RABIES Primarily a Zoonotic disease of warm

blooded animal such as :- Dogs, wild cats, Jackals, wolves etc.

It is caused by the Neurotropic RNA virus belongs to Rhabdoviridae type I (LYSSAVIRUS type I) is Bullet shaped virus

It is an acute Highly fatal viral dis: of CNS

Transmitted to man by: Bites

OR Licks of rabid animals

Rabies virus structure

EnvelopeMatrix protein

Source: http://www.cdc.gov

Glycoprotein

Nucleocapsid protein

History of Rabies Virus

Man described the disease in 2300 B.C.

The origin “rabhas”, meaning “to do violence” comes from ancient Indian Sanskrit dating 3000 B.C.

History of the Rabies VirusSince Roman times, man established the link between the infectivity of a rabid dogs saliva and the spread of the disease.

Because there is no cure for rabies, those that had been bitten by a rabid dog would commonly commit suicide to avoid the painful death that would inevitably follow.

History of the Rabies Virus Louis Pasteur was the first person to

diagnose that rabies targeted the CNS. Also determined that nervous tissue of an

infected human or animal also contained the virus.

In 1890 created the rabies vaccine and saved 9 year old child after he had been bit by a rabid dog.

Epidemiology87 countries contain Rabies, but more

cases are reported in Asia.In Indo-Pakistan rabies is a major

public health problem mainly due to presence of a large no: of stray dogs.

More than 30,000 people died of Rabies every year in Asia. Every year 10 million people require treatment and protection from Rabies which is great Financial loss.

RESERVOIR OF INFECTION

1) URBAN RABIES:

From Dogs and cats.

2) WILD LIFE RABIES: From jackals and foxes.

3) BAT RABIES: Vampire bats which live on the blood of animals and men.

These are one of the main causes of the death of bovine, around 0.5 to 1 million per year.

Source of Infection

Saliva of Rabid animal

Host Factors

All warm blooded animals including man.

Rabies in man is a dead-end infection.

Mode of Transmission

1. ANIMAL BITES

2. LICKS

3. AEROSOL

4. PERSON TO PERSON

INCUBATION PERIOD:

normally it is 3 - 8 wks

may be short that is 4 days

or may be prolonged for years.

CLINICAL PICTURE1. Prodromal symptoms

Headache, malaise, sore throat, low fever, pain at the site of bite

2. Excitation Symptoms sensory sys: involvement Aero phobia, excitation of N.S. Motor sys: inv: increase reflexes, muscle spasm,

Symp:inv: dilatation of Pupils. increase perspiration, salivation, and Lacrimation,

Mental changes: fear of death, anger, irritability and depression

Hydrophobia ( Fear of water)

sight or sound of water may produce spasm of degulation

the duration of illness is 2-3 days may be prolonged to 5-6 days

Stage of paralysis & coma

DEATH / Recovery

Clinical forms of rabies

encephalitic = furious ~ 80%

paralytic = dumb ~ 20%

Encephalitic rabies prodromal symptoms paresthesias/pain/pruritus at site of bite episodes of generalized arousal or

hyperexcitability separated by lucid periods

autonomic dysfunction hydrophobia

Paralytic rabies paresthesias/pain/pruritus at site of bite early flaccid muscle weakness

often begins in bitten extremity progresses to produce quadriparesis bilateral facial weakness

sensory examination is usually normal sphincter involvement fatal outcome often misdiagnosed as Guillain - Barré syndrome

DIAGNOSIS

1. History

2. Sign and symptom

3. Examination

4. Detection of Antigen by taking Skin Biopsy using Immunofluorescence

by virus isolation from Saliva & other secretions.

