Semester 2 - Non-enveloped Viruses Flashcards Preview

2nd year - Microbiology > Semester 2 - Non-enveloped Viruses > Flashcards

Flashcards in Semester 2 - Non-enveloped Viruses Deck (63):
0

What are some features of non-enveloped viruses?

Many are resistant to common disinfectants, desiccation, acidification = highly stable
Commonly associated with GI and respiratory tract infections

1

What are some examples of DNA viruses?

Adenovirus
Papillomaviruses
Paroviruses

2

What are some examples of RNA viruses?

Picornaviruses (poliovirus, rhinovirus, enterovirus)
Hepevirus
Noroviruses
Reoviruses (rotavirus)

3

What are some characteristics of Adenoviruses?

Large, dsDNA virus, 57 human serotypes
Highly stable virions - non-enveloped viruses more resistant to desiccation, acid treatment, etc.
Ubiquitous human virus, used as a vector of gene therapy/vaccination approaches
Infection often asymptomatic (depends on serotype)

4

How are genes expressed in Adenoviruses?

Occurs in the nucleus using host cell machinery
Genes are spliced and modified similarly to host genes
Early genes (E genes) enzymatic/regulatory
Late genes (L genes) structural

5

What are the symptoms of a respiratory adenovirus infection (1, 2, 5, 6, 14)?

Associated with acute respiratory disease
Croup (upper airway inflammation), hoarseness of the throat
Fever, rhinorrhea, cough, sore throat
Tonsilitis, bronchiolitis, pneumonia in more severe cases

6

What are the symptoms of an enteric Adenovirus (40, 41) infection?

Associated with gastroenteritis
Food-borne illness, fecal-oral transmission
Diarrhea, fluid and electrolyte loss

7

What are the signs and symptoms of conjunctivitis/keratoconjunctivitis Adenovirus (3, 4, 7, 8, 19, 37) infection?

Direct inoculation of the eye
Infection of the conjunctiva and/or cornea
Unilateral 'red-eye' may spread to both eyes
Highly contagious, also associated with fever and pharyngitis (pharyngoconjunctival fever)

8

What are the signs and symptoms of a hemorrhagic cystitis Adenovirus (11, 21) infection?

Inflammation of the bladder
Dysuria, painful urination, hematuria
Also associated with nephritis
More common in children/adolescents, and immunocompromised patients

9

How are the adenoviruses transmitted?

Mucosal (respiratory, fecal-oral)

10

How are the adenoviruses treated?

Generally self-resolving
Supportive treatment (treat symptoms)
Antivirals for more severe infections

11

What are some characteristics of Human Papillomaviruses (HPV)?

Large, dsDNA virus, >100 human serotypes
Infection of undifferentiated basal keratinocytes (skin, mucous membrane), replication in terminally differentiated epithelial cells
Utilize host DNA polymerase
Different serotypes are associated with distinct pathologies

12

What are some main characteristics of Genital warts?

HPV
Includes vulvar, penile, and anal warts, as well as oral papillomas
90% caused by serotypes 6, 11

13

How is HPV transmitted?

Contact, sexual

14

What are some characteristics of cancer caused by HPV?

Cervical, anal, oropharyngeal
Subtypes 16, 18, others
HPV drives cell cycle progression to activated cellular DNA polymerase for use by the virus
E6 early protein inhibits p53 tumor suppressor gene
E7 early protein inhibits pRb tumor suppressor gene

15

What is Gardasil and what serotypes does it work for?

Indicated for girls 9-26 years
Types 16, 18 cause 75% of cervical cancer genes
Types 6, 11 associated with most cases of genital warts
Recombinant subunit vaccine (L1 capsid protein)

16

What is the treatment for HPV?

Prevention - vaccine
Imiquimod (immune modulator)
Podofilox (inhibits topoisomerase II DNA replication)
Trichloroacetic acid (kills replicating cells)
Cryotherapy
Non-pharmacological interventions are suitable for many superficial warts

17

What does a PAP smear look for?

Abnormal cells
Not infection alone and not serotype

18

What are some characteristics of parvovirus?

(+) ssDNA, non-enveloped
Most members infect animals (canine, bovine etc) but NOT zoonotic
Replication occurs in the nucleus and utilizes host cellular functions
Virus particle is highly stable - resistant to dessication, acidification, and heat

19

How is parvovirus transmitted?

Fecal-oral

20

What are the symptoms of a parvovirus infection?

Hemorrhagic diarrhea and vomiting

21

What are the human parvoviruses?

Parvovirus B19
Adeno-associated virus (AAV)

22

What are the signs and symptoms of a Parvovirus B19 infection?

Generally asymptomatic
Children: erythema infectiosum, low grade fever, followed by rash on face spreading to extremeties (may last several weeks). Typically mild
Adults: rash more severe, typically itches. Arthritic symptoms and joint inflammation common (hands, wrists, knees, ankles)

23

How is Parvovirus B19 transmitted?

Respiratory droplets

24

What is the treatment for Parvovirus B19?

Supportive, typically unnecessary

25

What are some characteristics of Picornaviruses?

Small, (=) ssRNA, non-enveloped viruses (pico = small)
Icosahedral capsid comprised of 4 proteins VP1-4

26

What are the human pathogens of Picornaviruses?

Rhinovirus
Poliovirus
Coxsackie
Hepatitis A

27

Where does replication occur for the Picornaviruses?

Replication occurs in the cytoplasm
Direct translation of (+) genome into a single polyprotein, following by proteolytic cleavage by viral protease

28

What are the signs and symptoms of a Rhinovirus infection?

