1. Zoonosis Dr Wafaa Jamal

2. WLO Define the term zoonoses To know the mode of transmission of different types of zoonotic infections Describe common examples of bacterial, viral and parasitic zoonotic infection

3. Objectives Describe different modes of transmission of the diseases To be familiar with the common causative pathogens Understand the principles of management of these infections

4. Zoonoses Infectious diseases that can be transmitted from vertebrates (domestic & wild animals) to human Animal may or may not show obvious illness but can infect man Types: bacteria, viruses or parasites

5. Mode of transmission 1. Direct contact: with animal or its products e.g. Products of conception (Brucellosis) Infected bone meal (anthrax) Fish handler (erysipeloid) Abattoir worker (Q fever)

6. Mode of transmission 2. Inhalation: of excreta, secretions Dropping (psittacosis) Spores in wool (pulmonary anthrax) Secretions (Brucellosis) 3. Ingestion of food and milk products Salmonella, Campylobacter, Brucella, Q fever, Toxoplasma

7. Mode of transmission cont… 4. Saliva: bites or licks from infected animals e.g. rabies, Pasteurella multocida infection 5. Faeces: contaminate food, soil, surfaces handled by humans e.g. salmonellosis, hydatid disease, tetanus

8. Mode of transmission cont… 6. Urine Handling of animals directly or via swimming in contaminated water (Leptospirosis) 7. Blood and life tissues: rare Animal house attendants, zoo & lab workers: direct handling or inhaling aerosols from infected body or tissue of monkeys (Marburg virus disease, yellow fever)

9. Brucellosis Gram-negative coccobacilli Incubation peroid: 1week - 6months SpeciesAnimal reservoirGeographical distribution Brucella mellitensisgoats & sheepMediterranean area Brucella abortuscattleWorldwide Brucella suispigsUSA, Denmark

10. Brucellosis Epidemiology Ingestion of unpasteurized milk, milk products Direct contact with vaginal secretions, product of conception Inhalation: (laboratory accidents) Pathogenesis: intracellular in cells of reticuloendothelial system, inaccessible to PMN No person to person spread (few exception)

11. Brucellosis Clinical features Fever, arthritis, splenomegaly, hepatomegaly, CNS, orchitis, endocarditis Diagnosis Serology: standard agglutination test, ELSA Culture Treatment: rifampicin & doxycycline for 6 weeks

12. Anthrax Bacillus anthacis: Gram-positive bacilli, spore Disease of cattle, sheep Spores survive for years Acquire infection Occupational disease: workers handling contaminated hides, hair, wool of sheep, bone meal

14. Anthrax Pathogenesis Capsule – Polypeptide: D-glutamic acid – Inhibit opsonization, phagocytosis Plasmid encoded Toxin (binary toxin) – Protective factor: bind to receptor on macrophage – Lethal factor: inhibit cell function – Oedema factor: ↑ vascular permeability, shock

15. Anthrax Cutaneous anthrax (malignant pustule) Due to direct inoculatioin of skin from infected animal or its product Acquired – Industrial: leather workers, bone meal factories – Non-industrial: those work with animals

17. Anthrax Pulmonary anthrax (wool sorter’s disease) – Inhaling spores in workers handle contaminated wool – Fever, respiratory distress, death – Mortality rate ↑ Gastrointestinal anthrax – Ingestion of spores, lethal

18. Anthrax Diagnosis – Specimen: exudate from pustule, sputum – Gram stain – Culture Treatment Penicillin Prevention Vaccine workers at risk

19. Plague Yersinia pestis: Gram-negative bacilli Animal reservoir: rodents e.g. rats; man get infected by bite of infected rat fleas 3 forms 1.Bubonic plague  Painful enlargement of inguinal Lymph nodes  MR ↑ (50%) due to haemorrhagic sepsis

20. Plague 2. Pneumonic plague: inhalation of infected respiratory secretions, spread from one person to another, fatal 3. Septicaemic plague: primary or complication of pneumonic or bubonic plague Pathogenesis Capsule Somatic Antigen (V and W): resist phagocytosis

21. Plague Diagnosis Specimen: bubo pus Gram stain Culture Treatment Tetracycline

22. Pasteurella infection Pasteurella multocida: Gram-negative bacilli Reservoir: Upper respiratory tract of dogs, cats Bites or scratch from animal bite Infections: wound infection, septicemia Treatment Penicillin

