Table 1
Information on the samples characterised in the present study
| Sample | Flock | Type of flock | Voivodeship | Host | Strain | Subtype gag | Subtype env | Proposed subtype LTR | GenBank accession number |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | Single- | Małopolskie | sheep | 0016 | A13 | A13 | unassigned | ON637582 |
| species | |||||||||
| Single- | |||||||||
| 2 | 2 | species | Małopolskie | sheep | 209 | A1 | A1 | N/A | N/A |
| 3 | Single- | goat | 90472 | A1 | A1 | A1 | ON637581 | ||
| 4 | 3 | Podkarpackie | goat | 90960 | A1 | A1 | N/A | N/A | |
| 5 | species | goat | 90281 | A1 | A1 | N/A | N/A | ||
| 6 | sheep | 11 | B2 | B2 | N/A | N/A | |||
| 7 | Single- | sheep | 2437 | B2 | B2 | N/A | N/A | ||
| 8 | 4 | species | Lubelskie | sheep | 4106 | B2 | B2 | N/A | N/A |
| 9 | sheep | 4084 | B2 | B2 | N/A | N/A | |||
| 10 | sheep | Tryk2 | A12 | A12 | A12 | ON637584 | |||
| 11 | sheep | 5 | A12 | N/A | N/A | N/A | |||
| 12 | Mixed- | sheep | Tryk6 | A12 | A12 | A12 | ON637583 | ||
| 13 | 5 | species | Lubelskie | sheep | 10 | A12 | N/A | N/A | N/A |
| 14 | sheep | 13 | B2 | A12/B2 | N/A | N/A | |||
| 15 | sheep | 15 | A12 | A12 | N/A | N/A | |||
| 16 | goat | 2461 | B1 | B1 | N/A | N/A | |||
| 17 | 6 | Single- | Małopolskie | goat | 2462 | B1 | B1 | N/A | N/A |
| 18 | species | goat | 2466 | B1 | B1 | N/A | N/A | ||
| 19 | Single- | goat | 2991 | B1/A1 | B1 | N/A | N/A | ||
| 20 | 7 | species | Podkarpackie | goat | 2993 | A16 | A16 | A16 | ON637585 |
| 21 | 8 | Single- | Podlaskie | goat | 1202 | A12/A | B2/A12 | A16 | ON637586 |
| 22 | species | goat | 1203 | A | B1/A1/A12 | N/A | N/A | ||
| 23 | goat | 3085 | A17 | A17 | A17 | ON637551 | |||
| 24 | goat | 1561 | A17 | A17 | A17 | ON637545 | |||
| 25 | goat | 8370 | A17 | A17 | A17 | ON637608 | |||
| 26 | goat | 5616 | A17 | A17 | A17 | ON637546 | |||
| 27 | goat | 0042 | A17 | A17 | A17 | ON637541 | |||
| 28 | goat | 8344 | A17 | A17 | A17 | ON637553 | |||
| 29 | Single- | goat | 5675 | A17 | A17 | A17 | ON637554 | ||
| 30 | 9 | species | Mazowieckie | goat | 1485 | A17 | A17 | A17 | ON637547 |
| 31 | goat | 1580 | A17 | A17 | A17 | ON637548 | |||
| 32 | goat | 5686 | A17 | A17 | A17 | ON637544 | |||
| 33 | goat | 8172 | A17 | A17 | A17 | ON637549 | |||
| 34 | goat | 5621 | A17 | A17 | A17 | ON637543 | |||
| 35 | goat | 6909 | A17 | A17 | A17 | ON637542 | |||
| 36 | goat | 9431 | A17 | A17 | A17 | ON637540 | |||
| 37 | goat | 5654 | A17 | A17 | A17 | ON637550 | |||
| 38 | sheep | 6922 | A13 | N/A | A13 | ON637573 | |||
| 39 | Mixed- | sheep | 8063 | A13 | N/A | A13 | ON637576 | ||
| 40 | 10 | species | Małopolskie | sheep | 9179 | A13 | N/A | A13 | ON637575 |
| 41 | sheep | 7041 | A18 | N/A | A18 | ON637589 | |||
| 42 | sheep | 0090 | A18 | N/A | A18 | ON637588 | |||
| 43 | 11 | Mixed- | Małopolskie | sheep | 7010 | A18 | N/A | N/A | N/A |
| 44 | species | sheep | 7020 | A18 | N/A | A18 | ON637587 | ||
| 45 | sheep | 6981 | A13 | N/A | A13 | ON637580 | |||
| 46 | sheep | 9155 | A13 | N/A | A13 | ON637578 | |||
| 47 | Mixed- | sheep | 1406 | A13 | N/A | A13 | ON637579 | ||
| 48 | 12 | species | Małopolskie | sheep | 4742 | A18 | N/A | N/A | N/A |
| 49 | sheep | 1304 | A13 | N/A | A13 | ON637574 | |||
| 50 | sheep | 1911 | A13 | N/A | A13 | ON637577 | |||
| 51 | goat | 5826 | A5 | A5 | A5 | ON637566 | |||
| 52 | goat | 5819 | A5 | A5 | A5 | ON637568 | |||
| 53 | goat | 4742 | A5 | A5 | A5 | ON637569 | |||
