The frequency of abortive infections in the field is not well documented, with a study from Southern Germany identifying such infections using an anti-p45 antibody ELISA (p45 being the non-glycosylated form of gp70, the FeLV surface envelope glycoprotein) at a prevalence of 4% (22/495), in a population with 1% regressive infections (6/495) and 2% progressive infections (9/495) [18]. This evidence concerns the gene EMB and infection.