RABIESRABIES
EPIDEMIOLOGY &
PREVENTION
DR. SYED SANOWAR ALI
ASSOCIATE PROFSSOR
CHS, UMDC
EPIDEMIOLOGYEPIDEMIOLOGY
The study of the The study of the DISTRIBUTION and and
DETERMINANTS of health-related of health-related
states or events in specified population states or events in specified population
and application of this study to the and application of this study to the
control of health problemscontrol of health problems
1. DISTRIBUTION OF
DISEASE
A. When (time)
B. Who (person)
C. Where (place)
Descriptive Epidemiology Epidemiology
2. DETERMINANTS OF 2. DETERMINANTS OF
DISEASEDISEASE
A. Why
B. How
Analytical Epidemiology
DEFINITION
Human Rabies is a viral infection of the
CNS usually transmitted by contamination
of a wound with saliva from a rabid animal
and is virtually
100%fatal
once symptoms develop.
•Rabies is a zoonotic
disease (a disease that is
transmitted to humans from
animals) that is caused by a
virus.
GEOGRAPHIC
DISTRIBUTION
* Rabies Free Area in which no case has
occurred in human or any animal species for 2
years.
* Rabies is a major public problem in areas in which
Dogs are uncontrolled.
* Rabies is present on all continents with the
exception of Antarctica, but more than 95% of
human deaths occur in Asia and Africa. Once
symptoms of the disease develop, rabies is nearly
always fatal.
Rabies Human DeathsRabies Human Deaths
Annual human deaths worldwide are
approximately 55,000; every 15 minutes a
patient dies of rabies.
In the United States, there has been a mean of
3 deaths per year since 1990.
PAKISTANPAKISTAN
•In Pakistan 2000 - 5000 cases / yr.
•Rabies is endemic in Pakistan.
•Human rabies is not a notifiable
disease in Pakistan
•The main vector for rabies in Pakistan
is the domestic dog
KEY FACTS
•Rabies is a vaccine-preventable viral disease which
occurs in more than 150 countries and territories.
•Infection causes tens of thousands of deaths every
year, mostly in Asia and Africa.
•40% of people who are bitten by suspect rabid
animals are children under 15 years of age.
•Dogs are the source of the vast majority of human
rabies deaths.
•Immediate wound cleansing and immunization
within a few hours after contact with a suspect
rabid animal can prevent the onset of rabies and
death.
•Every year, more than 15 million people
worldwide receive a post-exposure vaccination to
prevent the disease – this is estimated to prevent
hundreds of thousands of rabies deaths annually.
KEY FACTS
INCUBATION PERIODINCUBATION PERIOD
Highly variable
usually 20 – 180 days,
peak at 30 – 60 days
MODE OF MODE OF
TRANSMISSIONTRANSMISSION
A- ANIMAL BITES : through rabid dog
bites and the saliva of the biting animal
contain the virus.
B- LICKS : licks on abraded skin and mucosa
transmit the disease.
Who is most at risk?
•Dog rabies potentially threatens over 3 billion
people in Asia and Africa.
•Poor people are at a higher risk (cost = US$ 49 in
Asia)
•Although all age groups are susceptible, rabies is
most common in children aged under 15 & majority
are male.
Rabies attacks the Rabies attacks the
Central Nervous Central Nervous
SystemSystem
Watch as the rabies virus
from an exposure on the
leg spreads up the spinal
cord to the brain and
throughout the rest of the
body.
Rabies virus entering
the body.
Headache, fever, sore throat
Nervousness, confusion
Pain or tingling at the site of the bite
Hallucinations
–Seeing things that are not really there
Hydrophobia
–“Fear of water" due to spasms in the throat
Paralysis
–Unable to move parts of the body
Coma and death
Signs / SymptomsSigns / Symptoms
Clinical DiagnosisClinical Diagnosis
PREVENTION PREVENTION
OF OF
HUMAN RABIESHUMAN RABIES
POST-EXPOSURE
PRE-EXPOSURE
PREVENTION PREVENTION
Pre-exposure
immunization in people
•Travellers spending a lot of time outdoors, especially in rural areas.
•People in certain high-risk occupations such as laboratory workers
dealing with live rabies virus and other rabies-related viruses.
•People involved in any activities that might bring them
professionally or otherwise into direct contact with Dogs.
•Children.
•Living in or visiting high risk areas.
PRE- EXPOSURE PRE- EXPOSURE
PROPHYLAXSISPROPHYLAXSIS
1. Vaccination of domestic dogs1. Vaccination of domestic dogs
2. Elimination of stray dogs2. Elimination of stray dogs
3. Eliminating rabies in dogs3. Eliminating rabies in dogs
4. Active Immunization Doses: 4. Active Immunization Doses:
Day 0,7 and 28 (100% response) Day 0,7 and 28 (100% response)
WHO Recommended Pre-exposure
3-dose series intramuscular
Pre-exposure
Exposure: No Rabies immunoglobulin
needed
day 0 7 21 or 28
3
Vaccine should never be administered
in the gluteal region.
Was There An Exposure?Was There An Exposure?