| 54 | goat | 7592 | A5 | A5 | A5 | ON637567 | |||
| 55 | 13 | Single-species | Podkarpackie | goat | 5962 | A5 | A5 | A5 | ON637565 |
| 56 | goat | 5994 | A5 | A5 | A5 | ON637570 | |||
| 57 | goat | 6038 | A5 | A5 | A5 | ON637572 | |||
| 58 | goat | 3038 | A5 | A5 | A5 | ON637571 | |||
| 59 | goat | 5870 | A5 | A5 | A5 | ON637564 | |||
| 60 | goat | 7134 | A12 | A12 | A12 | ON637562 | |||
| 61 | goat | 7102 | A12 | A12 | A12 | ON637561 | |||
| 62 | Mixed- | goat | 6808 | A12 | A12 | A12 | ON637560 | ||
| 63 | 14 | Wielkopolskie | goat | 7096 | A12 | A12 | A12 | ON637559 | |
| 64 | species | goat | 8891 | A12 | A12 | A12 | ON637557 | ||
| 65 | goat | 7219 | A12 | A12 | A12 | ON637558 | |||
| 66 | sheep | 0334 | B2 | N/A | A5 | ON637563 | |||
| 67 | goat | 3540 | B2 | B2 | A5 | ON637599 | |||
| 68 | goat | 0580 | B2 | B2 | A12 | ON637552 | |||
| 69 | goat | 0788 | B2 | N/A | A5 | ON637605 | |||
| 70 | goat | 9509 | A12 | A12 | A12 | ON637606 | |||
| 71 | goat | 9510 | A12/B2 | A12 | A12 | ON637602 | |||
| 72 | goat | 3533 | A12 | A12 | A12 | ON637609 | |||
| 73 | goat | 3535 | A12/B2 | A12 | A5 | ON637607 | |||
| 74 | goat | 0599 | B2 | A | A5/A12 | ON637603/ON637604 | |||
| 75 | goat | 8699 | A12 | A12 | A12 | ON637601 | |||
| 76 | sheep | 1 | A12 | A12 | A24 | ON637590 | |||
| 77 | Mixed- | sheep | 3 | A12 | A12 | unassigned | ON637594 | ||
| 78 | 15 | species | Lubelskie | sheep | 14 | A12/B2 | B2 | A24 | ON637600 |
| 79 | sheep | 20 | B2 | B2 | A5 | ON637598 | |||
| 80 | sheep | 21 | B2 | B2 | N/A | N/A | |||
| 81 | sheep | 29 | B2 | N/A | N/A | N/A | |||
| 82 | sheep | 4 | A12 | N/A | A24 | ON637591 | |||
| 83 | sheep | 6 | A12 | N/A | A24 | ON637597 | |||
| 84 | sheep | 13 | A12 | A12 | unassigned | ON637595 | |||
| 85 | sheep | 16 | A12 | A12 | unassigned | ON637596 | |||
| 86 | sheep | 33 | A12 | A12 | unassigned | ON637593 | |||
| 87 | sheep | 12 | A12 | A12 | N/A | N/A | |||
| 88 | sheep | 40 | A12 | A12 | unassigned | ON637592 | |||
| 89 | sheep | 3225 | A24 | N/A | A24 | ON637623 | |||
| 90 | Mixed- | sheep | 3188 | A24 | A24 | A24 | ON637622 | ||
| 91 | 16 | species | Podkarpackie | sheep | 3249 | A24 | A24 | A24 | ON637621 |
| 92 | sheep | 3201 | A24 | A24 | N/A | N/A | |||
| 93 | sheep | 3275 | B2 | A23 | A23 | ON637610 | |||
| 94 | sheep | 3691 | B2 | B | unassigned | ON637612 | |||
| 95 | sheep | 4018 | A23 | B | unassigned | ON637613 | |||
| 96 | sheep | 2590 | A23/B2 | A23 | A23 | ON637614 | |||
| 97 | sheep | 4315 | A23/B2 | A23 | A23 | ON637615 | |||
| 98 | 17 | Mixed- | Podkarpackie | sheep | 1622 | A23 | A23 | A23 | ON637616 |
| 99 | species | goat | 8046 | A5 | N/A | A5 | ON637617 | ||
| 100 | goat | 8039 | A5 | N/A | A5 | ON637618 | |||
| 101 | goat | 8008 | A5 | A5 | A5 | ON637619 | |||
| 102 | goat | 9692 | A5 | A5 | A5 | ON637620 | |||
| 103 | goat | 1318 | A5 | N/A | A5 | ON637611 | |||
| 104 | sheep | 9855 | B2 | B | A18 | ON637539 | |||
| 105 | 18 | Mixed- | Podkarpackie | goat | 4464 | A | N/A | A18 | ON637556 |
| 106 | species | sheep | 5023 | A24 | A | A5 | ON637555 | ||
| 107 | goat | goat2 | A27 | N/A | A27 | OM517095 | |||
| 108 | goat | goat3 | A27 | N/A | A27 | OM517100 | |||
| 109 | Single- | Warmińsko- | goat | goat4 | A27 | N/A | A27 | OM517105 | |
| 110 | 19 | species | Mazurskie | goat | goat5 | A27 | N/A | A27 | OM517114 |
| 111 | goat | goat6 | A27 | N/A | A27 | OM517117 | |||
| 112 | goat | goat7 | A27 | N/A | A27 | OM517122 |
[i] LTR – long terminal repeat; N/A– not available

