Exposure of rabbits to ultraviolet light-inactivated rabbit haemorrhagic disease virus (RHDV) and subsequent challenge with virulent virus

Abstract

This study investigated whether exposure to inactivated rabbit haemorrhagic disease virus (RHDV) can produce an antigenic response in rabbits and protect them from a subsequent challenge with virulent virus. The aim was to determine if the spreading of baits containing RHDV, which is a common management practice in New Zealand to reduce rabbit numbers, could result in protective immunity in wild rabbits. RHDV was inactivated by ultraviolet (UV) light using an electronic UV crosslinker with a UV dose of 168.48 W-s/cm2 and a UV intensity of 0.0078 W/cm2. Two groups of four rabbits were then inoculated with inactivated virus via oral and intramuscular routes. Rabbits were monitored for 30 days post-inoculation and then challenged orally with virulent virus. No rabbit exposed to inactivated RHDV developed clinical signs of RHD or had antibodies at day 30 post-infection and all animals died within 82 h after challenge with virulent virus. No antibodies were detected at the time of death. These findings suggest that exposure to virus completely inactivated by UV light in the field or on baits will not protect rabbits against challenge with virulent virus.

Inactivated virus vaccines from chemistry to prophylaxis: merits, risks and challenges

“…No antibodies were detected at the time of death. These findings show that vaccination with UV-inactivated RHDV does not protect rabbits against challenge with virulent virus in this study [92].…”

“…This procedure for virus inactivation has been tested to develop a KV vaccine against viruses such as rabbit hemorrhagic disease virus (RHDV) [92], murine leukemia virus strain Cas-Br-M [93] and PRRSV [79] and are summarized in Table 8.…”

Survival of rabbit haemorrhagic disease virus (RHDV) in the environment

“…As only infectious virus will result in an antibody response [33], viral replication in the body is necessary to obtain a constantly high antibody level. Antibody titres of the five surviving seroconverting rabbits (n= 6) reached their highest levels between 10 and 20 days, while Shien and colleagues [32] detected antibody peaks 3 weeks p.i.…”

Full inactivation of alphaviruses in single particle and crystallized forms

“…Poliovirus (PV), hepatitis A virus (HAV), Japanese encephalitis virus (JEV), tick borne encephalitis virus (TBEV), rabies virus, and influenza virus each have licensed inactivated vaccines produced from formaldehyde inactivated particles (Sanders et al, 2015). Vaccines for viruses inactivated with UV irradiation have been proven to be effective in producing virus-specific immune responses for murine leukemia virus strain Cas-Br-M (UV-Cas) (Sarzotti et al, 1994) and porcine reproductive and respiratory syndrome virus (PRRSV) (Vanhee et al, 2009), but this was not the case with the UV-inactivated vaccine for rabbit hemorrhagic disease virus (RHDV) (Henning et al, 2005).…”