A Comparative Evaluation of the Estimation of Rabies Virus Antibodies among Free-Roaming, Vaccinated Dogs in Bengaluru, India.

Lekshmi J Das,Nageshkumar Abhijit Kumar,Avinash Bhat,Ramakrishnaiah Sharada,Alur Kotrappa Santosh,Abi T Vanak,Shrikrishna Isloor,Konanduru Lingappa Phaniraj,Doddamane Rathnamma,Belamaranahally Muniveerappa Veeregowda

doi:10.3390/v14030484

Abstract

Vaccination is the practical solution for the prevention of rabies in dogs. Assessment of the immunogenicity of vaccination includes estimation of specific rabies virus neutralizing antibodies (VNA) in the target species. We undertook a study to estimate the levels of VNA in free-roaming dogs with a history of rabies vaccination in Bengaluru city, India. We compared the rapid fluorescent focus inhibition test (RFFIT) and an in-house quantitative indirect ELISA (iELISA). The study area comprised the jurisdiction of Bruhat Bengaluru Mahanagara Palike (BBMP), the Bengaluru civic body. The BBMP, along with several non-government organizations (NGO), were conducting a trap- neuter- vaccinate- release program for the prevention of dog rabies. Serum samples were collected from 250 free-roaming dogs from representative regions of BBMP, of which 125 had a VNA titre of 0.5 IU or more by the RFFIT. Furthermore, 126 dogs showed percent positivity values (PP values) more than the cut off PP value of 57.1 by the iELISA, accounting for 50.4% of satisfactory post-vaccinal serum conversion. The sensitivity and specificity of the iELISA was 94.4% and 95.2%, respectively. Based on these data, a quantitative iELISA may be a complementary tool for sero-monitoring immune responses of free-ranging animals after rabies vaccination.

Highlights

Rabies is a zoonotic viral disease caused by RNA viruses in the genus Lyssavirus of the family Rhabdoviridae [1]
Fluorescent foci was observed in the virus control (100 TCID50 virus) as well as in the serum samples with inadequate rabies virus neutralizing antibodies (VNA) indicating virus replication
Of the 250 samples analyzed by the rapid fluorescent focus inhibition test (RFFIT), 125 (50%) had rabies VNA titres ≥ 0.5 IU

Summary

Introduction

Rabies is a zoonotic viral disease caused by RNA viruses in the genus Lyssavirus of the family Rhabdoviridae [1]. Considering its agricultural and public health significance, rabies virus (RABV) is the most important member of the genus. Most dogs in India are thought to fall into the last three categories [7]. This feature is a major hurdle in rabies prevention and control. Dogs that are not confined to an owner’s property are considered free-roaming [8]. These free-roaming dogs could be both owned and allowed to roam freely or stray (including recently owned but lost from home or abandoned). The term free-roaming describes a lack of confinement [9,10]

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Conclusion