Mhr Topic 28: Picornaviruses And Caliciviruses

Front 1

Picornavirus (Genome, envelope, types)

Back 1

1) SS + RNA
2) No envelope (naked)
3) Enteroviruses and Rhinoviruses

Front 2

Enteroviruses (infection location and types)

Back 2

Infects the GI tract:
-Polioviruses
-Coxsackieviruses
-Echoviruses

Front 3

Picornavirus replication

Back 3

Cytosolic RNA-RNA replication.
1) Bind to cell surface, form a pore, inject viral genome
2) Polyprotein is formed, is cleaved by viral proteases
3) Replication occurs
4) Virons are released via Lysis

Front 4

Poliovirus (Infection, Disease)

Back 4

1) Infection is oral-fecal.
2) Primary infection is asymptomatic. Secondary tropism in the CNS results in flaccid paralysis, respiratory and cardiac failure, and encephalitis and poliomyelitis.

Front 5

Biphasic Infection Pattern

Back 5

Method by which picornaviruses cause disease.
Primary - usually in oropharynx and SI (disease minor or asymptomatic).
Secondary - Causes the severe disease in other location (CNS, muscle, liver, skin).

Front 6

Poliovirus diagnosis

Back 6

Detection of antiviral antibodies in serum.

Front 7

Strengths and weaknesses of Live attenuated virus

Back 7

Strengths:
-Creates Intestinal IgA antibodies which add extra protection and interfere with replication in the gut.
-Causes vaccination in others through spread
-Duration of immunity is longer
Weaknesses:
-Can revert back to virulent strain rarely
-Can cause disease in immunocompromised
-Co-infection with other enteroviruses causes immunization problem
-Requires refrigeration.

Front 8

Coxsackieviruses (infection, disease)

Back 8

1) Primarily fecal/oral but can also be aerosols.
2) Both groups can cause colds, rashes, and neuro complications like aseptic meningitis. Group A has tropism for skin, and mucus membranes causing herpangina, conjunctivitis, and hand foot mouth disease. Group B has tropism for hear, liver, pancreas and causes pleurodynia, myocarditis and pericarditis.

Front 9

Coxsackieviruses diagnosis

Back 9

Diagnosed via anti-viral antibodies. While one gets immunity for life, there is little cross reactivity between strains A and B.

Front 10

Picornavirus hosts

Back 10

Humans are only natural host

Front 11

Echoviruses disease

Back 11

Similar to Coxsackieviruses, aseptic meningitis is most common severe disease.

Front 12

Rhinoviruses (Infection and disease)

Back 12

1) Respiratory aerosols. Single particle can initiate infection. Replicate in upper epithelium.
2) Main cause of colds.incubation period is 2 days and typical recovery is 1 week.

Front 13

Calciviruses (genome, envelope, types)

Back 13

1) nonsegmented, + RNA genomes
2) no envelope (naked)
3) Noroviruses and sapoviruses

Front 14

Calciviruses (transmission, disease)

Back 14

1) Oral fecal, often on cruise ships
2) Cause 90% of non-bacterial gastroenteritis (gastric pain, vomiting, diarrhea). Incubation = 2 days, duration = 3 days