Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs
Abstract Background The diagnosis and management of canine heartworm disease is a growing concern for shelter veterinarians. Although the accuracy of commercial antigen test kits has been widely studied, recent reports have renewed interest in antigen blocking as a causative factor for false “no ant...
| Main Authors: | , , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
BMC
2017-11-01
|
| Series: | Parasites & Vectors |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13071-017-2443-7 |
| _version_ | 1818507764834500608 |
|---|---|
| author | Brian A. DiGangi Carly Dworkin Jason W. Stull Jeanette O’Quin Morgan Elser Antoinette E. Marsh Lesli Groshong Wendy Wolfson Brandy Duhon Katie Broaddus Elise N. Gingrich Emily Swiniarski Elizabeth A. Berliner |
| author_facet | Brian A. DiGangi Carly Dworkin Jason W. Stull Jeanette O’Quin Morgan Elser Antoinette E. Marsh Lesli Groshong Wendy Wolfson Brandy Duhon Katie Broaddus Elise N. Gingrich Emily Swiniarski Elizabeth A. Berliner |
| author_sort | Brian A. DiGangi |
| collection | DOAJ |
| description | Abstract Background The diagnosis and management of canine heartworm disease is a growing concern for shelter veterinarians. Although the accuracy of commercial antigen test kits has been widely studied, recent reports have renewed interest in antigen blocking as a causative factor for false “no antigen detected” results. The objectives of this study were to determine the prevalence of false “no antigen detected” results in adult dogs entering shelters in northern, southern, and western regions of the country and to identify historical and clinical risk factors for such results. Methods Serum samples were evaluated for Dirofilaria immitis antigen using a commercially available point-of-care ELISA; samples in which no antigen was detected underwent a heat treatment protocol and repeat antigen testing. Whole blood samples underwent Knott testing to identify the presence of microfilariae. Historical and clinical findings were analyzed using exact logistic regression. Results A total of 616 samples were analyzed. Overall prevalence of positive antigen test results (prior to heat treatment) was 7.3% and frequency of false “no antigen detected” results due to antigen blocking (ie, samples with no antigen detected prior to heat treatment and positive after heat treatment) was 5.2%. Among dogs that had no detectable antigen on the initial tests, dogs that had microfilariae detected via modified Knott testing (OR = 32.30, p-value = 0.013) and dogs that previously received a heartworm preventive (OR = 3.81, p-value = 0.016) had greater odds of antigen blocking than dogs without these factors. Among dogs that were heartworm positive, those without microfilariae detected had greater odds of antigen blocking than dogs with this factor (OR = 11.84, p-value = 0.0005). Geographic region of origin was significantly associated with occurrence of antigen blocking (p = 0.0036); however, blocking occurred in all regions sizably contributing to heartworm diagnoses. Of the 74 dogs found to be infected with heartworms in this study, 39.2% (29) had no detectable antigen prior to heat treatment. Conclusions Heat treatment of serum samples should be considered to improve diagnostic test accuracy, particularly in dogs that reportedly received a heartworm preventive prior to antigen testing regardless of region of origin. |
| first_indexed | 2024-12-10T22:22:31Z |
| format | Article |
| id | doaj.art-b8751df9e0e64eac9dc64a08a613c2cb |
| institution | Directory Open Access Journal |
| issn | 1756-3305 |
| language | English |
| last_indexed | 2024-12-10T22:22:31Z |
| publishDate | 2017-11-01 |
| publisher | BMC |
| record_format | Article |
| series | Parasites & Vectors |
| spelling | doaj.art-b8751df9e0e64eac9dc64a08a613c2cb2022-12-22T01:31:16ZengBMCParasites & Vectors1756-33052017-11-0110S212312810.1186/s13071-017-2443-7Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogsBrian A. DiGangi0Carly Dworkin1Jason W. Stull2Jeanette O’Quin3Morgan Elser4Antoinette E. Marsh5Lesli Groshong6Wendy Wolfson7Brandy Duhon8Katie Broaddus9Elise N. Gingrich10Emily Swiniarski11Elizabeth A. Berliner12Department of Small Animal Clinical Sciences, University of Florida, College of Veterinary MedicineDepartment of Small Animal Clinical Sciences, University of Florida, College of Veterinary MedicineDepartment of Veterinary Preventive Medicine, The Ohio State UniversityDepartment of Veterinary Preventive Medicine, The Ohio State UniversityDepartment of Veterinary Preventive Medicine, The Ohio State UniversityDepartment of Veterinary Preventive Medicine, The Ohio State UniversityHumane Society of Boulder ValleyDepartment of Veterinary Clinical