Epidemiology and Infection



A rabies serosurvey of domestic dogs in rural Tanzania: results of a rapid fluorescent focus inhibition test (RFFIT) and a liquid-phase blocking ELISA used in parallel


S. CLEAVELAND a1a2c1p1, J. BARRAT a3, M.-J. BARRAT a3, M. SELVE a3, M. KAARE a4 and J. ESTERHUYSEN a5
a1 Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
a2 Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK
a3 Centre National d'Études Vétérinaires et Alimentaires (CNEVA), Boite Postale 9, Domaine de Pixérécourt, Malzeville 54220, France
a4 Ministry of Agriculture, P.O. Box 162, Mugumu, Serengeti District, Tanzania
a5 Onderstepoort Institute for Exotic Diseases, Private Bag X6, Ondersterpoort 0110, South Africa

Abstract

During a serosurvey of domestic dogs in Tanzania, a rapid fluorescent focus inhibition test (RFFIT) and a liquid-phase blocking ELISA (LPBE) were used to measure rabies antibodies in vaccinated and unvaccinated dogs. Post-vaccination titres measured by LPBE correlated closely with those found by RFFIT. Of 567 unvaccinated dogs tested using the LPBE, 42 (7·4%) were seropositive, with titres exceeding 32. Of this group, 233 dogs were tested using the RFFIT and 115 (49·4%) were seropositive, with titres exceeding 0·5 IU/ml. Two lines of evidence pointed to the greater specificity of the LPBE when measuring rabies antibodies induced by natural infections: (a) no seropositive dogs were detected among the 162 unvaccinated dogs from the rabies-free island of Pemba, Tanzania, when using LPBE, whereas 15/145 (10·3%) dogs of the same group were seropositive using RFFIT; (b) among Tanzanian dogs there was a close association between the location of rabies cases and location of seropositive dogs when using LPBE, but not when using RFFIT. These results suggest that LPBE may be of value in rabies seroepidemiological studies and could be developed as a reference technique for the detection of rabies antibody in domestic dogs.

(Accepted March 9 1999)


Correspondence:
c1 Author for correspondence.
p1 Current address: Centre for Tropical Veterinary Medicine, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Roslin, Midlothian EH25 9RG, UK.


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