Table 2.
PCR techniques and information regarding primers, detected strains, animal species, country and diagnostic performance.
| PCR Type | Sample | Tarteted Genomic Region (Amplicon Size, bp) | Se (%)/Sp (%) | Concordance (%)/ k Value |
Reference Method/Diagnostic Matrix | Animal Species | Country | Ref |
|---|---|---|---|---|---|---|---|---|
| c-PCR | DNA (PBLs, MCPs and TSs) | LTR (291 bp) | 83.5%/100.0% (PBLs) 66.7%/100.0% (MCPs) 89.6%/100.0% (TSs) 97.7%/100.0% (overall) |
AGID A and ELISA B/BS | s | Spain | [70] | |
| RT-PCR and c-PCR |
DNA and RNA (PBLs, BS and BC) |
gag gene (748 bp) for c-PCR and RT-PCR LTR (291 bp) for c-PCR |
Complementary Se: -gag-PCR 0% (PBLs) and 24% (BC) -LTR-PCR 0% (PBLs and BC) -gag-PCR to LTR-PCR 54.6% (PBLs) -LTR-PCR to gag-PCR 0% (PBLs and BC) |
gag-PCR: k = 0.68 (PBLs) k = 0.69 (BC) LTR-PCR: K = 0.52 (PBLs) K = 0.59 (BC) gag-PCR with LTR-PCR: k = 0.73 (PBLs) k = 0.50 (BC) |
ELISA C/BS | s | Spain | [61] |
| n-PCR | DNA (PBMCs) | gag gene (500 bp) | Se: 73.0% (s) and 86.0% (g) | ELISAs C,D and AGID A/BS | s/g | Norway | [77] | |
| n-PCR | DNA (WB) | gag gene (1191 bp and 1327 bp) | 69.6%/100.0% | cell cultures/ isolated monocytes | g | Thailand | [78] | |
| n-PCR | DNA (PBLs, PBMCs, andBM) |
env gene (625 bp, 394 bp or 608 bp) gag gene (990 bp) |
47.0% | ELISA D/BS | s/g | Poland | [79] | |
| Semi n-PCR | DNA (PBMCs) | pol gene (412 bp and 404 bp) | Complementary Se: 25% | AGID A/BS | s/g | Greece | [80] | |
| Semi n(RT)-PCR | RNA (blood and milk) | pol gene (475 bp and 303 bp) | 62.0%/0.05 (ELISA and PCR in blood) 62.0%/0.2 (ELISA and PCR on milk) |
ELISA C/BP and milk | s/g | Spain | [48] | |
| Semi n(RT)-PCR c-PCR |
DNA and RNA (milk) |
pol gene for semi n(RT)-PCR (475 bp and 303 bp) LTR for c-PCR(291 bp) |
28.4%/68.9% (pol-PCR-s) 1.6%/95.5% (LTR-PCR-s) 53.9%/73.3% (pol-PCR-g) 7.7%/99.3% (LTR-PCR-g) |
k = 0.02 (pol-PCR-s) k = 0.02 (LTR-PCR-s) k = 0.12 (pol-PCR-g) k = 0.11 (LTR-PCR-g) pol-PCR with LTR-PCR: 73.2%/0.02 (s) 73.4%/0.06 (g) |
ELISA C/milk | s/g | Spain | [81] |
| qPCR | DNA (BCCs) |
gag gene (138 bp) LTR (291 bp) |
Se: gag-PCR 88.0% (s) 82.0% (g) LTR-PCR 83.0% (s) 40.0% (g) |
k: gag-PCR 0.73 (s)/0.37 (g) LTR-PCR 0.78 (s)/0.10 (g) |
ELISA C/BS | s/g | The Netherlands | [82] |
| qPCR | DNA (BCCs and MCPs) |
gag gene (138 bp) LTR (291 bp) |
