Safety study of the Bio-10-SAD Bern strain of the rabies virus on the rhesus macaque monkey species

Abstract

Based on a WHO recommendation, residual pathogenicity of the Bio-10-SAD Bern rabies virus strain (component of the Lysvulpen por. ad us. vet. vaccine) was tested on rhesus macaque monkeys. Each of the ten monkeys, females, two years old, was administered orally 2 ml × 10 9 TCID 50 of the Bio-10-SAD Bern rabies strain. The animals were monitored for 90 days. Subsequently, the animals were sacrificed and their brains were examined for presence of the vaccination rabies virus by the immunofluorescence and PCR methods. The occurrence of anti-rabies antibodies prior to and following administration of the vaccination rabies virus was also evaluated. No clinical signs of rabies were observed nor did any of the animals die of rabies following application of the virus. No rabies was detected in the study animals by post mortem examination. All of the 10 animals developed anti-rabies antibodies during the 90 days following administration of the rabies virus. It can be concluded, that Bio-10-SAD Bern virus administered at a dose equal to the tenfold maximum dose specified for field uses is safe to monkeys of the rhesus macaque species. This study is the first of its type performed in rhesus macaque monkey species.

Update on oral vaccination of foxes and raccoon dogs against rabies

“…All animals developed an immunological response post vaccination (Vrzal, 2013). Each animal was vaccinated orally with 2.0 mL of a 10 9 tissue culture infectious dose (TCID 50 ) of a Bio-10-SAD Bern strain and monitored for 90 days by clinical observation and rabies neutralising antibody determination.…”

“…Some modified-live rabies virus oral vaccines may have residual pathogenicity, depending on the level of attenuation of the viral strain (WHO, 2013), as the successive selections from the original strain may produce hazardous and uncontrolled results, and variants may remain pathogenic both in target and non-target species (Vrzal, 2013;WHO, 2013). A double mutation in a portion of the genome (codon 333) whose integrity is required for pathogenicity by the oral route allowed the selection of a highly attenuated virus (Mähl et al, 2014).…”

“…Brain tissue samples were analysed after euthanasia and were all negative for rabies virus. All animals developed an immunological response post vaccination (Vrzal, 2013).…”

Oral vaccination of dogs: a well-studied and undervalued tool for achieving human and dog rabies elimination

“…Residual pathogenicity of SAD B19 was also reported in wild rodents (5.7% of wild rodents receiving orally a field concentration died of rabies), as described [ 39 ]. In addition, adverse events were observed after administration of SAD Bern to wild rodents [ 40 ], wild and domestic carnivores [ 41 ] and baboons [ 42 ] but not to rhesus macaques [ 43 ].…”