Understanding Rabies: A Comprehensive Overview

‘Veterinary Epidemiology
& Zoonoses’
VPH-321
(Credit Hours-2+1)
undefined
Rabies/Lyssa/ Hdrophobia
Introduction
It is an acute fatal disease in man & other warm blooded animals
 
Characterized by:
Abnormal behavior,
Nervous disturbances such as motor nerve irritability,
Mania,
An attacking complex,
Inability to swallow,
Excessive salivation,
Impairment of consciousness,
Progressive ascending paralysis &
Death due to respiratory paralysis
Rabies claims nearly 
55000 human deaths
, worldwide
Mostly children
Presently the efforts at rabies control have enabled a marginal
reduction of rabies deaths from 30,000 to 20,000 in India
annually
Introduction
Lyssa virus
Family: 
Rhabdoviridae
RNA virus,
Bullet shaped (180 nm X 75 nm in dia.)
Highly fragile viruses
susceptible to standard disinfectants
Sunlight & moderate heat destroy the virus
There are 25 viruses in this genus, of which closely related
rabies viruses are called “
Classical rabies viruses
 
Etiology
Serotypes of rabies viruses are
:
1.
Lagos bat virus,
2.
Mokola virus,
3.
Duvenhage virus,
4.
European bat lyssa virus I (EBL I),
5.
European bat lyssa virus II (EBL II) &
6.
Australian bat lyssa virus
Etiology
 
Based on antigenicity, the virus is classified as fixed or street
rabies virus
 
Etiology
Worldwide distribution
 
Primary reservoirs:
Foxes, bats, raccoons, skunks, dogs, cats &  cattle
 
Transmission:
From fresh saliva via bite, scratch or abrasion by an rabid animal
Rabid dogs shed virus in saliva 5-7 days before showing signs
Cat does so for only 3 days before signs
Contamination of skin wounds by fresh saliva from infected animals
also a source of infection
Source & Transmission
Central nervous system disturbances
The clinical course especially (in dogs)
 
Can be divided into 3 phases:
The prodromal form
The excitative form
The paralytic form
 
Prodromal period: 1-3 days, animals either show signs of
paralysis or become vicious
 
Disease in animals
1.
In dogs
Furious form
 (changes in behaviour & stage of
excitement)
Tendency to bite either inanimate/animate objects
till death
Travel to long distance
Shows imaginary catching stance
Attempt to lick water but unable to drink water due
to the paralysis of pharyngeal & laryngeal muscles
Drooling of saliva
Photophobia
Changes in barking due to paralysis of vocal chords
Finally, dropped jaw & tongue will protrude & head
will drop down
Disease in animals
 
1.
In dogs
Dump form or paralytic form:
Isolated themselves in dark places
Paralysis of lower jaw (dropped jaw ), tongue, larynx &
hindquarters
Not capable to bite
 
 
 
 
2. In cats
Furious form is more common
 
Disease in animals
 
3. In cattle
Furious form is more common:
Violently attack other animals or
Attack to inanimate objects,
loud bellowing,
Incoordination of gait,
Excessive salivation,
Behavioral changes,
Muzzle tremor,
Aggression,
Sexual excitement,
Hyper excitability &
Pharyngeal paralysis
 
Disease in animals
Paralytic form:
Knuckling of hind fetlock,
Sagging & swaying of hind
quarter while walking,
Deviation of tail to one
side,
Drooling of saliva &
yawing movement
In sheep
:
Hyperexcitability,
salivation,
vocalization,
recumbency,
vigorous wool plucking,
excessive bleating does not occur but continuous bleating is
common & starring of eyes & twitching of lips
 
Disease in animals
In horse
:
Muscle tremors are frequent & common,
pharyngeal paralysis,
ataxia & lethargy,
Sudden onset of lameness in one limb followed by
recumbency & violent head tossing
 
In pigs
:
Twitching of nose,
excessive salivation,
chronic convulsion,
rapid chewing movement & may walk backward
Disease in animals
The incubation period: few months (usually 30 to 60 days),
 
Depending on
The distance of bite,
Severity of bite,
Amount of virus inoculated
Aggressive status of the rabid animal
 
