Can caprine arthritis encephalitis virus (CAEV) be transmitted by in vitro fertilization with experimentally infected sperm?

For each of the five fertilization trials of the experiment, frozen semen was prepared for in vitro capacitation at a concentration of 1 × 107 spz/ml and divided into three groups. One group was used as a control, while the two others were inoculated with 100 μl/ml of either culture medium from non-infected cells (placebo group) or cell culture medium containing virus at a concentration of 105 TCID50/ml (infected group). A total of 789 oocytes were used for IVF. For each of the five trials a group of oocytes were used as a non-infected control and were found to be caprine arthritis-encephalitis virus (CAEV) free. The other oocytes were divided in two equal batches. Oocytes in the first batch were in vitro fertilized with CAEV infected sperm (infected group) and the second batch were fertilized with CAEV non-infected sperm (placebo and control groups). After IVF, the zygotes of each group were washed 12 times. The CAEV genome was not detected (using RT-PCR) in the washing media of either the control or placebo groups from each trial. In contrast, the first three washing media from the infected group were consistently found to be positive for the CAEV genome (5/5), whereas subsequent washing media were CAEV-free (P < 0.05). Zygotes obtained using all semen groups tested negative for both the provirus and genome of CAEV. These results clearly show that the first four washes were sufficient to remove viral particles from CAEV infected fertilization media and that CAEV-free embryos can be produced by IVF using spermatozoa infected in vitro by CAEV.