ICL 1.11: Zoonotic Viruses II Flashcards

1
Q

which viruses are associated with rodent-born viruses?

A

BUNYAVIRIDAE
1. Hantaan virus

  1. Puumala virus
  2. Sin Nombre virus

ARENAVIRIDAE
1. Lassa virus

  1. Lymphocytic choriomeningitis virus (LCMV)
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2
Q

what are the characteristics of the bunyaviridae family?

A

enveloped, helical, tri-segmented, circular (-) sense ssRNA

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3
Q

what are the characteristics of the arenaviridae family?

A

enveloped, helical, segmented (-) sense ssRNA

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4
Q

how are rodent-born viruses transmitted?

A

breathing in rodent urine/feces and contaminated materials

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5
Q

how do you prevent rodent-born viruses?

A

rodent-born viruses are transmitted by breathing in rodent urine/feces and contaminated materials

so you can’t exactly get rid of the vector so instead you just have to clean up the mess

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6
Q

which viruses are in the hantavirus genus of the bunyavirus family and are rodent-transmitted viruses?

A
  1. Hantaan virus
  2. Puumala virus
  3. Sin Nombre virus

all other bunyaviruses are arboviruses!! aka transmitted by mosquitos! hantaviruses are the only rodent-transmitted bunyaviruses

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7
Q

what is the disease, occurrence and vector associated with the Hantaan virus?

A

disease = Korean HF

occurence = Asia

vector = field mouse

bunyaviridae family; hantavirus genus = enveloped, helical, segmented (-) sense ssRNA

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8
Q

what is the disease, occurrence and vector associated with the Puumala virus?

A

disease = HF with renal syndrome

occurrence = Europe, Asia

vector = bank vole

bunyaviridae family; hantavirus genus = enveloped, helical, segmented (-) sense ssRNA

**this is HF with renal syndrome while HF with jaundice would be yellow fever!

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9
Q

what is the disease, occurrence and vector associated with the Sin Nombre virus?

A

disease = Hantavirus pulmonary syndrome

occurrence = North and South America

vector = deer mouse

bunyaviridae family; hantavirus genus = enveloped, helical, segmented (-) sense ssRNA

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10
Q

what condition is more prevalent with old world vs. new world hantaviruses?

A

Old World: Hemorrhagic fever with renal syndrome (Asia) = Puumala virus

New World: Hantavirus pulmonary syndrome (americas) = Sin Nombre virus

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11
Q

what are the early and late symptoms of the hantavirus pulmonary syndrome?

A

EARLY SYMPTOMS

  • Fever
  • Headaches
  • Muscle aches
  • Stomach problems
  • Dizziness
  • Chills

LATE SYMPTOMS

  • fluid-filled lungs = pulmonary capillary leak
  • shortness of breath
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12
Q

what is hemorrhagic fever?

A

a fever with increased susceptibility to bleeding

includes flushing, petechiae, edema, hypotension, capillary leak and shock

malaise, myalgia, vomiting and diarrhea occur frequently

liver damage, DIC and antibody-dependent enhancement (ADE) can contribute to symptoms

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13
Q

which specific viruses in the arenaviridae family are rodent transmitted viruses?

A
  1. lassa virus

2. lymphocytic choriomeningitis (MCMV)

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14
Q

what is the disease, occurrence and vector associated with the lassa virus?

A

disease = lassa HF

occurrence = Africa

vector = rodent

arenaviridae family = enveloped, helical, segmented (-) sense ssRNA

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15
Q

what is the disease, occurrence and vector associated with the lymphocytic choriomeningitis virus?

A

disease = choriomeningitis

occurrence = worldwide

vector = rodent

arenaviridae family = enveloped, helical, segmented (-) sense ssRNA

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16
Q

which virus families are bat borne-viruses?

A
  1. rhabdoviridae
  2. filoviridae
    - ebola virus
    - marburg virus
  3. paramyxoviridae
    - nipah virus
    - hendra virus
  4. coronaviridae
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17
Q

what are the characteristics of the rhabdoviridae family?

A

enveloped, helical (-) sense ssRNA virus

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18
Q

what are the characteristics of the filoviridae family?

A

enveloped, helical (-) sense ssRNA virus

19
Q

what are the characteristics of the paramyxoviridae family?

A

enveloped, helical (-) sense ssRNA virus

20
Q

what are the characteristics of the coronaviridae family?

A

enveloped, helical (+) ssRNA virus

21
Q

how fatal is the rabies virus?

A

> 50K deaths/year worldwide

99.99% CFR once CNS involvement!! once the virus gets to the brain, the chances for survival are literally 0 but there are offically 2 documented survivors

22
Q

what are the natural hosts of the rabies virus?

A

wide host range: skunk, fox, coyote, raccoon, mongoose, rarely small rodents, bats!

it’s 95% canine-associated worldwide

but it’s 75% bat-associated in the USA because our dogs are vaccinated

23
Q

how many serotypes of rabies are there?

A

only 1!

this is really unusual for ssRNA viruses but this just means that’s its a stable virus that hasn’t changed alot over the years

24
Q

what is the shape of rhabdoviruses?

A

bullet shaped!

25
Q

how is rabies transmitted?

