One Health approach to zoonoses Flashcards
How often is rabies transmitted to humans?
99.9% dog bites
>99% dogs, <1% other carnivores, bats
On which continent are there the most deaths due to Rabies?
Asia, closely followed by Africa
What are the 2 rabies reservoirs?
Urban - domestic dogs - Africa, Asia, Latin America,
Sylvatic - wild animals (skunk, raccoons, bats) - Europe, N/S America, Asia
What does human outcome depend on? 3
Bite location Severity Serovar Age Immune status Clinical onset may not be immediate
How common is rabies in children?
over 40% cases are in children (unknown why, perhaps less educated)
Outline rabies pathogenesis
Bite: slow multiplication of virus in muscle cells (incubation)
Rapid transport of virus genomes in nerve axons
Rapid virus spread within CNS
Massive virus replication in nerve cells
Transport in nerve axons to salivary glands and other peripheral organs
VIRUS EXCRETION AND EXPRESSION OF CLINICAL SIGNS
Clinical signs - dog rabies
FURIOUS FORM (30%): agitated, aggressive, difficulty swallowing, salivation, seizures - death, incoordination, paralysis, coma and death
DUMB FORM (70%): dropped jaw, bone in throat, incoordination, paralysis and death
Outline rabies in livestock
Incubation = 10-40 days Morbidity = 3 days Both variable Death can occur per-acutely with no clinical signs Manifests as furious form in 80% animals
CS: changes to behaviour, aggression, head butting, drooling, animals can be restless, depressed, head tremors, incoordination, paralysis
Define PEP
Post-exposure prophylaxis
How many rabies vaccination boosters should you hav?
Boost 1/2 years after primary vaccination. Subsequent boosters should be given at 3-5 year intervals.
Define RIG
Rabies immunoglobulin
What are the 2 types of RIG that can be used in humans
Human RIG (HRIG) Equien RIG (ERIG)
As much of the RIG dose as anatomically feasible should be infiltrated in the area around the wound and the remaining volume is administered IM. RIG provides transiet protection during the period before vaccine-induced immunity is conferred (usually 1 week)
How can exposure to rabies be categorised?
CATEGORY 1 = touching or feeding animals licks on intact skin - NO Tx
CATEGORY 2 = nibbling of uncovered skin, minor scratches or abrasions without bleeding - Local treatment of wound and immediate vaccination
CATEGORY 3 - single or multiple transdermal bites or scratches, licks on broken skin, contamination of MM with saliva from licks, exposures to bats - local treatment of wound, immediate vaccination and administration of RIG.
Current limitations of RIG
short supply high cost difficulty in finding immune donors batch-to-batch variation of polyclonal sera risks related to use of blood products
What are possible alternatives to RIG?
serveral murine Abs
