doxycycline with or without supplemental imidocarb cleared E. canis infection for at least 6 months after immunosuppression for 6 weeks. A risk of reactivation of E. canis infection with immune suppression in previously treated dogs was considered minimum. Heartworm antigen testing is routinely performed to diagnose heartworm infections in dogs. The original diagnostic tests employed immune complex dissociation (ICD) methods to release antigen that was bound by endogenous canine antibodies. However, ICD methods were discontinued in the majority of commercially available assays due to improvements in assay technology (O'Connor T, et al. "Immunoassay applications in veterinary diagnostics." In: Wild D, ed. The Immunoassay Handbook. 4th ed. Great Britain: Elsevier, 2013: 623-645). Interference from immune complexes is not unique to heartworm diagnostics and various methods are available for ICD. The purpose of this study was to evaluate different methods of ICD for the detection of free heartworm antigen by microtiter plate ELISA and evaluate the performance of ICD in pet dogs. The original, USDA licensed PetChek Ã’ Heartworm Test (IDEXX Laboratories, Inc.) utilized pepsin at an acidic pH for ICD prior to antigen testing. Using a set of experimental samples, the pepsin method was compared to heat treatment, and acid treatment. All methods were found to release complexed antigen and produce positive results when the post-treatment samples were tested for heartworm antigen by microtiter plate ELISA. While heat treatment required a minimum of 600 lL of either serum or plasma, the pepsin and acid methods needed only 50 lL of the patient sample. To extend this to a field population, samples from 1115 patients were submitted to IDEXX Laboratories between 2014 and 2016 for investigation of discrepant heartworm results. Samples were evaluated with and without pepsin ICD using PetChek Ã’ Heartworm. A total of 112 patients became antigen positive with the ICD protocol only, 122 were positive with and without ICD but demonstrated at least a 50% increase in plate absorbance (OD), and 109 were positive both with and without ICD but had minimal change in plate OD following ICD. The remaining 772 patients did not have detectable antigen with and without ICD. In a prospective study, dogs receiving pre-adulticide heartworm treatment consisting of a macrocyclic lactone in combination with doxycycline were evaluated in the same way. Serial samples from 12 dogs revealed that 3 had a reduction in free circulating antigen within 4 weeks of initiating treatment. In all cases, free antigen levels could be recovered with ICD. Heartworm antigen testing with ICD can be a valuable adjunct diagnostic for those patients who have discrepant results, have intermittently used a macrocyclic lactone, or are receiving treatment. There is no information about fecal shedding of feline panleukopenia virus (FPV) in cats after modified-live vaccination. Aim of this study was to provide information about parvovirus DNA-shedding in recently vaccinated, adult, healthy cats and to assess related factors using Chi-squared and Fisher 0 s exact test. Forty cats were included in the study and were vaccinated with a commercial FPV modified-live vaccine. Feces of cats was tested for the presence of parvovirus DNA on day 7, 14, 21, and 28 by quantitative real-time PCR. Pre-and post-vaccination serum antibody titers were measured by hemagglutination inhibition on day 0, 7, a