RABIES• a ZOONOTIC DISEASE (a disease that is transmitted from animals to humans) that is caused by the Rabies Virus Source: WHO
THE RABIES VIRUS Rabies virus belongs to the order Mononegavirales, viruses with a nonsegmented, negative-stranded RNA genomes. Within this group, viruses with a distinct "bullet" shape are classified in the Rhabdoviridae family. The genus Lyssavirus includes rabies virus, Lagos bat, Mokola virus, Duvenhage virus, European bat virus 1 & 2 and Australian bat virus. Source: Center for Disease Control & Prevention
MAIN HOSTSDOGS BATS CATS & OTHERS1 Dogs are the main 2 Bats are the source 3 Cats are the most host and transmitter of most human common domestic of rabies. They are rabies deaths in the animals with rabies the source of United States of in the United States. infection in all of the America and estimated 55,000 Canada. Bat rabies Almost any wild or human rabies has also recently domestic animal can deaths annually in emerged as a public potentially get Asia and Africa. health threat in rabies, but it is very Australia, Latin rare in small rodents America and (rats, squirrels, western Europe. chipmunks) and lagomorphs (rabbits and hares).
TRANSMISSION You can get rabies only by coming in contact with: •Saliva •Brain/Nervous TissueSource: Center for Disease Control & Prevention
TYPE OF EXPOSUREBITE NON-BITE Templates 1 Any penetration of the skin 2 The contamination of by teeth constitutes a bite open wounds, abrasions, exposure. All bites, mucous membranes, or regardless of body site, theoretically, scratches represent a potential risk of (potentially contaminated rabies transmission, but with infectious material that risk varies with the from a rabid animal) species of biting animal, constitutes a nonbite the anatomic site of the exposure. bite, and the severity of the wound.
INCUBATION PERIOD• The incubation period for rabies is typically 1–3 months, but may vary from less than 1 week to more than 1 year.
INITIAL SYMPTOMS• Fever• Pain or an unusual or unexplained tingling, pricking or burning sensation (paresthesia) at the wound site.
FORMS OF THE DISEASECLASSIC RABIES PARALYTIC RABIES Templates People 1 with classic (furious) A rarer form of rabies, rabies exhibit signs of paralytic rabies, has been hyperactivity, excited linked to vampire bats. This behaviour, hydrophobia and form of rabies runs a less sometimes aerophobia. After dramatic and usually longer a few days, death occurs by course than the furious form. cardio-respiratory arrest. The muscles gradually become paralyzed, starting at the site of the bite or scratch. A coma slowly develops, and eventually death occurs.
PATHOPYSIOLOGY RABIES VIRUS Incubation Period Entry into break in skin (1 month – more1 (bites, abrasions, mucusa) than 1 year) Pain Headache Imminent thoracho-lumbar Invasion Fever Sore Throat involvement (PNS): Pupillary Phase Malaise Increased dilatation, Lacrimation Anorexia Sensitivity Increased thick saliva/foaming of the mouth. Excessive sweat Anxiety and fear Hydrophobia Excitement Mania and hallucinations Phase with lucid intervals Pronounced muscular stimulation and general tremor Convulsions Next Slide…
Continuation… Gradual weakness of muscle groups; muscle spasms cease, ocular palsy, vertigo PARALYTIC Templates (+) Babinski (lesions at pyramidal tract) PHASE HR shifting from tachycardia (100-1 (Depression Phase) 120) to bradycardia (40-60) Cheyne-Stokes breathing Local sensation diminished (pain, heat, cold) Bladder and intestinal retention (damage to the innervation of the COMA musculature of bladder and intestine Hydrophobia disappear Slight difficulty wallowing Ascending paralysis, flaccid paralysis of extremities until it DEATH reaches respiratory muscles Apathy, Stupor
DIAGNOSTIC EXAMS• Several tests are necessary to diagnose rabies ante-mortem (before death) in humans; no single test is sufficient.• Tests are performed on samples of saliva, serum, spinal fluid, and skin biopsies of hair follicles at the nape of the neck.• Reverse transcription polymerase chain reaction (RT-PCR).• Serum and spinal fluid are tested for antibodies to rabies virus.• Skin biopsy specimens are examined for rabies antigen in the cutaneous nerves at the base of hair follicles.
PREVENTION• Responsible pet ownership (Immunization)• Thoroughly clean ALL BITES AND SCRATCHES made by animal with strong medicinal soap or solution• Report immediately rabid or suggestive of rabies domestic or wild animals to proper authorities• Pre-exposure to high-risk individuals
DOH PROTOCOLS• If dog is apparently healthy, observe the dog for 14 days. If it dies or shows signs suggestive of rabies, consult a physician• If the dog shows signs suggestive of rabies, kill the dog immediately and bring head for lab exam. Submit for immunization while awaiting for results• If the dog is not available for observation (killed, died, or stray) submit for immunization
POST-EXPOSURE PROPHYLAXISCATEGORY I: touching or feeding animals, licks on intact skin.POST-EXPORSURE MEASURES: None CATEGORY II: nibbling of uncovered skin, minor scratches or abrasions without bleeding. POST-EXPOSURE MEASURES: Immediate vaccination and local treatment of the wound Category III: single or multiple transdermal bites or scratches, licks on broken skin; contamination of mucous membrane with saliva from licks, exposures to bats. POST-EXPOSURE MEASURES: Immediate vaccination and administration of rabies immunoglobulin; local treatment of the wound
MEDICAL INTERVENTIONS• Local wound treatment. Wash with soap and water. Use iodine or other disinfectants• Antibiotics and Anti-tetanus as prescribed by Physician• Rabies-specific treatment. Active immunization (Human Diploid Cell Rabies Vaccine) and passive immunization (Rabies Immune Globulin)