5. ANIMAL SUSCEPTIBILITY
INFECT ALL WARM BLOODED ANIMALS
INCLUDING HUMANS.
SUSCEPTIBLE ANIMALS ARE MAINLY Dogs, Cattles,
Sheep, Goats, Bats, cats, foxes Cotton Rats
6. Changes on propagation in animals
STREET VIRUSES: these are freshly isolated strains from lab.
*mimic wild viruses
*long and variable incubation period
Produce INTRACYTOPLASMIC inclusion bodies( NEGRI bodies)
FIXED VIRUSES: are street viruses propagated in rabbit by brain to
brain passage loose certain properties and become fixed
*don’t produce inclusion bodies
*don’t multiply in extraneural tissue
*don’t infect salivary gland
*multiply rapidly in 4-6 days
Used for vaccination
7. PATHOGENESIS
TRANSMISSION:
TO HUMANS MAINLY BY BITE OF INFECTED
ANIMAL
DOG BITE IS MOST COMMON
BAT BITE MOSTLY GOES UNNOTICED
LINK ON ABRASION OR MUCOSA
INHALATION OF INFECTED AEROSOLS OF BATS
CORNEA TRANSPLANTATION
8. SPREAD OF VIRUS
MULTIPLY LOCALLY: AT SITE OF INOCULATION
IN MUSCLE OR CONNECTIVE TISSUE
VIRAL ENTRY TO PERIPHERAL NEURONS: VIRUS
BINDS TO NICOTONIC ACETYLCHOLINE
RECEPTOR AT NEUROMUSCULAR JUNCTION
NEURONAL SPREAD: CENTEPRATELLY ALONG
MOTOR NERVES VIA RETROGRADE FAST AXON
TRANSPORT
CNS INFECTION: MOSTLY MENTAL SYSTEM SUCH
AS HIPPOCAMPUS AND CEREBELLUM
9. SPREAD OF VIRUS
CENTRIFUGAL SPREAD: FROM CNS THROUGH
SENSORY AND AUTONOMIC NERVES TO TISSUES
AS SALIVARY GLANDS TO PANCREAS ,KIDNEY
,HEART, RETINA AND CORNEA
VIREMIA DOESN'T OCCUR
SHED IN SALIVA
11. CLINICAL MANIFESTATIONS
INCUBATION PERIOD
20-90 DAYS (CAN BE 1 WEEK -19 YEARS)
INVERSELY RELATED TO DISTANCE FOR VIRUS TO
TRAVEL FROM SITE OF INCUBATION ;HENCE
SHORTER IN
CHILDRENS,SHORT PEOPLE, BITES ON HEAD,
NECK AND UPPER LIMBS, LOW HOST IMMUNITY
12. CLINICAL SPECTRUM OF RABIES
1) SHORT PRODOMINAL PHASE:
LASTS FOR 2-10 DAYS
CHARACTERIZED BY NON SPECIFIC SYMPTOMS
FEVER,PHOTOPHOBIA,SORETHROAT,ABNORMSL
SENSATION AROUNMD WOUND, NAUSEA
13. 2)ACUTE NEUROLOGICAL PHASE:
*ENCEPHALITIC RABIES. SYMPTOMS ARE
.HYPEREXCITABILITY
ANXIETY,HYPERACTIVITY,AGITATION,BIZARRE
BEHAVIOUR
HYPEREXCITABILITY IS FOLLOWED BY LUCID
INTERVAL
AUTONOMIC (SYMPATHETIC)
DYSFUNCTION:↑SALIVATION,↑LACRIMATION
↑PERSPIRATION,CARDIAC ARRHYTHMIA
PARALYTIC OR DUMB RABIES: IN PARTIALLY
VACCINATED AND BAT RABIES INFECTED PEOPLE
CHARACTERIZED BY FLACCID PARALYSIS USUALLY
FROM BITTEN LIMB
14. 3) COMA AND DEATH
PATIENT DEVELOPS COMA LEADING DEATH
AFTER ACUTE NEUROLOGICAL PHASE
DEATH OCCOURS IN 14 DAYS SOMETIMES IN 30
DAYS
15. LAB DIAGNOSIS
ANTIGEN DETECTION -BY IF
VIRAL ISOLATION-MOUSE AND CELL LINE
INOCULATION
ANTIBODY DETECTION FROM SERUM AND CSF-BY
MNT,RFT-IT,FAVN,IFA,HAI AND CFT.
VIRAL RNA DETECTION BY-RT-PCR
NEGRI BODY DETECTION IN
HISTOPATHOLOGICAL STAINING OF BRAIN
BIOPESIS
16. FULL FORMS OF TESTS
MOUSE NEUTRALIZATION TEST (MNT)
RAPID FLUORESCENT FOCUS INHIBITION TEST
(RFFIT)
FLUORESCENT Ab VIRUS NEUTRALIZATION
TEST (FAVN)
INDIRECT FLUORESCENCE ASSAY (IFA)
HEMAGGLUTINATION YTEST (HAI)
COMPLEMENT FIXATION TEST (CFT)
17. NEGRI BODIES DETECTION
USEFUL FOR POSTMORTEM DIAGNOSIS OF
RABIES
IT IS AN INTRACYTOPLASMIC EOSINOPHILIC
INCULSIONS WITH CHARACTERISTIC
BASOPHILIC GRANULES
SPHERICAL OR OVAL IN SHAPE