EN
Serological and histopathological studies and virus isolation from sows and/or fetuses are used to diagnose PRRS. In order to explain changes in the infected animal, biochemical examinations of blood serum should be done. The aim of the studies was explain if piglets coming from sows seropositive to Lelystad virus after the end of colostral immunity, develop significant changes in blood serum biochemical parameters during the next 4 weeks. Blood samples for biochemical studies were collected from 4-week-old piglets. Next, samples were collected twice at 2 week intervals from 20 randomly selected piglets from the same litters. An increase above the standards of inorganic phosphorus, potassium, bilirubin, and activity of AST, ALT and ALP was discovered. Below accepted standard were natrium, glucose and total protein. Clinical symptoms like apathy, anorexia, internal body temperature up to 40.2°C, hair bristling and emaciation, were observed in piglets older than 4 weeks. The level of the blood serum biochemical parameters, clinical symptoms and gross lesions indicate that in piglets from sows infected with Lelystad virus a malignant malnutrition-like syndrome occurs.