1. Epidemiology Animal bites Animal Bites and Bite Infection 2. Complications Dr Claire Dendle 3. Management 4. Prevention Epidemiology 1. Epidemiology Large public health problem Australia Every year 2% population bitten Thompson MJA 2006 100,00 require medical treatment 13,000 seek hospital treatment Financial costs > $7 million in hospital costs Bennett 2001 The reluctant historian Animal bites Fear of repercussions for the animal Illegal exotic pets Human Bites What does the biting? Dogs > Cats > Humans > Rodents Dogs Male, unsterilized dogs Free roaming Known to owner Breed German Shepherd, Pit Bull, Heelers, Dobermans, Rottweilers Pit Bulls implicated in >50% US fatal attacks 1
Dogs Children under 5 Males Face/head/neck Who gets bitten? Cats Females Hands Chapman BMJ 2000 Who gets bitten? Vets 2188 significant injuries 26% Bites, dogs 87% Not muzzled Suggest increased muzzle use Lucas 2000 2. Complications of animal bites Mortality of vets from animal bites Nienhaus 2005 Complications Tissue damage 2
Jaw pressure Animal Jaw pressure (pounds per square inch) Humans 120 Tasmanian Devil 200 Dog 320(230-550) Great White shark 667 Tiger 1050 Gorilla 1300 Crocodile 5000 Bite wound infection Complications Bite Wound infection Infecting organisms Oral flora animal Host flora (skin) Environmental Animal bite infections POLYMICROBIAL Unusual pathogens characteristic species Guide antibiotic management Risk of infection dependent on species High risk cat/human/monkey Moderate risk dog/rodent Pasteurella in animals Colonizer upper respiratory tract Human disease - contact with healthy animals Causes diseases in animals Acquisition of a new serotype Fowl cholera Bovine haemorrhagic septicaemia Swine allergic rhinitis Rabbits snuffles 3
Pasteurella taxonomy Pasteruella multocida - human infections Subspecies differentiated by PCR Complete genome sequence Pasteurella clinical features Skin and soft tissue infection Rapid onset within 3 hours Cellulitis within 24 hours Septic arthritis/osteomyelitis/necrotizing fasciitis Pneumonia Septicemia Case reports Meningitis, endocarditis Pasteurella transmission Animal to human Bites(dog and cats) Licks(dog and cat) Wade 1999. A lick may be as bad as a bite Kissing (dogs and cats) Close physical contact Bryant 2007. A tale of two cats Human to human Horizontal transmission Vertical transmission Microbiology per animal species 4
50 infected bite wounds POLYMICROBIAL +++ Median no. isolates = 5 Aerobes and anaerobes Talan Pasteurella spp. 50% P. dagmis, P. canis C. carnimorsus 4.7% Staphylococcal spp. MRSA, S. intermedius Streptococcal spp. Neisseria spp. Dog bites Capnocytophaga carnimorsus 4% dog bites Immunosuppressed Splenectomised Rapid progression and death Cat bites 57 cat bites 75% Pasteurella spp. Polymicorbial TalanNEJM Bartonella henselae 30% Australian cats asymptomatic bacteraemia Rodent bites Organisms Streptobacillus moniliformis Spirillum minus Salmonella Spp. Rat bite fever Emerging disease Monkey bites Aerobic and anaerobic organisms Cercopithecine herpesvirus 1 Herpes simiaeor B virus Old world macaques Transmitted by bite or scratch Fatal encephalitis Human bites Purposeful injuries present late Inter-canine distance 3 cm adult teeth High risk of infection Clenched fist injuries Organisms Median no. of isolates = 4 Talan 2003 Aerobes Streptococci, Staphylocooci spp. Anaerobes Eikenella Corrdans Fusobacterium, Peptostreptococcus, Prevotella, Porphyromonas s 5
Bat Bites Native Australian mammals Australian Bat Lyssavirus Similar but not identical to rabies virus 2 Australian cases 100% mortality Prophylaxis all bat bits Rabies immunoglobulin Rabies vaccination Regardless incubation period Animals Cows, horses, camels Pigs Possums Snakes Lizards Turtles Crocodiles Fish Seals Actinobacillisspp. S.aureus Aeromonas spp. Pasteurella aerogenes Actinobaciilusspp. Tularaemia Venom sterile Salmonella spp. Edwardsiella tarda Pseudomonas spp. Aeromonas spp. Streptococcus agalactiae Vibrio spp. Aeromonas spp. Erysipilothrixrhusiopathei Mycobacteria marinum Mycoplasma spp. 6
Psychological trauma Complications Psychological trauma Post traumatic stress disorder Case reports 3000 people from Adelaide 50% feared dog attack 21% changed their behavior Prospective study 12/22 children PTSD 2-9 months after incident Peters 2004 Tricky management issues Management of animal bite wounds Wound management Uninfected wounds antibiotic prophylaxis? Infected wounds antibiotic choice? Assessment of wound History Examination Explore carefully Identify foreign bodies (teeth) Assess penetration of bone and joint Assess nerve, motor and vascular function Document (diagrams and photographs) Imaging Foreign bodies/bone and joint penetration High risk wounds Injury type Crush, Puncture Involvement of underlying structures Biting animal Cat bite Human bite Host factors Site of bite hands/feet/groin Immunocompromise 7
Risk ratio 0.58 (95%CI 0.38-0.82) 14 treated per 1 infection prevented Prophylaxis Use for high risk wounds Tetanus Australian Bat Lyssavirus/Rabies Hepatitis B/HIV Antibiotic prophylaxis Cummings 1994 Broad spectrum Culture based Antibiotic choice Consider unusual organisms if unusual species Cover Pasteruella spp. Avoid 1 generation cephalosproins Avoid flucloxacillin Avoid erythromycin Causes of therapeutic failure Incorrect antibiotics prescribed Failure to recognized joint penetration Failure to remove foreign body Primary closure high risk wounds Failure to provide discharge instructions Take home points Animal bite prevention Large pubic health problem Meticulous wound management cleansing/irrigation/exploration/debridement Pasteurella spp Common isolate many animal species Resistant to flucloxacillin/1st gen cephalosporins Emerging infections MRSA ABL(2 fatal cases) prophylaxis all bat bites Tulareamia Psychological trauma 8
Thank-you 9