Common Paediatric Viruses

Common Paediatric Viruses

Measles

·        Highly contagious paramyxovirus spread by coughing and nasal droplets

·        Epidemiology:

o  Overall mortality 0.5%

o  Risk of infection 100% if not immunised

o  Epidemics occur every 7 years 

o  Incidence up to 3000 notifications in epidemic years. Lab confirmations drop in epidemics as high incidence ® high PPV of clinical diagnosis. Very few cases in non-epidemic years will actually be measles 

·        Presentation:

o  Incubation 10 – 14 days

o  Fever, ALWAYS a cough (“measles bronchiolitis), coryza, conjunctivitis for 2 –3 days 

o  Then red maculo-papular rash beginning on face and spreading to rest of body. White spots on cheery-red buccal mucosa for 24 hours before rash (Koplik‟s Spots) – pathognomonic 

·        Treatment: Supportive, antibiotics for 2^ndary infection

·        Complications:

o  Otitis media (10%)

o  Pneumonia (1 – 5%) 

o  Encephalitis (0.1%): 15% die and 25% left severely disabled. 1 in 100,000 develop the fatal grey matter degenerative disorder Subacute Sclerosing Panencephalitis (SSPE)

·        Vaccine: 

o  Live attenuated virus. Now MMR2 given at 4 years to ­ time between epidemics and address 2 – 5% chance of primary vaccine failure in first dose 

o  Mild fever, malaise or rash develops in about 1% 7 – 10 days after vaccination

o  1 in 1 million develop encephalitis (1,000 fold less likely than if infected with wild virus)

o  Contraindicated during pregnancy and in immunocompromised hosts

Mumps

·        Contagious paramyxovirus spread by saliva and droplets

·        ~ 80 notified cases per annum.  Used to be 3 – 4 year epidemics, now longer

·        Presentation:

o  Incubation 2 – 3 weeks

o  70% develop fever and swelling and tenderness of salivary glands

o  15% have aseptic meningitis

o  0.2% develop encephalitis

o  20% of post-pubertal males have painful orchitis

o  Case fatality is 0.02% - usually from encephalitis

·        Infective 1 week before and after parotid swelling starts 

·        Vaccine: Live attenuated virus (contraindicated during pregnancy and immunosuppression). Efficacy 95%. Only introduced because it can piggy back other vaccinations

Non-Polio Enteroviruses

·        Include Coxsackie A and B, echoviruses and enteroviruses 

·   Cause: non-specific febrile illnesses, pharyngitis, gastroenteritis, viral meningitis, encephalitis, pericarditis, myocarditis, hepatitis, haemorrhagic conjunctivitis, etc

·        Viral exanthem: macular rashes, maculo-papular, vesicular and petechial rashes 

·        Hand, Foot and Mouth Disease: Coxsackie A16. Mild illness, low-grade fever and sore throat. Scattered vesicular lesions in the mouth with similar lesions surrounded by erythematous areolae on the hands and feet. 

·        Incubation for 3 – 6 days, infectious for at least 1 week after onset of symptoms 

·        Diagnosis: culture (including from faeces – if isolates persist for several weeks may be unrelated to illness), possible PCR for blood and CSF. Serology difficult

Human Herpes 6 and 7 (Roseola Infantum)

·        Acute febrile illness of young children for several days with occipital adenopathy, then reduced fever and appearance of a fine red maculo-papular rash over the trunk and arms for 1 – 2 days (confused with antibiotic rash) 

·        70% of 2 year olds are sero-positive.  Serology and PCR problematic due to latent infection

·        Incubation 5 – 15 days

·        Rare complications: encephalitis or benign intracranial hypertension

Erythrovirus (Parvovirus) B19

·        = Erythema Infectiosum or Slapped Cheek Syndrome

·        Mild illness, fever in 30%, bright red rash on cheeks for 2 – 3 days 

·        A few days later, a maculo-papular, then lace-like rash may appear on arms, then trunk, buttocks and thighs. May recur over following weeks after hot baths 

·        Incubation 4 – 14 days

·        Infectious period is before the rash appears 

·  Complications: Adolescents and adults may also have polyarthralgia/arthritis, aplastic crisis if chronically anaemic (eg immunocompromised)