Norwalk &Calici Viruses

fackrel@Uwindsor.ca

Norwalk Viruses

• Structure

• Classification

• Multiplication

• Clinical manifestations

• Epidemiology

• Diagnosis

• Control

Baron’s Web Site

Structure

• If the AIDS virus were the size of a basketball, Norwalk wouldn't be much bigger than a softball.

Norwalk Virus Structure

• ill-defined somewhat lace-like

• distinct from the featureless appearance of poliovirus.

• Bar = 50 nanometers

Discovery of Norwalk Virus

• First recorded epidemic attributed to Norwalk virus occurred in an elementary school in Norwalk, Ohio, in 1968.

• Bacteria-free fecal filtrates derived from adult patients were fed to volunteers.
  • These volunteers consequently became ill
  • evidence that gastroenteritis could be induced with a nonbacterial agent.

The illness that infected a field of football players last fall is thought to be second only to the common cold as a source of sickness

The illness that infected a field of football players last fall is thought to be second only to the common cold as a source of sickness

LAURA BEIL The Dallas Morning News

major cause of epidemic acute and mild gastroenteritis, or diarrhea,

• major cause of epidemic acute and mild gastroenteritis, or diarrhea,

• older children and adults.

Symptoms & Treatment

• nausea, vomiting, diarrhea, abdominal cramps
  • occasionally fever
  • begin within 40 hours (range 12 - 72 hours) of consuming contaminated food.

• self-limiting illness
  • usually persists < 48 hours,
  • can last a long as 1 week

Annual Incidence Viral food borne diseases

• Norwalk-like viruses
  • 23,000,000

• Rotavirus
  • 3,900,000

• Astrovirus
  • 3,900,000

• Hepatitis A
  • 83,391

• Total Viral food borne 30,883,391

• Total Microbial food borne incidence
  • 38,629,64

CDC

NLV Reservoir

• Thought to be restricted to humans but can occur often in calves (44%) and sometimes (2%) in pigs.

• calves and pigs may be reservoir hosts of NLVs.

Hygiene against diseases transmitted via the fecal-oral route

• Always wash your hands with soap and water any time you might have touched human or animal feces, changed diapers, cleaned up feces, or gardened. Always wash your hands before eating.

• Avoid sex that may involve contact with feces.

Water Safety

• Do not drink or swallow water directly from rivers, lakes, streams, pools, or spas,

• if you travel abroad you may want to avoid drinking water that has not been boiled.
  • boiling drinking water for one minute, will destroy any viruses in it.

DONE!!!