Herpetovirdae CMV and EB Lecture 7 Flashcards
CMV description and differences
Large inclusions in nucleus (owl eyes) as seen by microscopy of HE stain, perinuclear cytoplasmic inclusions and overall enlargement of the cell.
very similar to other herpesviruses with several exceptions
size of genomic DNA is greater for CMV compared to other herpesvirus
virus particle has a double stranded DNA genome plus viral messenger RNA (exception to the rule that virus have either DNA or RNA as their genome)
Replication of CMV
occurs in a variety of cells in culture including fibroblastic, epithelial, and macrophage. Duration of infection can be 4 to 6 weeks before CPE is a prominent feature of infection
in humans latent infections can be established in monocytes and certain bone marrow cells, reactivated by immunosuppression (HIV)
Virus progeny remain cell associated in cell cultures and in vivo and are primarily transmitted within the body via infected lymphocytes and leukocytes, also infects vascular endothelial cells
Disease possibilities of CMV
congenital infection, perinatal infection, infection of normal (not compromised) children and adults, recipients of transplantations and transfusions, infection of immunocompromised individuals.
Cytomegalic inclusion disease (CID) Congenital infection
primary infection of mother (no clinical signs in mom, virus in urine) > CMV infects fetus in utero.
visceral organs are targeted.
Possible outcomes of congenital infection (CMV):
death in utero, rare
infection of liver (jaundice) and spleen
brain microcephaly (retardation)
thrombocytopenic purpura (reduced numbers of platelets and skin hemorrhage)
chorioretinitis
low brith weight
rash
in apparent infections
Most common virus caused congenital infection
more common than rubella since rubella vaccine has reduced rubella cases
a carrier state occurs probably involving lymphoid tissue where virus is shed via secretions
CMV infection post partum
- acquired newborn infections: infections of new born acquired in birth canal (last trimester CMV secreted in cervix as a result of reactivation of latent infection), infected newborn secrets virus; newborn can also acquire infection from mother’s milk; mostly asymptomatic unless newborn is premature or immunocompromised
- normal children and adults: most infections asymptomatic; saliva, urine, tears, blood can serve as the vehicles for viral transmission. Transmitted by sex in adults, semen and cervical secretions have virus or virus infected lymphocytes
heterophile antibody negative mononucleosis
CMV infection post partum 2
Post transfusion mononucleosis at 3-4 weeks after transfusions (lymphocyte in transfusion carry CMV); tissue and organ transplants also can transmit virus infection, more severe infection if patients is immunosuppressed by drugs, CMV significant cause of failure of kidney transplant.
reactivation of latent disease as a result of pregnancy, immunosuppression (AIDS)
may result in unusual disease manifestation including mononucleosis and pneumonitis, CMV retinitis, digestive tract ulceration, colitis and esophagitis.
Infectious process CMV
biological fluids that are introduced into the oral cavity (aerosol): Upper respiratory infection, including the regional lymph nodes, initiates the infectious process. Most often the early stages of infection are silent. Infected lymphocytes and monocytes serve to spread the infection to secondary sites including the spleen/lymph nodes, salivary glands, kidney tubules, cervix, testes and epididymis. Temporary reduction in T cell responsiveness.
A. hepatitis, pneumonitis (acute local inflamation in lungs and may have an immunopathological basis), mononucleosis (heterophile negative)
B. chronic carrier conditions can be established even with inapparent infections
TORCH complex acronym for agents causing congenital infections and defects
Toxoplasmosis: toxoplasma gondii protozoan
Other: tremponema pallidium syphilis, listeria, gram + rod (listera monocytogenes)
Rubella
Cytomegalic inclusion disease
Herpes simplex virus
