A Diagnostic Algorithm for Detection of Antibodies to Influenza A Viruses in Dogs in Italy (2006–2008)

Abstract

Abstract. Since 2004, there have been several reports of Influenza A virus (FLUAV) infection in dogs. Dogs have been infected with equine influenza H3N8, avian influenza H3N2 and H5N1, and the pandemic H1N1 virus. Because of recent avian and equine influenza outbreaks in Italy, the objectives of the present study were to estimate the level of exposure of Italian dogs to influenza A viruses and to assess a diagnostic algorithm for detection of FLUAV exposure in dogs. Sera collected from 6,858 dogs from 2006 to 2008 were screened in a competitive enzyme-linked immunosorbent assay (cELISA) for antibodies to the highly conserved influenza A nucleoprotein. Samples positive in the cELISA were confirmed by testing in hemagglutination inhibition (HI) and fluorescent antibody test (FAT). Two seropositive dogs had antibodies to H3 hemagglutinin proteins, consistent with exposure to recent canine and equine subtype H3N8 viruses. Using a Bayesian model, the sensitivity and specificity of the cELISA were estimated as 93.98% (probability intervals [PI]: 81.67-99.08%) and 98.71% (PI: 98.43-98.96%), respectively. After accounting for the imperfect sensitivity and specificity of the cELISA, the Bayesian posterior prevalence of FLUAV exposure among tested Italian dogs was 0.5% (PI: 0.1-1.4%). The study results indicate that screening with a cELISA for influenza A nucleoprotein antibody, followed by confirmatory testing with HI and/or FAT, is a highly sensitive and highly specific approach for diagnosing FLUAV exposure in dogs.

Evidence of pandemic H1N1 influenza exposure in dogs and cats, Thailand: A serological survey

“…All serum samples were screened for the presence of influenza A nucleoprotein antibodies by using a commercially available multi‐species competitive NP‐ELISA kit (ID Screen®, ID Vet, Montpellier, France) following to the manufacturer's instructions (Dundon et al, ). This diagnostic tool showed a 93.98% sensitivity and 98.71% specificity in previous study (De Benedictis et al, ). Briefly, sera were diluted with dilution buffer and then incubated in 96‐well microplates coated with influenza A antigen at 37°C for 1 hr.…”

Serologic Evidence of Pandemic (H1N1) 2009 Infection in Dogs, Italy

“…Testing for antibody to influenza A nucleoprotein was performed by using a commercially available competitive ELISA (cELISA) (ID Screen Influenza A Antibody Competition Assay; ID Vet, Montpellier, France), according to the manufacturer’s instructions. Previous work from our laboratory has assigned a sensitivity of 93.98% and specificity of 98.71% to this cELISA for the testing of canine serum samples ( 8 ). In total, 29 serum specimens tested at a 1:10 dilution, all from dogs, were positive after a second confirmatory screening.…”

Diagnostic performance of the canine Influenza A Virus subtype H3N8 hemagglutination inhibition assay

“…For large-scale serological surveys to determine H3N8 CIV seroprevalence, especially in populations where virus circulation is unknown, the HI assay is recommended as a sensitive and specific confirmatory test of high-throughput screening assays such as competitive nucleoprotein enzyme-linked immunosorbent assays. 5,10 Use of RBC species other than the turkey or chicken in the H3N8 CIV HI assay decreased sensitivity. Turkey and chicken RBCs provided comparable results for most samples tested, but nearly one third of the samples had a 2-fold lower titer with chicken RBCs.…”

“…[2][3][4]8,9,13,15,22,24,26,27 To date, there is no evidence of H3N8 CIV circulation in other countries. 5,18,19,23 Similar to other host-adapted mammalian Influenza A virus strains, H3N8 CIV is efficiently transmitted between dogs and can cause outbreaks of influenza-like illness (ILI) in communal housing settings such as racing greyhound kennels, boarding and/or training facilities, and animal shelters. 3,4,8,9,13,15,22,24,36 Molecular analyses of H3N8 CIV isolates indicate prior transmission of a Florida sublineage (clade 1) H3N8 equine Influenza A virus (H3N8 EIV) from horses to dogs, followed by viral adaptation to the new canine host.…”