Infection reaches to CNS symptoms begin to show
The infection is effectively untreatable & usually fatal within days
Death almost invariably results 
2-10 days 
after first symptoms
Drinking cause extremely painful laryngeal spasm
Patient refuses to drink (
hydrophobia-fear of water
)
Muscle spasm, laryngospasm & extreme excitability are present
Disease in human
Convulsions occur
Thick tenacious saliva
Increased lacrimation,
Frequent micturition
 Increased perspiration.
The initial symptoms of rabies are often mild fever & pain or
paresthesia at the wound site
 
Furious rabies is rapidly fatal: 
hydrophobia or aerophobia, phobia
towards sound, hyperactivity and fluctuating consciousness
 
Flaccid paralysis 
ascending with pain in the affected muscles & mild
sensory disturbances will precede death from respiratory paralysis
Disease in human
Classification of exposure based
involvement of risk
Class I-
Slight or negligible risk
Licks on healthy/
unbroken skin
Scratches without oozing
of blood
Class II-
Definite but moderate risk
Consumption of unboiled milk from
suspected animals
Licks on fresh cuts
Scratches with oozing of blood
All bites except on head, neck, face,
palm and fingers
Minor wounds less than five in
number
Class III-
Severe/ grave risk
Licks on mucosa
Bites on head, Neck, face,
      palm & fingers
Lacerated wounds on any
       part of the body
Bites from wild animals
1.
Sign & symptoms
 
2.
Fluorescent antibody test (FAT)
Corneal impression smear, as well as brain
Highly specific & rapid test (99.9%)
Detects different strains using monoclonal antibody
The identifiable strains correlate well with species & geographic
distributions observed
 
3. Identification of Negribodies 
(intracytoplasmic inclusion bodies) in
the brain impression smear by Seller's staining technique
 
4. Virus isolation
 
from body fluid or brain tissue
 
5. Molecular techniques
Diagnosis
Negri bodies
Post-exposure care to prevent rabies includes:
Washing & scrubbing the wound with phenolic soap and/or plenty
of running tape water
Application of antiseptics
Avoiding bandaging or suturing of wound, or point of contact
Administering anti-rabies immunizations as soon as possible
Anti-rabies vaccine should be given for category II & III exposures
(follow post exposure schedule)
Treatment
Post exposure schedule
If the animal is not previously immunized,
 
Post exposure vaccination on
0-day (the day starts within 24 hours after bite), 3
rd
, 7
th
, 14
th
, 28
th
 &
if necessary, on 90
th
 day (Essen's schedule)
 
If the animal is immunized annually
 0 day, 3
rd
 and 7
th
 day, put the
animal under observation for 10 days
If the animal dies, should follow the full regimen (5 doses)
Treatment
Pre-exposure schedule
 
Type of vaccine:
Inactivated (from cell culture or embryonated egg vaccine)
Number of doses:
Three: 0, 7
th
 & 21
st
 or 28
th
 day given by IM or ID route (vaccine should
not be given in the gluteal region)
Booster:
 After one year then every five years
Contraindication:
Severe reaction to previous dose
Adverse reactions:
Mild local or systemic reactions; rare neuroparalytic reactions
reported
Special precautions:
Do not use animal-brain-derived vaccines
Vaccination
Postexposure immunization:
Upto 50% of human rabies immune globulin is infiltrated around the
wound; the rest is administered IM
(ERIG or HRIG: anti-rabies antibody)
Human Diploid Cell Vaccine (HDCV)
:
5 injections IM at days 0, 3, 7, 14, & 28
 
Vaccination of domestic animals
Enforced animal control measures 
(Animal Birth Control and Anti-
rabies vaccination programme: ABC-AR)
Controlling stray dog population
Proper immunization of household dogs 
(ABC-AR programme)
Vaccination 
of high risk personnel
Awareness programme among public
Prevention
Slide Note
Embed
Share

Rabies is an acute fatal disease affecting humans and warm-blooded animals, characterized by abnormal behavior, nervous disturbances, excessive salivation, and respiratory paralysis. It claims around 55,000 human lives globally, with efforts in rabies control showing marginal success. The etiology of rabies involves the Lyssa virus, a highly fragile RNA virus belonging to the Rhabdoviridae family. Different serotypes and classifications of the virus exist, with primary reservoirs being foxes, bats, and other animals. Transmission occurs through fresh saliva from rabid animals via bites, scratches, or abrasions.


