Cytomegalovirus
Cytomegalovirus, also known as Human Herpesvirus (HHV-5), CMV OR
HCMV is a common virus that is found around the world. Individuals affected
with this kind of virus may not know they have it since it seldomly causes
symptoms.
What is Cytomegalovirus?
Cytomegalovirus (CMV) is a double-stranded DNA virus and is a member of
the Herpesviridae family.
● CMV shares many attributes with other herpes viruses, including
genome, virion structure, and the ability to cause latent and
persistent infections.
● At least 60% of the US population has been exposed to CMV, [1]
with a prevalence of more than 90% in high-risk groups (eg, male
homosexuals).
● Cytomegalovirus usually causes an asymptomatic infection;
afterward, it remains latent throughout life and may reactivate.
● Symptomatic CMV disease in immunocompromised individuals
can affect almost every organ of the body, resulting in fever of
unknown origin, pneumonia, hepatitis, encephalitis, myelitis,
colitis, uveitis, retinitis, and neuropathy.
Pathophysiology
Cytomegalovirus is a lytic virus that causes a cytopathic effect in vitro and in
vivo.
● When the host is infected, CMV DNA can be detected with
polymerase chain reaction (PCR) in all the different cell lineages
and organ systems in the body.
● Upon initial infection, CMV infects the epithelial cells of the
salivary gland, resulting in a persistent infection and viral
shedding.
, ● Infection of the genitourinary system leads to clinically
inconsequential viruria.
● Despite ongoing viral replication in the kidney, renal dysfunction is
rare except in renal transplant recipients, in whom CMV is
associated with rare cases of glomerulopathy and possible graft
rejection.
Statistics and Incidences
In the United States, nearly one in three children are already infected with
CMV by age five.
● In developing countries, most infections are acquired during
childhood, whereas, in developed countries, up to 50% of young
adults are CMV seronegative.
● The incidence of CMV seropositivity rises with age and in a
US-based study was reported to increase from 36% in children
aged 6-11 years to 91% in individuals older than 80 years.
● Other factors associated with CMV seropositivity include ethnicity
(77% in Mexican Americans and 71% in blacks), [6] female sex,
foreign-born status, and low socioeconomic status.
● Depending on the population surveyed, CMV may be found in
40%-100% of people, depending on socioeconomic conditions.
Causes
Causes of cytomegalovirus may include:
● Contact with fluids. CMV is mainly transmitted by contact with
fluids that contain the virus (e.g., saliva, urine, semen, cervical
mucus,blood breastmilk).
● Blood transfusion. Transfusion of multiple blood units is a risk
factor for CMV mononucleosis and has been implicated in
postoperative fever or fever in patients following trauma.
● Increased hospital stay. CMV frequently reactivates in critically ill
patients and may be linked to increased length of hospital and/or
Cytomegalovirus, also known as Human Herpesvirus (HHV-5), CMV OR
HCMV is a common virus that is found around the world. Individuals affected
with this kind of virus may not know they have it since it seldomly causes
symptoms.
What is Cytomegalovirus?
Cytomegalovirus (CMV) is a double-stranded DNA virus and is a member of
the Herpesviridae family.
● CMV shares many attributes with other herpes viruses, including
genome, virion structure, and the ability to cause latent and
persistent infections.
● At least 60% of the US population has been exposed to CMV, [1]
with a prevalence of more than 90% in high-risk groups (eg, male
homosexuals).
● Cytomegalovirus usually causes an asymptomatic infection;
afterward, it remains latent throughout life and may reactivate.
● Symptomatic CMV disease in immunocompromised individuals
can affect almost every organ of the body, resulting in fever of
unknown origin, pneumonia, hepatitis, encephalitis, myelitis,
colitis, uveitis, retinitis, and neuropathy.
Pathophysiology
Cytomegalovirus is a lytic virus that causes a cytopathic effect in vitro and in
vivo.
● When the host is infected, CMV DNA can be detected with
polymerase chain reaction (PCR) in all the different cell lineages
and organ systems in the body.
● Upon initial infection, CMV infects the epithelial cells of the
salivary gland, resulting in a persistent infection and viral
shedding.
, ● Infection of the genitourinary system leads to clinically
inconsequential viruria.
● Despite ongoing viral replication in the kidney, renal dysfunction is
rare except in renal transplant recipients, in whom CMV is
associated with rare cases of glomerulopathy and possible graft
rejection.
Statistics and Incidences
In the United States, nearly one in three children are already infected with
CMV by age five.
● In developing countries, most infections are acquired during
childhood, whereas, in developed countries, up to 50% of young
adults are CMV seronegative.
● The incidence of CMV seropositivity rises with age and in a
US-based study was reported to increase from 36% in children
aged 6-11 years to 91% in individuals older than 80 years.
● Other factors associated with CMV seropositivity include ethnicity
(77% in Mexican Americans and 71% in blacks), [6] female sex,
foreign-born status, and low socioeconomic status.
● Depending on the population surveyed, CMV may be found in
40%-100% of people, depending on socioeconomic conditions.
Causes
Causes of cytomegalovirus may include:
● Contact with fluids. CMV is mainly transmitted by contact with
fluids that contain the virus (e.g., saliva, urine, semen, cervical
mucus,blood breastmilk).
● Blood transfusion. Transfusion of multiple blood units is a risk
factor for CMV mononucleosis and has been implicated in
postoperative fever or fever in patients following trauma.
● Increased hospital stay. CMV frequently reactivates in critically ill
patients and may be linked to increased length of hospital and/or