A bite (penetration of the skin by
teeth) from a known or suspect rabid animal
Scratches, abrasions, open wounds (bleeding within
24 hrs), or mucous membranes (eyes) contaminated
with saliva or other potentially infectious material
from a known or suspect rabid animal
Other contact - such as petting an animal or contact
with urine, feces - does NOT constitute an exposure
10 Day Confinement 10 Day Confinement
& Observation Period& Observation Period
Clinical course usually less than 7 days - animal
dead before end of 10 days
Rabies Vaccination Status of Rabies Vaccination Status of
AnimalAnimal
Lower risk if animal has been regularly
vaccinated
But NO vaccine is 100% effective
Put as much weight on animal
behavior & health status
PREVENTION OF HUMAN PREVENTION OF HUMAN
RABIESRABIES
POST- EXPOSURE PROPHYLAXSIS
A) if the animal shows signs of rabies orA) if the animal shows signs of rabies or
dies within 10 days of observation. dies within 10 days of observation.
B) If the biting animal can not be tracedB) If the biting animal can not be traced
or or identified .identified .
In general if a biting dog does not die
with in 10 days, Rabies is unlikely.
RABID DOG
PEP
Post-exposure prophylaxis (PEP)
•Local treatment of the wound.
•Initiated as soon as possible after exposure; a
course of potent and effective rabies vaccine that
meets WHO recommendations.
•Administration of rabies immunoglobulin, if
indicated.
A) POST EXPOSURE
PROPHYLAXSIS
LOCAL TREATMENT OF WOUND
A. Mechanical removal By
1. Soap and water :
using copious amounts of solution
2. Virucidal solution :
1% povidone-Iodine or 70% alcohol
B. Suturing : not done
C. Anti biotics & Antitetanus measures.
VACCINE TYPESVACCINE TYPES
NERVOUS TISSUE VACCINE (NTV)
a- Antigenicity was poor
b- Multiple Injections were required.
c- Post vaccination Encephalitis was frequent problem.
This vaccines are still in use in
many
places in the world .
Human diploid cells Human diploid cells
vaccinevaccine
(HDCV)(HDCV)
1.1.ACTIVE ACTIVE
IMMUNIZATIONIMMUNIZATION
Human Diploid Cells VACCINEHuman Diploid Cells VACCINE
(HDCV)(HDCV)
A. No. of doses : 05A. No. of doses : 05
Day 0, 3, 7, 14 and 28 Day 0, 3, 7, 14 and 28
B. Quantity : B. Quantity : 1 ml1 ml
C. Route : Intra-muscular (Arms)C. Route : Intra-muscular (Arms)
Standard intramuscular regimen. One
dose into deltoid on each of days:
Essential intramuscular Regimen
WHO Recommended PEP
Schedule
5 vials
5 visits
day 0 3 7 14 28
Rabies immunoglobulin
2. PASSIVE IMMUNIZATION2. PASSIVE IMMUNIZATION
IMMUNE GLOBULIN IMMUNE GLOBULIN
Human rabies immune globulin
A. No. of doses : 01 as soon as possible
B. Quantity : 20 IU / Kg
C. Route : Half dose Intra-muscular (Arms)
Half dose subcutaneously
around the bite site
If Person having weight 60 KgIf Person having weight 60 Kg
Human rabies immune globulinHuman rabies immune globulin
20 IU / Kg20 IU / Kg
20 x 60 = 1200 IU20 x 60 = 1200 IU
600 IU I/M & 600 IU S/C around the 600 IU I/M & 600 IU S/C around the
bite site.bite site.
EQUINE RABIES IMMUNE GLOBULINEQUINE RABIES IMMUNE GLOBULIN
A. No. of doses : 01 as soon as possibleA. No. of doses : 01 as soon as possible
B. Quantity : 40 IU / KgB. Quantity : 40 IU / Kg
C. Route : Half dose Intra-muscular (Arms)C. Route : Half dose Intra-muscular (Arms)
Half dose subcutaneously Half dose subcutaneously
around the bite site around the bite site
after test dose after test dose
Anaphylaxis is a rare. Anaphylaxis is a rare.
If Person having weight 60 KgIf Person having weight 60 Kg
EquineEquine rabies immune globulin rabies immune globulin
40 IU / Kg40 IU / Kg
40 x 60 = 2400 IU40 x 60 = 2400 IU
1200 IU I/M & 1200 IU S/C around the 1200 IU I/M & 1200 IU S/C around the
bite site.bite site.
HYDROPHOBIA ?HYDROPHOBIA ?
Destruction of brain stem Destruction of brain stem
neurons inhibitory to the neurons inhibitory to the
neurons of the nucleus neurons of the nucleus
ambiguous which control ambiguous which control
Inspiration.Inspiration.
Why Hydrophobia does Why Hydrophobia does
not occur in other not occur in other
diseases ?diseases ?
Only Rabies combines Only Rabies combines
brain stem Encephalitis brain stem Encephalitis
with an intact Cortex and with an intact Cortex and
maintenance of maintenance of
consciousnessconsciousness