Biomedical Engineering Reference
In-Depth Information
*Poliovirus
*Enterovirus 68
109
*Rhinovirus A and B
Hepatovirus
*Hepatitis A, alternately human enterovirus type 72
Members of Class Picornaviridae have a small RNA genome, as small as
7 kilobases (i.e., 7000 nucleotides) in length. The picornaviruses include two
subclasses: Enterovirus and Hepatovirus.
Members of Class Enterovirus are among the most prevalent human
pathogens. In active infections, the virus can often be recovered from feces
and respiratory secretions. Poliovirus, spread by contaminated fecal material,
produces a paralytic syndrome characterized by inflammation and destruction
of the anterior horn cells of the spinal cord. Many poliovirus infections do not
result in disease, but disease-free infected individuals are carriers, transiently
producing infective virus. Aside from poliovirus, other enteroviruses may dis-
play neurotropism, producing aseptic meningitis and flacid paralysis [135].
There are a huge number of serotypes in Class Enterovirus, spread among the
Coxsackievirus, Echovirus, and Enterovirus viruses. They produce non-specific
flu-like illnesses, and various strains produce distinctive syndromes such as hand-
foot-mouth disease, herpangina, and hemorrhagic conjunctivitis, and Bornholm
disease (epidemic pleurodynia). Enterovirus infections are common pediatric mala-
dies. Infections in newborns can be severe, with hepatitis, encephalitis, and sepsis.
Class Enterovirus also includes the rhinoviruses, which contains more than 100
variant strains. The rhinoviruses account for most instances of the common cold.
Class Hepatovirus contains hepatitis A, a cause of hepatitis. As you would
expect from a member of Class Enterovirus, hepatitis A is typically spread by
the fecal
oral route. The resulting hepatitis is acute, and generally subsides
without sequelae. Unlike hepatitis B and C, hepatitis A does not progress to
chronic hepatitis and cirrhosis.
Group IV (
)ssRNA
Astroviridae
*Astrovirus species
1
Members of Class Astroviridae, like those of Class Picornaviridae and
Class Caliciviridae, lack an envelope. The class contains one species that
is pathogenic in humans: Astrovirus. Astrovirus causes enteritis. Infections
are especially common in children, accounting for more than 5% of enteritis
cases in the pediatric age group.
Infectious species:
Enterovirus
Coxsackievirus (flu-like illness, hand-food-mouth disease, herpangina,
hemorrhagic conjunctivitis, aseptic meningitis; in newborns, myocarditis,
meningoencephalitis, hepatitis)
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