Uploaded on Jul 23, 2024 | 0 Views


Download Presentation

Please find below an Image/Link to download the presentation.

The content on the website is provided AS IS for your information and personal use only. It may not be sold, licensed, or shared on other websites without obtaining consent from the author. Download presentation by click this link. If you encounter any issues during the download, it is possible that the publisher has removed the file from their server.

E N D

Presentation Transcript


  1. Veterinary Epidemiology & Zoonoses VPH-321 (Credit Hours-2+1)

  2. Rabies/Lyssa/ Hdrophobia

  3. Introduction It is an acute fatal disease in man & other warm blooded animals Characterized by: Abnormal behavior, Nervous disturbances such as motor nerve irritability, Mania, An attacking complex, Inability to swallow, Excessive salivation, Impairment of consciousness, Progressive ascending paralysis & Death due to respiratory paralysis

  4. Introduction Rabies claims nearly 55000 human deaths, worldwide Mostly children Presently the efforts at rabies control have enabled a marginal reduction of rabies deaths from 30,000 to 20,000 in India annually

  5. Etiology Lyssa virus Family: Rhabdoviridae RNA virus, Bullet shaped (180 nm X 75 nm in dia.) Highly fragile viruses susceptible to standard disinfectants Sunlight & moderate heat destroy the virus There are 25 viruses in this genus, of which closely related rabies viruses are called Classical rabies viruses

  6. Etiology Serotypes of rabies viruses are: 1. Lagos bat virus, 2. Mokola virus, 3. Duvenhage virus, 4. European bat lyssa virus I (EBL I), 5. European bat lyssa virus II (EBL II) & 6. Australian bat lyssa virus

  7. Etiology Based on antigenicity, the virus is classified as fixed or street rabies virus Sl. No. Fixed rabies virus Street rabies virus 1. The intradermal route in rabbits virus is passaged by serial It is from naturally occurring infection 2. Incubation period is fixed and shorter (6-7 days) Incubation period is variable (11-47 days) 3. It does not produce Negri bodies It (Intracytoplasmic inclusion bodies) produces Negri bodies 4. No shedding of virus in the saliva Shedding of virus in the saliva 5. The virus is not virulent and self- limiting. Used for vaccine production. The virus is virulent and not self- limiting. Pathogenic to warm blooded animals.

  8. Source & Transmission Worldwide distribution Primary reservoirs: Foxes, bats, raccoons, skunks, dogs, cats & cattle Transmission: From fresh saliva via bite, scratch or abrasion by an rabid animal Rabid dogs shed virus in saliva 5-7 days before showing signs Cat does so for only 3 days before signs Contamination of skin wounds by fresh saliva from infected animals also a source of infection

  9. Disease in animals Central nervous system disturbances The clinical course especially (in dogs) Can be divided into 3 phases: The prodromal form The excitative form The paralytic form Prodromal period: 1-3 days, animals either show signs of paralysis or become vicious

  10. Disease in animals 1. Furious form (changes in behaviour & stage of excitement) Tendency to bite either inanimate/animate objects till death Travel to long distance Shows imaginary catching stance Attempt to lick water but unable to drink water due to the paralysis of pharyngeal& laryngeal muscles Drooling of saliva Photophobia Changes in barking due to paralysis of vocal chords Finally, dropped jaw & tongue will protrude & head will drop down In dogs

  11. Disease in animals 1. In dogs Dump form or paralytic form: Isolated themselves in dark places Paralysis of lower jaw (dropped jaw ), tongue, larynx & hindquarters Not capable to bite 2. In cats Furious form is more common

  12. Disease in animals 3. In cattle Furious form is more common: Violently attack other animals or Attack to inanimate objects, loud bellowing, Incoordination of gait, Excessive salivation, Behavioral changes, Muzzle tremor, Aggression, Sexual excitement, Hyper excitability & Pharyngeal paralysis Paralytic form: Knuckling of hind fetlock, Sagging & swaying of hind quarter while walking, Deviation of tail to one side, Drooling of saliva & yawing movement

