Table 3.
Results of the comparison of different methods for virological peste-des-petits-ruminants virus (PPRV) diagnosis in cattle and South American camelids (SAC) after experimental intranasal infection with PPRV lineage IV strain Kurdistan/2011. Different sample matrices (swab, tissue, blood) were analyzed from cattle (C), alpacas (A) and llamas (L) using two SLAM-expressing cell lines (VDS and CHS-20) for virus isolation, three PCR assays for real-time quantitative reverse-transcription PCR (RT-qPCR), antigen ELISA (Ag-ELISA) and lateral flow device (LFD). RT-qPCR was found the only suitable virological method for the detection of PPRV infection in cattle and SAC. Similarly, RT-qPCR was previously found most suitable for the detection of PPRV infection in sheep, pigs and wild boar but not LFD (Schulz et al. 2018 [9]). In contrast, for sheep and suids, PPRV isolation with cell culture and antigen detection with Ag-ELISA was possible for selected samples, and detection of PPRV infection was generally possible with all four methods in goats (Schulz et al. 2018 [9]). Samples detected positive are highlighted in bold.
| Serial No. | Animal Trial ID |
Animal Species |
Sample Material | Animal ID | dpi | SLAM-Cells (Max. TCID50/mL on VDS or CHS) * |
Detection of PPRV-Np by RT-qPCR (Cq Value) | Ag-ELISA (OD NC %) | LFD (pos/neg) | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| (Trial No.) | Bao et al. 2008 | Batten et al. 2011 | |||||||||
| 35 | C-G (1) | cattle | oronasal | swab | C3 | 5 | neg | 27.02 | 28.22 | 13 | neg |
| 36 | C-G (1) | cattle | oronasal | swab | C1 | 6 | neg | 32.01 | 30.73 | 46 | neg |
| 37 | C-G (1) | cattle | fecal | swab | C3 | 7 | neg | 40.28 | 35.48 | −12 | neg |
| 38 | C-G (1) | cattle | oronasal | swab | C3 | 7 | neg | 30.16 | 31.43 | 15 | neg |
| 39 | C-G (1) | cattle | conjunctival | swab | C2 | 7 | neg | 32.17 | 32.23 | 1 | neg |
| 40 | C-G (1) | cattle | mediastinal ln. | tissue | C1 | 17 | neg | 44.16 | 36.07 | −12 | neg |
| 41 | C-G (1) | cattle | bronchial ln. | tissue | C2 | 17 | neg | 36.11 | 34.84 | −17 | neg |
| 42 | C-G (1) | cattle | palatine tonsil | tissue | C3 | 17 | neg | 30.06 | 30.55 | 1 | neg |
| 43 | C-G (1) | cattle | retropharyng. ln. | tissue | C3 | 17 | neg | 31.84 | 31.45 | −6 | neg |
| 44 | C-G (1) | cattle | ileal peyer’s patches | tissue | C3 | 17 | neg | 33.36 | 34.11 | −11 | neg |
| 45 | SAC-GL (2) | llama | oronasal | swab | L5 | 4 | neg | 38.37 | 39.00 | −10 | neg |
| 46 | SAC-GL (2) | alpaca | oronasal | swab | A1 | 7 | neg | No Cq | 36.58 | 15 | neg |
| 47 | SAC-GL (2) | alpaca | oronasal | swab | A2 | 8 | neg | 39.21 | 33.85 | −13 | neg |
| 48 | SAC-GL (2) | alpaca | EDTA-blood | blood | A3 | 8 | neg | No Cq | 37.68 | 0 | neg |
| 49 | SAC-GL (2) | llama | fecal | swab | L6 | 14 | neg | No Cq | 38.61 | −24 | neg |
| 50 | SAC-GL (2) | alpaca | palatine tonsil | tissue | A1 | 28 | neg | No Cq | 33.88 | −21 | neg |
| 51 | SAC-GL (2) | alpaca | mediastinal ln. | tissue | A1 | 28 | neg | No Cq | 32.56 | 9 | neg |
| 52 | SAC-GL (2) | alpaca | retropharyng. ln. | tissue | A2 | 28 | neg | No Cq | 35.32 | 9 | neg |
| 53 | SAC-GL (2) | llama | mandibular ln. | tissue | L6 | 29 | neg | No Cq | 33.28 | −20 | neg |
| 54 | SAC-GL (2) | llama | bronchial ln. | tissue | L6 | 29 | neg | No Cq | 32.93 | −20 | neg |
| PPRV cell culture virus, strain Kurdistan/2011 | pos control | 10^5.5 | 18.56 | ND | ND | pos | |||||
dpi, days after experimental infection; in, infected by intranasal inoculation; ND, not defined; neg, negative; No Cq, Cq = 45; PPRV-Np, PPRV-nucleoprotein gene; pos, positive; RT-qPCR, real-time quantitative reverse transcription-PCR; SLAM cells, cells expressing signaling lymphocyte activation molecule (CD150); VDS, ‘Vero.dog.SLAM.tag’ vero cells expressing the dog SLAM protein (von Messling et al. 2003 [43]); CHS-20, Monkey CV1 cell line expressing the goat SLAM protein (Adombi et al. 2011 [42]); LFD, lateral flow device, PESTE-TEST, Field test for Peste des Petits Ruminants Virus Infection, BDSL IRVINE LIMITED and The Pirbright Institute, Pirbright, UK, detecting PPRV H protein; Ag-ELISA, ID Screen® PPR Antigen Capture sandwich ELISA, ID.vet, detecting PPRV N protein; OD NC %, optical density % negative control (neg < 20%; pos ≥ 20%); * virus titration was conducted on VDS and CHS cells after freezing and thawing (note: for swab samples titers may be up to 10^2.5 TCID50/ml higher after freezing-thawing (Schulz et al. 2018 [9]).