Paediatric Viral Diseases Flashcards
Why are different strains of viruses important?
Immunity against one strain does not protect against other strains, e.g. rhinovirus
Viruses can continually evolve to form new strains, e.g. influenza
How is measles transmitted?
Airborne
How is diphtheria transmitted?
Saliva
How is smallpox transmitted?
Airborne droplet
How is polio transmitted?
Faecal-oral route
How is rubella transmitted?
Airborne droplet
How is mumps transmitted?
Airborne droplet
How is HIV/AIDS transmitted?
Sexual contact
How is pertussis transmitted?
Airborne droplet
How is SARS transmitted?
Airborne droplet
How is influenza transmitted?
Airborne droplet
How is ebola transmitted?
Bodily fluids
What are the different ways viruses are acquired and spread?
Respiratory
Faecal-oral
Close exposure/skin or mucous membrane contact
Contact with blood
Animal vectors
How are viruses spread by respiratory pathways?
Droplets - contaminated environment, exposure to mucous membranes
Aerosol - breathed directly in
How are viruses spread by faecal-oral route?
Food and water
Contaminated environment
e.g. norovirus, enterovirus, hepA, hepE
What are examples of blood-borne viruses and how are they spread?
HIV, HepB, HepC
Contamination of cuts
Inoculation of mucous membranes
Through the skin - ‘needlestick injury’
How can the risk of spreading blood-borne viruses be reduced?
Universal precautions
Testing of healthcare workers performing exposure prone procedures (EPPs)
Infection control especially important in dialysis
What are some animal vectors that can spread viruses?
Arthropods - insects, ticks e.g. dengue
Warm-blooded animal - dog bite e.g. rabies
How can viruses spread from close exposure?
Skin to skin/mucous membranes
e.g. HSV
How are viruses spread by sexual transmission?
Virus in body fluids - semen, saliva e.g. HIV
Via mucous membranes
How can viral infection be prevented pre exposure?
Hygiene
Avoidance
Pre-exposure vaccination
How can viral infection be prevented post exposure?
Post-exposure prophylaxis - Immunoglobulin, vaccination
What family does RSV belong to?
Paromyxoviridae
What are the subtypes of RSV?
A and B
How is RSV transmitted?
Droplet
Describe respiratory syncytial virus (RSV)
ssRNA 15-19kb length
Most common cause of bronchiolitis and pneumonia in children < 1yo
By age 3-5yrs infection is universal
Seasonal - winter in temperate zones and rainy season in tropics
Can lead to death and closure of units
Serious infection is life threatening for people having BMT
What infection does RSV cause?
Upper and lower respiratory tract infection
What does RSV cause in young children?
Laryngotracheobronchitis (croup)
Barking cough and breathlessness
What does RSV cause in adults?
Common cold
Flu-like illness
How is RSV diagnosed?
PCR
How can RSV be prevented in babies?
Intramuscular injections of Palivizumab
How is RSV treated?
Hydration
Oxygen
General nursing care
Antibaterials if secondary infection suspected with/without Ribavirin - toxic so rarely used but may improve lung function
What type of virus is rubella?
RNA
Enveloped virus
What family does rubella belong to?
Matonaviridae
What are symptoms of rubella in children?
Fever
Runny nose
Red eyes
Fine pink maculopapular rash that starts on face then trunk then arms and legs
What else can occur in rubella infection?
Posterior auricular lymphadenopathy - enlarged lymph nodes behind the ear
What are symptoms of congenital rubella?
Cataracts, glaucoma
Heart defects
Deafness
Developmental delay
Low birth weight
How is rubella transmitted?
Respiratory spread and droplets
Highly infectious
Humans are the only host
May be infectious from one week before rash appears and remain infectious for another week after it appears
How is rubella diagnosed?
PCR
Detection of IgM by serology
How is rubella prevented pre-exposure?
MMR vaccine
How is rubella prevented post-exposure?
Post-exposure prophylaxis with MMR vaccination or human normal immunoglobulin (HNIG)
How is HNIG done for rubella?
HNIG from pooled plasma from donors outside the UK
Ideally administered within 72hrs of exposure but up to 6 days
Who is HNIG used for?
In pregnancy
Infants <6months
Immunosuppressed
In other groups MMR is used
What type of virus is measles?
Single stranded RNA
Enveloped helical
What family does the measles virus belong to?
Paramyxovirus
What genus does measles virus belong to?
Morbillivirus
What are some other paramyxoviruses?
Mumps
Parainfluenza
RSV
Metapneumovirus
What is the incubation period of measles?
Typically 10 days but can range from 7 to 18 days
May be prolonged in immunocompromised
Individuals are highly infectious from beginning of their illness
After recovery there is life long immunity
How is measles transmitted?
Droplet infection e.g. coughs and sneezes
What are symptoms of measles virus?
Start with high fever, conjunctivitis, cough, runny nose and sometimes diarrhoea before a maculopapular rash develops
Rash is often intense and blotchy and will last about a week starting on the face
What can be seen with measles infection?
Koplik spots - small white spots on inside of cheeks
What are some complications of measles infection?
Pneumonia
Ear infections
More rarely meningitis and encephalitis
What is subacute sclerosing panencephalitis (SSPE)?
A fatal neurodegenerative complication of measles
Occurs many years later (7-10yrs)
Characteristic changes in EEG
How does SSPE present?
Mood changes
Sleeplessness
Forgetfulness which rapidly progresses over 1-3 years
What happens if you get measles in pregnancy?
If infection occurs during pregnancy and individual is not immune may result in miscarriage, stillbirth or pre-term delivery
Who are the at risk groups for measles infection?
