Epidemiology and Infection

Use of ELISAs in field studies of rabbit haemorrhagic disease (RHD) in Australia

B. D. COOKE a1c1, A. J. ROBINSON a1, J. C. MERCHANT a1, A. NARDIN a2 and L. CAPUCCI a2
a1 CSIRO, Wildlife and Ecology, GPO Box 284, Canberra, ACT, Australia 2601
a2 Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia, Via Bianchi 7, 25124 Brescia, Italy


ELISA techniques developed for the veterinary diagnosis of Rabbit Haemorrhagic Disease (RHD) in domestic rabbits were used for studying the epidemiology of RHD in Australian wild rabbits. The combination of ELISA techniques that distinguished IgA, IgG and IgM antibody responses and a longitudinal data set, mainly based on capture-mark-recapture of rabbits, provided a reliable basis for interpreting serology and set the criteria used to classify rabbits' immunological status. Importantly, young with maternal antibodies, immune rabbits and rabbits apparently re-exposed to RHD were readily separated. Three outbreaks of RHD occurred in 1996–7. The timing of RHD outbreaks was mainly driven by recruitment of young rabbits that generally contracted RHD after they lost their maternally derived immunity. Young that lost maternal antibodies in summer were not immediately infected, apparently because transmission of RHDV slows at that time, but contracted RHD in the autumn when conditions were again suitable for disease spread.

(Accepted November 10 1999)

c1 Author for correspondence.