Establishing a serological surveillance protocol for rabbit hemorrhagic disease by combining mathematical models and field data: implication for rabbit conservation

Abstract

Rabbit hemorrhagic disease (RHD) became endemic in wild rabbit populations in the Iberian Peninsula after its first arrival in 1988. This had significant implications for both the economy and environmental conservation because rabbits are one of the main game species in the Iberian Peninsula and a keystone species in the Mediterranean ecosystems. As a consequence it is planned to include RHD surveillance in the Spanish Wildlife Disease Surveillance Strategy. Nevertheless, there is no practical methodology included in this program to help conservationists and gamekeepers understand the impact of disease on wild rabbit populations. Results from sera collected during the hunting season from 11 rabbit populations of Central and South Spain, which differed on their population abundance and trends, allowed us to use mathematical models to interpret the serological results gathered and determine the best strategy for finalizing a future plan of RHD surveillance. Put simply, we focused our field surveys within the hunting season (October-January), and those times when the rabbit populations are in their highest (June or July). Field results showed that both rabbit abundance and population trend are closely related to the prevalence of RHD antibodies when rabbit abundance was at its annual low point (usually October-November). Rabbit population trends were positive only if antibody prevalence was high (>40%), and always negative if prevalence was low. Moreover, all rabbit populations where abundance was low always showed low antibody prevalence. Since our models predicted a low variability in the prevalence obtained thorough the hunting season, it is suggested that future serological surveys should be carried out within this 3 period to avoid problems related to the low sample size in low density rabbit populations.4

Conservationists, hunters and farmers: the European rabbit Oryctolagus cuniculus management conflict in the Iberian Peninsula

“…) is poorly understood (but see Calvete , Cotilla et al. ). Furthermore, the roles of predation and hunting in rabbit population dynamics in conflict areas have not been investigated, and the potential differences in their effects on the two rabbit subspecies are not understood.…”

Wild Rabbit Management in the Iberian Peninsula: State of the Art and Future Perspectives for Iberian Lynx Conservation

“…An Iberian Wildlife Disease Surveillance Strategy could be designed in order to monitor the impact and evolution of viral diseases on rabbit populations. Cotilla and colleagues [76] recently proposed a protocol, to be included in the Spanish Wildlife Disease Surveillance Strategy, for monitoring RHD based on the prevalence of antibodies to this disease and the abundance of rabbits. These authors concluded that managers and conservationists should urgently focus their efforts on rabbit populations with low antibody prevalence against RHD, and base their strategies on tested management measures that ensure an increase in abundance allowing rabbits to overcome the suppressive impact of this disease [76].…”

Widespread exposure to Sarcoptes scabiei in wild European rabbits (Oryctolagus cuniculus) in Spain

“…Third, the effect of concomitant diseases may exacerbate what would otherwise be an asymptomatic mange infection (Balestrieri et al, 2006). For example, wild rabbit populations are known to suffer from periodical outbreaks of myxomatosis and RHD with mortality rates varying between years and places (Calvete et al, 2002;Cotilla et al, 2010) that may be related with mange outbreaks. In fact, we found an association between the presence of antibodies to S. scabiei and to myxoma virus.…”