Emergeing viruses Filoviruses (Marburg and Ebola) Arenaviruses (LASSA and related viruses), Bunyaviruses (Sin Nombre Virus)

Question 1

Describe Filoviruses

Answer 1

Virus: Marburg virus
Disease: Hemorrhagic fever
Virus: Ebola virus
Disease: hemmorrhagic fever

Question 2

Filovirus Transmission

Answer 2

Contact with infected monkeys or tissues secretions or body fluids
Contact with infected humans
Accidental injection, contaminated syringes

Question 3

Filovirus at risk or risk factors

Answer 3

-Monkey handlers
-Health care workers attending sick

Question 4

Filovirus distribution of virus

Answer 4

-Endemic in monkeys in Africa
No seasonal incidence

Question 5

Filovirus vaccines or antiviral drugs

Answer 5

None

Question 6

Filovirus disease mechanisms

Answer 6

-Acquired from monkeys or infected humans
-Virus replication causes necrosis in liver, spleen, lymph nodes, and lungs.
-Hemorrhage causes edema and shock

Question 7

What are unique and shared features of filoviruses compared to other non-segmented negative strand RNA viruses?

Answer 7

-Ebola and Marburg viruses cause severe hemorrhagic disease (unique).
- Negative strand RNA, single strand genome; genes arranged linearly on genome (shared)
Enveloped virions (shared)
-Morphology of viroions = U shaped, 6 shaped, or circular shape 80 nm in diameter, up to 14,000 nm long (unique)
-Synthesis of both secreted and membrane bound surface glycoprotein (unique)
- Novel viral protein VP24 = inhibits the induction of the host anti-viral genes by blocking interferon signaling (unique)

Question 8

Describe the structure of Ebola virus

Answer 8

The interaction between nucleoprotein subunits is not as rigid as other viruses such as tobacco mosaic virus so Ebola virus often shows a wavy structure

Question 9

True or False: Naked RNA is not enough to cause infection

Answer 9

True

Question 10

U shape advantageous true or false?

Answer 10

True, according to evolution

Question 11

What are the symptoms of Ebola virus infection?

Answer 11

-Fever greater than 38.6 C or 101.5 F
-Severe headache
-Muscle pain
-Weakness
-Diarrhea
-Vomiting
-Abdominal (stomach) pain
- Unexplained hemorrhage (bleeding or bruising) (viruses destroy tissue integrity, blood vessels can’t get blood).
-

Question 12

Ebola virus health outcomes

Answer 12

Symptoms may appear anywhere from 2-21 days after exposure to ebola average is 8-10 days
Recovery depends on good supportive clinical care and patient immune response
people who recover from ebola develop antibodies that last for at least 10 years.

Question 13

Transmission of Ebola virus

Answer 13

-Spread through direct contact (via broken skin or mucuous membranes in eyes, nose, or mouth)
-blood or body fluids (including urine, saliva, sweat, feces, vomit, breast milk, semen) of a person who is sick with Ebola
- Objects (needles/syringes) that have been contaminated with the virus.
-Infected animals
-Virus not spread through the air or by water or in general by food; in Africa may be spread as a result of handling bushmeat.
-No evidence that mosquitos or other insects can transmit Ebola virus; only mammals (human, bats, monkeys, and apes) have so far been infected with the Ebola virus.
-Healthcare providers caring for Ebola patients and family/friends in close contact with Ebola patients are at the highest risk of getting sick since they may come in contact with infected bloody/body fluids of patients.

Question 14

True or False, reassortment of RNA segments of 2 different strains of influenza produce new isolates of influenza which can lead to new viruses with the potential to cause pandemics.

Answer 14

True

Question 15

Hantavirus transmission

Answer 15

Rodents are the host to the virus
Virus is present in feces, urine, and saliva
If it becomes airborne it can be inhaled by humans and result in infection.
Can also enter the body through open wounds and rodent bites.

Question 16

What happens in the early stages of hantavirus?

Answer 16

Fever
Muscle aches
Fatigue
Nausea
Abdominal pain

Question 17

What happens in late stage hantavirus

Answer 17

Hantavirus pulmonary syndrome
coughing
shortness of breath
fluid filling in the lungs
40% mortality rate

Question 18

New world Hantaviruses (Americas)

Answer 18

Lead to Hantavirus pulmonary syndrome (HPS)

Question 19

Old World Hantavirus known in Europe and Asia

Answer 19

Can cause hemmorhaic fever with renal syndrome (HFRS)

Question 20

What is the most important hantavirus in the US that can cause HPS?

Answer 20

Sin Nombre virus spread by the deer mouse

Question 21

Hantavirus is part of what virus family?

