RABIES AND ITS PREVENTIVE MANAGEMENT
Dr M Amir Sohail MBBS DCH
Rabies - A killer disease widespread
throughout the world
It is estimated every 15 minutes one person dies
of rabies, & 15,00,000 bites occur per year
Rabies is endemic in most parts of the world & severe in
developing countries of Africa, Asia & South America, where 99% of world’s human rabies
death occur
Rabies free countries
• Antartica• Australia• British Isles• Cyprus• Japan
• New Zealand• Malaysia• Singapore• Taiwan• Lashwadeep,
Andaman & Nicobar Islands
BANGLADESHAlmost 80000 people seek post-exposure vaccination and 2000
people die of rabies
Hospital records indicate about 2000 cases per yearHospital records indicate about 2000 cases per year
Prevalence of Human Rabiesin Bangladesh
Prevalence of Human Rabiesin Bangladesh
(Z. Ahmed, 4th Int. Symp.On Rabies in Asia, Vietnam, March 2001)
(Z. Ahmed, 4th Int. Symp.On Rabies in Asia, Vietnam, March 2001)
Statistics from I.D.H, Dhaka aloneStatistics from I.D.H, Dhaka alone
173173
101101
151151
140140
171171162162
132132120120116116
145145
00
5050
100100
150150
200200
19911991 19921992 19931993 19941994 19951995 19961996 19971997 19981998 19991999 20002000
nn
Statistics from IDHYear1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
Rabies cases116
120
132
162
171
140
145
151
101
173Z. Ahmed, 4th Int. Symp. On Rabies Vietnam 2001
Children often suffer the major burnt of the trauma due to
animal bites and in several studies account for 60% of
animal bite casesTK Ghosh, Journal of APCRI, 1999; pp21-25
Rabies virus• RNA virus; family - Rhabdoviridae, genus -
Lyssavirus• Bullet shaped• Resistant to cold, dryness, decay & is known to
remain infectious for weeks in cadavers• Readily inactivated by soap, common disinfectants
(Dettol, Savlon, tincture iodine, povidone iodine), acid & alkali, UV light, pasteurization, 40% alcohol
ANIMAL RESERVOIR OF VIRUS
• All mammals are capable of being infected with rabies
• Dogs major vector of transmission of rabies (99% of human rabies transmitted by dog, 90% people seek PET line areas where canine rabies is endemic)
• Other predominant reservoir - cats, jackals, wolves, foxes, mongoose, skunks, raccoons, coyotes, bats
RABIES RESERVOIR IN DIFFERENT COUNTRIES
• Dogs• Foxes• Jackals• Raccoons• Mongooses• Skunks• Bats
Major vector of rabies throughout the world, especially Asia, Latin America & Africa
Eastern Europe, Subartic & eastern parts of N. America, Suartic Asia
Asia & Africa
Eastern United States
Yellow mongoose in Asia & Africa, Indian mongoose in the Caribbean Islands
Midwestern United States, Western Canada
Vampire bats from Northern Mexico to Argentina, insectivorous bats in N. America & Europe
TRANMISSION OF VIRUS
• Broken skin
• Intact mucous membrane
• Aerosol
• Organ transplant
INCUBATION PERIOD
• Average - 30 to 90 days, but varies from days to years
• Depends on degree & site of bite, amount of virus inoculated & host factor (age/ immunodeficiency)
Lower extremity is the commonest site of exposure in 65% of cases followed by the
upper extremity in 28.8%, head, neck & face in 5.8%, abdomen in
5.8% and chest in 0.6%AK Dutta, Journal of APCRI, 1999; pp26 30
PATHOGENESIS IN HUMANS
• Inoculation of the virus mainly through a bite from infected animal
• Multiplication, penetration in the local nerve ending & spread by the axonal route towards CNS
• Virus spread within brain
• Migration through peripheral nerves in the secretory & excretory glands
CLINICAL MANIFESTATION
Prodromal symptoms
Headache, restlessness, fever
Itching at the site of bite, even if it is healed
Classical Manifestation
Occurs in 80- 90% of patients
• Hyperexitability
• Hydrophobia
• Aerophobia
• Photophobia
• Respiratory paralysis, cardiac arrest, death in 1-5 days
Paralytic Rabies
Less common
• Gradual ascending paralysis
• Stupor, coma & death in 1-2 weeks
• Hydrophobia usually absent
LABORATORY DIAGNOSIS
Antemortem