Sore throat, nasal congestion, runny nose, sneezing, cough
Muscle ache, muscle weakness, fatigue
Seasonal epidemiological pattern of infection

29

How is the Rhinovirus transmitted?

Respiratory droplets

30

What is the treatment for Rhinovirus?

Supportive

31

What are some characteristics of the Rhinovirus?

Non-enveloped virus - resistant to desiccation, relatively stable
>100 serotypes - multiple rhinovirus infections in one individual

32

What are some characteristics of the Polio virus?

Causes poliomyelitis
Occurs primarily in children <5 years
Worldwide vaccination has left only a few endemic areas of disease (Afghanistan, Pakistan, Nigeria)

33

What are the signs and symptoms of a polio virus infection?

Mild/asymptomatic disease in 95% of individuals
Abortive poliomyelitis 5%: self resolving in about 10 days, URT, GI and flu like symptoms
Non-paralytic aseptic meningitis 1-2%: self-resolving in 10 days, stiffness in the neck, back, legs, muscle spasms

34

How is the polio virus transmitted?

Fecal-oral

35

What are the three types of CNS invasion of polio virus?

Spinal (most common): anterior horn cells of spinal column, asymmetrical paralysis)
Bulbar: bulbar region of brainstem (vagus, accessory, glossopharyngeal) affects swallowing, breathing, lung/heart function, neck movement
Bulbospinal/respiratory polio: cervical vertebrae, phrenic nerve (diaphragm) requires ventilator

36

What is post-polio syndrome?

Chronic, slow to develop, not associated with shedding/infection
Muscle weakness and extreme fatigue
Pathophysiology unknown - neurological involvement

37

What are the signs and symptoms of a Coxsackievirus infection?

Causes acute febrile illness in symptomatic patients
Fever, nausea, vomiting, fatigue, muscle weakness
Associated with aseptic meningitis in children, infectious myocarditis and pericarditis in susceptible individuals

38

What are the symptoms of a Coxsackie A infection?

Hand, foot and mouth disease
Fever, malaise, rash, and ulcerating lesions on the hands and feet
Herpangina - blisters or ulcers in mouth and throat
Conjunctivitis

39

What are the symptoms of a Coxsackie B infection?

Fever, abdominal pain, chest pain, headache

40

What is the treatment for a Coxsackievirus infection?

Supportive
Symptoms last 1-2 weeks and resolve spontaneously, shedding may occur for weeks following resolution of symptoms

41

What are some characteristics of Hepatitis A?

(+) ssRNA, noneveloped picornavirus
Polyprotein synthesis followed by proteolytic cleavage
1.4 million cases/year globally

42

What are the clinical features of Hepatitis A?

Range from mild to severe
Sudden onset fever, malaise, anorexia, abdominal discomfort
10% patients have recurrent illness for 6-9 months following infection

43

How is Hepatitis A transmitted?

Contaminated food/water
Associated with travellers

44

What is the treatment for Hepatitis A?

Supportive
Vaccine preventable (inactivated) Combo A/B
Heat food/water to >84 C for more than 1 min or chlorinate

45

What are some characteristics of Hepatitis E?

Enteric
Hepevirus (+) ssRNA, non-enveloped

46

How is Hepatitis E transmitted?

Fecal-oral (contaminated water, pork/deer meat)
Blood products (rare)

47

What are the signs and symptoms of a Hepatitis E infection?

Fever, fatigue, nausea, anorexia
Abdominal pain, joint pain
Jaundice, dark-coloured urine
Generally self-limiting
Pregnant women - mortality rate high during 3rd trimester
Risk of fulminant hepatitis

48

What is the treatment for Hepatitis E?

Treatment supportive
No vaccine currently approved in North America

49

What is the function of Alanine transaminase?

ALT converts alanine to pyruvate following lactic acid production in muscles

50

What does elevated ALT indicate?

Liver pathology

51

What is cirrhosis?

Fibrosis, scarring, generation of nodules in the liver
Ascites - fluid retention in the abdominal cavity
Jaundice, increased bruising/bleeding
Leads to HCC (Hepatocellular carcinoma)

52

What are some characteristics of the Norovirus?

Calicivirus family (+) ssRNA nonenveloped
5 genogroups, multiple genotypes

53

How does the Norovirus replicate?

By polyprotein synthesis followed by cleavage

54

What are the clinical features of a Norovirus infection?

Severe acute diarrhea and vomiting

55

What is the treatment for Norovirus?

Supportive (rehydration, electrolyte replacement)
Self resolving 24-72 hours

56

How is the Norovirus transmitted?

Fecal-oral (highly contagious

57

What are some characteristics of the Rotavirus?

Reovirus family dsRNA, nonenveloped
11 segmented genome
5 serotypes (A-E)
Most common cause of severe diarrhea in young children (90% serotype A)

58

How does the Rotavirus replicate?

In the cytoplasm using viral replication/transcriptional machinery, host translational machinery

59

What is NSP4 virulence factor?

Enterotoxin of the Rotavirus
Causes calcium secretion followed by fluid accumulation in the GI tract

60

What are the signs and symptoms of a rotavirus infection?

Fever, vomiting
Diarrhea, abdominal pain lasting 3-8 days

61

How is the rotavirus transmitted?

Fecal-oral
Virus is highly stable, can survive for several hours on inanimate objects

62

How is a Rotavirus infection treated?

Supportive (oral rehydration, IV rehydration in severe cases)
Vaccine available - oral live attenuated virus
Low risk intussusception (Bowel obstruction due to intestinal prolapse) following vaccine administration