Cytomegalovirus

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Cytomegalovirus

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Cytomegalovirus

  1. 1. Cytomegalovirus Dr.T.V.Rao MD
  2. 2. Cytomegalovirus Cytomegalovirus (from the Greek cyto-, "cell", and - megalo-, "large") is a viral genus of the viral family known as Herpesviridae or herpes viruses. The species that infects humans is commonly known as human CMV (HCMV) or human herpesvirus-5 (HHV-5), and is the most studied of all cytomegaloviruses
  3. 3. Properties of the CMV Belong to the betaherpesvirus subfamily of herpesviruses double stranded DNA enveloped virus Nucleocapsid 105nm in diameter, 162 capsomers The structure of the genome of CMV is similar to other herpesviruses, consisting of long and short segments which may be orientated in either direction, giving a total of 4 isomers. A large no. of proteins are encoded for, the precise number is unknown. Dr.T.V.Rao MD 3
  4. 4. tegument 200 nm envelope glycoproteins capsid DNA core Human Cytomegalovirus Virion Structure
  5. 5. Why are herpes viruses (and especially CMV) so fascinating from an evolutionary standpoint? 1.They are ancient 2.Latency = highly evolved 3.While many viruses deal with evolution “passively” (i.e. mutate), herpesviruses “actively” target mechanisms Dr.T.V.Rao MD 5
  6. 6. Human Cytomegalovirus A complex -herpes virus Large genome (230kb) Slow replicating Restricted host range Infects 60-90% of the population worldwide, typically asymptomatic infection Infection in immunocompromised individuals life threatening Stem cell and solid organ transplant recipients HIV infected individuals Dr.T.V.Rao MD 6
  7. 7. Spread of CMV CMV spreads from person to person through body fluids, such as blood, saliva, urine, semen and breast milk. CMV spread through breast milk usually doesn't make the baby sick. However, if pregnant and develop an active infection, can pass the virus to baby.
  8. 8. Consequences of CMV Infections Cancer patients receiving intensive chemotherapy regimens can get infected Infection in utero: Leading cause of infectious disease related birth defects 1 in 100 infected; 1 in 1000 present symptoms/pathology Mild to severe hearing loss Cognitive deficits Physical abnormalities Dr.T.V.Rao MD 8
  9. 9. Pathogenesis Once infected, the virus remains in the person for life and my be reactivated from time to time, especially in immunocompromised individuals. The virus may be transmitted in utero, perinatally,or postnatally. Perinatal transmission occurs. .
  10. 10. Clinical Manifestations Congenital infection - may result in cytomegalic inclusion disease Perinatal infection - usually asymptomatic Postnatal infection - usually asymptomatic. However, in a minority of cases, the syndrome of infectious mononucleosis may develop which consists of fever, lymphadenopathy, and splenomegaly. The heterophile antibody test is negative although atypical lymphocytes may be found in the blood. Dr.T.V.Rao MD 10
  11. 11. Clinical Manifestations Immunocompromised patients such as transplant recipients and AIDS patients are prone to severe CMV disease such as pneumonitis, retinitis, colitis, and encephalopathy. Reactivation or reinfection with CMV is usually asymptomatic except in immunocompromised patients.
  12. 12. Complications CMV mononucleosis. This syndrome resembles infectious mononucleosis, but the Epstein-Barr virus (EBV) causes classic mononucleosis
  13. 13. Complications Intestinal complications. CMV infection of intestines can result in diarrhoea, fever and abdominal pain; inflammation of colon; and blood in stool.
  14. 14. Complications Nervous system complications. A variety of neurological complications have been reported as a result of CMV infection in the nervous system. These may include inflammation of your brain (encephalitis). Lung complications. CMV can cause inflammation of lung tissue (pneumonitis)
  15. 15. Congenital Infection Defined as the isolation of CMV from the saliva or urine within 3 weeks of birth. Commonest congenital viral infection, affects 0.3 - 1% of all live births. The second most common cause of mental handicap after Down's syndrome and is responsible for more cases of congenital damage than rubella.
  16. 16. Transmission to Foetus Transmission to the foetus may occur following primary or recurrent CMV infection. 40% chance of transmission to the foetus following a primary infection. May be transmitted to the foetus during all stages of pregnancy.
  17. 17. Cytomegalic Inclusion DiseaseCNS abnormalities - microcephaly, mental retardation, spasticity, epilepsy, periventricular calcification. Eye - choroidoretinitis and optic atrophy Ear - sensorineural deafness Liver - hepatosplenomegaly and jaundice which is due to hepatitis. Lung - pneumonitis Heart - myocarditis Thrombocytopenic purpura, Haemolytic anaemia Late sequelae in individuals asymptomatic at birth - hearing defects and reduced intelligence. Dr.T.V.Rao MD 17
  18. 18. CMV retinitis
  19. 19. Laboratory Diagnosis Virus Isolation conventional cell culture is regarded as gold standard but requires up to 4 weeks for result. More useful are rapid culture methods such as the DEAFF test which can provide a result in 24-48 hours. Serology the presence of CMV IgG antibody indicates past infection. The detection of IgM is indicative of primary infection although it may also be found in immunocompromised patients with reactivation. Dr.T.V.Rao MD 19
  20. 20. Treatment Congenital infections - it is not usually possible to detect congenital infection unless the mother has symptoms of primary infection. If so, then the mother should be told of the chances of her baby having cytomegalic inclusion disease and perhaps offered the choice of an abortion. Dr.T.V.Rao MD 20
  21. 21. TreatmentPerinatal and postnatal infection - it is usually not necessary to treat such patients. Immunocompromised patients - it is necessary to make a diagnosis of CMV infection early and give prompt antiviral therapy. Anti-CMV agents in current use are ganciclovir, forscarnet, and cidofovir.
  22. 22. Prevention CMV infection can be contagious if the infected person comes in close or intimate contact with another person. One should avoid kissing and sexual contact with an infected person. The virus may also spread among young children in day care settings. When planning blood transfusions or organ transplants, the CMV status of the donor can be checked to avoid passing CMV to a recipient who has not had CMV.
  23. 23. Prevention No licensed vaccine is available. There is a candidate live attenuated vaccine known as the Towne strain but there are concerns about administering a live vaccine which could become latent and reactivates. Prevention of CMV disease in transplant recipients is a very complicated subject and varies from center to center. It may include the following measures. Dr.T.V.Rao MD 23
  24. 24. Prevention Screening and matching the CMV status of the donor and recipient Use of CMV negative blood for transfusions Administration of CMV immunoglobulin to seronegative recipients prior to transplant Give antiviral agents such as acyclovir and ganciclovir prophylactically. Dr.T.V.Rao MD 24
  25. 25. Programme Created by Dr.T.V.Rao MD for Medical and Paramedical Students in Universal Health Care Email. doctortvrao@gmail.com Dr.T.V.Rao MD 25

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