• Skin biopsy from nuchal region
• Corneal impression & saliva smear
Postmortem
• Brain - Negri bodies
• Biological test
MANAGEMENT OF RABIES PATIENT
• Isolation• iv rehydration,
prednisolone, mannitol• Sedatives,
antipyretics, analgesics, antihistamines & anticonvulsants
• Medical attendants - self protection
• Avoid contact with saliva, other body fluids
• Pre-exposure vaccinationWash clothes & other objects
• Room to be washed
RABIES IS A 100% FATAL DISEASE
PREVENTION OF RABIES IN MAN
• Post-exposure treatment
• Pre-exposure immunization
POST-EXPOSURE TREATMENT
• Wound treatment
• Anti-rabies immunization
a. Anti-rabies vaccine
b. Anti-rabies sera/immunoglobulin
WOUND TREATMENT
• Clean & flush wound with profuse water & soap
• Application of viricidal agents
• Thorough exploration of wound, debriment & removal of dirt, dead tissue, foreign bodies
• No dressing/bandaging & avoid suturing
• Proper tetanus prophylaxis
• Systemic antibiotics
RABIES VACCINATION
On July 6, 1885, Louis Pasteur saved a young boy - Joseph Meister bitten by a rabid dog by vaccinating him
with an attenuated virus strain obtained by repeated passage from a
rabbit spinal cord
THE PROGRESS OF RABIES VACCINE IN 100 YEARS
Brain of adult animals
Brain of suckling animals
Embryonated eggs
CELL CUTURE
Human diploid cell
Purified Chick Embryo Cell
Purified Vero Cell Vaccine
NERVE TISSUE VACCINE
Prepared from sheep brain
Virus inactivated with phenol
Composition - 5% infected sheep brain suspension
NERVE TISSUE VACCINE
• High drop out rate- large volume
- daily administration over 7-14 days
- sc tissue of anterior abdominal wall
• Poorly immunogenic
• High incidence of local & systemic reactions
• High risk of neurological complication (1:5000 - 1:1100)
TISSUE CULTURE VACCINE
• Human diploid cell
• Purified Chick Embryo Cell
• Purified Vero Cell Vaccine
TISSUE CULTURE VACCINE
• Relatively painless
• Highly immunogenic
• Very well tolerated
• 5 spaced-out injections in the arm instead of daily injection in abdomen
• Small volume
• Hardly any neurological complaint
• Pre-exposure prophylaxis for high risk person
• Can be given at any stage of pregnancy
Since 1983, the WHO has indicated its support for the trend to limit or abandon completely,
where economically and technically possible, the production of encephalogenetic brain tissue
vaccine, and strongly advocates discontinuation of the nerve tissue vaccines in favour of these cell
culture vaccines in both developed and developing countries
WHO Expert Committee on Rabies, 7th Report, WHO Technical Series 709
(“Essen” Scheme)
Post exposure prophylaxis(Essen schedule)
One injection each on day
0, 3, 7, 14, 30 & 90(optional)Day 0 is the day of first injection & Days
3, 7, etc are to be counted from Day 0
Rabies immunization with tissue culture vaccine
• Preferred site - deltoid region
• In infants & children - lateral aspect of thigh
• Avoid gluteal region
• Same dose for age group
• Use reconstituted vaccine in 6-8 hours
Preferred site : Deltoid
In infants and small children:antero-lateral aspect of thethigh
Avoid gluteal region.- inadvertant deposition of vaccine in thick S.C. adipose tissue instead of muscle, retards immune response
Same dose for all age groups
Use reconstituted vaccine in6-8 hours
Preferred site : Deltoid
In infants and small children:antero-lateral aspect of thethigh
Avoid gluteal region.- inadvertant deposition of vaccine in thick S.C. adipose tissue instead of muscle, retards immune response
Same dose for all age groups
Use reconstituted vaccine in6-8 hours
INDICATIONS FOR ANTI_RABIES IMMUNIZATION
• Stray animal & not available for observation
• Animal shows clinical signs of rabies
• Animal is proved positive for rabies by laboratory examination
SITUATIONS WHERE ANTI-RABIES IMMUNIZATION IS NOT REQUIRED
• Drinking of boiled milk of rabid animal
• Biting animal has remained healthy & alive for 10 days (??)
