Rabies Vaccination for Sheep and Goats: Influence of Booster on Persistence of Antibody Response.

Simple Summary: Rabies is causing a serious threat to humans and animals almost worldwide. Immunization against the disease is important in four aspects: public health protection, animal health, economic impact, and regulatory compliance. Rabies affects a wide range of mammals, including domestic pets, livestock, and wild animals. Infected animals, usually bitten by an infected wild animal, suffer from severe neurological symptoms and eventually die. In Israel, mandatory vaccination of dogs as well as wildlife surveillance exists. When it comes to farm animals, the vaccination policy depends on a risk analysis. However, little is known regarding the optimal immunization protocol needed to protect small ruminants. To find an optimal vaccination strategy, we tested the effect of one and two doses of vaccine on sheep and goats. Initially, animals were vaccinated with one dose, and half of them received a second dose (booster) a month later. The level of antibodies was tested a month and a year later. The study demonstrated a different immune response between the different species, as one-dose vaccinated sheep showed a low maintenance of protection a year later, compared with the booster-receiving group. On the other hand, 80% of the goats which received a single dose had a sufficient antibody level a year later. Infrequent rabies cases occur in Israel, endangering humans and animals. While dogs receive mandatory vaccinations, farm animals are vaccinated voluntarily. However, optimal vaccination protocol for small ruminants is lacking. The aim of this study was to test the immunological responses to the rabies vaccine, with or without a booster, in sheep and goats; 70 ewes and 49 does participated in the trial. Following the first vaccine, 88% of the ewes and 100% of the does had a sufficient level of rabies antibodies (>0.5 IU/mL) 30 days post-vaccination. A year later, 82% of the ewes that had received a booster dose remained protected, whereas 46% of the non-boosted ewes had a sufficient antibody level. For does, 83% of those receiving a booster maintained sufficient antibody levels 1 year later; 80% of the non-boosted does remained protected, demonstrating no significant contribution of the booster dose in this group of goats. However, while the initial immunological response of the does was higher, the change in response between 1 month and 12 months post-vaccination differed significantly between species, with a greater titer reduction in the does. Differential immunological responses between individuals and between species warrant longer-term studies to recommend a proper vaccine protocol for each species. [ABSTRACT FROM AUTHOR]