Herpes Viruses

Cytomegalovirus

Presentation Outline

• Structure

• Classification

• Multiplication

• Clinical manifestations

• Epidemiology

• Diagnosis

• Control

Latent Infections

• ALL herpes viruses can establish latent infections. The viral genome may become incorporated into the host DNA or remain extrachromosomal

• Latent viruses can be reactivated by stress, menstruation or uv light

• Reactivation may be asymptomatic or lead to mild or severe disease.

Herpes Diagnosis

• Isolation of virus by tissue culture

• herpevirinae cause cytopathic effects

• intranuclear fluorescence of scrapings using fluorescent antibodies

• PCR being developed

CMV retiniitis is diagnosed clinically

Cytomegalovirus

Cytomegalovirus

• Cytopathic effect on the host cell. The cell swells and a large inclusion body forms in the nucleus.

• Transmission:

• not highly infectious, virus found in saliva, urine and blood.

• infants and children acquire CMV from other children.

• congenital. In utero, at birth during perinatal period.

• see clinical note in the textbook.

• Clinical forms of Cytomegalovirus infection

• Congenital:

• the following possibilities relate to the congenital type.

• severe deformities and death.

• survive with serious defects - physical and mental.

• survive with out deformities.

• newborns: - Enlarged liver and spleen, jaundice, capillary bleeding, microcephaly, ocular inflammation.

Disseminated cytomegalovirus

• Symptoms:

• fever, severe diarrhea, hepatitis, arthritis, pneumonia, high mortality.

• activation of inapparent infection.

• also due to:
  • immunosuppressive therapy.
  • cancer.
  • AIDS.

• Virus in blood or organ:

• post transfusion.

• post organ transplant.

• Cytomegalovirus mononucleosis:

• teenage, young adult similar to other mono.

Epidemiology of CMV

• whereever human populations tested - high percentage (40-100%) were positive for the antibodies.

• newborns 7.5% positive in the USA & UK.

• woman of child bearing age were 20-100% positive in many countries that were studied (pregnant - virus in the urine).

• IV drug users were 100% positive for the antibodies.

• homosexual males were 30% positive for the antibodies - high percentage shed virus.

• Transmission:

• saliva, respiratory mucus, milk, urine, semen, cervical secretions, feces and lymphocytes.

• Diagnosis:

• the differential diagnosis in neonates must include toxoplasmosis, rubella, herpes simplex, bacterial sepsis.

• in adults it must be differentiated from Epstein-Barra and hepatitis A & B.

Cytomegalovirus - con’t

• Laboratory diagnosis:

• virus can be grown from all organs.

• many serological tests.

• Treatment:

• gancyclovir, foscarnet, hyperimmune CMV immunoglobulin, have some effect.

• interferon does not prevent infection or promote recovery.

• Prevention:

• no animal can be found that can be infected with CMV.

• Two deterents:

• vaccine stimulated antibodies may not be protective. Patients already seropositve can be reinfected.

• a vaccine could be oncogenic.

EBV and burkitt’s lymphoma were shown to be the same virus when a lab technician acquired mononucleosis while working with the Burkitt’s lymphoma virus.

Cytomegalovirus

• Urine isolate

Intranuclear inclusions

• The cell swells and a large inclusion body forms in the nucleus.

Cytomegalovirus

• Nuclear & cytoplasmic inclusions

Transmission: CMV

• not highly infectious, virus found in saliva, urine and blood.

• infants and children acquire CMV from other children.

• congenital. In utero, at birth during perinatal period.

Congenital: CMV

• the following possibilities relate to the congenital type.

• severe deformities and death.

• survive with serious defects - physical and mental.

• survive with out deformities.

• newborns: - Enlarged liver and spleen, jaundice, capillary bleeding, microcephaly, ocular inflammation.

Disseminated cytomegalovirus

• fever, severe diarrhea, hepatitis, arthritis, pneumonia, high mortality.

• activation of inapparent infection.

• also due to:
  • immunosuppressive therapy.
  • cancer.
  • AIDS.

Virus in blood or organ:

• post transfusion.

• post organ transplant.

Cytomegalovirus mononucleosis:

• teenage, young adult similar to other mono.

Epidemiology of CMV

• high percentage (40-100%) were positive for the antibodies.

• newborns 7.5% positive in the USA & UK.

• woman of child bearing age were 20-100% positive in many countries that were studied (pregnant - virus in the urine).

• IV drug users were 100% positive for the antibodies.

• homosexual males were 30% positive for the antibodies - high percentage shed virus.

Transmission:

• saliva, respiratory mucus, milk, urine, semen, cervical secretions, feces and lymphocytes.

Differential Diagnosis:

• the differential diagnosis in neonates must include toxoplasmosis, rubella, herpes simplex, bacterial sepsis.

• in adults it must be differentiated from Epstein-Barra and hepatitis A & B.

Laboratory diagnosis: CMV

• virus can be grown from all organs.

• many serological tests.

Treatment: CMV

• gancyclovir, foscarnet, hyperimmune CMV immunoglobulin, have some effect.

• interferon does not prevent infection or promote recovery.

Prevention:CMV

• no animal can be found that can be infected with CMV.

• Two deterents:

• vaccine stimulated antibodies may not be protective. Patients already seropositve can be reinfected.

• a vaccine could be oncogenic.