23. Erysipeloid Erysipelothrix rhusiopathiae: Gram-positive bacilli Reservoir: fish, birds, swine, pigs Wound infections during handling of meat, fish especially if skin abrasion

25. Leptospirosis Leptospira species: spirochaetes Epidemiology Survive in stagnant water & wet soil for long time esp. if pH ↑ Animal reservoirs: – Small wild animals e.g. rodents – Domestic animals e.g. pigs, cattle, puppies Penetrate abraded & intact skin, conjunctiva, mucous membrane→ blood → kidneys, CNS

27. Leptospirosis Transmitted to man by direct or indirect contact with animal urine Acquire infection – Wet occupation e.g. sugar cane field, rice field, farms, sewage workers – Leisure activities: swimming pools, play with infected pet Incubation period: 5-14 days 16 serogroups

28. Leptospirosis Leptospira canicola serogroup: canicola fever: aseptic meningitis; (dogs, pigs) L. icterohaemorrhagiae serogroup: Weils’s disease: fever, jaundice, proteinuria, subconjunctival haemorrhage, hepatorenal failure; (rats) L. hebdomadis serogroup: (cattle) Diagnosis: serology: IgM, IgG Treatment: Penicillin

29. Salmonellosis: Salmonella species Reservoir: chicken, turkey, cattle Food poisoning Campylobacter infection: Campylobacter species Reservoir: poultry, dogs Food poisoning

30. Listeriosis Listeria monocytogenes: Gram-positive bacilli Reservoir: cattle, pigs, rodents, birds, fish Man get infection: direct contact with animals (stool), eat raw meat, soft cheese, infected milk Infections – Flue like illness: vets, farm workers, butchers – Meningo-encephalitis, sepsis: neonates, Immunosuppressed

31. Listeriosis Diagnosis – Specimen: blood, CSF, vaginal swabs – Culture – Identification GPB β-haemolysis Motility at room temperature but not at 37°C Catalase positive Treatment: ampicillin

32. Bovine tuberculosis Mycobacterium bovis Infect lungs of cattle; mammary glands (during chronic disease) Acquire infection: ingestion of unpasteurized milk Infections – Cervical adenitis – Mesenteric adenitis

33. Q fever Coxiella burnettii Animal reservoir: Sheep, cattle Acquire infection – Handling infected animals or their products (infected placenta or meat) – Inhaling contaminated dust – Drinking infected unpasteurized milk

34. Q fever Infections – Flue like illness – Pneumonia – Infective endocarditis – Hepatosplenomegaly Diagnosis: Serology Treatment Tetracycline

35. Rabies Bullet-shape rhabdo RNA virus Virus present in saliva of infected animal Penetrate abrasion in skin or intact mucous membrane of animals and man → peripheral nerves → CNS (neurons: intracytoplamic inclusions - Negri bodies) Animals develop rabies: dogs, foxes, cats, cattle, monkeys Man get infection by bite from infected animal

36. Rabies Incubation period 4-13 weeks (shorter if bitten on face, shoulder, upper limbs) Clinical Features Rabies: sore throat, fever, irritability, discomfort at site of bite Encephalomyelitis Excitement, convulsions, muscle spasm (hydrophobia), death due to heart or respiratory arrest

37. Toxoplasmosis Epidemiology Toxoplasma gondii multiply in ileum of cat → oocysts in stool Acquire infection – Contact with cats or soil contaminated with oocyst – Ingestion of raw or under cooked meat of animals (intermediate host ) e.g. cattle, pigs

39. Toxoplasmosis Clinical features Asymptomatic: healthy, febrile illness with LN+ Immunosuppressed: menengoencephalitis, myocarditis Congenital toxoplasmosis: chorioretinitis, cerebral calcification Diagnosis: Serology: IgM Treatment: pyrimethamine + sulfadiazine + folinic acid

40. Lyme disease Borrelia burgdorferi Acquired by bite of tick (Ixodes spp.) after feeding on infected animal (deer) Europe, USA, China, Australia Manifestation: – Early localized: skin rash (2-3weeks) – Early disseminated: (weeks-months): LN +, arthritis, CNS, carditis – Late persistent : (1 st year): CNS, joint, skin lesions

41. Lyme disease Diagnosis – Serology, ELISA – PCR – CSF serology Treatment: doxycycline or amoxicillin Prevention: avoid tick exposure