A
  1. most common is transmission by bite directly from an infected host
  2. corneal/other transplants
  3. wounds
  4. rarely, aerosol

no cases of human-human transmissions

26
Q

how does rabies spread in the body?

A

spreads via the nerves! there is NO detectable viremia!

if you get bit by a dog in the foot, the virus will replicate at the bite site and then get into a neuron

once it’s in the neuron, it’s protected and it will travel along the neuron and progress to you brain

so if you get bit on your toe it’ll take a while to get to the brain and you’ll have time to protect yourself from rabies but once it does get to the brain, the symptoms will be so severe that you won’t survive

the average incubation period is 2weeks-18 months depending on where you get bit

27
Q

what do you do if you’ve been bit by a host with rabies?

A

rabies vaccine! it’s a killed vaccine

if you use the vaccine, you’ll have post-exposure protection against the rabies and have an antibody response even though you’re getting the vaccine after you’ve been bit – this is because it takes such a long time for the virus to reach the CNS you have time to generate antibodies

the catch is that the virus is hiding in the neurons and the antibodies won’t be able to reach it but the good news is that virus has to travel between neurons and in the time that it leaves one neuron to get to the other, the antibodies have the opportunity to neutralize the virus and protect us!

so post-exposure vaccination is possible because it takes so long for the virus to get to its final destination in the brain

28
Q

what are the steps of a rabies infection from bite to CNS involvement?

A
  1. virus enters via animal bite
  2. virus replicates in muscle at site of bite

rabies has a glycoprotein that binds to nicotinic acetycholine receptors in the post-synaptic membrane of the neuromuscular junction – there in the motor neurons, it replicates

  1. virus infects nerve in peripheral nervous system and moves by retrograde transport
  2. virus replicates in dorsal root ganglion and travels up spinal cord to brain
  3. brain infected
  4. virus travels from brain via nerves to other tissues such as eye, kidneys, salivary glands,etc.
29
Q

what are the symptoms associated with rabies?

A

they’re variable and often misdiagnosed but they include:

  • fever
  • headache
  • malaise
  • encephalitis!!
  • nausea
  • vomiting
  • myalgia
  • hydrophobia
  • confusion
  • hallucinations
  • seizures
  • paralysis
  • respiratory failure
  • lung infilatrates
  • coma
  • death
30
Q

when do you vaccinate people for rabies?

A
  1. if they’ve been bitten by an infected host

2. if they’re at risk for getting rabies like a vet, wildlife officer, world traveler, researcher etc.

31
Q

what is the Milwaukee protocol?

A

rabies treatment where you put the patient into a chemically induced coma and administering antiviral drugs

in a coma, things move slower in the body so we think this also slows down the virus and gives the drugs a chance to work

32
Q

how do you diagnose rabies?

A
  1. presence of neutralizing antibodies in serum/CSF (may be too late)
  2. direct fluorescence on biopsy (nuchal, brain), also on animal
  3. RT-PCR saliva
  4. post-mortem staining of brain slice
33
Q

what are Negri bodies?

A

they are cytoplasmic inclusion bodies in a neuron that are associated with the rabies virus

they are diagnostic for rabies!!

just looks like a purple circle in the cytoplasm of the cell

34
Q

what are the different types of inclusion bodies associated with viruses?

A
  1. Negri bodies = rabies cytoplasmic inclusion bodies
  2. Cowdry bodies = herpes nuclear inclusion bodies
  3. Guarnieri bodies = poxvirus cytoplasmic inclusion bodies
35
Q

what are the characteristics of the ebola/marburg viruses?

A

filoviridae family = enveloped, helical (-) sense ssRNA virus

“thread like”

influenza can also look like a thread so this is NOT diagnostic!

36
Q

how are the ebola/marburg viruses transmitted?

A

human to human

so you can get ebola from a dead body during the burial process or if you’re a caregiver to a sick person…

37
Q

what is the mortality of the ebola/marburg viruses?

A

CFR can be as high as 60-90% for some strains

there’s also super high viremia so this virus has a high CFR, is transmitted human-human and the blood is full of virus….this is just a bad combination

38
Q

what are the symptoms of the ebola/marburg viruses?

A
  • HF
  • petechiae
  • end organ failure
  • high viremia

eventually fatal because of severe blood loss leading to hypovolemic/hemmoragic shock

39
Q

which specific filoviridae viruses are bat-borne viruses?

A
  1. ebola virus

2. marburg virus

40
Q

which specific paramyxoviriuses are bat-borne viruses?

A
  1. Nipah virus

2. Hendra virus

41
Q

how are the nipah and hendra viruses transmitted?

A

host = fruit bats and pigs (mainly bats)

transmitted by contaminated fruits/date palm sap – there are fruit bats in the sap trees and people were eating the sap and getting sick…

there are also human-human cases

paramyxoviridae family = enveloped, helical (-) sense ssRNA virus

42
Q

how do you treat the nipah and hendra viruses?

A

no treatment….

supportive care only

CFR = 75%…..

43
Q

what are the symptoms of the nipah and hendra viruses?

A
  • acute respiratory distress

- encephalitis

44
Q

which diseases are there travel vaccines for?

A
  1. Yellow fever virus
  2. Rabies
  3. Flu
  4. TBEV (not available in US)