Table 3.
Results of the screening for XMRV performed on human and animal sampling populations.
| Sampling population | DNA source | N | No. of positive samples | No. of negative samples | Primers | Comments |
|---|---|---|---|---|---|---|
| Human ME/CFS patients | Peripheral blood | 47 | 2 | 45 | 1 + 2 | Amplicons were not reproducible and often associated with spurious extra-bands |
| Human controls | Peripheral blood | 53 | 0 | 53 | 1 + 2 | |
| Laboratory mouse strain BDF | Peripheral blood | 1 | 1 | 0 | 1 + 2 | Reproducible band of the correct size. Identity was confirmed by sequencing |
| Laboratory mouse strain Ts65Dn | Tail tip | 10 | 10 | 0 | 1 + 2 | Scarce reproducibility of independent amplifications. Extra-bands were often observed |
| Laboratory white rat (Wistar) | Tail tip | 10 | 0 | 10 | 2 | |
| Brown laboratory rat (Rattus norvegicus) | Tail tip | 5 | 0 | 5 | 2 | |
| Wood mouse (Apodemus sylvaticus) | Tail tip | 11 | ? | ? | 2 | Very scarce reproducibility: two samples were positive in 4/7 repetitions; five in 2/7 repetitions |
| Non-reproducible extra-bands were always observed | ||||||
| Badger (Meles meles) | Fur | 25 | 0 | 25 | 2 | |
| Stone marten (Martes foina) | Feces | 15 | 0 | 15 | 1 + 2 | |
| Weasel (Mustela nivalis) | Feces | 15 | 0 | 15 | 2 | |
| Fox (Vulpes vulpes) | Peripheral blood | 14 | 0 | 14 | 1 + 2 | |
| Hare (Lepus europaeus) | Peripheral blood | 23 | 0 | 23 | 2 | |
| Bovines (various breeds) | Peripheral blood | 23 | 0 | 23 | 1 + 2 |
All amplifications have been repeated at least twice, always in the presence of the positive control (BDF laboratory mouse). Sequencing has been performed on amplicons obtained with our new primers. 1: primers by Ref. (31); 2: newly designed primers.
?: variable among repetitions.