Rabies

background

An acute viral infection resulting in encephalomyelitis, which is almost always fatal. Death results from respiratory paralysis.

World-wide

Almost all human cases of rabies occur in developing countries, particularly Asia and Africa. World-wide, there are an estimated 65,000-87,000 deaths a year. Most human deaths follow dog bites for which adequate post-exposure prophylaxis was not, or could not, be provided.1

Potential Threats to Irish Citizens

Ireland is designated a ‘Rabies-free area’. However, potential threats to human health exist.
They include:

Foreign travel to rabies endemic countries. Bites or scratches from animals within endemic countries always pose the possibility of this rare but serious risk
Animal smuggling
Lifting of trade barriers
Migrating bats. Bat rabies cases have been reported in a number of European countries since 1985. The death of a UK bat handler in 2002 was reported following exposure to an infected bat

Transmission

Infection is usually transmitted by the bite of a rabid warm-blooded animal in a rabies endemic area. However, the animal may not show any signs of illness at the time. Dogs, foxes, raccoons, skunks and bats can all act as reservoirs for rabies. The principal hosts for rabies are dogs and bats (particularly insect eating bats).

Incubation Period

The incubation period is generally between 3-8 weeks (rarely as short as 9 days or as long as 7 years). It depends on wound severity, wound site in relation to nerve supply and distance from the brain, amount and strain of virus, protection provided by clothing and other factors.

Pre-Exposure Protection:

Rabies Human Diploid Cell Vaccine (HDCV) is used for pre-exposure protection of those at risk. For primary pre-exposure protection, four 1.0 ml doses of HDVC should be given, one each on days 0, 7, 28, and 365 by deep subcutaneous or intramuscular injection in the deltoid region. Single booster doses of vaccine should be given at 2-3 year intervals for those at continued risk.

Risk groups include:

Laboratory personnel working with rabies
Those likely to be in direct contact with imported animals – at animal quarantine centres; at zoos; at research centres; at ports; authorised carrying agents for imported animals; veterinary and technical staff at the Dept of Agriculture
At-risk workers in enzootic areas abroad (e.g. veterinarians; zoologists; park rangers)
Long-term travellers to rabies endemic areas
Healthcare workers who are likely to come into close contact with a patient with rabies
Bat handlers

Post Exposure Treatment:

Travellers who have been exposed to the possibility of rabies while abroad should seek immediate medical attention. Indications for post exposure treatment, on return to Ireland, are dependent on
1. Rabies risk in country of incident (whether none/low/high) and
2. Immunisation status of individual

Rabies vaccine (HDCV)

May be indicated alone or in combination with human rabies specific immunoglobulin (HRIG) for post-exposure treatment. HRIG is used after exposure to rabies (where the rabies risk in the country of incident is high and where the individual is either unimmunised or incompletely immunised) to give rapid protection until rabies vaccine, which should be given at the same time, becomes effective.

Further information is available from the Department of Public Health – Southern Area.

Checklist for Treatment of Animal Bites/Scratches (Rabid/Suspected Rabid Animal)

Clean and wash wound under running water with soap or detergent
No scrubbing, sutures or wound closure unless unavoidable
Apply either 70% ethanol, tincture of aqueous solution of iodine or povidone iodine
Tetanus prophylaxis and antibiotics if necessary
Post exposure immunisation may be required (Human Rabies Specific Immunoglobulin HRIG and/or vaccination with Rabies Human Diploid Cell Vaccine HDCV as indicated)