Small ruminant lentiviruses (SRLV) affect sheep and goats. Though in many cases clinical signs are hardly noticeable, infections in both species may produce economic losses due to an insidious drop in milk production, weight loss or decrease in progeny. Diagnosis is problematic because there is no gold standard diagnostic test and the inconvenience in obtaining blood samples. This book supplies evidence that milk is an adequate sample for diagnosis instead of blood, especially for serology, and that a serological method, such as ELISA, should be used in combination with a molecular biology...