Spillover Chapter 1: Pale Horse Quiz
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Questions and Answers

Which of the following are zoonotic diseases? (Select all that apply)

  • Cancer
  • Ebola (correct)
  • Swine flu (correct)
  • Bird flu (correct)

    • What is zoonosis?

    Diseases that transfer from animals to humans.

    What are the three categories of zoonotic diseases?

    Spillover, emerging, and re-emerging.

    Why was eliminating or eradicating polio and smallpox easier than Lyme disease and AIDS?

    <p>There are no vaccines for Lyme disease or AIDS, whereas polio and smallpox are not zoonotic.</p> Signup and view all the answers

    What is a reservoir host?

    <p>A host in which a pathogen can live and multiply with limited to no harm to the host.</p> Signup and view all the answers

    Which disease spilled over in Australia in 1994?

    <p>Hendra (formerly classified as equine morbillivirus).</p> Signup and view all the answers

    Hendra was caused by which type of virus?

    <p>A paramyxovirus from the Henipavirus family.</p> Signup and view all the answers

    What is the case fatality rate for humans infected with Hendra?

    <p>57%</p> Signup and view all the answers

    How is Hendra transmitted to humans?

    <p>Through exposure to body fluids and tissues of infected horses.</p> Signup and view all the answers

    What type of exposure leads to transmission of Hendra to horses?

    <p>Exposure to virus in the urine of infected flying foxes.</p> Signup and view all the answers

    How many horses were infected with Hendra from 1994 to 2016?

    <p>Approximately 70 horses.</p> Signup and view all the answers

    What supportive treatments are being developed for humans infected with Hendra?

    <p>Developing a treatment for passive immunity by injecting antibodies.</p> Signup and view all the answers

    Of bat carers, how many people showed signs of Hendra exposure?

    <p>0</p> Signup and view all the answers

    What was the amplifying host for Hendra?

    <p>Horses.</p> Signup and view all the answers

    What is foot and mouth disease?

    <p>A disease with asymptomatic carriers (sheep), amplifying hosts (pigs), and high pathogenicity (cows).</p> Signup and view all the answers

    What proportion of zoonotic diseases originate in wildlife?

    <p>7 out of 10 zoonotic diseases.</p> Signup and view all the answers

    What is bushmeat?

    <p>A term used for wild game hunted or gathered in most parts of the world.</p> Signup and view all the answers

    Which of the following are major emerging infectious diseases?

    <p>All of the above</p> Signup and view all the answers

    Study Notes

    Zoonotic Diseases

    • Zoonotic diseases include swine flu, bird flu, SARS, AIDS, yellow fever, dengue, ebola, and plague.
    • These diseases transfer from animals to humans, posing significant health risks.

    Zoonosis

    • Zoonosis is the term for diseases that transfer from animals to humans.
    • Since 1981, zoonotic diseases have resulted in approximately 30 million deaths.
    • Hundreds of millions of deaths have been attributed to zoonotic diseases since the 20th century.

    Categories of Zoonotic Disease

    • Spillover: A new zoonotic infection emerging from animal hosts.
    • Emerging: A surge of new disease cases in a new population.
    • Re-emerging: Increasing cases of disease in previously affected populations.

    Challenges in Disease Eradication

    • Polio and smallpox elimination was easier due to the lack of zoonotic transmission.
    • Lyme disease and AIDS lack vaccines, complicating eradication efforts.

    Reservoir Host

    • A reservoir host is a species where a pathogen can live and multiply without causing significant harm.
    • Reservoir hosts are crucial for the survival of various pathogens.

    Hendra Virus

    • First identified in Australia in 1994 as Hendra virus, formerly known as equine morbillivirus.
    • Caused by the paramyxoviridae Henipavirus family.

    Hendra Infection Statistics

    • Between 1994-2016, around 70 horses were infected, primarily in Queensland and New South Wales.
    • Approximately 7 humans were infected with a 57% case fatality rate, experiencing flu-like symptoms and respiratory issues.
    • The incubation period for Hendra virus ranged from 9 to 16 days.

    Transmission

    • Hendra virus is transmitted to humans through exposure to infected horse fluids.
    • No known human-to-human transmission has occurred.
    • Horses acquire the virus from contact with infected flying foxes' urine, which acts as a natural host.

    Dogs and Hendra

    • A dog tested seropositive for Hendra in 2013 but showed no significant symptoms.
    • Horses are considered the amplifying hosts.

    Disease Spectrum

    • The progression of zoonotic diseases includes exposure, infection, pathogenicity, serious disease, and mortality.

    Infectivity and Mortality

    • Infectivity measures a microorganism’s ability to infect hosts.
    • Mortality is assessed based on the number of deaths in relation to exposed individuals.

    Serious Disease and Mortality Causes

    • Both race horses and humans experience significant disease and mortality from Hendra infection.

    Flying Foxes and Hendra Outbreaks

    • Flying foxes were expected to be the reservoir due to their presence in outbreak areas and large group migrations.

    Treatment and Prevention for Humans

    • Supportive treatment is offered, while research is ongoing for passive immunity treatments.
    • Preventive measures include vaccinations for horses and early recognition of the disease, especially for veterinarians.

    Infection Rates Among Bats and Carers

    • Zero bat carers showed signs of Hendra exposure, while 50% of bats assessed showed signs of infection.

    Amplifying Hosts

    • Horses serve as the amplifying hosts for the Hendra virus.
    • Pigs are identified as amplifying hosts for foot and mouth disease.

    Foot and Mouth Disease Insights

    • Sheep act as asymptomatic carriers; pigs amplify the virus, while cows experience the largest pathogenic effects.
    • A single outbreak of foot and mouth disease could cost the U.S. economy $27 billion in a year.

    Hendra as an Emerging Infectious Disease

    • Initially viewed as a spillover incident, Hendra virus is now recognized as an emerging infectious disease due to increased cases.

    Historical Emerging Infectious Diseases

    • Notable recent emerging diseases include HIV/AIDS, Ebola, and Zika.
    • The Spanish flu pandemic of 1918/1919 caused around 50 million deaths, believed to have originated from ducks.

    Zoonotic Disease Statistics

    • Zoonotic diseases make up about 60% of infectious diseases in humans.
    • 75% of emerging or re-emerging infectious diseases are zoonotic in nature.

    Future Epidemic Concerns

    • The next major infectious disease epidemic is likely to originate from wildlife, with 70% of zoonotic diseases emerging from wild sources.
    • Bushmeat is a common term for meat sourced from wild animals, relevant to zoonotic disease spread.
    • Ebola outbreaks are closely associated with bushmeat consumption and wildlife contact.

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    Description

    Test your knowledge on zoonotic diseases with this quiz based on Chapter 1 of Spillover. Explore key terms and their definitions related to the transmission of diseases from animals to humans. Perfect for students and anyone interested in epidemiology.

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