Effect of maternal immunity on the immune response to oral vaccination against rabies in young foxes.
OBJECTIVE
To determine effect of maternal antibodies on immune response to oral vaccination against rabies in young foxes.


METHODS
250 cubs from 48 vixens.


METHODS
Sera were obtained from cubs of 36 vaccinated (maternally vaccinated [MV+]) and 12 nonvaccinated (MV-) vixens between 23 and 71 days of age and tested for neutralizing antibodies. Seventy-one MV+ cubs and 33 MV-cubs were vaccinated orally with modified-live virus vaccine SAD B19. Geometric mean titer (GMT) was determined in these cubs approximately 21, 39, and 57 days after vaccination. In a subsequent experiment, 10 vaccinated MV+ cubs, 6 vaccinated MV- cubs, and 6 control cubs were challenge inoculated with virulent rabies virus approximately 100 days after vaccination.


RESULTS
Serum GMT of nonvaccinated MV cubs (0.23 U/ml) was significantly greater than that of non-vaccinated MV- cubs (0.15 U/ml). The GMT of vaccinated MV+ cubs 21, 39, and 57 days after vaccination were 2.85, 2.11, and 0.79 U/ml, respectively, and were significantly less than those of vaccinated MV- cubs (12.19, 6.76, and 4.02 U/ml, respectively). All challenge-inoculated cubs with GMT < 0.5 U/ml succumbed to rabies.


CONCLUSIONS
Partially impaired immune response in cubs < 8 weeks old from vaccinated vixens causes insufficient protection against rabies. Inhibition of the immune response persists longer than the period during which maternal antibodies are detectable. Thus, oral vaccination campaigns for young foxes in areas where vaccination has been performed need to be reconsidered.
Müller
T F
TF
Institute for Epidemiological Diagnostics, WHO Collaborating Centre for Rabies Surveillance and Research, Wusterhausen, Germany.
Schuster
P
P
Vos
A C
AC
Selhorst
T
T
Wenzel
U D
UD
Neubert
A M
AM
D000284:Administration, Oral; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood; D005260:Female; D005589:Foxes / Q000276:immunology* / Q000821:virology; D007112:Immunity, Maternally-Acquired / Q000276:immunology*; D009500:Neutralization Tests / Q000662:veterinary; D011818:Rabies / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D011819:Rabies Vaccines / Q000008:administration & dosage / Q000276:immunology* / Q000592:standards; D011820:Rabies virus / Q000254:growth & development / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary*
D000914:Antibodies, Viral; D011819:Rabies Vaccines