Bites and Dog Viruses

• Dog: most common cause of reported bites (80-90% of bites) • Cat: second most common cause of reported bites (5-15% of bites) • People: third most common cause of reported bites (2.3-23% bites reported by ER physicians)

• Staffordshire terrier (aka American Pit bull) • Bullmastiff (Presa Canario) • Rottweile

• infection • trauma • disfigurement with required surgical repair • PTSD (selective mutism

The average dog bite claim cost insurers $16,600 (USD)

• Must hold a restricted dog licence • Must carry liability insurence (no less than $1 million dollars) • Dog must be muzzled, leashed, and under control No penalities if the resticted dog is provoked

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Zooanthroponosis (reverse zoonosis): transmission –man to animal Anthropozoonosis: transmission animal to man

Most bites from dogs and cats are polymicrobial (2-4 different or microorganisms isolated/wound) - usually including 1 anaerobic organism per wound (38% cat bites/ 76% dog bites) - Anaerobic: Bacteroides (Capnocytophaga canimorsus), Fusobacterium Peptostreptococcus - Aerobic: Staphylococcus, Streptococcus, Pasteurella multocida - Pasteurella multocida: normal flora of oral cavities (cats 70-90%; dogs 50-66%)

Pasteurella multocida: normal flora of oral cavities (cats 70-90%; dogs 50-66%) - Cat bite wounds: 50-80% - Dog bite wounds: 25% - Cats: 24 hours following bite: swelling, pain, Sequelae: septic (arthritis), osteomyelitis, sepsis, pneumonia, endocarditis and meningitis, Death can occur in systemic injury following untreated infection

Pathogen of dog bites Found in oral cavity: 18% cats and 16% dogs - Serious injury in immunocompromised patients infected with Capnocytophaga canimorsus - Local infection, sepsis, myocarditis, meningitis, eye infections and pneumonia - Rapid progression of disease can lead to death

True

Rabies rhabdoviridae - Retrovirus - Bullet shaped - Can manifest as dumb or furious form - ~100% death rate once sympotms show Travels through the nervous system

Furious form: Cats, dogs, and horses Dumb form: ruminants (Cows, sheep)

1-12 months

1) clean wound immediately with soap/iodine solution and water 2) Human rabies immunoglobulin (once at the beginning of treatment) followed by vaccination Prevention: vaccination - Vaccines are available for dogs, cats, horses (i.e. Rabvac-3) and people (IMOVAX)

• “Sloppy genetics” • Relatively easy to transfer species

Paramyxovirus: Single stranded RNA virus - Highly contagious: the second most important infectious disease affecting canines - Affects domestic and wild cinines - Also ferrets and rarely cats - Resivoir in wild candids and domestic dogs

Mammals - Rinderpest - phocine distemper - morbillivirus - wild feline Terrrestrial Carnivores - Ferret (canine distemper) - Procyonidae - Viverridae Avian - Newcastle’s disease Humans - Nipah virus - Measles

• Aerosol (water droplets, nasal), other secretions urine, feces, ocular secretion…tears) • Shared food and water bowls • Transplacental (mother to fetus) Highly contagious: shed 60-90 days carrier animals. Survive in environment: 48 hours @ 25C and 14 days @ 5C

Pathogenesis (nervous, respiratory and lymphoid tissue) - 24 hours following exposure (i.e. lungs), virus travels to lymphoid tissue (lymph nodes, spleen, tonsils) to replicate to large numbers (day 4-6) - Travels to intestine and nervous tissue (day 8-9)

Clinical signs: up 70% dogs (subclinical), show very mild to no clinical signs and these dogs recover - Acute form: high mortality- occurs within 14-21 days of exposure - Respiratory signs and intestinal signs (1-3 weeks), hemorrhage, pneumonia, conjunctivitis (surrounding eye) - Nervous tissue (inflammation, demyelination): paralysis, seizures (‘chewing-gum fits’), visual and vestibular changes - Immunosuppression - Chronic: skin thickening (seen with neurological signs), eye, lung, brain, gut, vision problems

White matter: axons - Loss of axons myelin - vacuolation - Myelin helps ‘insulate’ the axon - Needed for normal nerve signal transduction Demyelination is an effect of Canine Distemper

ICH was previous known as enzootic encephalitis of foxes was first seen in dogs 1930 - Infects: dogs, wild canids (fox, wolf, coyotes), Ursidae (bears) - Infections widespread (Europe, NA, Australia) - Member of adenovirus (DNA virus) - Infects/replicates liver, kidney and endothelial cells (cells that line blood vessels endothelial cells)

• Transmission: animal-animal contact-saliva, urine, feces, respiratory droplets, or indirect (environment) • Animals shows signs of illness: 4-9 following exposure • Mortality 10-30% in naïve animals