• Mere touching of a rabid animal
• Bite or scratch over clothing without tearing or piercing it & no sign of injury on skin at all
• Unprovoked & accidental bites by rodents, rats, mice, hares, rabbits, birds, bats & insects
With the advent of modern tissue culture vaccines, and in view of the fact that literature
records several instances where the animal has outlived the man it has bitten, there is no
longer a rationale in observing the animal while withholding treatment
AK Dutta, SK Kanwal, Journal of APCRI, 1999; pp5-13
The post exposure vaccination allows for the rapid induction of
antibodies against rabies virus and to be successful, a full course
should be administered as early as possible at an appropriate
site, and without any delay
Unfavourable host factors like alcoholism, malnutrition,
immunosuppressive treatment, certain chronic disease
- two initial intramuscular injection of the vaccination into both deltoid muscle
followed by the classical regimen
The post exposure vaccination allows for rapid induction of
antibodies against rabies virus and to be successful, a full course
should be administered as early as possible at an appropriate
site, and without any delay
Management of patients, who are previously vaccinated within last
5 years and have re-exposure, involves as always, local
treatment of the wound and repeat vaccination with 2 booster
doses on days 0 and 3
RABIES IMMUNOGLOBULIN
• Single or multiple transdermal bites or scratches (especially near the CNS)
• Contamination of mucous membrane with saliva
Post-exposure Prophylaxis of Rabiestogether with RIG (“Essen” Scheme)
Post-exposure Prophylaxis of Rabiestogether with RIG (“Essen” Scheme)
RABIES IMMUNOGLOBULIN
• Equine RIG - 40IU/kg
• Human RIG - 20IU/kg
• Single dose at the same time as the first dose of vaccine• RIG should be infiltrated around & into the wound.
Any remaining RIG should be injected intramuscularly at a distance from the site of vaccine innoculation
Pre-exposure prophylaxis for high risk persons
• Veterinary doctors
• Doctors treating rabies patients
• Laboratory personnel
• Hunters
• Animal attendants
• Postman
One injection each on days :
0 28 56
0 7 21 or 28
or
Pre-exposure prophylaxis
Day 0, 7, 21 or 28
Day 0, 28 & 56
Booster after 1 year & subsequently 1 injection every 3-5 years
Factors adversely influencing response
• Inappropriate local wound treatment• Delayed initiation of PET• Vaccination not in deltoid region• No rabies immunoglobulin• Failure to infiltrate RIG locally• Treatment with RIG 24 hours before vaccination• Host factors• Vaccination not completed
POINTS TO REMEMBER• Rabies is 100% fatal disease• Immediate & early wound treatment to remove traces of saliva is
very important• Suturing of wounds to be avoided• Correct PET, including the use of serum in high risk exposure, is life
saving• There is no contraindication for post-exposure immunization
including pregnancy, lactation, AIDS and other infectious condition• TCV are superior & safe, & is always preferred & injected
intramuscularly into deltoid (thigh in children) & never in gluteal region
In an endemic & enzootic country where every animal bite is considered a risk, immediate
starting of vaccine in low risk exposures and serum and vaccine
in higher risk exposure is strongly recommended
THANK YOU
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