rabies - a public health view
TRANSCRIPT
Rabies A public health view
Dr. S. A. Rizwan, MD
Assistant Professor,
Dept. of Community Medicine,
VMCHRI, Madurai.
Learning objectives
At the end of the lecture
you should be able to
Summarize the burden of
rabies
Describe the
epidemiological features of
rabies
Describe the steps in
management of dog bites
List the steps for control of
rabies
2
Recap
What is zoonosis?
Types/categories of zoonoses
What is epizootic and enzootic?
3
Introduction
Primarily a zoonosis
Carnivores - dogs,
cats, foxes
Nearly 100% fatal
Aka Hydrophobia
4
Burden of disease
Worldwide
Exceptions are there
55,000 deaths/yr
17 mil animal bite cases/yr
20,000 deaths/yr in India
Commonly in children 5-14 yr
5
Worldwide distribution of rabies risk
6
EPIDEMIOLOGICAL FEATURES
7
Agent
Family Rhabdoviridae
Lyssavirus type 1
Bullet shaped, RNA
Street and fixed virus
8
Source of infection
Saliva of rabid
animal
Virus in saliva 4
days prior to
symptoms
Dogs – 99%, rarely
bats, wild animals
9
Host
All warm blooded
animals
Man – dead end
High risk – lab staff,
veterinarians,
hunters
10
Modes of transmission
Contact of saliva with broken skin and mucosa
Bite or scratch
Aerosol in bat rabies
Transplantation
Man to man – not yet
Ingestion of unpasteurized milk
Meat unconfirmed
11
Incubation period
Highly variable
Days to months to years
Commonly 1-3 mo
7 days to many years
Depends on severity
Shorter in bites on head, upper limbs, wild animal bites
12
Pathogenesis
From bite site ~>
local tissue ~>
peripheral nerves ~>
CNS
CNS ~> nerves ~>
muscle, adrenals,
skin and SALIVA
13
Clinical features of rabies
Prodromal – fever, headache, tingling at bite site, 3-4 days (only specific)
Widespread excitation sensory, motor, sympathetic, mental systems
Aerophobia, hydrophobia
14
Clinical features of rabies
Hydrophobia is
pathognomic
Duration of illness is
2-3 days or 5-6 days
Abrupt death or
coma
15
Clinical features of rabies
16
Diagnosis
Mainly clinical
h/o dog bite
Immunofluorescence
of skin biopsy
CSF analysis
17
Treatment
Non specific
Isolation
Quiet room
Sedatives, painkillers
Muscle relaxants
Hydration
Respiratory and cardiac support
Barrier nursing
18
PREVENTION AND CONTROL
OF RABIES
19
Prevention of human rabies
Vaccination
Post-exposure
Pre-exposure
Previously vaccinated
20
Post-exposure treatment
Local treatment
Cleaning
Chemicals
Suturing
Antibiotics/ TT
Vaccination
Type of vaccine
Various regimens
Guidelines/
categories
Immunoglobulin
21
Harmful traditional practices
22
Categories of animal exposure
Category Description Severity Action
1
• Touching
• Feeding
• Licks (intact skin)None None
2
• Minor scratches
• Minor abrasions
(no bleeding)Minor
Local treatment
Vaccine
3
• Transdermal bite (bleeding)
• Licks (broken skin)
• Licks/saliva (mucous
membrane)
• Bats
Severe
Local treatment
Vaccine
Immunoglobulin
23
Categories of animal exposure
High risk bites Biting mammal known
reservoir
Animal looks sick
Unprovoked bites
Animal not vaccinated
Animal not identified
Wild animals
24
Post-exposure treatment
Vaccination
Type of vaccine
CCV
EEV
Various regimens
Immunoglobulin
Discontinuation of
schedule
25
Regimens of vaccination
Intramuscular
Essen regimen
Zareb regimen
Intradermal
Mod. Thai RC
26
My experience
27
Common regimens – unvaccinated
Intramuscular Intradermal
5 doses, 5 visits, 5
vials
Single site (deltoid)
0.5 ml
On days 0, 3, 7, 14,
28
4 doses, 4 visits, <2
vials
Two sites (both
deltoids)
0.1 ml per site
On days 0, 3, 7, 28
28
Common regimens – previously vaccinated
Intramuscular Intradermal
2 doses
Single site (deltoid)
0.5 ml
On days 0, 3
2 doses, 2 visits
Single site
0.1 ml
On days 0, 3
29
Immunoglobulin
Human Ig (20 IU/kg), Equine (40 IU/kg)
Around the wounds as much as possible
Remaining at a distant site
Risk of anaphylaxis
30
Pre-exposure prophylaxis
For people at high
risk
Animal doctors
Lab staff
Travellers
Animal handlers
Intramuscular or
intradermal
3 doses
On days 0, 7 & 21 (or
28)
Antibody titre every 6
mo and repeat dose if
it is <0.5 IU/ml
31
AEFI with Rabies vaccine
32
Safe and well
tolerated
Erythema, pain,
swelling
Fever, headache,
dizziness, GI sympt.
CI – previous
reaction to
components of
vaccine
No CI as such
Patients on
chloroquine sh.
receive IM vaccine*Nervous tissue vaccine are banned in India since 2004
Rabies in dogs
>90% of human
rabies are due to
dog bites
Dog control is the
key to rabies control
in India
33
Rabies in dogs
Incubation period 3-
8 weeks
Furious rabies: mad
dog syndrome
Dumb rabies
Death within a week
Lab diagnosis:
fluorescent antibody
test
microscopic exam of
brain
mouse inoculation
corneal test
34
Immunization of dogs
All dogs sh be
vaccinated at 3-4 mo
and then at regular
intervals
Inactivated and live
vaccines
Oral vaccines – for
foxes placed as baits,
Germany, Canada,
Switzerland
Urban rabies
Dog control (eliminate/
vaccinate)
Registration/ licensing
Restraint in public
places
Killing rabid dogs
Imported dogs
quarantine
Health education
35
Review 1
Rabies is
a) Direct zoonoses
b) Cyclo-zoonoses
c) Meta-zoonoses
d) Sapro-zoonoses
36
Review 2
All are true about rabies except:
a) It is a DNA virus
b) Vaccine virus has fixed incubation period
c) Incubation period depends upon site of bite
d) All bites on fingers with laceration are class III
injuries
37
Review 3
For the treatment of case of class III dog bite, all
of the following are correct except:
a) Give Immunoglobulins for passive immunity
b) Give ARV
c) Immediately stitch wound under antibiotic
coverage
d) Immediately wash wound with soap and water
38
Review 4
A rabies free area is one with no indigenously
acquired cases
a) In man for 2 years
b) In animals for 1 year
c) In man or animal for 2 years
d) In man or animal for 1 year
39
Review 5
Rabies free country is:
a) Taiwan
b) Russia
c) Canada
d) France
40
Review 6
Bite of which of the following animals do
not result in human rabies?
a) Dog
b) Mouse
c) Horse
d) Cat
41
APCRI
42
