Safety evaluation of the SAG2 rabies virus mutant in Tunisian dogs and several non-target species.

The safety of the SAG2 rabies virus, a highly attenuated mutant of the SAD strain intended to vaccinate dogs by the oral route, was evaluated in local Tunisian dogs and in five other local species likely to consume vaccine baits. These species were the domestic cat (Felis catus), the jackal (Canis aureus), the jerboa (Jaculus orientalis), the merion (Meriones sp.) and the gerbil (Gerbillus campestris). The vaccine was administered orally to 21 dogs, 11 cats and eight jackals and orally or intramuscularly to 62 wild rodents of the above-mentioned species. Seven dogs, one cat, five jackals all juvenile and with poor health status) and two rodents died for intercurrent causes. The others were observed for 60-180 days. No animal showed any rabies symptom. Seroneutralizing antibodies were observed in all experimental groups, only after vaccination, with the highest rate being observed in jackals and rodents. The rabies virus was detected in the oral cavity of three cats 6 h after oral instillation, but was not isolated later either in saliva or in salivary glands. Tissue samples (brain and salivary glands) from dead or euthanized animals were examined for the rabies virus antigen by a fluorescent antibody test. No rabies antigen was detected. These trials confirm the safety of the SAG2 strain on the Tunisian species already demonstrated by other authors on many other target and non target species.

Rabies mass vaccination campaigns in Tunisia: are vaccinated dogs correctly immunized?

Among the 301 dogs vaccinated against rabies in a suburban area of Tunis, 165 were sero-surveyed for 13 months. One month after vaccination, 65% of the dogs less than 1 year of age and 76-84% of the older dogs had significant antibody titers. One month after annual revaccination, these percentages ranged between 92% and 100%. Puppies (less than 3 months old) responded to vaccination with no significant interference by passive maternal immunity. Based on these percentages, a 93% rate of protection may be expected for vaccinated dogs. This study confirms that all dogs (even those less than 3 months of age) must be vaccinated during mass campaigns. The expected protection conferred by locally produced potent vaccines reaches 79-99% based on the age of the dogs. The alleged relative inability of local dogs to respond to vaccination cannot explain the partial success of rabies control in Tunisia.

Identification of the virus of rabbit haemorrhagic disease in Tunisia.

During 1992 and 1993, outbreaks of an acute, highly fatal disease mainly affecting adult rabbits were observed in Tunisia. The clinical and pathological findings were consistent with rabbit haemorrhagic disease. A monoclonal antibody designated PG4G3 specific for surface determinants of the rabbit haemorrhagic disease virus was used to identify the aetiological agent by ELISA and by colloidal gold immunoelectron microscopy; a haemagglutination test and conventional immunoelectron microscopy were also used. The results confirmed the first recorded cases of the disease in Tunisia.

[Seroepidemiological survey of influenza and infectious anemia in Equidae in northeastern Tunisia]. / Enquête séroépidémiologique sur la grippe et l'anémie infectieuse des equidés dans le nord-est tunisien.

Using the haemagglutination inhibition and immunodiffusion tests, a national serological survey was carried out to detect antibodies to equine influenza (EI) (A/equi/1/Prague 56 and A/equi/2/Miami 63) and equine infectious anaemia (EIA) in horse sera collected in northeastern Tunisia. 533 samples were analysed for EIA antibodies. All were negative. 13.6% of 433 equine sera tested for EI antibodies were positive. These results are discussed and compared with others obtained in Tunisia and bordering countries.