Primi risultati sull'efficacia del vaccino Startvac® nella prevenzione delle mastiti da S. aureus: Trial italiano

This paper reports on the efficacy of using Startvac® versus mastitis. A field trial was carried out in two farms at Lombardy, Italy in which the four aspects of vaccine effectiveness was considered. The four aspect includes the impact of vaccination on the rate of new infections, second it concerns on the impact of vaccination on the degree of infectivity of an animal infected, thirdly it addresses the impact of vaccination on the rate of cure of the infection; and the finally, the fourth aspect concerns the vaccination reduction of clinical symptoms related to infection. The two farms were selected based on the size the herd was 480 lactating cows in total. Vaccination of animals was made according to the protocol registration vaccine for a total of three doses, with the first dose 45 days prior to the date of delivery, the second administration to 10 days before the date of childbirth, and the third dose at 52 days post-partum. The results of the study are presented randomized relating to about half of the trial (13/18 months). The prevalence of S. aureus in herds under study is about 10% at the level of samples of single quarter, while the prevalence of coagulase-negative staphylococci amounted to approximately 5%. These prevalence rates indicate that farms considered the presence of these microorganisms have a sufficient the correct evaluation of the effectiveness of the vaccine. Results showed no significant difference in S. aureus present in milk samples examined between vaccinated and control animals. However, the average duration of infection by S. aureus is significantly shorter in vaccinated animals compared to animals of control. The estimate of the effectiveness of the vaccine on cure rate animals are only about equal to 0.73 (73%). The initial results indicate that the vaccine is effective against the incidence and for the cure rate of infections with S. aureus. However, the data are still incomplete and will take several months of additional data to confirm and further stabilize the initial estimates of effectiveness of the vaccine.