RABIESRABIES• 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

Agent Factors:Agent Factors:

AgentAgent

(LYSSAVIRUS type I) (LYSSAVIRUS type I) Rhabdoviridae type IRhabdoviridae type I

Bullet shaped

• 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 VirusHistory of the Rabies Virus

•Outbreak of rabies in Europe

in 20th century spawned the

Vampire myth- linked to bats.

•Rabies epidemic in 13th

century France may have

spurred Werewolf myth as

well- linked to wolves.

•Rabies is commonly spread

by bats and wolves and other

wildlife like foxes

History of the Rabies VirusHistory of the Rabies Virus

• Since 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 VirusHistory 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 Joseph Meister after he had been bit by a rabid dog.

EpidemiologyEpidemiology87 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.

• Estimated Annual Human Rabies Cases 2005

• North America 4 - 8• Europe 10 - 20• Latin America 200 - 400• Africa 500 - 1,000• Asia 30,000 - 40,000

• FREE RABIES ZONE:

• Australia, • China, Iceland, • Ireland,• Japan, • New Zealand etc

Types of Rabies virusTypes of Rabies virusSTREET VIRUS

Definition: the virus recovered from naturally occurring cases of rabies is called “street virus”

Sources: it is naturally occurring virus. It is found in saliva of infected animal.

(continue)

FIXED VIRUS

Definition: the virus which has a short, fixed and reproducible incubation period is called “fixed virus

Sources: it is prepared by repeated culture in brain of rabbit such that its I.P. is reduced & fixed

Features

1. It produces Negri bodies

2. Incubation period is long i.e. 20 to 60 days

3. It is pathogenic for all mammals

4. Cannot be used for preparation of vaccine

Features

1. It does not form Negri bodies

2. Incubation period is constant between 4-6 days

3. It can pathogenic for humans under certain conditions

4. Is used for preparation of antirabies vaccine

RESERVOIR OF INFECTIONRESERVOIR OF INFECTION

1) URBAN RABIES:

From Dogs and cats.

2)2) WILD LIFE RABIES WILD LIFE RABIES: : From jackals and foxes.From jackals and foxes.

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

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

Source of InfectionSource of Infection

• Saliva of Rabid animal

Host FactorsHost Factors

• All warm blooded animals including man.

• Rabies in man is a dead-end infection.

Mode of TransmissionMode 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.

PATHOGENESISPATHOGENESIS

Replicate in muscle and C.T. --- attach to nerve ending --- CNS --- than centrifugally in peripheral nerve to many tissue including Skeletal muscle, heart, adrenal gland and skin --- salivary gland

CLINICAL PICTURECLINICAL 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

(summary(summary)) Transmission of Rabies Transmission of Rabies

Cl:Picture Cl:Picture

• The rabies infection and the symptoms that accompany it is classified by five stages:

1. Incubation (1-3 months)

2. Prodromal, where first symptoms occur

3. Acute neurological phase

4. Coma

5. Death or recovery

DIAGNOSISDIAGNOSIS

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 MeasuresControl Measures

• Notification

• Isolation

• Disinfection

• Immunization

Prevention of human rabiesPrevention of human rabiespost Exposure prophylaxispost 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• No more treatment with Ammonium

compound • No Carbolic acid and Nitric acid as it leave

very bad scar

c, Suturing

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)

Vaccines for immunizationVaccines 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 VaccineType of Vaccine

NERVOUS TISSUE VACCINE (NTV)a. Derived from adult animal nervous

tissue eg. Sheepb. Derived from suckling mouse brain

Type: Killed viral vaccineDose: 2.5 ml S/C (Ant. Abdominal wall)Schedule: 14 doses

Type of Vaccine (conti)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)Type of Vaccine (conti)

CELL CULTURE VACCINESa. 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

PASSIVE IMMUNIZATIONPASSIVE 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

Classification Of ExposuresClassification Of Exposures1. Class I (slight Risk) 07 injection

a. Licks on healthy unbroken skin.

b. Scratches without oozing of blood.

2. Class II (Moderate Risk) according to the Schedule plus one booster dose after 3 week

a. Licks on fresh cuts.

b. Scratches with oozing of blood.

c. All bites except those on head, neck, face, palms and fingers.

d. Minor wounds less than 5 in number.

3. Class III (Severe Risk) according to the Schedule plus Two booster dose one after one week and another 2 week

a. all bites or scratches with oozing of blood on neck, head, face, palms and fingers.

b. Lacerated wounds on any part of the body.

c. Multiple wounds 5 or more in number.

d. Bites from wild animals.

IMMUNITYIMMUNITY

• 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 measuresGeneral 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

Pre-Exposure Prophylaxis• It is done in persons who have high risk of

repeated exposures.

Animal Handlers

Wildlife officers

Veterinarians

Lab: staff working with rabies virus

Protected by:- Cell-culture vaccine 1ml I/M

OR 0.1ml I/D ( 0,7& 28day)

Post-exposure R/ of persons

(who have been vaccinated previously)

HDC vaccine (1ml I/M 0,3 & 7 day 0

Rabies in DogsRabies in Dogs • Incubation period: 3-8 wks.• Clinical features: Rabies in dogs may manifest itself

in two forms.a. Furious Rabies. This the typical mad-dog syndrome characterized by. i. change in behavior.ii. Tendency to run away from home, wander aimlessly

and biting humans and animals.iii. Change in voice due to paralisis of laryngeal muscles.iv. Excessive salivation & foaming at the angle of the

mouth.v. Paralysis of the whole body leading to coma & death.

b. Dumb Rabies.

i. The excitative or irritative stage is lacking.

ii. The disease is predominantly paralytic.

iii. Dog withdraws itself from being seen or disturbed.

iv. It elapses into a stage of sleepiness and dies in about 3 days.