LTR-PCR: 21.0%/- (BCCs-g) 50.0%/94.0%(MCPs-g) 82.0%/80.0% (BCCs-s) 70.0%/99.0% (MCPs-s) gag-PCR: 39.0%/- (BCCs-g) 61.0%/88.0% (MCPs-g) 89.0%/81.0% (BCCs-s) 89.0%/89.0% (MCPs-s) |
between PCRs: 77.0%/0.45 (BCCs-g) 83.0%/0.63 (BCCs-s) 87.0% /0.76 (MCPs-g) 87.0%/0.75 (MCPs-s) 90.0%/0.76 (MCPS of bulk milk-g) |
ELISA C/BS | s/g | The Netherlands | [49] |
| qPCR | DNA (PBLs) |
gagMA (113 bp) LTR (101 bp) |
Se: 89.9% (gagMA-PCR) 80.2% (LTR-PCR) 79.0% (overall) |
k = 0.72 | ELISA E/BS | s/g | Slovenia | [83] |
| qPCR | DNA(PBLs and BC) | gag gene (524 bp) | 88.0%/100.0% (PBLs-s) 83.3%/100.0% (PBLs-g) 63.0%/100.0% (blood clot-s) 21.0%/100.0% (blood clot-g) 75.0%/100.0% (blood clot-s) 25.0%/100.0% (blood clot-g) |
ELISA C,F,G,H,I and AGID J/BS qPCR in PBLs |
s/g | Belgium | [27] | |
| qPCR | DNA (PBMCs and MCPs) | gag gene (524 bp) | relative values: 81.0%/88.0% | 84.0% concordance | qPCR in PBMCs | g | Belgium | [47] |
| Semi n-qPCR | DNA (PBLs) | pol gene (455 bp and 416 bp) | Se: 86.0% Relative Se: 28.0% |
79.0%/0.58 | ELISA G/BP | s/g | Greece | [84] |
| q(RT)-PCR | DNA (WB) and RNA (WB and BS) | env gene (114 bp) | qPCR: 83.3%/87.5% RT qPCR: 58.3%/66.6% |
ELISA D,E/BS | s/g | Italy | [85] | |
| q(RT)-PCR | DNA and RNA (PBLs and lung samples) | gag gene (524 bp) | 86.7%/80.0% 60.9%/75.0% |
87.0% 61.0% |
AGID A/BS ELISA C/BS | s/g | Βelgium | [86] |
c-PCR: conventional PCR; n-PCR: nested PCR; qPCR: quantitative (real-time) time PCR; RT-PCR: reverse transcription PCR; PBLs: peripheral blood leukocytes; PBMCs: peripheral blood mononuclear cells; MCPs: milk cells pellets; TSs: tissue samples; BS: blood serum; BP: blood plasma; BC: blood clot; BCCs: buffy coat cells; WB: whole blood; BM: bronchoalveolar macrophages; bp: base pairs; Se: sensitivity; Sp: specificity; k value: kappa coefficient; s: sheep; g: goats; Ref: reference. A: Maeditect, Veterinary Laboratory Agency, Weybridge, UK; B: Innotest MVV, Innogenetics, Gent, Belgium; C: ELITEST-MVV, HYPHEN BioMed, France; D: VISNA-MAEDI/CAEV, Institut Pourquier, Montpellier, France; E: Checkit CAEV/MVVELISA Bommeli AG/Idexx Laboratories, Liebefeld, Switzerland; F: MVV/CAEV p28 Ab screening test, Idexx, Westbrook, ME, USA; G: ID screen® MVV/CAEV, IDVet Innovative Diagnostics, Grabels, France; H: LSIVetTM Ruminant Maedi-Visna/CAEV serum ELISA kit LSI, Thermo Fisher Scientific, Waltham, MA, USA; I: Eradikit™ SRLV, IN3 diagnostic, Italia; J: AGID CAEV P28 kit, Idexx, Westbrook, ME, USA.