Fig. 1
Neighbour-joining phylogenetic tree based on the alignment of the long terminal repeat fragment. Sequences from this study are labelled by coloured circles (red – subtype A17; green – subtype A5; orange – subtype A23; pink – subtypes A18 and A13; brown – subtypes A16 and A1; yellow – subtype A27; blue – subtype A24; light blue – A12; black – unassigned) and their names are preceded by the flock origin and the animal species (s – sheep; g – goat). Reference small ruminant lentivirus strains are shown by name followed by GenBank accession number and subtype. Numbers at the branches indicate the percentage of bootstrap values obtained from 1,000 replicates

Fig. 2
Maximum-likelihood phylogenetic tree based on the alignment of the long terminal repeat fragment. Sequences from this study are labelled by coloured circles (red – subtype A17; green – subtype A5; orange – subtypes A23 and A1; pink – subtypes A18 and A13; brown – subtype A16; yellow – subtype A27; blue – subtype A24; light blue – A12; black – unassigned) and their names are preceded by the flock origin and the animal species (s – sheep; g – goat). Reference small ruminant lentivirus strains are shown by name followed by GenBank accession number and subtype. Numbers at the branches indicate the percentage of bootstrap values obtained from 1,000 replicates

Fig. 3
Unweighted pair group with arithmetic means phylogenetic tree based on the alignment of the long terminal repeat fragment. Sequences from this study are labelled by coloured circles (red – subtype A17; green – subtype A5; orange – subtype A23; pink – subtypes A18 and A13; brown – subtypes A16 and A1; yellow – subtype A27; blue – subtype A24; light blue – A12; black – unassigned) and their names are preceded by the flock origin and the animal species (s – sheep; g – goat). Reference small ruminant lentivirus strains are shown by name followed by GenBank accession number and subtype. Numbers at the branches indicate the percentage of bootstrap values obtained from 1,000 replicates

Fig. 4
WebLogo for alignment of long terminal repeat sequences of small ruminant lentivirus strains belonging to groups A, B, C and D. The heights of the letters are a measure of how well conserved the residues are. The boundaries between U3, R and U5 are indicated by arrows. Transcription factor AML (vis), AP-1, AP-4 TATA box and polyadenylation signal (poly A) binding sites are shown in boxes

Fig. 5
Alignment of U3-R sequences of the long terminal repeat region from Polish small ruminant lentivirus (SRLV) strains. Sequences are aligned against the prototype K1514 and Cork strains representative of SRLV groups A and B, respectively. Dots indicate identity with Cork, and dashes represent gaps. Boundaries between U3, R and U5 are indicated by straight arrows. AP-1, AP-4 and AML (vis) motifs, the TATA box and polyadenylation signal (poly A) are marked by boxes

Fig. 6
The BootScan analysis of recombination in the alignments. The analysis was performed with the pairwise distance model with a window size of 200, step size of 20 and 1,000 bootstrap replicates by the RPD4 program. a – recombination even in almost all subtype A12 strains; b – recombination event in all subtype A5 strains