Epidemiological analysis of setbacks in oral vaccination in the final stage of fox rabies elimination in densely populated areas in Germany.

Despite a long history of oral vaccination of foxes (OVF) against rabies, in a few restricted areas of Germany rabies is still endemic, posing a continuous risk of re-introduction of rabies into adjacent, rabies-free areas. The endemic area is characterized by a high density population. It is hypothesized that the degree of urbanization in the area under consideration influences the number of rabies cases via the mode of bait distribution. In urban areas vaccine baits are distributed by hand, whereas in non-urban areas baits can be distributed aerially with the help of fixed-winged aircraft. Statistical analysis of the effect of the mode of bait distribution upon the number of rabies cases shows a significant influence. In areas where baits are distributed by hand the number of rabies cases is significantly higher than the expected number. This finding forces managers to reassess the procedure of bait distribution by hand in urban areas, taking into account the ecologically and biologically different dynamics of urban fox populations. If the oral vaccination of foxes in urban areas can be refined, rabies eradication in Germany is expected to succeed in due course.