Impact of Rabies Vaccination History on Attainment of an Adequate Antibody Titre Among Dogs Tested for International Travel Certification, Israel - 2010-2014.

Rabies is endemic in wildlife or domestic carnivore populations globally. Infection of domestic dogs is of particular concern in many areas. In regions where domestic animals are at risk of exposure to rabies virus, dogs should be routinely vaccinated against rabies to protect both pet and human populations. Many countries require demonstration of an adequate level of serum rabies neutralizing antibodies to permit entry of dogs during international travel. We analysed rabies titres of dogs seeking travel certification in Israel to assess demographic and vaccine history factors associated with antibody titres below the acceptable threshold for travel certification. Having received only one previous rabies vaccination and a longer duration since the most recent vaccination was received were primary risk factors for not achieving an adequate rabies virus neutralizing antibody titre for travel certification. These risk factors had stronger effects in younger animals, but were consistent for dogs of all ages. In particular, these findings reiterate the importance of administering at least two rabies vaccinations (the primo vaccination and subsequent booster) to ensure population-level protection against rabies in dogs globally.

Emergence of dog rabies in the northern region of Israel.

Between 1979 and 2000, foxes constituted the main reservoir of rabies in the Northern regions of Israel. Following the implementation of the fox-targeted oral vaccination programme (ORV) in 1998, rabies was eradicated from this area. Subsequently during 2004-2007, the biological and molecular characterization of the rabies isolates showed that stray dogs emerged as the main animal reservoir in Northern Israel while lower numbers of cases were reported in domestic animals. The virus isolates from foxes and dogs differed, in their molecular characterization, suggesting two distinct separate lineages. The transition from fox-mediated rabies to dog-mediated rabies is of great concern to public health because of the close contact between dogs and the human population.

Rabies virus detection by RT-PCR in decomposed naturally infected brains.

The warm climate of Israel and mishandling of the cadavers during transit to the laboratory requires an accurate method for diagnosis of rabies in decomposed tissues. By using the reverse transcriptase polymerase chain reaction (RT-PCR) 10 decomposed brain samples that collected between 1998 and 2000 were diagnosed as negative by direct fluorescent antibody test (FAT), were found positive. Three of the 10 decomposed brains were confirmed as positive by isolation of rabies virus in tissue culture and by mouse inoculation (MIT) while the other seven decomposed samples were found positive only by RT-PCR. Direct sequencing and molecular analysis of a 328bp fragment of the N gene of all the rabies sequences confirmed their geographical origin. These results demonstrated the importance of the RT-PCR in the detection of rabies virus in decomposed naturally infected brains, especially in cases when the sample is not suitable for other laboratory assays. Thus, the RT-PCR can provide a positive diagnosis; however, when a negative result is obtained due to the nature of the decomposed tissue that can be caused by technical reasons and a false negative might be the case.