Epidemiology : outbreaks
of adenovirus infection are not uncommon in military establishments, and
some types of adenovirus infection have been associated with conjunctivitis
in the past. In Feb 2004 following an outbreak of conjunctivitis affecting
about 230 soldiers in 6 barracks in northern and southern Hessen, some
4700 members of the 14000 troops stationed in Hesse by the German Federal
Armed Forces have have been withdrawn from service. The bases at Schwalmstadt
(where the epidemic began), Schwarzenborn, Stadtallendorf, and Neustadt
will be closed for 3 weeks while the premises are disinfected
-
Japan : prior to 1995, most isolates were (in descending order) adenovirus
types 3, 2 and 1. In 1997, most were types 2, 3 and 7. In 1999, most were
types 2, 3 and 1. Adenovirus type 7 infection rates peak during May to
September, with 55 percent of patients in the age group 0 to 4 years. An
nationwide outbreak of Adenovirus 7 infection (75 cases) was reported in
1995. During 1991 to 2003, laboratory reports ranged from 1200 to 3000
per year.
-
17 032 isolates were recovered during 1982 to 1993 (includes 1080 in 1993):
6722 respiratory, 3428 eye and 1605 gastrointestinal.
-
10 010 isolates were recovered during 1995 to 1999: 7207 respiratory, 1321
eye and 1677 gastrointestinal.
-
reports for 2003 included 886 isolates of adenovirus type 3; and 1421 respiratory,
84 eye and 269 gastrointestinal isolates.
Reports of pharyngoconjunctival fever ranged from 6249 (in 1997) to 15
812 (in 1991).
-
these data represent cases reported by general physicians, internists
and ophthalmologists.
-
40,714 cases of pharyngoconjunctival fever were reported by pediatric
sentinel clinics in 2003.
Notable outbreaks:
-
1973 : an outbreak (28 cases) of adenovirus 8 epidemic keratoconjunctivitis
was reported at a babies' home in Sapporo.
-
1990 (publication year) : an outbreak (14 cases) of adenovirus 37 keratoconjunctivitis
was reported in an ophthalmology clinic in Yokohama.
-
1996 to 1997 : an outbreak (14 cases) of severe adenovirus 7 infection
was reported on a pediatric ward in Hokkaido.
Proteomics :
-
serotypes A, C, D, E and F all use :
-
primary receptor : Coxsackievirus
B and Adenovirus receptor (CAR / CVADR / CXADR), which interacts
with the head domain of the adenoviral fiber protein, also called
fiber
knob. CAR is almost ubiquitously expressed (expecially in hepatocytes).
Adjacent epithelium cells maintain cell contacts through homotypic interactions
of the CAR protein, an immunoglobulin superfamily member that also serves
as the receptor for adenoviruses. However, CAR exhibits polarized basolateral
expression and might block virus escape to the apical surfaces when viral
progeny are shed on basolateral surfaces. But adenoviruses express the
protein fiber, which competitively inhibits CAR-CAR interactions, disrupting
epithelial integrity. Thus, fiber is an adenovirus virulence factor that
promotes viral dissemination. After the initial binding step, the viral
particle achieves endocytotic internalization via interaction with ...
-
secondary receptors : avb3
, avb5
(and avb1?)
integrins, which interact with the penton base. Integrin aM
mediates attachment but not internalization of adenovirus virions in monocytes,
while integrin aV also mediates internalization
via clathrin-dependent endocytosis in both monocytes and epithelial cells.
-
serotype B uses CD46 / MCP
as receptor
Adenovirus internalized by alveolar macrophages is degraded with a half-life
of 6 h while in epithelial cells < 5% is degraded by 48 h.
Genomics : it integrates into
adenovirus/SV40
integration site 1 (ASVS1)
-
E1B19K is a Bcl-2
ortholog.
They persist in lymphoid tissues, rhinopharynx, bowel and kidney (excreted
in urines during
pregnancy
).
=>
clinical
manifestations : adenovirus infections are usually asymptomatic, but
may be associated with diseases of the respiratory, ocular and gastrointestinal
tract (types 40 and 41). It has been estimated that adenoviruses are responsible
for 5-10% of paediatric respiratory infections (predominantly
pharyngoconjunctival
fever (PCF)
).
Respiratory infections in children are short-lived and rarely life-threatening.
Outbreaks of adenovirus respiratory infections have been common among military
recruits (mainly types 4, 7, 14 and 21), where rates of hospitalisation
have reached 20%. As a result vaccines were developed against adenovirus
types 3, 4, 7 and 21, but later withdrawn. Most outbreaks of pharyngoconjunctivital
fever in school-age children have occurred occur during the summer, whereas
the outbreaks among military recruits have occurred during winter, probably
reflecting a different mode of transmission. Adenovirus types 8, 9 and
11 have been associated with outbreaks of keratoconjunctivitis (also known
as shipyard eye) in adults. However, whereas multiple serotypes from different
species have been described as causing cases or limited, irregular outbreaks
of ocular disease in humans, there are only a few serotypes that regularly
cause larger outbreaks or epidemics. The 2 types of ocular disease that
are commonly caused by adenoviruses are
pharyngoconjunctival
fever (PCF)
and
epidemic
keratoconjunctivitis (EKC)
.
An interesting observation is that the 3 serotypes that cause EKC (Ad8,
Ad19, and Ad37) use a cellular receptor (sialic acid) that is different
from the cellular receptors used by other adenoviruses (CAR or CD46)
Laboratory examinations :
basophilic
Cowdry type B inclusion bodies
Therapy : at present, there are no licensed
antivirals available to any of the adenoviruses. Cidofovir intravenously
at 5 mg/kg weekly for 2 consecutive weeks, then every 2 weeks until 3 consecutive
ADV-negative samples were documented from all previously invoved sites
is safe and effective in pediatric HSCT recipients
ref
Prevention : an adenovirus type 4 vaccine
and a triple type 4, 7 and 21 vaccine were employed with some degree of
success in the USA. However, these vaccines are no longer in production,
and there is some evidence that outbreaks of adenovirus-associated illness
affecting military recruits are on the increase.
Used as
transfection vector
.