  13. Disease in animals In sheep: Hyperexcitability, salivation, vocalization, recumbency, vigorous wool plucking, excessive bleating does not occur but continuous bleating is common & starring of eyes & twitching of lips

  14. Disease in animals In horse: Muscle tremors are frequent & common, pharyngeal paralysis, ataxia & lethargy, Sudden onset of lameness in one limb followed by recumbency & violent head tossing In pigs: Twitching of nose, excessive salivation, chronic convulsion, rapid chewing movement & may walk backward

  15. Disease in human The incubation period: few months (usually 30 to 60 days), Depending on The distance of bite, Severity of bite, Amount of virus inoculated Aggressive status of the rabid animal Infection reaches to CNS symptoms begin to show The infection is effectively untreatable & usually fatal within days Death almost invariably results 2-10 days after first symptoms Drinking cause extremely painful laryngeal spasm Patient refuses to drink (hydrophobia-fear of water) Muscle spasm, laryngospasm & extreme excitability are present

  16. Disease in human Convulsions occur Thick tenacious saliva Increased lacrimation, Frequent micturition Increased perspiration. The initial symptoms of rabies are often mild fever & pain or paresthesia at the wound site Furious rabies is rapidly fatal: hydrophobia or aerophobia, phobia towards sound, hyperactivity and fluctuating consciousness Flaccid paralysis ascending with pain in the affected muscles & mild sensory disturbances will precede death from respiratory paralysis

  17. Classification of exposure based involvement of risk Class I- Slight or negligible risk Licks unbroken skin Scratches without oozing of blood on healthy/ Class II- Definite but moderate risk Consumption of unboiled milk from suspected animals Licks on fresh cuts Scratches with oozing of blood All bites except on head, neck, face, palm and fingers Minor wounds less than five in number Class III- Severe/ grave risk Licks on mucosa Bites on head, Neck, face, palm & fingers Lacerated wounds on any part of the body Bites from wild animals

  18. Diagnosis 1. Sign & symptoms 2. Fluorescent antibody test (FAT) Corneal impression smear, as well as brain Highly specific & rapid test (99.9%) Detects different strains using monoclonal antibody The identifiable strains correlate well with species & geographic distributions observed 3. Identification of Negribodies (intracytoplasmic inclusion bodies) in the brain impression smear by Seller's staining technique 4. Virus isolation from body fluid or brain tissue Negri bodies 5. Molecular techniques

  19. Treatment Post-exposure care to prevent rabies includes: Washing & scrubbing the wound with phenolic soap and/or plenty of running tape water Application of antiseptics Avoiding bandaging or suturing of wound, or point of contact Administering anti-rabies immunizations as soon as possible Anti-rabies vaccine should be given for category II & III exposures (follow post exposure schedule)

  20. Treatment Post exposure schedule If the animal is not previously immunized, Post exposure vaccination on 0-day (the day starts within 24 hours after bite), 3rd, 7th, 14th, 28th & if necessary, on 90th day (Essen's schedule) If the animal is immunized annually 0 day, 3rd and 7th day, put the animal under observation for 10 days If the animal dies, should follow the full regimen (5 doses)

  21. Vaccination Pre-exposure schedule Type of vaccine: Inactivated (from cell culture or embryonated egg vaccine) Number of doses: Three: 0, 7th & 21st or 28th day given by IM or ID route (vaccine should not be given in the gluteal region) Booster: After one year then every five years Contraindication: Severe reaction to previous dose Adverse reactions: Mild local or systemic reactions; rare neuroparalytic reactions reported Special precautions: Do not use animal-brain-derived vaccines

  22. Prevention Postexposure immunization: Upto 50% of human rabies immune globulin is infiltrated around the wound; the rest is administered IM (ERIG or HRIG: anti-rabies antibody) Human Diploid Cell Vaccine (HDCV): 5 injections IM at days 0, 3, 7, 14, & 28 Vaccination of domestic animals Enforced animal control measures (Animal Birth Control and Anti- rabies vaccination programme: ABC-AR) Controlling stray dog population Proper immunization of household dogs (ABC-AR programme) Vaccination of high risk personnel Awareness programme among public

Related


More Related Content

giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#giItT1WQy@!-/#