title: Heat treatment of serum samples from stray dogs naturally exposed to Dirofilaria immitis and Dirofilaria repens in Romania.
abstract: Pre-heating of serum samples has been shown to reverse false negative antigen tests for Dirofilaria immitis infection in dogs. Here the authors report the results of serum sampling in a population of dogs naturally exposed to D. immitis and Dirofilaria repens infection by testing in ELISA before and after heat treatment. Of 194 dogs sampled from four cities in Romania, D. immitis circulating antigens were found in 16 (8.2%) non heated samples and in 52 (26.8%) heated samples. Of the 108 dogs examined by Knott test, 24 dogs (22.2%) were positive for circulating mf. Subsequent PCR identification showed six dogs had D. immitis mf only, 12 dogs, had only D. repens mf, and 5 were positive for both. Fifty% of dogs with circulating D. immitis mf had positive antigen tests before and after heating, while the other 50% reverted to positive only after heat treatment. Sixty% of dogs with mixed D. immitis/D. repens infection were antigen positive before and after heating, while the other 40% converted to positive after heating. Antigen testing for D. immitis in the 12 dogs with only D. repens mf gave conflicting results. Only two dogs (16%) were antigen negative both before and after heat treatment. Six dogs (50%) became antigen positive after heating and four dogs (30%) were antigen positive both before and after heat treatment. Results would suggest that: false negative result for antigen testing can be reverted by heating of the serum sample; dogs infected with D. repens may have also an occult infection with D. immitis; heat treatment of serum from D. repens-infected dogs can reveal an occult infection with D. immitis.
authors.affiliation: Ion Ionescu de la Brad, University of AgriculturalSciences and Veterinary Medicine Iasi, Faculty of Veterinary Medicine, M. Sadoveanu Alley No. 8, 700489, Iasi, Romania.
authors.forename: L
authors.initials: L
authors.lastname: Ciucă
authors.affiliation: Dipartimento di Scienze Medico-Veterinarie, Università di Parma, via del Taglio 10, 43121, Parma, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Genchi
authors.affiliation: Dipartimento di Scienze Medico-Veterinarie, Università di Parma, via del Taglio 10, 43121, Parma, Italy. Electronic address: kramerlh@unipr.it.
authors.forename: L
authors.initials: L
authors.lastname: Kramer
authors.affiliation: Dipartimento di Scienze Medico-Veterinarie, Università di Parma, via del Taglio 10, 43121, Parma, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Mangia
authors.affiliation: Ion Ionescu de la Brad, University of AgriculturalSciences and Veterinary Medicine Iasi, Faculty of Veterinary Medicine, M. Sadoveanu Alley No. 8, 700489, Iasi, Romania.
authors.forename: L D
authors.initials: LD
authors.lastname: Miron
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via della Veterinaria, 1, Naples, Italy.
authors.forename: L Del
authors.initials: LD
authors.lastname: Prete
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via della Veterinaria, 1, Naples, Italy.
authors.forename: M P
authors.initials: MP
authors.lastname: Maurelli
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via della Veterinaria, 1, Naples, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Cringoli
authors.affiliation: Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Via della Veterinaria, 1, Naples, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Rinaldi
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000097:blood; D019937:Diagnostic Techniques and Procedures / Q000662:veterinary*; D004183:Dirofilaria immitis; D060348:Dirofilaria repens; D004184:Dirofilariasis / Q000175:diagnosis* / Q000453:epidemiology; D004283:Dog Diseases / Q000175:diagnosis* / Q000453:epidemiology; D004285:Dogs; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards / Q000662:veterinary*; D005188:False Negative Reactions; D006358:Hot Temperature; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012383:Romania / Q000453:epidemiology
chemical_list: D000947:Antigens, Helminth
keywords: Antigen test; Dirofilaria repens; Dirofilariaimmitis; Occult infection; Pre-treatment heat