Rabies

Question 1

Symptoms of rabies

Answer 1

Incubation period 20-60 days
○ Occasionally 5-6 days
○ 1-3% >6months
○ Reportedly up to 6 years (but unexplained)

Acute fatal encephalitis
○ Paralytic (Dumb) and Furious
○ Accompanied by non-specific febrile illness

Anxiety, confusion, agitation, delirium, hallucinations, abnormal behaviour, insomnia, seizures, loss of consciousness

Death in 1-5 days

(Disease always referred to as rabies even if caused by non-rabies lyssavirus)

Question 2

WHO PEP guidelines for rabies

Answer 2

Immediately wash wounds

PEP should be instituted immediately (vaccine)

Observe animal, or euthanise to test

Control disease in dogs through vaccination

Question 3

Clinical signs of rabies in dogs

Answer 3

Incubation period 7 days to several months
○ 50% within one month and 80% within 4 months
○ i.e. Exceptionally long and highly variable

Prodromal stage
○ Behavioural stage, pyrexia, dilated pupils, nictitating membrane across eye, salivation

Two end-stages
○ Dumb rabies: (80% dogs) incoordination, ‘dropped jaw’, ‘bone in throat’, paralysis, death
○ Furious rabies: agitated, aggressive, phonation, salivation, dysphagia, seizures, incoordination, paralysis, death

Question 4

Clinical signs of rabies in cats

Answer 4

Prodromal: subtle behavioural changes, pyrexia

Acute: 80% aggressive, irritable, restless, anorexia, salivation, phonation, lethargy, paralysis, death

Most dead-end hosts, usually die within 3-4dd

Question 5

Clinical signs of rabies in horses

Answer 5

Often present with choke, prior to obvious central signs

Most common animals transmitting to vets in East Africa pre-vaccination, usually dead end

Question 6

Clinical signs of rabies in ruminants

Answer 6

Most dead end, but high % furious form

Weakness, bellowing, depression, incoordination

Question 7

Canine rabies vaccines

Answer 7

Inactivated tissue culture vaccines

Initial vaccine at 3 months then booster at 2-3 year intervals depending on brand: IM or SQ - not ID

Under field conditions vaccinate all pups, including < 3 months of age

Several vaccines on market, quite similar constituents

Nobivac Rabies
○ Pasteur strain, aluminium phosphate adjuvant booster 3 years

Pfizer Defensor

Merial Rabisin

Virbac Canigen

Question 8

Control of canine rabies

Answer 8

Cell culture vaccine - duration of immunity 3-4 years

Strong empirical and theoretical support for target of vaccinating 70% of dogs in preventing epidemics
○ 90% reduction at least in risk of epidemics
○ Due to public concerns, rabies must be almost eliminated in order to see reduced PEP uptake

Newer oral vaccines becoming available, not yet in widespread use

Avoid culling at all costs, it is ineffective, removes attention from effective control, and may make things worse

Question 9

When did the UK become rabies free

Answer 9

1922

Question 10

How many annual deaths from rabies?

Answer 10

59.000