Viral Infections in Childhood Flashcards
What are the steps in the viral cycle?
Attachment, entry, uncoating, synthesis of viral components, assembly and release
What kind of viral nucleic acid is present in parvovirus?
Single stranded DNA
What kind of viral nucleic acid is present in retroviruses (e.g. HIV)?
Double-stranded DNA
Outline viral attachment
There must be a binding site on the virus and the plasma membrane of the cell; the cell must have all of the right intracellular components in order for the virus to replicate
Outline viral entry
If the virus is enveloped; there is membrane fusion and sometimes receptor-mediated endocytosis of the virus into the cell
Outline viral uncoating
This can occur in the endosome (receptor-mediate endocytosis due to low pH and lysosomal enzymes), cytosol or nuclear membrane. This results in the migration of the virus to the right part of the cell to begin vision production
Outline the synthesis of viral components
Viral mRNA enables cellular machinery to make viral polypeptides and nucleic aicds
Outline assembly and release
Release of new visions is mediated by cell lysis or budding
What type of virus are herpes (simplex, VZV, CMV, Epstein-Barr, HHV), hepatitis B and poxvirus?
Enveloped DNA virus
What type of virus are papillomavirus, adenovirus and parvovirus?
Non-enveloped DNA viruses
How does cytomegalovirus infection present?
Appears like glandular fever
What are the potential consequences of CMV infection in children?
Sensorineural hearing loss and neuro-developmental delay; in addition to neutropenia and thrombocytopenia
What condition is caused by Epstein Barr virus?
Infectious mononucleosis (glandular fever)
Who tends to get Epstein Barr infections?
15-25 years olds - glandular fever
What how HHV-6/7 infection present?
Known as roseola infant or exanthema subitum with sudden onset of high fever which suddenly stops and a rash appears.
Tends to affect those between 6months to 2 years old
What are the stages of hepatitis B infection?
Tolerance, clearance, latency and reactivation
What are the potential consequences of a chronic hepatitis B infection?
Liver cirrhosis and hepatocellular carcinoma
Which serotypes of papillomavirus are carcinogenic (cervical cancer)?
Papillomavirus serotypes 16/18
Which serotypes of papillomavirus give rise to genital warts?
Serotypes 6/11
How may adenovirus infection present?
Implicated in upper respiratory tract infections such as pneumonia
Why is parvovirus an opportunistic infection?
Doesn’t affect non-susceptible hosts
How does a healthy, non-susceptible individual respond to a parvovirus infection?
The virus attaches to the blood group P antigen, so if an individual lacks this antigen they’re not susceptible to infection
How does a highly susceptible individual respond to a parvovirus infection?
If an individual has the blood group P antigen, the virus will attach and replicate in red cell precursors, leading to aplastic crisis in those with haematological problems (e.g. sickle cell disease)
What are the symptoms associated with parvovirus infection?
From least to most severe: asymptomatic, slapped cheek, arthropathy, aplastic crisis and foetal loss
What type of virus are MMR, influenza, hepatitis C and HIV?
Enveloped RNA viruses
What type of virus are rotavirus, enterovirus and hepatitis A?
Non-enveloped RNA viruses
What are the signs of measles infection?
7-14 day incubation period before symptoms where Kolik spots and rash develops
What are the signs of rubella infection?
Fever, occipital lymphadenopathy, mild rash
What are the signs of congenital rubella (classic triad)?
Eyes - cataracts, glaucoma
Ears - sensorineural deafness
Heart- VSD or pulmonary artery stenosis (narrowing)
What are the signs of influenza infection?
Bronchiolitis - inflammation of the bronchioles leading to cough, respiratory distress and wheeze
What are the signs/symptoms of rotavirus infection?
Fever, vomiting and watery diarrhoea
