scholarly journals Decreased Sensitivity of the Serological Detection of Feline Immunodeficiency Virus Infection Potentially Due to Imported Genetic Variants

Viruses ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 697 ◽  
Author(s):  
Julia Frankenfeld ◽  
Theres Meili ◽  
Marina Meli ◽  
Barbara Riond ◽  
A. Helfer-Hungerbuehler ◽  
...  
Keyword(s):  
Feline Immunodeficiency Virus ◽  
Point Of Care ◽  
Diagnostic Efficiency ◽  
Rt Pcr ◽  
Viral Loads ◽  
Feline Immunodeficiency Virus Infection ◽  
Immunodeficiency Virus ◽  
Screening Assays ◽  
Diagnostic Sensitivity And Specificity ◽  
Point Of Care Tests

Feline immunodeficiency virus (FIV) is a lentivirus of domestic cats worldwide. Diagnosis usually relies on antibody screening by point-of-care tests (POCT), e.g., by enzyme-linked immunosorbent assays (ELISA), and confirmation using Western blot (WB). We increasingly observed ELISA-negative, WB-positive samples and aimed to substantiate these observations using 1194 serum/plasma samples collected from 1998 to 2019 primarily from FIV-suspect cats. While 441 samples tested positive and 375 tested negative by ELISA and WB, 81 samples had discordant results: 70 were false ELISA-negative (WB-positive) and 11 were false ELISA-positive (WB-negative); 297 ambiguous results were not analyzed further. The diagnostic sensitivity and specificity of the ELISA (82% and 91%, respectively) were lower than those reported in 1995 (98% and 97%, respectively). The diagnostic efficiency was reduced from 97% to 86%. False ELISA-negative samples originated mainly (54%) from Switzerland (1995: 0%). Sixty-four false ELISA-negative samples were available for POCT (SNAPTM/WITNESSR): five were POCT-positive. FIV RT-PCR was positive for two of these samples and was weakly positive for two ELISA- and POCT-negative samples. Low viral loads prohibited sequencing. Our results suggest that FIV diagnosis has become more challenging, probably due to increasing travel by cats and the introduction of new FIV isolates not recognized by screening assays.

scholarly journals Is the glass half full? Extraction-free RT-LAMP to detect SARS-CoV-2 is less sensitive but highly specific compared to standard RT-PCR in 101 samples

2020 ◽  
Author(s):  
John J. Schellenberg ◽  
Margaret Ormond ◽  
Yoav Keynan
Keyword(s):  
Point Of Care ◽  
N Gene ◽  
Nasopharyngeal Swab ◽  
Lower Sensitivity ◽  
Rt Pcr ◽  
Public And Private ◽  
Viral Loads ◽  
Negative Results ◽  
Viral Transport Medium ◽  
Point Of Care Tests

AbstractThe current scale of public and private testing cannot be expected to meet the emerging need for higher levels of community-level and repeated screening of asymptomatic Canadians for SARS-CoV-2. Rapid point-of-care techniques are increasingly being deployed to fill the gap in screening levels required to identify undiagnosed individuals with high viral loads. However, rapid, point-of-care tests often have lower sensitivity in practice. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) for SARS-CoV-2 has proven sensitive and specific and provides visual results in minutes. Using a commercially available kit for RT-LAMP and primer set targetting nucleocapsid (N) gene, we tested a blinded set of 101 archived nasopharyngeal (NP) swab samples with known RT-PCR results. RT-LAMP reactions were incubated at 65°C for 30 minutes, using heat-inactivated nasopharyngeal swab sample in viral transport medium, diluted tenfold in water, as input. RT-LAMP agreed with all RT-PCR defined negatives (N=51), and all positives with Ct less than 20 (N=24), 65% of positives with Ct between 20-30 (N=17), and no positives with Ct greater than 30 (N=9). RT-LAMP requires fewer and different core components, so may not compete directly with the mainline testing workflow, preserving precious central laboratory resources and gold standard tests for those with the greatest need. Careful messaging must be provided when using less-sensitive tests, so that people are not falsely reassured by negative results – “glass half empty” – in exchange for reliable detection of those with high levels of virus within an hour, using <$10 worth of chemicals – “glass half full”.

Effect of primary-stage feline immunodeficiency virus infection on subsequent feline calicivirus vaccination and challenge in cats

AIDS ◽  
1991 ◽  
Vol 5 (6) ◽  
pp. 747-750 ◽  
Author(s):  
Susan Dawson ◽  
Neil R. Smyth ◽  
Malcolm Bennett ◽  
Rosalind M. Gaskell ◽  
Christine M. McCracken ◽  
...  
Keyword(s):  
Virus Infection ◽  
Feline Immunodeficiency Virus ◽  
Feline Calicivirus ◽  
Primary Stage ◽  
Feline Immunodeficiency Virus Infection ◽  
Immunodeficiency Virus

scholarly journals Gamma Interferon/Interleukin 10 Balance in Tissue Lymphocytes Correlates with Down Modulation of Mucosal Feline Immunodeficiency Virus Infection

2004 ◽  
Vol 78 (8) ◽  
pp. 4011-4019 ◽  
Author(s):  
Paul R. Avery ◽  
Edward A. Hoover
Keyword(s):  
Viral Replication ◽  
Feline Immunodeficiency Virus ◽  
Treatment Strategies ◽  
Interleukin 10 ◽  
Gamma Interferon ◽  
Cytokine Balance ◽  
Feline Immunodeficiency Virus Infection ◽  
Immunodeficiency Virus ◽  
Lentiviral Infection ◽  
Lentiviral Infections

ABSTRACT Understanding the early cytokine response to lentiviral infections may be critical to the design of prevention and treatment strategies. By using the feline immunodeficiency virus (FIV) model, we have documented an interleukin 10 (IL10)-dominated response in lymphoid tissue CD4+ and CD8+ T lymphocytes within the first 4 weeks after mucosal FIV infection. This profile coincided with the period of high tissue viral replication. By 10 weeks postinfection, tissue viral levels decreased significantly, and gamma interferon (IFNγ) production in CD8+ T cells had increased to restore the IL10/IFNγ ratio to control levels. Concurrently, increased production of IL6 and viral RNA was detected in macrophages. These temporal associations of viral replication with cytokine balance in tissues suggest roles for IL10 in the permissive stage of infection and IFNγ in the subsequent down modulation of lentiviral infection.

Elevation of feline interleukin 6-like activity in feline immunodeficiency virus infection

1992 ◽  
Vol 65 (3) ◽  
pp. 207-211 ◽  
Author(s):  
Takashi Ohashi ◽  
Ryo Goitsuka ◽  
Toshihiro Watari ◽  
Hajime Tsujimoto ◽  
Atsuhiko Hasegawa
Keyword(s):  
Virus Infection ◽  
Interleukin 6 ◽  
Feline Immunodeficiency Virus ◽  
Feline Immunodeficiency Virus Infection ◽  
Immunodeficiency Virus
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