Micro 10 Ex 2

Front 1

the most virulent pathogens that affect human beings.
They are classified into two genera

Back 1

Marburg virus and Ebola virus

Front 2

Ebola virus genome

Back 2

, linear, nonsegmented, negative-stranded RNA.
Noninfectious, complementary to viral mRNA
Transcribed into subgenomic mRNAs encoding 7 structural proteins.

Front 3

Where does the ebola virus replicate?

Back 3

cytoplasm

Front 4

Ebola viruses cause

Back 4

severe haemorrhagic fever which leads to multisystem dysfunction.
incubation period 4-10 days.

Front 5

Ebola disease is characterized by

Back 5

pharyngitis, nausea, and severe vomiting of blood and production of blood stools.

If fatal, death occurs 6-9 days after onset of the clinical disease.

All sick individuals have circulating viral antigen. Mortality rate is up to 90%.

Front 6

High risk patients for Ebola are

Back 6

traveled into areas where hemorrhagic fever occurred recently.

been in contact with with body fluids from a person with hemorrhagic fever.

worked in a laboratory environment handling the viruses.

Front 7

The most lethal ebola strain to humans

Back 7

Zaire ebolavirus

Front 8

Ebola virus reservoir

Back 8

Fruit bats

Front 9

How does Ebola virus causes viral replication?

Back 9

Ebola VP 35 inhibits activation of PKR protein which induces the viral replication

Front 10

Detection of Ebola virus is via

Back 10

ELISA, RT-PCR and immunohistochemistry.

Front 11

Ebola tx

Back 11

No vaccine or antiviral drugs are available to control filovirus infections.

Treatment is limited to the supportive measure. Antibody-containg serum and interferon therapies have been tried in patients with filovirus infection.

Infected patients should be quarantined and contaminant animals should be sacrificed.

Handling of this family of viruses or contaminated materials requires biosafety level 4 facilities.

Front 12

Bunyaviruses are typically spread by

Back 12

mosquitoes, ticks, or flies. However, the hantaviruses are the exception where they are carried by rodents.

Front 13

Bunyaviruses are the causative agents of

Back 13

encephalitis and hemorrhagic fevers.

The viruses are classified as biohazard level 3 or 4 pathogens.

Front 14

Bunyaviruses genome

Back 14

enveloped, segmented, negative-stranded RNA viruses.

Viral particles are roughly spherical and 90-120 nm in diameter.

Viruses encode structural and non-structural proteins

Front 15

Unique features of bunyaviruses:

Back 15

Share common morphology and basic components
Virion is enveloped with three (L, M, S) negative-sense RNA genome strands. Organized in a nucleocapsid, but virion has no matrix protein

Front 16

bunyaviruses replicate in

Back 16

cytoplasm.

Virus can infect humans and arthropods.
Virus in arthropod can be transmitted to its eggs.

Front 17

bunyaviruses are transmitted by

Back 17

bite of an infected arthropod
California encephalitis group is transmitted by Aedes mosquito

Front 18

Aedes mosquito characteristics

Back 18

Aedes mosquitoes are daytime feeders and live in forest
Aedes mosquitoes lay eggs in small pools of water trapped in places such as trees and tires.
Virus is able to pass into ovary and infect arthropod eggs, allowing virus to survive during winter.

Front 19

People at risk of bunyaviruses

Back 19

People in the habitat of the arthropod vector (e.g., campers, forest rangers and woodsmen for California encephalitis virus).

Front 20

bunyaviruses Geography/Season

Back 20

Disease incidence correlates with vector distribution (more common in summer).

Front 21

Initial viremia by bunyaviruses causes

Back 21

flu-like symptoms

Front 22

Establishment of secondary bunyavirus viremia may allow virus access to specific target tissues

Back 22

Particular target tissue determines the nature of disease
May include central nervous system, vascular endothelium, or other organs (hemorrhagic fevers/encaphalitis).

Front 23

Immune response to bunyavirus

Back 23

Antibody is important in controlling viremia.
Interferon and cell-mediated immunity may prevent the outgrowth of infection

Front 24

Encephalitis is caused by

Back 24

La Crosse virus

Front 25

Hemorrhagic necrosis caused by

Back 25

Rift Valley fever virus

Front 26

pathogenesis of rift and la crosse virus

Back 26

Front 27

how to detect bunyaviruses

Back 27

Enzyme-linked immunoasorbent assay (ELISA) may detect antigen in clinical specimens from patents with viremia.

The reverse-transcription-polymerase chain reaction (RT-PCR) test can be used to detect viral nuclei acids.

Virus-neutralization assays can be used to indentify the virus.

Assays for immunoglobulin (Ig) M are useful in the documentation of acute infection and IgG analysis is used to document recent infection.

Front 28

bunyaviruses tx

Back 28

No specific therapy is available for infections of Bunyaviruses.

Human disease is prevented by interruption of the contact between humans and the vector.

Arthropod vectors are controlled by eliminating the growth conditions for the vector.

Rodent control minimizes the transmission of many viruses, especially hantaviruses.

Front 29

Arenaviruses
genome

Back 29

enveloped virion with two circular, negative-sense RNA genome segments (L, S). Virion appears sandy because of ribosomes that are packaged in particle.
S genome segment is ambisense (both positive and negative sense)

Front 30

Arenavirus infections are

Back 30

are zoonoses, establishing persistent infections in rodents.
Pathogenesis of arenavirus infections is largely attributed to T-cell immunopathogenesis.

Front 31

Arenaviruses can infect macrophages and may cause release of

Back 31

mediators of cell and vascular damage.

Front 32

Arenaviruses Tissue destruction is exacerbated by

Back 32

T cell mediated immune responses.
Virus infects specific rodents and is endemic to rodents habitat (mainly tropics).

Front 33

Humans become infected with arena virus through

Back 33

inhalation of aerosolized urine and feces, or through contaminated foods.

Front 34

An arenavirus infection is usually diagnosed on the basis of

Back 34

serological findings. These virus are too dangerous for routine isolation.

Front 35

Ribovirin has limited activity against

Back 35

arenaviruses and supportive therapy is all that is available for patients with arenavirus infections.
These rodent-borne infection can be prevented by limiting contact with the vector.