28. Epidemiology and prevention of enteric viral infections

From greek.doctor

Viral enteric infections

  • Rotavirus
  • Norovirus
  • Poliovirus

Rotavirus

  • Epidemiology
    • The leading cause of severe diarrhoeal disease in infants and children worldwide
    • Most common cause of diarrhoeal deaths in developing countries
    • Most common during the winter in temperate climates
      • Year-round in tropical climates
    • Virtually all children in developing countries are infected before they reach age 3
    • RV can also infect adults
      • Especially institutionalized and hospitalized
  • Transmission
    • Spreads rapidly among nonimmune children
    • Faecal-oral
    • Respiratory droplets
    • Contaminated objects
  • Symptoms
    • Watery diarrhoea
    • Vomiting
    • Abdominal pain
  • Vaccine
    • Live attenuated oral vaccine
    • Childhood vaccine
      • At week 6 and month 3

Norovirus

  • A calicivirus
  • Epidemiology
    • Most common cause of winter gastroenteritis (stomach flu)
    • Most common cause of adult gastroenteritis
    • Common in developed and developing countries
    • Outbreaks common in
      • Nursing homes
      • Hospitals
      • Cruise ships
  • Transmission
    • Faecal-oral
    • Person-to-person
    • Virus can survive freezing and heating to 60 degrees
    • Virus can shed in asymptomatic people for 2 weeks
  • Clinical features
    • Self-limiting
    • Diarrhoea
    • Vomiting
    • Abdominal cramp
    • Diarrhoea
    • Fever
  • No vaccine

Poliovirus

  • Epidemiology
    • Mainly affects children under 5
    • In pre-vaccine era virtually all children had polio in their life
  • Transmission
    • Humans are the only known reservoir
    • Faecal-oral
  • Clinical features
    • 95% develop very mild, flu-like symptoms
    • 4% may develop aseptic meningitis, myalgia
    • 1% develop paralytic poliomyelitis
  • Treatment
    • Mild cases are self-limiting
    • No cure for severe form
  • Surveillance for acute flaccid paralysis
    • = the gold standard for detecting poliomyelitis
  • Prevention
    • Vaccine
    • Clean water
    • Hygiene
  • Oral polio vaccine (Sabin)
    • Used in countries with high incidence of polio, or neighbours with high incidence of polio
    • Live attenuated
    • Gives long-lasting immunity
    • Gives immunity at the mucous membranes of the intestines
    • The attenuated virus can be excreted in faeces and immunize other people
    • Has a small risk of vaccine-associated paralytic polio
  • Inactivated polio vaccine (Salk)
    • Used in most countries
    • Killed virus
    • Given by IM injection
    • No risk of vaccine-associated paralytic polio
    • More expensive