SYNONYM OR CROSS REFERENCE: Human enterovirus B Footnote 1, enteric cytopathogenic human orphan (ECHO) virus, Boston exanthem disease
CHARACTERISTICS: Echoviruses are members of the genus Enterovirus and family Picornaviridae. Parechoviruses were previously classified as members of the genus Enterovirus, but have recently been separated into their own genus based on their unique biological propertiesFootnote 2. Echoviruses are small non-enveloped viruses with a single-stranded positive-sense RNA genome. Echoviruses are 30 nm in diameter. There are 28 serotypes of Human echoviruses, which are all classified in the species human enterovirus B Footnote 1.
PATHOGENICITY/TOXICITY: The majority of infections are asymptomatic. The most common symptomatic manifestation of infection is an acute nonspecific febrile illness with or without exanthem Footnote 1. Echoviruses are frequently associated with aseptic meningitis. Symptoms include acute onset of fever, headache, photophobia, nausea and vomiting. Fever may subside for several days and then recur. Generally, symptoms resolve in about 1 week. Severe illness and death are uncommon and most patients completely recover Footnote 3Footnote 4. Other clinical syndromes have been less commonly associated with echovirus infections, including paralysis, encephalitis, respiratory disease, diarrhea, hepatic disturbance, exanthems and enanthems, conjunctivitis, asthenia, pericarditis, and myocarditis Footnote 1Footnote 4-7. Epidemics in neonatal intensive care units have very high morbidity and mortality ratesFootnote 8.
EPIDEMIOLOGY: Worldwide distribution. In temperate climates, incidence peaks during the summer and fall months; in the tropics, transmission occurs year-round Footnote 3. Enteroviruses, including echoviruses, predominantly affect children. Other risk factors include lower socioeconomic status, large household size, crowded living conditions, living in urban areas, and areas with poorer sanitation Footnote 3Footnote 4.
HOST RANGE: Humans Footnote 9.
INFECTIOUS DOSE: The dose required to infect 50% of volunteers in one study was calculated to be 919 pfu for Echovirus 12 Footnote 10.
MODE OF TRANSMISSION: Transmitted by fecal-oral (most significant), respiratory, transplacental, perinatal, and self-inoculation routes Footnote 1Footnote 3. Fomites may also transmit viruses Footnote 3.
INCUBATION PERIOD: Variable, typically 2 – 10 days Footnote 9.
ZOONOSIS: No evidence of spread from animal to humans Footnote 9.
DRUG SUSCEPTIBILITY/RESISTANCE: No antiviral medications are currently approved for the treatment of enterovirus infections. Pleconaril has shown antiviral activity against echoviruses in vitro Footnote 11.
SUSCEPTIBILITY/RESISTANCE TO DISINFECTANTS: Echoviruses are susceptible to 0.3% formaldehyde and 0.3 – 0.5 ppm free chlorine. They are resistant to 70% alcohol, substituted phenolic, ether, and various detergents Footnote 9.
SURVEILLANCE: Traditionally diagnosed by the isolation of viral particles from clinical specimens; however, PCR-based tests are becoming more commonFootnote 13. The use of viral culture is declining as not all serotypes grow well in culture.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Most cases are self-limiting and recover with supportive care. No antiviral therapy is available Footnote 3.
LABORATORY-ACQUIRED INFECTIONS: At least three cases of laboratory-acquired infections have been reported Footnote 14.
SPECIAL HAZARDS: None
RISK GROUP CLASSIFICATION: Risk Group 2.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 15.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 15.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up Footnote 15.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism by autoclave, chemical disinfection, gamma irradiation, or incineration before disposing Footnote 15.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled Footnote 15.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: December 2011
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright © Public Health Agency of Canada, 2011 Canada