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Table 3 Outcome of target gene sequencing of RT-qPCR FCoV-positive samples

From: Limitations of using feline coronavirus spike protein gene mutations to diagnose feline infectious peritonitis

Sample source (number of RT-qPCR positive samples) Outcome of target gene sequencing Sequencing result (number of samples; median, and range, relative copy number per reaction)
Cats with FIP
 Tissue (n = 222)a Success (n = 206) Non-mutated FCoVs (n = 4; 337, 2.6 × 105 to 5.4)
Mixed non-mutated and mutated FCoVs (n = 12; 1.1 × 103, 2.3 × 106 to 33)
M1058L (n = 10; 731, 4.4 × 105 to 33)
Double-mutated FCoVs (M1058L and S1060A) or mixed mutated FCoVs (n = 2; 2.3 × 106 and 7.6 × 104)
Mutated FCoVs (n = 190; 1.3 × 104, 1.2 × 108 to 1.2)
M1058L (n = 186; 1.4 × 104, 1.2 × 108 to 1.2)
S1060A (n = 4; 1.8 × 104, 9.0 × 106 to 4.2 × 103)
Failure (n = 16) Low copy number (n = 4; 6.2, 19 to 4.1)
Presence of serotype 2 FCoVs (n = 12; 8.3 × 103, 2.5 × 107 to 41)
 Fluid (n = 39)b Success (n = 34) Non-mutated FCoVs (n = 4; 190, 1.3 × 103 to 41)
Mixed non-mutated and mutated (M1058L) FCoVs (n = 4; 15, 1.1 × 103 to 5.8)
Mutated FCoVs (n = 26; 457, 1.1 × 106 to 2.7)
M1058L (n = 25; 457, 1.1 × 106 to 2.7)
S1060A (n = 1; 3.2 × 103)
Failure (n = 5) Low copy number (n = 1; 2.7)
Presence of serotype 2 FCoVs (n = 4; 639, 2.0 × 104 to 27)
 Faeces (n = 31) Success (n = 29) Non-mutated FCoVs (n = 13; 1.1 × 105, 1.2 × 107 to 285)
Mixed non-mutated and mutated (M1058L) FCoVs (n = 2; 1.9 × 104 and 91)
Mutated (M1058L) FCoVs (n = 14; 63, 1.7 × 104 to 1.2)
Failure (n = 2) Presence of serotype 2 FCoVs (n = 2; 178 and 27)
Cats without FIP
 Tissue (n = 20) Success (n = 17) Non-mutated FCoVs (n = 2; 2.1 × 103 and 5.0)
Mixed non-mutated and mutated (M1058L) FCoVs (n = 1; 2.7)
Mutated (M1058L) FCoVs (n = 14; 63, 9.4 × 103 to 4.7)
Failure (n = 3) Low copy number (n = 3; 5.0, 11 to 4.7)
 Fluid (n = 1) Success (n = 1) Mutated (M1058L) FCoVs (n = 1; 11)
 Faeces (n = 7) Success (n = 6) Non-mutated FCoVs (n = 6; 330, 1.5 × 104 to 19)
Failure (n = 1) Low copy number (n = 1; 2.6)
  1. aSequencing was not performed on 13 FCoV RT-qPCR positive tissue samples from FIP cats as no corresponding tissue in formalin were available for analysis.
  2. bOne FCoV RT-qPCR positive fluid sample was lost from analysis.