Sciences, Louisiana State University, School of Veterinary MedicineDepartment of Veterinary Clinical Sciences, Louisiana State University, School of Veterinary MedicineAustin Humane SocietyLarimer Humane SocietyPet Orphans of Southern CaliforniaDepartment of Population Medicine and Diagnostic Sciences, Cornell UniversityAbstract Background The diagnosis and management of canine heartworm disease is a growing concern for shelter veterinarians. Although the accuracy of commercial antigen test kits has been widely studied, recent reports have renewed interest in antigen blocking as a causative factor for false “no antigen detected” results. The objectives of this study were to determine the prevalence of false “no antigen detected” results in adult dogs entering shelters in northern, southern, and western regions of the country and to identify historical and clinical risk factors for such results. Methods Serum samples were evaluated for Dirofilaria immitis antigen using a commercially available point-of-care ELISA; samples in which no antigen was detected underwent a heat treatment protocol and repeat antigen testing. Whole blood samples underwent Knott testing to identify the presence of microfilariae. Historical and clinical findings were analyzed using exact logistic regression. Results A total of 616 samples were analyzed. Overall prevalence of positive antigen test results (prior to heat treatment) was 7.3% and frequency of false “no antigen detected” results due to antigen blocking (ie, samples with no antigen detected prior to heat treatment and positive after heat treatment) was 5.2%. Among dogs that had no detectable antigen on the initial tests, dogs that had microfilariae detected via modified Knott testing (OR = 32.30, p-value = 0.013) and dogs that previously received a heartworm preventive (OR = 3.81, p-value = 0.016) had greater odds of antigen blocking than dogs without these factors. Among dogs that were heartworm positive, those without microfilariae detected had greater odds of antigen blocking than dogs with this factor (OR = 11.84, p-value = 0.0005). Geographic region of origin was significantly associated with occurrence of antigen blocking (p = 0.0036); however, blocking occurred in all regions sizably contributing to heartworm diagnoses. Of the 74 dogs found to be infected with heartworms in this study, 39.2% (29) had no detectable antigen prior to heat treatment. Conclusions Heat treatment of serum samples should be considered to improve diagnostic test accuracy, particularly in dogs that reportedly received a heartworm preventive prior to antigen testing regardless of region of origin.http://link.springer.com/article/10.1186/s13071-017-2443-7CanineHeartwormDirofilaria immitisAntigen testDiagnosisImmune complex |
| spellingShingle | Brian A. DiGangi Carly Dworkin Jason W. Stull Jeanette O’Quin Morgan Elser Antoinette E. Marsh Lesli Groshong Wendy Wolfson Brandy Duhon Katie Broaddus Elise N. Gingrich Emily Swiniarski Elizabeth A. Berliner Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs Parasites & Vectors Canine Heartworm Dirofilaria immitis Antigen test Diagnosis Immune complex |
| title | Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs |
| title_full | Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs |
| title_fullStr | Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs |
| title_full_unstemmed | Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs |
| title_short | Impact of heat treatment on Dirofilaria immitis antigen detection in shelter dogs |
| title_sort | impact of heat treatment on dirofilaria immitis antigen detection in shelter dogs |
| topic | Canine Heartworm Dirofilaria immitis Antigen test Diagnosis Immune complex |
| url | http://link.springer.com/article/10.1186/s13071-017-2443-7 |
| work_keys_str_mv | AT brianadigangi impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT carlydworkin impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT jasonwstull impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT jeanetteoquin impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT morganelser impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT antoinetteemarsh impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT lesligroshong impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT wendywolfson impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT brandyduhon impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT katiebroaddus impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT elisengingrich impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT emilyswiniarski impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs AT elizabethaberliner impactofheattreatmentondirofilariaimmitisantigendetectioninshelterdogs |