Iahi: 3.06 - Viruses Of Childhood

Front 1

What are the viruses that affect childhood?

Back 1

- Measles (Paramyxovirus)
- Mumps (Paramyxovirus)
- Rubella (Togavirus)
- Parvovirus B19
- Adenovirus (sometimes)
- Varicella Zoster (HHV-3)
- Human Herpes Virus 6 (HHV-6) - Roseola

Front 2

What is the difference between the respiratory viruses and the viruses of childhood?

Back 2

Cause viremia after replication in upper respiratory tract --> Target organs and symptoms

Front 3

What is an exanthem? Which viruses cause them?

Back 3

- Widespread rash usually occurring in children
- Measles, Rubella, Roseola, Chicken Pox, Erythemia Infectiosum

Front 4

What are the diseases that are prevented with an MMR vaccine? Types of viruses?

Back 4

- Measles and Mumps = Paramyxoviruses (-ssRNA - helical)
- Rubella = Togavirus (+ssRNA - icosahedral)

Front 5

How are Measles, Mumps, and Rubella spread? What do they lead to?

Back 5

- Respiratory transmission --> Systemic infections (viremia)
- Protected from re-infection and disease after natural infection

Front 6

How are immunizations so effective against Measles, Mumps, and Rubella?

Back 6

- Each virus only has a single antigenic type
- Each virus has a systemic replication phase prior to infecting target organ - Abs can limit or block virus at this stage
- Humans are only known host

Front 7

What are the characteristic symptoms of Measles (Paramyxovirus) infection?

Back 7

- Koplik spots (red spots w/ blue-white center on buccal mucosa)
- Maculopapular rash (all over including hands and feet)
- 3 C's: Cough, Coryza (Cold), Conjunctivitis
- Photophobia

Front 8

What kind of vaccine is for MMR? When is it administered?

Back 8

- Live, attenuated viruses
- 12-15 months and 4-6 years

Front 9

What are the characteristic symptoms of Rubella (German Measles - Togavirus) infection?

Back 9

- Can cause asymptomatic infections
- Children - mild rash disease (truncal distribution)
- Adults - more severe w/ arthritis or arthralgia
- Neonates < 20 weeks - congenital defects

Front 10

Which of the MMR viruses causes congenital defects in neonates <20 weeks? What symptoms?

Back 10

- Rubella (German Measles - Togavirus)
** Cataracts / ocular defects
** Heart defects (Patent Ductus Arteriosus)
** Deafness
- Intrauterine growth retardation
- Failure to thrive
- Mortality w/in first year
- Microencephaly
- Mental retardation

Front 11

What are the characteristic symptoms of Mumps (Paramyxovirus) infection?

Back 11

POM-poms:
- Parotitis (inflammation of parotid glands - swollen neck)
- Orchitis (inflammation of testes)
- Meningitis (aseptic)
Mumps makes your parotid glands and testes as big as POM-poms

Front 12

What kind of virus is Parvovirus B19?

Back 12

(-)ssDNA linear, no envelope (smallest DNA virus); icosahedral

Front 13

What cells are affected by Parvovirus B19? How?

Back 13

- Actively replicating RBC progenitors in bone marrow
- Receptor is blood group P antigen (globoside)
- Requires host cells to be in S phase for replication
- Uses cellular DNA Polymerase to replicate

Front 14

Which virus affects RBC progenitors in the bone marrow?

Back 14

Parvovirus B19

Front 15

What are the symptoms of Parvovirus B19?

Back 15

- Usually inapparent infection
- Erythemia Infectiosum (Fifth disease) - bright red cheeks ("slapped cheeks" rash) w/ maculopapular rash
- Aplastic crises in sickle cell disease
- 4-14 day incubation

Front 16

What are the complications of Parvovirus B19 infection?

Back 16

- Anemia due to reduced cell number and reduced hemoglobin
- In chronic hemolytic anemia, leads to aplastic crises d/t destruction of RBC progenitors
- In fetus: still births, generalized edema (fetal hydrops), anemia, CHF, fetal death

Front 17

What is the immune response to Parvovirus B19?

