Lecture 8 Flashcards
Viruses
What nucleic acid do viruses have?
RNA or DNA never both
What is the role of nucleic acid
the infectious genetic material
What are surface antigens made of?
-protein or
carbohydrate
Wha tis the structure that encloses the genetic material of the virus and serves to protect it from damage
Capsid
List the steps of viral replication
1)Adsorption
2)penetration and uncoating
3)Nucleic acid and protein synthesis
4)Assembly
5)Release
How do we detect viral infections?
1) detect the virus itself
2)Detect the immune response…antibodies against the virus! DIRECT ELISA
What are ways of viral diagnosis?
A) detection in clinical specimen
2)Detection in patients immune response
What are some ways for Detection in clinical
specimen
1) Visualization by electron microscopy
2)Detection in clinical specimen (cell culture)
What consists of Cell culture in Detection in clinical
specimen
Cytopathic:hijaking of cellular machinary
hemagglutination: viruses that have hemagglutinin protein on their surface clump with RBC
immunofluorescence
What happens in Cytopathic
The virus defies the last step of replication… the whole cell is destroyed and particles are released… therefore If there is virus you get holes in cell culture
What is DIAGNOSTIC TEST
Rise in antibody concentration
What does Indirect elisa measure?
measure if patient made antibodies.
what does Immunnity test check?
presence or absence of IGG or IGM immunoglobulinobins
Difference between direct and indirect elisa?
Direct: detects antigen in sample
indirect: detect the antibody that is made by the patient + how many antibodies made.
List the 6 differetn types of respitory viruses.
- Influenza viruses
- Parainfluenza viruses
- Respiratory syncytial viruses
- Rhinoviruses
- Coronavirus
- Echoviruses, coxsackie viruses, herpes viruses
(occasional respiratory tract infection)
Difference btween influenza type A and type B?
Type A:major epidemics
Type B:milder disease
How can i diagnose viruses with the influenza family
haemagglutinin.. becuase they produce it
Who does parainfluenza affect most?What are the symptoms?Treatment
age 5 and below, respitory infections/croup,Bronchiolitis…NO VACCINE
who does Respiratory syncytial virus affect? what does infect?Treatment? Antiviral
children ages 2 and below,Pneumonia and bronchiolitis, NO VACCINE, Ribavizine
What class of respisotry viruses is the common cold? WHats different about it?
rhinovirus. No cross immunity
What do enteric viruses infect?
intestinal / lymphoid cells
Give 3 examples of enteric viruses
Poliovirus, coxsackievirus, echovirus
Enteric viruses Multiply in GI tract but they RARLEY cause what?
gastroenteritis
What virus are humans the only host to?
poliovirus
What does poliovirus do?
invades the host nervous system
how are all enterics diagnosed
1)isolation: from stool samples up to 5-6 weeks from infection and CSF
2)Serology: acute and convalescent phases
How is polio prevented?
Salk vaccine or Sabin vaccine
what is salk vaccine and when is it used? what is the problem with it?
killed/innactivated vaccine used for immunocompromised. Problem is Virus can still colonize (does not produce IgA)host GI tract
What is Sabin vaccine
LIVE attenuated… ; host will produce IgA and IgG. protected against intestinal colonization
Coxsackieviruses… treatment
Groups A and B
No vaccine
what does echovrius cause and is thier any treatment
causes aseptic memigntis and minor respitory illnesse. NO VACCINE
What are the viruses causing diarhhea and who do they affect
Rotavirus:infants 6 month-2 years… 17 and under
Norovirus: 18 and older
How is rotavirus diagnoses?
electron microscopy or immunological testing from stool samples
How to prevent norovirus?
HIGHLy infectious no vaccine; handwashing and
isolation of infected individuals
What are the viruses causing rashes
Measles
* Rubella (German measles)
* Varicella (chickenpox)
* Herpes simplex (HSV)
* Papilloma virus
what symptoms do you get with Measles
rash first appears behind
ears, forehead and nostrils then
spreads to whole body;
BLOTCHY appearance
How is measles prevented?
Immunoglobulin: can suppress disease if given within
5 days of contact with virus and live attenuated vaccine
…. is VERY dangerous for non-immune pregnant
women
rubella
