Organism, Causative Agent, or Etiologic Agent
Hepatitis E virus (HEV) as the only member of the genus Hepevirus in the family Hepeviridae. It is a single stranded, positive sense RNA virus. Four genotypes of HEV infecting mammals are currently recognized. Host range is known to include pigs, sheep, deer, rabbits and humans. Other mammals including dogs, cats and rodents are suspected hosts.
Hepatitis E virus is usually spread by the fecal-oral route. Viral shedding lasts for about two weeks after disease onset. The most common source of infection, particularly in developing counties, is fecally contaminated drinking water. In developed countries sporadic outbreaks have occurred following consumption of uncooked/undercooked pork or deer meat. Consumption of shellfish was a risk factor in a recently described outbreak.
The signs and symptoms of Hepatitis E are similar to those of other types of acute viral hepatitis: fever, fatigue, jaundice (skin or whites of eyes turning yellow), loss of appetite, nausea, vomiting, abdominal pain, dark urine and clay colored stools. Children are usually asymptomatic or have mild disease.
Prevention of Hepatitis E relies primarily on good sanitation and the availability of clean drinking water. Travelers to developing countries can reduce their risk for Hepatitis E by not drinking unpurified water. Boiling and chlorination of water will inactivate HEV. Immune globulin is not effective in preventing Hepatitis E. No FDA-approved vaccine for Hepatitis E is currently available in the United States.
School Exclusion Policy
Children with fever should be excluding from school or childcare until fever free for 24 hours without the use of fever suppressing medications. Children with diarrhea should be excluding from school or childcare until after diarrhea free for 24 hours without the use of diarrhea suppressing medications. Rules for exclusion of sick children from school and childcare are outlined in the Texas Administrative Code, specifically Rule 97.7 for schools and Rule 746.3603 for childcare.
Recent Texas Trends
Hepatitis E is believed to be uncommon in the United States. However, some studies have found a high prevalence of antibodies to HEV in the general population. When hepatitis E does occur, it is usually the result of travel to a developing country where Hepatitis E is endemic. Thus far a dozen cases have been reported among persons with no history of travel to HEV-hyperendemic countries, three of those cases have occurred in Texas. No clear exposure was identified for these domestically acquired (non-travel related) cases.