Envigo Rat Models Proven to be Susceptible to Intra-Vaginal HSV-2 Infection and Protectable by Attenuated HSV-1 Against Symptomatic HSV-2

A scientific collaboration between Envigo and the Department of Infectious Disease at the University of Gothenburg, Sweden has unveiled study findings into rat models and their susceptibility to intra-vaginal herpes simplex virus-2 (HSV-2) infection. A synopsis of the study and its conclusions are outlined in a poster entitled "Novel rat models to study primary genital herpes simplex virus-2 infection."

Sheryl Wildt, Envigo's Global Manager of Genetic Quality and Breeding, commented, "There is an urgent need for a vaccine against herpes simplex virus type-2 (HSV-2), not only because HSV-2 is a common sexually transmitted virus, but also because HSV-2 infection facilitates transmission of HIV. Limitations to HSV-2 genital mouse models and guinea pig models led us to investigate whether our Envigo rat stocks or strains were susceptible to HSV-2 infection and, if so, to determine if attenuated HSV-1 could serve as a protection against symptomatic HSV-2 infections in susceptible animals.

To our knowledge, there are no previous studies describing rats as a genital model of HSV-2 infection."

The Envigo study demonstrated that several Envigo rat models are susceptible to genital HSV-2 infection, with the outcome varying between different stocks or strains. The F344/NHsd strain proved to be the most susceptible and may be suitable as an alternative or complementary animal model for efficacy studies for prophylactic vaccine candidates. The Hsd:Sprague DawleyR SDR stock, being the least susceptible, can be used to study protective immune mechanisms involved in the primary asymptomatic HSV-2 infection. This model also has the potential to recapitulate the human genital HSV-2 infection. Furthermore, Envigo also investigated if prior HSV-1 infection is protective against HSV-2 infection. All HSV-2 infected rats previously infected with attenuated HSV-1 survived and developed no genital or systemic symptoms.

Consequently, the described Envigo rat models provide a new approach to investigate the protective effects of anti-viral microbicides and vaccine candidates as well as to study asymptomatic primary genital HSV-2 infection.

More information about this study can be found on a poster available here.