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BY AWAIS AHMED #1219 MD 3. CYTOMEGALOVIRUS. Table of contents. Introduction Pathogenesis CMV structure Replication Immunity Transmission Epidemiology Signs and symptoms Lab findings Treatment Prevention. Introduction.
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BY AWAIS AHMED #1219 MD 3 CYTOMEGALOVIRUS
Table of contents • Introduction • Pathogenesis • CMV structure • Replication • Immunity • Transmission • Epidemiology • Signs and symptoms • Lab findings • Treatment • Prevention
Introduction • The cytomegalovirus (CMV) is a viral genus belonging to the viral family of herpesviruses • The species Human cytomegalovirus (HCMV) effects humans and is the most studied. Also known as Human herpesvirus 5 (HHV-5) • Belongs to subfamily Betaherpesvirinae
Introduction continued • The virus remains latent in body for long periods of time • Although found throughout the body it is mostly associated with salivary gland in humans • Infects 60 to 90 percent of the world population…is asymptomatic • It is life threatening in immunocompromised patients (people with HIV)
Pathogenesis • Replicating viruses disrupt the cytoskeleton, causing massive cell enlargement, which is the source of the virus' name • CMV infection of blood vessel endothelial cells in humans is a major cause of atherosclerosis. • CMV encodes a protein, UL16, which prevents Natural killer cells from upregulation (growth), this allows CMV to stop the death of the host cell
Replication • Cytomegalovirus (CMV) is a double-stranded DNA virus • Slow replicating • Large genome (230 kilo bases of DNA)
Replication • After CMV infects a cell the viral capsid is transported to the nucleus • Viral DNA is released and transcribed by the host cell machinery • CMV not only releases viral DNA, it also releases viral mRNA • mRNAs are delivered to the cell cytoplasm when the viral envelop fuses with the plasma membrane at the beginning of infection • mRNA stay in the cytoplasm and are translated into proteins
Immunity • immunity against CMV is both humoral and cellular • There are many antibodies directed against the viral glycoproteins (gB and gH) that probably participate in blocking the cell infection • T-cell response against CMV is based on their memory function
Transmission • generally passed from infected people to others through direct contact with body fluids, such as urine, saliva, or breast milk • Sharing syringes and needles • CMV is sexually transmitted, Unprotected sex • Spread through transplanted organs and blood transfusions • CMV can be transmitted from a pregnant woman to her fetus during pregnancy (mother’s blood crosses over the placenta and infects the fetus’ blood)
Epidemiology • More in developing countries • Between 50% and 70% of women of childbearing age in the United States have been infected with CMV • CMV is the most common viral infection that infants are born with in the United States • About 1 in 150 children are born with congenital (present at birth) CMV infection
Signs and Symptoms • CMV usually is an asymptomatic infection • Produces mild flulike symptoms; afterward, it remains latent throughout life and may reactivate. • Primary CMV infection may be a cause of fever of unknown origin. • Pharyngitis may be present • Symptoms develop 9-60 days after primary infection. • Examination of the lungs may reveal fine crackles. • The lymph nodes and spleen may be enlarged
Signs and Symptoms In immunocompromisedindividuals: • Pneumonia, hepatitis, encephalitis, colitis, uveitis, retinitis, and neuropathy • Rare symptoms are: pericarditis, myocarditis, thrombocytopenia, and hemolytic anemia. • Patients with HIV infection: CMV involves the entire GI tract and Retinitis
Lab findings • Antibody testing for CMV IgG and IgM
Treatment • There's no cure for CMV • kind of treatment depends on the symptoms and their severity • Antiviral drugs slow the virus reproduction • Ganciclovir (cannot usually be given during pregnancy, side effects is bone marrow suppression)
Prevention • Wash your hands often • Do not share food, drinks, or eating utensils used by young children • Avoid contact with saliva when kissing a child
References • http://en.wikipedia.org/wiki/HCMV_(human_cytomegalovirus) • http://www.nejm.org/doi/full/10.1056/NEJM198010233031702 • http://www.bio-pro.de/magazin/thema/03997/index.html?lang=en&artikelid=/artikel/04026/index.html • http://bio114.wikispaces.com/Ch • http://www.medicinenet.com/cytomegalovirus_cmv/article.htmris+Cyto+Route+of+Entry