Control Measures Notification Isolation Disinfection Immunization

Prevention of human rabiespost Exposure prophylaxis

1. General consideration:- Aim is to neutralize virus before entering CNS

2. LOCAL WOUND TREATMENT a, Cleansing of wound(soap & water) b, Chemical treatment: Either Alcohol 400-700 ml /liter Tincture Iodine

c, Suturing not recommended

d, Anti Rabies Serum

e, Antibiotic and ATS

f, Observe the animal for 10 days

3, Immunization 1,NERVOUS TISSUE VACCINE (NTV

2, Human diploid cell vaccine (HDCV)

Evaluation of Animal Recommendation

Healthy and available for 10 days observation

No treatment unless animal develops clinical signs of rabies

Rabid or suspected rabid Immediate treatment*

Unknown (e.g., escaped) Consult local public health department

*Discontinue treatment if tests on animal prove negative.

Rabies postexposure guide: exposure to dogs, cats, and ferrets

Vaccines for immunizationDefinition:

it is fluid or dried preparation of Rabies “Fixed” virus grown in the Neural tissue of

Rabbits, Sheep, Goats, Mice or Rats OR in embryonated duck eggs OR in cell culture

Nervous Tissue vaccine

Duck embryo vaccine

Cell culture vaccine

preparation From fixed virus grown in brain of sheep or other animals

potency Low or variable Eliminate Neuroparalytic factors

More potent

more safer

Doses Large nos: are required Fewer doses of small volume

Side effects Severe & fatal reactions Allergic risks Fewer

Uses Exposed subjects Used in UK,USA in past 1, (HDC) safe, potent Pre & post expos:Immunization

Suckling mouse brain V Devoid of Neuroparalytic effect

Used in Latin America Improvement over adult animal nervous tissue V

Now purified DEV developed

Improvement over adult animal nervous tissue V

Not available in India & Pakistan

2Tissue culture 2nd G (Non-human)

Potent, low cost

WHO recommendatio

Type of VaccineNERVOUS TISSUE VACCINE (NTV)

a. Derived from adult animal nervous tissue eg. Sheep

b. Derived from suckling mouse brainType: Killed viral vaccineDose: 2.5 ml S/C (Ant. Abdominal wall)Schedule: 14 doses

Type of Vaccine (conti)Duck Embryo Vaccine (DEV)

Type: Killed viral vaccine

Dose: 1 ml S/C ( Ant. Abdominal wall)

Schedule: 14 doses OD

not available in Pakistan

Type of Vaccine (conti)CELL CULTURE VACCINES

a. Human diploid cell vaccine (HDCV)b. Second generation tissue culture vaccine

(non- Human)Type: Killed viral vaccineDose: 1 ml IM Schedule: on 0, 3, 7, 14, 28 day,

booster on day 90

Adverse Reactions to Rabies Vaccines

Most common side-effects of rabies vaccines:

Systemic reactions such as headache, myalgia, malaise (5-40%)

Mild to moderate local reactions at injection site (30-74%)

PASSIVE IMMUNIZATION Horse Anti Rabies serum: 40 iu / kg at

0 day Human rabies immunoglobin (HRIG):

20 iu / kg around the wound and rest in IM on 0 day

Booster doses are essential whenever anti rabies serum is given with the vaccine

IMMUNITY Duration of Immunity is upto 06 month If again bite by rapid animal than dose

according to blood titre

if more than 0.5 i.u. / ml than only two dose 0, 3 day

if less than 0.5 i.u. / ml than 0, 3, 7 day

General measures Regist:,licensing & taxation of dog. Muzzling of dogs Yearly mass vaccination of dog Destruction of stray dogs Facilities for diagnosis of rabies in dogs Destruction of wildlife where the animals are

known to be the reservoir of infection. Publicity

Preexposure rabies prophylaxis

3 doses of rabies vaccine (days 0, 7, and 21 or 28)

May check rabies antibody titre periodically – want >0.5 IU/mL

after a rabies exposure:

2 doses of IM rabies vaccine (days 0 and 3)

no HRIG

Day 0 7 21 28

Pre-exposure rabies prophylaxis

Tissue culture vaccine: 1 dose IM or 0.1 ml ID

Rabies prevention - Summary Rabies is a preventable disease. Failure to recognize a risk of infection results in

human deaths. Increased awareness of sources and routes of

virus transmission could save lives. Pre-exposure vaccination should be used widely. Post-exposure treatment is urgent. For previously vaccinated people post -exposure

treatment is simpler, cheaper and more effective.