Development of a Non-Meat-Based, Mass Producible and Effective Bait for Oral Vaccination of Dogs against Rabies in Goa State, India.

Andrew D Gibson,Alasdair King,Santosh Desai,Vilas Naik,Gowri Yale,Julie Corfmat,Richard J Mellanby,Steffen Ortmann,Ad Vos,Thomas Müller,Stella Mazeri,Luke Gamble,Ian Handel,Berend Mdec Bronsvoort

doi:10.3390/tropicalmed4030118

Abstract

Introduction: To achieve the global goal of canine-mediated human rabies elimination by 2030 there is an urgent need to scale-up mass dog vaccination activities in regions with large dog populations that are difficult to access; a common situation in much of India. Oral rabies vaccination may enable the vaccination of free-roaming dogs that are inaccessible to parenteral vaccination, and is considered a promising complementary measure to parenteral mass dog vaccination campaigns. WHO and OIE have published detailed minimum requirements for rabies vaccines and baits to be used for this purpose, requiring that baits must not only be well-accepted by the target population but must also efficiently release the vaccine in the oral cavity. For oral rabies vaccination approaches to be successful, it is necessary to develop baits which have a high uptake by the target population, are culturally accepted and amenable to mass production. The aim of this study was to compare the interest and uptake rates of meat-based and an egg-based prototype bait constructs by free roaming dogs in Goa, India. Methods: Three teams randomly distributed two prototype baits; an egg-flavoured bait and a commercial meat dog food (gravy) flavoured bait. The outcomes of consumption were recorded and compared between baits and dog variables. Results: A total of 209 egg-bait and 195 gravy-bait distributions were recorded and analysed. No difference (p = 0.99) was found in the percentage of dogs interested in the baits when offered. However, significantly more dogs consumed the egg-bait than the gravy-bait; 77.5% versus 68.7% (p = 0.04). The release of the blue-dyed water inside the sachet in the oral cavity of the animals was significant higher in the dogs consuming an egg-bait compared to the gravy-bait (73.4% versus 56.7%, p = 0.001). Conclusions: The egg-based bait had a high uptake amongst free roaming dogs and also enabled efficient release of the vaccine in the oral cavity, whilst also avoiding culturally relevant materials of bovine or porcine meat products.

Highlights

To achieve the global goal of canine-mediated human rabies elimination by 2030 there is an urgent need to scale-up mass dog vaccination activities in regions with large dog populations that are difficult to access; a common situation in much of India
Prevention of human deaths from rabies could be achieved through increasing access to post-exposure prophylaxis (PEP), ensuring that anyone bitten by a rabid dog received comprehensive post-exposure prophylaxis
The results showed that oral rabies vaccination (ORV) of dogs is a feasible option for India as similar high bait acceptance rates were observed

Summary

Introduction

To achieve the global goal of canine-mediated human rabies elimination by 2030 there is an urgent need to scale-up mass dog vaccination activities in regions with large dog populations that are difficult to access; a common situation in much of India. Conclusions: The egg-based bait had a high uptake amongst free roaming dogs and enabled efficient release of the vaccine in the oral cavity, whilst avoiding culturally relevant materials of bovine or porcine meat products. In several settings in Africa, it has been shown that the majority of free roaming dogs are owned and high vaccination coverage can be achieved through mobilizing dog owners to present their dogs at static vaccination locations or to roaming vaccination teams travelling door-to-door, described as central point (CP) or door-to-door (DD) methods respectively [5,6,7] In countries such as India, a large proportion of free-roaming dogs are either owned, but cannot be readily handled by their owner, or are truly ownerless and cannot be restrained by anyone in the local community [8,9]. DD and CP approaches do not access a high enough proportion of dogs to interrupt rabies virus transmission and there is a clear need to develop novel approaches to vaccinate inaccessible dogs

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