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| Edgar catches the news (NB this is not an official entrant in our David Attenborough giveaway as I took the photo...but how could anyone resist?) |
A study just published in
the Veterinary Record looked at the efficacy of antirabies vaccination in dogs
and found that only 39.67 dogs demonstrated protective antibody levels.
This raises major
questions about stray dogs vaccinated against rabies. A single vaccination is
no guarantee, though a number of aid programs are designed to deliver one vaccine to all animals. This is important - but not enough to establish protective immunity.
We are very fortunate not to have rabies in Australia, but it’s a
scary disease. I should at this point state that rabies is NOT a core vaccination in Australia for companion animals and is only given by Government and AQIS certified vets to animals for the purposes of export to other countries.
Interestingly the factors
found to play a role in immunity and maintenance of a protective antibody titre
in dogs were regular vaccination, regular exercise, companionship, non-descript
breed, desexing, and being over one year old. Stressed, poorly cared for
animals are less likely to mount an effective immune response.
The study looked at 300
serum samples from dogs vaccinated for rabies at Madras Veterinary CollegeTeaching Hospital in Chennai, India – a rabies endemic area. To be included in
the study, dogs had to be three months old, clinically well and have had at
least one rabies vaccination.
Animals less than one year
old were less likely to have a protective antibody titre, possibly because they
are less capable of mounting an effective immune response following vaccination
– a good incentive to revaccinate these animals.
Interestingly, desexed
animals were better able to maintain a protective antibody titre than entire
animals. A previous study found that castrated mice responded to antigenic stimulation
better than entire mice, with twice the number of T lymphocytes, but it isn’t
known if this is the explanation here.
Dogs fed a variety of food
– rather than a monotonous and likely deficient diet – were also more likely to
have a protective antibody titre suggesting that better nutrition leads to
better immunity.
Antibody titres were
significantly higher in animals receiving multiple rabies vaccinations. Except
in adult dogs that had a history of previous immunisation, a single dose of
antirabies vaccine was not enough to maintain a good protective antibody titre
for twelve months in 50 per cent of adult dogs and puppies.
It’s a reminder of the
importance of re-vaccination, especially in endemic countries.
Meanwhile would you
believe that there are some insanely irresponsible people out there who are
falsifying rabies vaccination certificates? The impact of such an act could be
huge – ranging from leading to human and animal deaths to introducing rabies
into a non-endemic country. You can read more about it at the Worms and Germs
blog here. It is totally unacceptable to play Russian Roulette with infectious diseases.
Reference
Yale G, Ganesan PL,
Tirumurugaan KG, Madhusudana SN, Vijaya Bharathi M, Thangavelu A, Yajaman
Belludi A, Sanyal S and Taj S (2014). Factors affecting duration of immunity of
rabies vaccination in dogs. Vet Rec Open 2014;1:e000023
doi 10.1136/vropen-2013-000023
