Biomedical Engineering Reference
In-Depth Information
B19 (Chapter 40). These diseases take their names from an historical diag-
nostic dilemma faced by pediatricians, who regularly encountered six clinical
syndromes of childhood rashes. Four of the childhood rashes had known
etiologies. The fifth and sixth rashes, both caused by organisms that were
not yet identified, were referred to as “fifth disease” and “sixth disease”.
Subsequently, the viral causes of these two diseases were discovered, but the
numeric names held.
Human herpesvirus type 8 (HHV8) is a DNA-transforming virus that can
cause Kaposi's sarcoma, primary effusion lymphoma, and some forms of
Castleman's disease. Kaposi's sarcoma is a cancer characterized by focal
proliferations of small blood vessels, occurring most often in the skin.
Immune-suppressed patients (e.g. transplant recipients) who are carriers of
the latent HHV8 virus, may develop Kaposi's sarcoma within a few months
of immunosuppression. Interestingly, if immunosuppression is halted, the
Kaposi's sarcoma may regress [124]. It is presumed that sustained viral repli-
cation is necessary for early tumor growth.
Cytomegalovirus infects about half of the world population, with most
individuals suffering no ill-effects. Once infected, the virus usually persists
for the life of the individual. In a minority of cases, particularly among
immune-compromised individuals (e.g. organ transplant recipients and AIDS
patients) and newborns, the virus may produce severe neurologic disease.
The disease is known as cytomegalic inclusion body disease, and, as the
name suggests, a large nuclear inclusion body characterizes actively infected
cells. When the virus is transmitted transplacentally, by mothers infected
during their pregnancy, the newborn may suffer developmental damage to
the brain and other organs.
Group I, dsDNA
Unassigned
Nonenveloped
Adenoviridae
*Human adenoviruses A through G
Papillomaviridae
*Human papillomavirus
Polyomaviridae
*BK polyomavirus
*JC polyomavirus
*Simian virus 40
Class Adenoviridae contains the human adenoviruses of which there are
57 types, with different clinical syndromes associated with specific subtypes
of the virus. Most adenoviral diseases are either respiratory, conjunctival
(i.e. viral conjunctivitis), or gastroenteritic. Infections may present clinically
as tonsillitis (simulating strep throat), pharyngitis (croup), otitis media,
pneumonia, meningoencephalitis, and hemorrhagic cystitis. Adenoviruses are