Immunocompromised patients - infection may be severe and possible fatal
Pregnant women - may cause miscarriage or premature labour
Infants < 1 year - infection may be very severe and possibly fatal
How is measles diagnosed?
PCR - oral swab, throat swab
Positive during prodrome (early signs and symptoms) and when rash is present
What family does mumps virus belong to?
Paramyxovirus
What is the incubation period for mumps?
16-18 days
Describe mumps infection
Highly contagious
Spread via respiratory secretions
Pain and swelling in parotid (salivary glands)
Prodrome - fever, headache, malaise
What are some rare serious complication of mumps in hcildren?
Orchitis (testicular swelling)
Meningitis
Encephalitis
Hearing loss
Pancreatitis
How is mumps prevented?
MMR vaccine
How is mumps diagnosed?
Saliva swap and serology for IgG/IgM
Describe chickenpox
Usually occurs in childhood <10yo
Caused by varicella zoster virus (VZV)
90% British adults are immune
Usually mild illness
More severe in adults with higher rates of complications
Mild prodrome
Who are the groups at risk of severe disease with chickenpox?
Pregnant women
Premature babies (<28weeks)
Neonates born to susceptible mothers
Immunocompromised patients
What is the incubation period of chickenpox?
10-21 days
What does VZV cause?
Chickenpox and shingles
What type of virus is VZV?
Herpes virus
Describe VZV
Chickenpox is primary systemic infection with lifelong immunity to chickenpox - travels from skin to root ganglion along sensory nerves
Shingles occurs due to reactivation from root ganglia, up sensory nerves, to the skin - usually in one dermatome
How is VZV transmitted?
Direct contact with lesions or by respiratory spread from someone with chickenpox
What are complications of VZV?
Bacterial superinfection with Staph and Strep
Encephalitis
Pneumonia
Describe chickenpox rash
Prodrome of malaise, fever, headache 1-2 days before rash appears
Vesicular rash starts on trunk or face - papules, vesicles, pustules
Successive crops over days - croping is characteristic of chickenpox
Lesions of different stages of development
Describe the pathogenesis of varicella
Day 0 - infection of conjunctivae and/or mucosa of upper resp tract
Day 2 - viral replication in regional lymph nodes
Day 4-6 - primary viraemia
Day 8-10 - viral replication in liver, spleen and possibly other organs
Day 11-12 - secondary viraemia
Day 14 - infection of skin and appearance of vesicular rash
How is VZV diagnosed?
Usually clinically
Detection of VZV DNA by PCR from green topped virology swab
Assay also detects HSV1/2 as another common cause of vesicular rash
Serology for detection of VZV IgM
How is VZV treated?
Acyclovir advised for patients at risk of severe disease, not routinely recommended for chickenpox in children
Acyclovir available as oral or IV formulation
How can VZV be prevented?
Live attenuated vaccine pre-exposure
Hygiene
Avoidance of people with chickenpox/exposed shingles
Post exposure prophylaxis with acyclovir/VZIG (varicella zoster immunoglobulin) for immunocompromised/pregnant
What type of virus is enterovirus?
Non enveloped RNA viruses
Many serotypes
What family do enteroviruses belong to?
Picornaviridae
How are enteroviruses spread?
Faecal/oral route and respiratory droplets
What is the clinical presentation of enterovirus?
Febrile (with fever) illness often with rash
Aseptic meningitis usually in <1yo
Vesicular lesions in mouth, feet, buttocks, genitals
Herpangina - ulcers and lesions in mouth, sore throat, fever
Polio
What type of virus is Epstein Barr virus (EBV)?
ds DNA virus
One of the Herpes viruses
Describe EBV
Often asymptomatic in children
Mononucleosis - lymphadenopathy, malaise, fever
Splenic rupture
Often become infected in childhood and adolescence
Rash if ampicillin given
Prevention - hygeine
How is EBV diagnosed?
Serology for VCA IgG, EBNA IgG and IgM by ELISA
PCR from whole lood
Heterophile Ab - Abs produced against poorly defined Ags; in adolescents, heterophile Abs have high specificity and sensitivity in diagnosis of primary EBV infection
Often negative in children
What type of virus is cytomegalovirus (CMV)?
ds DNA enveloped virus
One of the Herpes viruses
Describe infection with CMV
Primary infection often asymptomatic in children or similar to glandular fever
Can cause congenital infection if susceptible pregnant women infected during pregnancy - deafness, developmental delay, low birth weight
How is CMV transmitted?
Via close contact with secretions
How is CMV treated?
Antiviral treatment not indicated in most children
Usually self limiting
In immunocompromised children or congenital infection can use ganciclovir/vaganciclovir
What type of virus is rotavirus?
ds DNA non-enveloped virus
Describe rotavirus infection
Can cause viral gastroenteritis in <5yo especially diarrhoea causing dehydration, requiring intravenous fluids
High mortality
How is rotavirus spread?
Faecal/oral route
How is rotavirus diagnosed?
Antigen detection or PCR
How is rotavirus prevented?
Hygiene
Infant vaccination Rotarix in UK routine schedule - given at 8 and 12 weeks of age
What type of virus is adneovirus?
ds DNA non-enveloped virus
What family does adenovirus belong to?
Arenaviridae
How is adenovirus transmitted?
Respiratory and faecal/oral route
How many serotypes of adenovirus are there?
88 in humans causing different illnesses - respiratory infection, conjunctivitis, gastroenteritis, severe disease in immunocompromised
How is adenovirus diagnosed?
Clinically
PCR from respiratory swab or blood
No antivirals required unless immunocompromised then cidofovir
Currently no licensed vaccine
