Comparative evaluation of a point-of-care immunochromatographic test SNAP 4Dx with molecular detection tests for vector-borne canine pathogens in Hong Kong

There are no comprehensive studies on the performance of commonly used point-of-care diagnostic enzyme immunoassay for common arthropod-borne canine pathogens. A comparative evaluation of an immunochromatographic test for these infections with a comprehensive polymerase chain reaction (PCR) test panel was performed on 100 pet dogs and 100 stray dogs without obvious clinical symptoms. Of the 162 positive test results from both immunochromatographic test and PCR, there was 85.2% concordance. The 24 discordant results between serology and PCR occurred in tests involving Ehrlichia canis (14) and Anaplasma platys (10), which may be related to the time of infection. No positive cases of borreliosis or rickettsiosis were detected. One important limitation of the immunochromatographic test was its lack of testing for babesiosis and hepatozoonosis. The former is the most prevalent arthropod-borne canine infection in our cohort (41%). Coinfections were found in 19% stray dogs and 6% of pet dogs with both tests (p<0.01). Seventeen and 8 samples from stray and pet dogs, respectively, were initially positive in the PCR test for Ehrlichia. However, on sequencing of the PCR amplicon, 10 from stray and 2 from pet dogs were found to be Wolbachia sequences instead, with 100% nucleotide identity to the 16S rRNA sequence of Wolbachia endosymbiont of Dirofilaria immitis. The presence of Wolbachia DNAemia (6%) correlated well with the molecular test and immunochromatographic antigen test for D. immitis. © Copyright 2011, Mary Ann Liebert, Inc.published_or_final_versio

Complete genome sequences of novel canine noroviruses in Hong Kong

We report the complete genome sequences of two novel isolates of norovirus isolated from the fecal swab specimens of dogs in Hong Kong. The complete viral genome is approximately 7.6 kb in length and consists of 3 overlapping open reading frames encoding the ORF1 polyprotein, VP1, and VP2, respectively. Analysis of the VP1 sequence suggested that these noroviruses are divergent from known noroviruses and may represent a novel phylogenetic clade within the genus.link_to_OA_fulltex

Epidemiological and clinical characteristics of patients with anti-interferon-gamma autoantibodies associated with opportunistic infections in Hong Kong

OS185: Oral Session - Immunity and immunogenetics of infections in immunocompromised hosts - no. OS090

Complete genome sequence of a novel picornavirus, canine picornavirus, discovered in dogs

We discovered a novel canine picornavirus in fecal, nasopharyngeal, and urine samples from dogs. The coding potential of its genome (5'-VP4-VP2-VP3-VP1-2A-2B-2C-3A-3B-3C pro-3D pol-3', where 3C pro is 3' protease and 3D pol is 3D polymerase) is similar to those of other picornaviruses, with putative P1, P2, and P3 sharing 54% to 58%, 60%, and 64% to 67% amino acid identities with bat picornavirus groups 1, 2, and 3. © 2012, American Society for Microbiology.link_to_OA_fulltex

Epidemiology, Seroprevalence, and Clinical Manifestations of Immunodeficiency due to Autoantibody Against Interferon Gamma in Hong Kong

Poster presentation: Infectious Diseases: no. P137-0079Introduction/Project Objectives: Patients with adult-onset immunodeficiency due to autoantibodies against interferon gamma (anti-IFN-γ autoantibodies) may develop disseminated and/or recurrent opportunistic infections, including non-tuberculous mycobacteriosis, non-typhoidal salmonellosis, burkholderiosis, penicilliosis, and herpes zoster. While the condition appears to be especially common among Asians, including Chinese residents in Hong Kong, Taiwan, and mainland China, the seroprevalence rate of anti-IFN-γ autoantibodies among these populations is unknown. Moreover, the full spectrum of infective and non-infective clinical manifestations of this immuondeficiency syndrome is not fully understood. This retrospective case-control analysis aimed to investigate the epidemiology, seroprevalence rate, and clinical manifestations of this emerging immunodeficiency syndrome in Hong Kong. Methods: This study was approved by the Institutional Review Board of The University of Hong Kong/Hospital Authority Hong Kong West Cluster. Archived serum samples from subjects aged ≥18 years, with or without opportunistic infections, were tested by a screening enzyme immunoassay and an IFN-γ spiking assay for the presence of anti- IFN-γ autoantibodies. The patients' clinical data were retrieved from the Hospital Authority Electronic Patient Record (ePR) system and entered into a predesigned database. Comparisons between patient groups were evaluated by the Chi-square test (categorical variables) and Mann-Whitney U-test (continuous variables). All statistical analyses were performed using SPSS18.0 for Windows. P<0.05 was considered statistically significant. Results: 3198 serum samples from 3198 patients were tested. Overall, anti-IFN-γ autoantibodies were detected in 34 serum samples (34/3198, 1.1%) in the screening enzyme immunoassay. These included 11 patients with opportunistic infections including non-tuberculous mycobacteriosis, penicilliosis, non-typhoidal salmonellosis, burkholderiosis, and/or herpes zoster (11/133, 8.3%), 4 subjects aged >65 years without these opportunistic infections (4/783, 0.5%), 14 patients with autoimmune diseases without these opportunistic infections (14/753, 1.9%), and 5 patients with chronic HBV/HCV infection without these opportunistic infections (5/764, 0.7%). The seroprevalence rate of anti-IFN-γ autoantibodies in subjects without opportunistic infections was ~1%, which was significantly lower than that of patients with opportunistic infections (8.3%, P<0.001). Some patients with high-titer serum neutralizing anti-IFN-γ autoantibodies also developed reactive (Sweet's syndrome and lobular panniculitis) and infective dermatoses. Anti-IFN-γ autoantibodies were strongly associated with HLA-DR*15:02/16:02 and HLA-DQ*05:01/05:02 among the affected patients. Conclusions: These findings helped to optimize the diagnostic and treatment protocols for this emerging immunodeficiency syndrome. Routine screening for anti-IFN-γ autoantibodies in asymptomatic patients is unlikely warranted. A working algorithm for the diagnosis and treatment of patients with dermatoses associated with anti-IFN-γ autoantibodies was established. Our non-laborious screening enzyme immunoassay could be adopted by clinical laboratories

Resequencing microarray for detection of human adenoviruses in patients with community-acquired gastroenteritis: A proof-of-concept study

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