Answer 21

Buyavirus family
Associated with hemorrhagic fever and renal syndrome
In 1993, Sin Nomrbre virus was associated with acute respiratory illness in southwestern US
> 50% mortality rate
first report of acute hantavirus associated illness in America
Hantavirus in other parts of the world are not associated with severe respiratory illness
Primarily spread through deer mice
Likely from rat excrement

Question 22

Bunyaviruses transmission

Answer 22

Arthropod bites
Rodent Excretea

Question 23

Bunyavirus at risk or risk factors

Answer 23

people in the area of vector (campers)

Question 24

Bunyavirus distribution of virus

Answer 24

depends on distribution of vector on rodents
disease is more common in summer

Question 25

Bunyavirus vaccine or antiviral drugs

Answer 25

none

Question 26

Bunyavirus disease mechanisms

Answer 26

Transmitted by arthropod bite or rodent excreta Primary viremia then secondary viremia leads to virus spread to target tissues including CNS various organs and vascular endothelium Antibody is essential for controlling viremia

Question 27

Characteristics of hantaviruses

Answer 27

No arthropod vector established which is unique Rodent hosts Transmission by aeroslozation of rodent excrement

Question 28

What is the clinical presentation of hantavirus pulmonary syndrome?

Answer 28

Most frequent: - fever -myalgia -nausea/vomiting - cough Other: -dizziness -arthalgia -shortness of breath Rare: Rhinorrhea Sore throat

Question 29

Sin Nombre Virus Summary

Answer 29

Family: Bunyaviridae Transmission: Vertebrate hosts no arthropod vectors Viral Particles: spherical 80-120 nm Structural proteins: glycoproteins: G1, G2, nucleoprotein: N Genome: ss RNA, tri segmented, negative polarity

Question 30

Arenavirus: Lymphocytic Choriomeningeitis virus

Answer 30

Disease: Febrile, flu like myalgia; meningitis

Question 31

Arenavirus: Lassa Virus

Answer 31

Lassa fever: severe systemic illness, increased vascular permeability shock

Question 32

Arenavirus: Junin virus

Answer 32

Argentine hemorrhagic fever: similar to Lassa fever but more extensive bleeding

Question 33

Arenavirus: Machupo virus

Answer 33

Bolivian hemorrhagic fever

Question 34

Arenavirus transmission

Answer 34

Contact with infected rodents or their secretions or body fluids

Question 35

Arenavirus at risk or risk factors

Answer 35

Lymphocytic chiorimentigis virus: contact with pet hamsters, areas with rodent infestation. Other arena viruses: habitat of rodents

Question 36

Arenavirus distribution of virus

Answer 36

Lymphocytic choriomeningitis virus: hamsters and house mice in Europe, Americas, Australia, possibly Asia Other arena viruses: Africa, South America, US, No seasonal incidence

Question 37

Arenavirus vaccines or antiviral drugs

Answer 37

No vaccines antiviral drug ribavirin

Question 38

Arenavirus disease mechanisms

Answer 38

Transmitted from persistently infected rodents Persistent infection of rodents caused by neonatal infection and induction of immune tolerance Viruses infect macrophages and release mediators of cell and vascular damage Tissue destruction caused by T cell immunopathology

Question 39

More arena virus facts

Answer 39

Latin for Sandy Enveloped virus or pleomorphic single stranded genome divided into 2 RNA segments Two genes on each segment encoding a total of 5 proteins

Question 40

Lassa fever pathogenesis comes from?

Answer 40

T cells

Question 41

Key Points: Negative Strand RNA Viruses

Answer 41

General Features: All viruses are enveloped with genomic RNA in a helical RNP Virions carry viral transcriptase (RNA dependent RNA polymerase) Transcription template is an RNP complex Some virion glycoproteins have special features/activities Cause many different types of disease

Question 42

Viruses with non-segmented genomes (paramyxoviruses, rhabodo viruses, filoviruses)

Answer 42

Synthesize multiple mRNA from one genomic RNA

Question 43

Viruses with segmented genomes (bunyaviruses, arena viruses, orthomyoxiviruses)

Answer 43

Potential for segment re assortment disease implications Influenza has many unique features during virus replication which takes place in nucleus.

Question 44

Which of the following statements about Sin Nombre virus (a hantavirus) is also true for rabies virus? A) It carries out mRNA synthesis in the cytoplasm of infected cells? B) It can be transmitted by exposure to rodent excreta C) It carries a segmented genome in its virion particle D) There is no approved vaccine against the virus E) None of the above

Answer 44

A) It carries out mRNA synthesis in the cytoplasm of infected cells?

Question 45

Which of the following properties is NOT shared by measles virus and Ebola virus A) Encode their own RNA dependent RNA polymerase B) Utilize mRNA editing during their infectious cycle C) Assemble virus particles in the cytoplasm of infected cells D) Transmission by blood borne route E) Enveloped various

Answer 45

D) Transmission by blood borne route