RABIES• It is an acute• Highly fatal viral dis: of CNS Transmitted to man by:• Bites OR• Licks of rabid animals
• Primarily a Zoonotic disease of warm blooded animal• such as :-• Dogs,• wild cats,• Jackals,• wolves etc.
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 Transmission1. ANIMAL BITES2. LICKS3. AEROSOL4. PERSON TO PERSON
Agent (LYSSAVIRUS type I) Rhabdoviridae type I• It is Bullet shaped Neurotropic RNA virus
Types of Rabies virus STREET VIRUS FIXED VIRUSDefinition: the virus Definition: the virusrecovered from which has a short, fixednaturally occurring and reproduciblecases of rabies is incubation period iscalled “street virus” called “fixed virusSources: it is naturally Sources: it is preparedoccurring virus. It is by repeated culture infound in saliva of brain of rabbit.infected animal.
RESERVOIR OF INFECTION1) 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 andmen. These are one of the main causes of the death ofbovine, around 0.5 to 1 million per year.
• 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 Virus•Outbreak of rabies in Europein 20th century spawned theVampire myth- linked to bats.•Rabies epidemic in 13thcentury France.•Rabies is commonly spreadby bats and wolves and otherwildlife like foxes.
History 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 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.
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.
• 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
• 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 bite3. 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 producespasmthe duration of illness is 2-3 days maybe prolonged to 5-6 daysStage of paralysis & comaDEATH / Recovery
(summary) Transmission of Rabies 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
DIAGNOSIS1. History2. Sign and symptom3. Examination4. 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 rabies post Exposure prophylaxis• General consideration:- Aim is to neutralize virus before entering CNS• 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, Suturingd, Anti Rabies Serume, Antibiotic and ATSf, Observe the animal for 10 days
Vaccines for immunizationDefinition: it is fluid or dried preparation of Rabies “Fixed” virus grown in the Neural tissue of Rabbits, Sheep, Goats, Mice or RatsOR in embryonated duck eggsOR in cell culture
Type of Vaccine NERVOUS TISSUE VACCINE (NTV)• Derived from adult animal nervous tissue eg. Sheep• Derived from suckling mouse brain Type: Killed viral vaccine Dose: 2.5 ml S/C (Ant. Abdominal wall) Schedule: 14 doses
Type of Vaccine (conti) Duck Embryo Vaccine (DEV)Type: Killed viral vaccineDose: 1 ml S/C ( Ant. Abdominal wall)Schedule: 14 doses ODnot available in Pakistan
Type of Vaccine (conti) CELL CULTURE VACCINES• Human diploid cell vaccine (HDCV)• Second generation tissue culture vaccine (non- Human) Type: Killed viral vaccine Dose: 1 ml IM Schedule: on 0, 3, 7, 14, 28 day, booster on day 90
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
Classification Of Exposures• Class I (slight Risk) 07 injectionb. Licks on healthy unbroken skin.c. Scratches without oozing of blood.• Class II (Moderate Risk) according to the Schedule plus one booster dose after 3 week• Licks on fresh cuts.• Scratches with oozing of blood.• All bites except those on head, neck, face, palms and fingers.• Minor wounds less than 5 in number.• Class III (Severe Risk) according to the Schedule plus Two booster dose one after one week and another 2 week• all bites or scratches with oozing of blood on neck, head, face, palms and fingers.• Lacerated wounds on any part of the body.• Multiple wounds 5 or more in number.• Bites from wild animals.
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
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 virusProtected 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 Dogs• Incubation period: 3-8 wks.• Clinical features: Rabies in dogs may manifest itself in two forms.• Furious Rabies. This the typical mad-dog syndrome characterized by.• change in behavior.• Tendency to run away from home, wander aimlessly and biting humans and animals.• Change in voice due to paralisis of laryngeal muscles.• Excessive salivation & foaming at the angle of the mouth.• Paralysis of the whole body leading to coma & death.
a. Dumb Rabies.• The excitative or irritative stage is lacking.• The disease is predominantly paralytic.• Dog withdraws itself from being seen or disturbed.• It elapses into a stage of sleepiness and dies in about 3 days.