Impact of maternal vaccination frequency on antibody titres against RHDV in rabbit kits

Abstract

Rabbit Hemorrhagic Disease (RHD) poses a serious threat to rabbits, both in wildlife and on farms. Vaccination is an important tool to limit ecological and economic losses, however there is a window of susceptibility between the decline of maternal immunity and the age of authorized vaccine administration in rabbit kits. This study aimed to evaluate whether a more frequent, off-label vaccination protocol in breeding does results in higher antibody titres in does and enhanced maternal immunity in their 4-week-old and 10-week-old young to bridge this gap, by comparing two Dutch farms using different RHDV vaccination strategies. Serological analysis demonstrated significant differences in antibody titres between breeding does from the two farms where 75% of does vaccinated quarter yearly surpassed the protective threshold as provided by the ELISA manufacturer, against 25% in does vaccinated annually. Furthermore, a strong positive correlation between antibody titres of the does and their 4-week-old kits was observed, however none of the kits were seropositive by definition of the ELISA test. While more frequent vaccination of does increases their antibody titres and is associated with higher titres in their young, a challenge study is needed to determine whether the kits are protected from disease caused by RHDV.