Lecture 1.3 - Zoonosis

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Questions and Answers

What is the primary route of transmission for Psittacosis?

Inhalation of aerosolized bacteria (correct)

Contaminated food and water

Vector-borne transmission

Direct contact with infected birds

Which of the following is a symptom of Cat-scratch disease?

Seizures

Diarrhea

Numbness in the face

Headache (correct)

What is the primary risk group for Psittacosis?

Occupational exposure and immunosuppressed individuals (correct)

Individuals with a history of asthma

People living in urban areas

Children under 5 years old

What is the primary route of transmission for Tuberculosis?

Ingestion Signup and view all the answers

Which of the following is a zoonotic disease caused by Mycobacterium bovis?

Zoonotic Tuberculosis Signup and view all the answers

Which of the following protozoa infections is commonly found in young dogs?

Giardia Signup and view all the answers

What is the primary occupational hazard for people working with farm animals?

Orf Signup and view all the answers

What is the most common source of zoonotic disease in the UK?

Pets in the home Signup and view all the answers

Which of the following is a risk factor for Salmonellosis?

Very young children Signup and view all the answers

Which of the following is a bacterial infection that can be contracted by people working in zoos with exotic animals?

Bacterial infections, especially with primates Signup and view all the answers

What is the name of the fungal infection commonly transferred to children, the elderly, and immunosuppressed patients?

Dermatophytoses Signup and view all the answers

What is the primary risk of Toxoplasmosis during pregnancy?

Miscarriage, still birth, and birth defects Signup and view all the answers

What is the recommended precaution for pregnant women to avoid Toxoplasmosis?

Avoid changing cat litter trays Signup and view all the answers

What is the bacterial infection transmitted through cat bites or scratches?

Cat scratch fever Signup and view all the answers

What is the primary characteristic that defines a zoonosis?

A disease that is naturally transmissible from vertebrate animals to humans Signup and view all the answers

Which of the following is a reason why zoonotic diseases are important in general practice?

Pets in the home can transmit zoonotic diseases to humans Signup and view all the answers

Which of the following is an example of a zoonotic disease transmitted through direct contact?

Dermatophytosis (ringworm) Signup and view all the answers

What is the primary reservoir for influenza A viruses?

Avian hosts Signup and view all the answers

What is the mechanism by which influenza A viruses can undergo a change in their genome?

Point mutations and reassortment Signup and view all the answers

What is the function of the Haemagglutinin (H) protein in influenza A viruses?

Binds virus particle to cell to initiate infectious cycle Signup and view all the answers

Which of the following is a characteristic of reassortment in influenza A viruses?

Results in a change in the viral genome Signup and view all the answers

Which of the following groups of people is particularly vulnerable to zoonotic diseases?

Pregnant women and individuals with compromised immune systems Signup and view all the answers

Study Notes

Zoonosis

A disease or infection that is naturally transmissible from vertebrate animals to humans
Major cause of emerging human disease
Wide ranging causative agents: bacterial, viral, fungal, protozoan, prion (variant Creutzfeldt-Jakob disease)

Importance of Zoonotic Disease

General practice vs hospital medicine
Pets in the home
Occupational hazards
Wildlife
Hobbyists
Young, elderly, and immunosuppressed patients
Pregnancy

Routes of Transmission

Direct contact: dermatophytosis (ringworm), Orf (Parapoxvirus), Sarcoptic Mange (Sarcoptes scabiei)
Scratches/bites: cat scratch fever (Bartonella henselae), Rabies (Lyssavirus)
Inhalation: Psittacosis (Chlamydophila psittaci)
Ingestion: vCJD, Tuberculosis (M.bovis), Campylobacter, Salmonella
Faeco-oral: Toxoplasmosis (Toxoplasma gondii)

Influenza A Viruses

Most influenza viruses originate from birds
Aquatic birds are the main natural reservoir for influenza A viruses
Great zoonotic potential as can infect various avian and mammal hosts and transmit to humans
High potential for genome change by point mutations and reassortment
Rate of point mutations is higher in humans than in avian hosts
Reassortment -> concern for new respiratory pandemics
Subtype according to two surface proteins: Haemagglutinin (H) and Neuraminidase (N)

Tuberculosis

Caused by Mycobacteria that are part of the Mycobacteria tuberculosis complex
Zoonotic tuberculosis caused by Mycobacterium bovis
Primary route of transmission: ingestion
Occupational risk of airborne transmission
Challenges: differentiation for M.tuberculosis clinically and in the laboratory, misdiagnosis, and treatment (resistance to Pyrazinamide)

Salmonellosis

Generally considered a food-borne illness (eggs, Salmonella enteritidis)
Less commonly known risk from pet reptiles
Salmonella enteritidis outbreaks associated with risk from skin, faeces, and feed animals
Education is very important
At-risk groups: very young children particularly

Pets in the Home

Most common source of zoonotic disease in the UK: dermatophytoses, Toxoplasmosis, cat scratch fever, Psittacosis, protozoa infections, and Rabies

Dermatophytoses

'Ringworm' - fungal, not parasitic
Risk species: dogs, cats, guinea pigs, rabbits
Can be non-pruritic in animals
Difficult to identify in long coats
Commonly transferred to children, the elderly, and immunosuppressed patients

Toxoplasmosis

Infection with Toxoplasma gondii
Risk from cat faeces and infected meat
Can cause miscarriage, stillbirth, and birth defects
Education of pregnant patients: avoid changing cat litter trays, wear gloves when gardening, wash fruit and vegetables before use

Cat Scratch Fever

Bacterial infection with Bartonella henselae
Can occur through any bite or scratch that breaks the skin
Cats under 1 year old more likely to carry
Asymptomatic in cats
Symptoms: round, raised purulent lesions at site of injury, fever, enlarged local lymph nodes, headache, and severe systemic complications

Psittacosis

Bacterial infection with Chlamydophila psittaci
Carried by all species of bird, with parrots and pigeons at highest risk
Transmission: primarily inhalation
Incubation: 1-4 weeks
Symptoms: flu-like symptoms to severe pneumonia
At-risk groups: occupational exposure, immunosuppressed and young/elderly individuals, pregnant women

Protozoa Infections

Examples: Giardia, Cryptosporidium, and Coccidia
Giardia: common in young dogs, especially from poor breeding backgrounds

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Description

Test your knowledge of zoonotic diseases, their transmission routes, symptoms, and risk groups. This quiz covers Psittacosis, Cat-scratch disease, Tuberculosis, and other animal-borne diseases.