Rabies: 100% Fatal but 100% Preventable Disease

Rabies
•Dr Bharat Vaishnav
•Senior Resident

Contents
Introduction
Problem statement
Epidemiological
determinants
Rabies in Man
Prevention of Rabies

What is Rabies?
• Rabies is an infectious viral disease of CNS.
• Also known as “Hydrophobia”
• Caused by Lyssavirus type 1.
• About 99% of human cases are caused by dog bite.
• Highly fatal disease.
• Zoonotic disease of warm blooded animals
• It is 100 % fatal but 100% preventable

Problem Statement
Death
• In Africa : 40,000/year (About 4/lakh population at risk)
• In India : 20,000/year (About 2/lakh population at risk)
• Endemic in India (Lakshadweep and Andaman & Nicobar Islands)
• Geographical distribution
• Rabies is enzootic and epizootic disease.
• A “Rabies-free area” : No cases of in man or animal species for 2
years

Agent factor
• By lyssavirus type-1
• Bullet shaped SS RNA virus
• Family Rhabdoviridae
• Two antigens: Glycoprotein (G protein) and internal nucleoprotein
• Virus with long variable incubation period called “street virus”
• Virus with constant incubation period called “fixed virus”

Source of infection:
• Saliva of a rabid animal from 5 days before onset of clinical symptoms till death
of the animal.
Host factors:
• Warm blooded animals
• Dead- end infection
• Occupational exposure

Animals Transmitting Rabies:
Domestic
 Dogs & Cats
Wild
 Foxes & Jackals
 Monkeys
 Mongoose
 Bears
 Bats
Peridomestic
 Cows & Buffaloes
 Sheep & Goats
 Pigs
 Donkeys
 Horses
 Camels

Modes of Transmission
• Bites from infected animals or licks on Broken Skin or Mucous Membrane,
Scratches
• Rarely by inhalation or via transplantation
Incubation Period (In Man):
• 1-3 months (vary from 7 days to many years)
• Depend on the site & severity of the bite, number of wounds, amount of
virus injected, species, protection provided by clothing and treatment
taken.

Clinical Manifestation:
Furious Type ( 80%)
Prodromal symptoms
Tingling/numbness at the
bite site
Aerophobia, phonophobia,
photophobia, Hydrophobia
Death (cardio-respiratory
failure)
Paralytic Type ( 20%)
Tingling / numbness at bite
site
Non specific symptoms
Ascending Paralysis
Coma
Death (cardio - respiratory
failure)

• Mental changes- fear of death, anger, irritability and depression
• Hydrophobia
• Convulsions which leads to Death
• Duration of illness: 2- 3 days or may prolonged to 6 days

Diagnosis:
• Clinical diagnosis
• Antigen detection using Immunofluorescence of skin biopsy
• Virus isolation from saliva
Treatment:
• Isolation
• Sedatives and morphine- relieve anxiety and pain
• Hydration, diuresis and intensive therapy in the form of cardiac and respiratory
support.
• Universal precautions – Pre exposure prophylaxis for medical team, family
caregivers

Risk increased with
a. If the animal shows signs of rabies or dies within 10
days of observation.
b. If the biting animal cannot be traced or identified.
c. Unprovoked bites.
d. Laboratory tests of the brain of the biting animal are
positive for rabies.
e. All bites by wild animals.

Prevention
A. Post-exposure prophylaxis.
B. Pre-exposure prophylaxis.
C. Post-exposure treatment of persons who have been vaccinated previously.

Categories of contact and recommended post-
exposure prophylaxis (PEP)
Categories of contact with suspect rabid
animal
Post - exposure prophylaxis measures
Category I – touching or feeding animals, licks
on intact skin
Category II – nibbling of uncovered skin, minor
scratches or abrasions without bleeding
Immediate vaccination and local treatment of
the wound
Category III – single or multiple transdermal
bites or scratches, licks on broken skin ;
contamination of mucous membrane with
saliva from licks, contacts with bats
Immediate vaccination and administration of
rabies immunoglobulin; local treatment of the
wound

Local treatment of Wounds
1. Cleansing
2. Chemical
treatment
3. Suturing
4. Antibiotics
and anti-
treatment
measures
With soap under
running tap for at
least 15 minutes
Used virucidal agent
(alcohol, tincture,
0.015 iodine)
Bite wounds not be immediately
sutured to prevent the spread of
virus into deeper tissues. It should be
done 24-48 hrs later

Types of Rabies vaccine
1.Nervous tissue vaccines (NTV)
a. derived from adult animal nervous tissue (sheep).
b. derived from suckling mouse brain
2.Duck embryo vaccine (DEV)
3. Cell-culture vaccines
c. Human diploid cell (HDC) vaccine
d. "second generation" tissue culture (animal cell)
vaccines

A) Intramuscular Essen Regimen :
Dose : 0.5 ml, 5 doses
Site : Deltoid or anterolateral
aspect of thigh (<2 years)

B) Updated Thai Red Cross (TRC) regimen
• Dose : 0.1 ml / ID site
• Site : Upper arm over each deltoid
• Schedule : 2- 2- 2- 0- 2
Day 0 3 7 14 28
Sites x2 x2 x2 x0 x2

Which regimen to be used?
ID regimen should be used if the following two conditions are met:
1. Healthcare facility large & large number of patients come within 6
hours so vial can be fruitfully utilized.
2. Trained healthcare personnel

Passive Immunization: RIG & RMAb
 All category III exposures, irrespective of status of biting
animal.
 Administer even when treatment is delayed (but not after
7 days of start of vaccination)
 In re-exposure cases (completed post exposure
prophylaxis previously) RIGs are not indicated.

RIG..
 Human Rabies
Immunoglobulin (HRIG) : 20 IU/kg body wt
(Max of 1500 IU)
 Equine Rabies
Immunoglobulin (ERIG) : 40 IU/kg body wt
(Max of 3000 IU)
MAB:
Rabishield 3.33IU/kg

RIG Infiltration:
Positive test reaction: Induration >10mm
If skin test is positive – HRIG is preferred
If ERIG has to be administered then pre treat with
Adrenaline / Epinephrine and with Antihistamine
before administering full dose.

RIG is most effective when administered locally and
early.
Infiltrate as much as possible into and around the
wounds
If RIG is insufficient to infiltrate all the wounds,
dilute it with sterile normal saline

In India HDCV, PCEC and PDEV are available.

Pre-Exposure Prophylaxis (PrEP)
• High risk of exposure : Veterinarians, wildlife officers etc.
• Not in acute illeness
• IM route : one injection 0 and 7 day (o.5 ml)
• ID Route : two injection 0 and 7 day (0.1 ml)

Previously vaccinated individuals:
• If CCV then alleast 2 doses (ID/IM)
• IM regimen: one injection (0 and 3rd day)
• ID regimen: two injection (0 and 3rd day)

Repeated Exposure:
• Within 3 months: No PEP required
• After 3 months: Two doses 0 and 3

Rabies: 100% Fatal but 100% Preventable Disease

Rabies: 100% Fatal but 100% Preventable Disease

More Related Content

Similar to Rabies: 100% Fatal but 100% Preventable Disease

Recently uploaded

Rabies: 100% Fatal but 100% Preventable Disease

Editor's Notes