Back 17

Circulating immune complexes, primarily IgM w/ virions, then IgG

Front 18

How is Parvovirus B19 spread?

Back 18

- Respiratory transmission
- Mother-->Fetus

Front 19

Which viruses of childhood are spread through fecal/oral transmission and lead to GI symptoms (gastroenteritis, diarrhea, vomiting)?

Back 19

- Rotavirus (Reovirus)
- Norovirus (Calicivirus)

Front 20

What is the number one cause of fatal diarrhea in children?

Back 20

Rotavirus (Reovirus) --> ROTA = Right Out The Anus

Front 21

Which viruses of childhood are spread through fecal/oral transmission and lead to viremia (target organs and symptoms)?

Back 21

Picornaviruses:
- Poliovirus
- Enteroviruses (Coxsackie virus and Echovirus)
(All except Rhinoviruses - not spread fecal/oral)

Front 22

When do enteroviruses (Coxsackievirus and Echovirus) occur most commonly?

Back 22

July-October

Front 23

What are the common causes of childhood viral meningitis? Symptoms?

Back 23

- Enteroviruses (Coxsackievirus and Echovirus)
- Mostly in children < 5 yo
- Very severe in infants < 1 month: fever, irritability, poor eating, hard to awaken
- Adults: headache, fever, chills, nausea, vomiting, stiff neck, sensitivity to light
- Also, Poliovirus can cause aseptic and paralytic meningitis

Front 24

Which virus causes herpangina? What is this?

Back 24

- Coxsackie A viruses (Enterovirus - Picornavirus)
- Severe sore throat (mouth blisters)

Front 25

Which virus causes hand, foot, and mouth disease? What is this?

Back 25

- Coxsackie A viruses (Enterovirus - Picornavirus) and Enterovirus 71
- Mild fever, sore throat, fatigue, loss of appetite, vesicular lesions

Front 26

What are the types of symptoms for Poliovirus? Percent of incidence?

Back 26

- Inapparent / subclinical infection - 90-95%
- Mild / minor illness - 4-8%
- Aseptic meningitis - 1-2%
- Paralytic poliomyelitis - 0.1-2%

Front 27

What are the characteristics of the inapparent/subclinical infection of Poliovirus?

Back 27

- Virus recovered from throat and / or stool
- Patient is asymptomatic
- 90-95% of infections

Front 28

What are the characteristics of the mild / minor illness from infection of Poliovirus?

Back 28

- Minor undifferentiated febrile illness
- Occasional upper respiratory infection
- Influenza like illness, gastroenteritis
- 4-8% of infections

Front 29

What are the characteristics of an aseptic meningitis infection of Poliovirus?

Back 29

- Minor illness that progresses to CNS
- Stiffness and pain in back and neck
- Disease lasts 2-10 days, rapid and complete recovery
- 1-2% of infections

Front 30

What are the characteristics of a paralytic meningitis infection of Poliovirus?

Back 30

- Initial non-specific febrile illness
- Spectrum of paralytic disease is variable (only isolated muscle groups or extensive paralysis)
- Asymmetric flaccid paralysis
- Lower extremities involved more than upper
- Large muscle groups involved more often
- Bulbar paralysis - involves CNs, medulla, respiratory compromise, death 5% overall
- Slow recovery (2 years for 100%)
- Residual paralysis - complication

Front 31

What are the symptoms of Post-Polio Syndrome?

Back 31

- Affects polio survivors 10-40 years after recovery
- Sx: fatigue, new muscle weakness, muscle pain w/ muscle twitching, sleeping problems, breathing difficulties, decreased ability to tolerate cold temp, joint pain
- Not life-threatening

Front 32

What are the causes of Post-Polio Syndrome?

Back 32

Death of individual nerve terminals in motor units that remain after initial attack (no evidence for persistent infection)