Human Diseases Caused by Viruses and Prions Flashcards by Imani B

Airborne Diseases

How do humans transmitted airborne diseases?

viruses are propelled from the respiratory tract by coughing, sneezing, or vocalizing

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routes of viral transmission

airborne
arthropods
direct contact
food and water
zoonotic

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Airborne Diseases

examples of airborne diseases

chickenpox
flu
measles
mumps
RSV
rubella
smallpox

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Chickenpox (varicella)

Chickenpox is a DNA virus, a member of…

herpesviridae

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Chickenpox (varicella)

Humans serve as a….

reservoir and source

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Chickenpox (varicella)

How is chickenpox acquired?

droplet inhalation into respiratory system

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Chickenpox (varicella)

Describe chickenpox

result from initial infection
individuals that recover are immune, but not free of the virus
vaccine prevents or shortens illness

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Shingles (herpes zoster)

What is shingles?

a reactivated form of chickenpox

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Shingles (herpes zoster)

Where does the shingles virus reside?

episome in cranial and sensory neurons
- reactivation – virus migrates down neuron

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Shingles (herpes zoster)

How is shingles treated?

supportive; acylovir and others

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Influenza

What is influenza?

a respiratory system disease caused by influenza virus

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Influenza

What type of virus is influenza?

RNA virus; segmented genome

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Influenza

What are the 3 genera?

A, B, and C

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Influenza

How is influenza acquired?

by inhalation or ingestion of respiratory secretions

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Influenza

Subtypes of influenza are based on…

hemagluttinin (HA) and neuraminidase (NA)

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Influenza

What are NA and HA?

membrane surface glycoproteins

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Influenza

What are HA and NA functions?

part of viral attachment and virulence

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Influenza

How many antigenic forms do HA and NA have?

18 HA
11 NA

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Influenza

antigenic drift

due to accumulation of mutations in a strain
- vaccine mismatch

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Influenza

antigenic shift

due to reassortment of genomes when two different strains of flu viruses (from humans and animals) infect the same cell and are incorporated into a single new capsid
- epidemics

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Arboviruses

What are arboviruses?

viruses transmitted by bloodsucking arthropods from one vertebrae host to another

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Arboviruses

What are arboviruses capable of doing?

multiply in tissues of vector without producing disease
- vector acquires a lifelong infection

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Arboviruses

What three clinical syndromes can arboviruses be placed into?

undifferentiated fevers, with or without rash
encephalitis-inflammation of the brain; fatality rate is usaully high
hemorrhagic fevers - frequently severe and fatal

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Arboviruses

What are treatment options available for arboviruses?

supportive treatment, no vaccine

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# Arboviruses What are some examples of arboviruses?

- chikungunya - dengue - west nile virus - zika

# Dengue and Dengue Hemorrhagic Fever What type of virus is dengue?

enveloped RNA virus - worldwide distribution, endemic in over 100 countries where mosquito vectors are found

# Dengue and Dengue Hemorrhagic Fever What are the dengue serotypes?

DENV-1 through DENV-4

# Dengue and Dengue Hemorrhagic Fever What are symtpoms of dengue?

- fever - rash - joint and bone pain - muscle aches - mild bleeding of the gums - easy bruising lasting 3 to 10 days

# Dengue and Dengue Hemorrhagic Fever What does the first infection with one serotype DENV result in? (ex. DENV-1)

the formation of neutralizing antibody, which limits infection

# Dengue and Dengue Hemorrhagic Fever What does the second infection with a different DENV serotype result in? (ex. DENV-2)

the binding of anti-DENV-1 antibody - this opsonizes rather than neutralizes the virus, which uses phagocytic immune cells as productive cells

# Dengue and Dengue Hemorrhagic Fever antibody-dependent enhancement

occurs if an individual is later bitten by a mosquito carrying any of the other serotypes - antibodies will recognize the E protein of the serotype even though it is structurally distinct, leading to DHF

# Zika What type of virus is zika?

enveloped RNA virus in the Flaviviridae

# Zika How can zika be transferred?

- transmitted by many species of Aedes mosquitoes - can be transmitted person to person in bodily fluids like breast milk and semen

# Zika What are symptoms of zika?

- mild fever - rash - joint pain - conjuntivitis that resolves in 3 to 7 days

# Zika What percentage of people are symptomatic with zika?

only about 18% of people

# Zika What birth defect in zika known to cause?

microcephaly

# Direct Contact Diseases How are direct contact disease transmitted?

through direct personal contact

# Direct Contact Diseases What are examples of direct personal contact?

- touching - kissing - sexual contact - contact with body fluids - contact with open wounds

# Direct Contact Diseases What are some examples of direct contact diseases?

- HIV - cold sores - common cold - herpes - mononucleosis - poliomyelitis - herpes - hepatitis

What does the phrase "food and water are vehicles for viral disease" mean?

several viruses cause common food-borne and waterborne diseases

# Gastroenteritis (Viral) What is acute viral gastroenteritis?

inflammation of stomach or intestines

# Gastroenteritis (Viral) What demographic is affected by acute viral gastroenteritis?

important disease of infants and children - leading cause of childhood death in developing countries

# Gastroenteritis (Viral) How is acute viral gastroenteritis transmitted?

fecal-oral route

# Gastroenteritis (Viral) What are the major virus groups that cause acute viral gastroenteritis?

- rotaviruses - adenoviruses - astroviruses - bocaparvoviruses - caliciviruses - parechoviruses

# Gastroenteritis (Viral) How many cases of norovirus caused acute gastroenteritis cases are there per year in the US?

20 million cases/year

# Gastroenteritis (Viral) T/F: Acute gastroenteritis due to norovirus is usually self-limited disease.

TRUE

# Gastroenteritis (Viral) What are treatment options for acute gastroenteritis due to norovirus?

for symptomatic patients there is supportive therapy

# Gastroenteritis (Viral) For gastroenteritis caused by rotavirus what are treatment options?

vaccination - vaccination has reduced number of hospitalizations and deaths

# Zoonotic Diseases What are zoonotic diseases?

human viral infections in animal reservoirs before transmission to and between humans

# Zoonotic Diseases What are some examples of zoonotic diseases?

- ebola and marburg diseases - hantavirus pulmonary syndrome - rabies

# Ebola Hemorrhagic Fever What type of virus is it?

member of single-stranded, negative sense RNA family called the Filoviridae

# Ebola Hemorrhagic Fever How is it transmitted?

direct contact with ebola victim, body fluids or clinical samples - bats are a natural reservoir

# Ebola Hemorrhagic Fever What is it?

severe multisystem syndrome in which the host vascular system is damaged leading to vascular leaking (hemorrhage) and dysfunction (coagulopathy)

# Ebola Hemorrhagic Fever What are treatment options?

supportive therapy; no treatment available

# Hantavirus Pulmonary Syndrome (HPS) What type of virus is it?

single-stranded, negative sense RNA virus in Bunyaviridae family

# Hantavirus Pulmonary Syndrome (HPS) How is it transmitted?

to humans by inhalation of virus particles shed in urine, feces, or saliva of infected rodents

# Hantavirus Pulmonary Syndrome (HPS) Are there any mortality risks for this?

potentially deadly for humans but do not cause disease in their reservoir (rodent) hosts

# Hantavirus Pulmonary Syndrome (HPS) What are the treatment options?

supportive therapy; no specific treatment avaibable

# Rabies What type of virus is it?

negative-strand, bullet-shaped, RNA virus - highly neurotropic

# Rabies How are rabies transmitted?

primarily by bites of infected animals

# Rabies How frequently are rabies seen in the US?

fewer than 10 cases per year in the US

# Rabies First rabies...

enter the host cell and multiply.

# Rabies After multiplication, rabies then...

enter nervous system and spread to the spinal cord - first specific symptoms may occur

# Rabies Rabies rapidly progresses into ?? as the virus spreads through the ??.

- encephalitis - central nervous system

# Rabies Rabies finally spreads to the ??; including ?? where it is...

- peripheral nerves - salivary glands - shed in saliva

# Rabies What are the symptoms of rabies?

- pain or paresthesia at wound site - anxiety - irritability - depression - fatigue - loss of appetite - fever - sensitivity to light and sound

# Rabies How soon do the symptoms of rabies appear?

2 to 16 weeks after exposure

# Rabies What does rabies quickly progress to?

- paralysis - death via destruction of brain regions that regulate breathing

# Rabies How is rabies diagnosed?

- previously by microscopy - currently direct immunofluorescent antibody (DFA), serology for antirabies antibody, and by PCR testing

# Rabies How are rabies treated?

- postexposure vaccination - preexposure vaccination of individuals with high risk of exposure, dogs, and cats

# Prions and Disease Induction Over Time prions

protein infectious particles - abnormally folded proteins which induce normal forms of protein PrPC to abnormally fold

# Prions and Disease Induction Over Time BSE agent

another name for prions

# Prions and Disease Induction Over Time T/F: BSE agent survives GI passage and is neurotropic.

TRUE

# Prions and Disease Induction Over Time What is a primary symtpom of prions?

dementia

# Prions and Disease Induction Over Time What are prion infections usually accompanied with?

motor dysfunction

# Prions and Disease Induction Over Time When do prion symptoms typically appear?

after prolonged incubation - lasts from months to years prior to death

# Prions and Disease Induction Over Time What are the effects of prions on the brain?

- produce spongiform brain degeneration - deposition of amyloid plaques

# Prions and Disease Induction Over Time What disease do prion infections share a lot of similarities with?

alzheimer's disease

# Prions and Disease Induction Over Time How are prion disease categorized?

- familial (inherited) types - sporadic types - acquired types

# Prions and Disease Induction Over Time TSEs

transmissible spongiform encephalopathies

# Prions and Disease Induction Over Time What are TSEs?

fatal neurodegenerative disorders caused by prions

# Prions and Disease Induction Over Time TSEs remain ?? for months or years.

clinically silent

# Prions and Disease Induction Over Time How do TSEs typically end?

in profound disability or death

# Prions and Disease Induction Over Time What are some disease examples of TSEs?

- Kuru - Creutzfeldt-Jakob (CJD) disease - variant CJD - bovine spongiform encephalopathy (BSE) - scrapie - FFI

# Prions and Disease Induction Over Time How are prion disease transmitted?

- medical procedures - genetic - food-borne