Cytomegalovirus

See also: MVC

The cytomegalovirus (or MVC ) is a Virus responsible for generally unperceived infections passing. Its pathogenic character occurs especially among patients whose immunizing defenses are weak: treaties by immunodepressor, reached by the AIDS, fetus. An infection with cytomegalovirus in the expectant mother can cause lesions at the fetus. It acts of the congenital fetal infection most frequent in the developed countries .

The virus

The cytomegalovirus belongs to the family of the herpesvirus which includes/understands: virus of the herpes simplex, the Virus of Epstein-Barr and the Virus of the chicken pox-shingles. This family of virus is characterized by her capacity to produce latent and persistent infections. Its structure comprises a genome, a capsid, an envelope covered with glycoprotéïnes. The genome (DNA) is packed in a proteinic structure called Capside, which has a polyhedric geometrical conformation.

List species

  • Cercopithecine herpesvirus 5 ( CeHV-5 ) - cytomegalovirus of the green Monkey - African green monkey cytomegalovirus
  • Cercopithecine herpesvirus 8 ( CeHV-8 ) - cytomegalovirus of the Monkey rhesus - Rhesus monkey cytomegalovirus
  • Human herpesvirus 5 ( HHV-5 ) - human cytomegalovirus - Human cytomegalovirus ( HCMV )
  • Pongine herpesvirus 4 ( PoHV-4 )
Species candidates:
  • Aotine herpesvirus 1 ( AoHV-1 ) - Herpesvirus aotus 1
  • Aotine herpesvirus 3 ( AoHV-3 ) - Herpesvirus aotus 3

Epidemiology

The man is the only reserve of this virus and its transmission is done by contact because it is a very fragile virus. This virus is transmitted by all body secretions: salivate, blood, sperm, tears, mother's milk, secretions of the vagina and cervix. This infection has a world distribution without seasonal rate/rhythm.

Cytomegalovirus and pregnancy

Introduction

Between 0,3% and 2,4% of the expectant mothers contract this disease during the pregnancy. Half of the fetuses of these women will be reached by the virus.
  • 10% of these fetuses will have clinical and/or echographic demonstrations of the infection with serious after-effects (microcephalus, dilation of the ventricles of the brain, attacks ocular);
  • 10% of the fetus not presenting any clinical sign or echographic will develop at the end of a few years a deafness.

Maternal primary infection:

In the not immunized expectant mother, the most important risk factor is to have an infant, especially if it goes in crib. The contamination is done especially during the exchanges or of the division of covers.

Private clinic in the adult: primary infection of the expectant mother - 80% of the cases: asymptomatic - 10% of the cases: syndrome grippal - 5% of the cases: prolonged fever A syndrome mononucleosic is often present.

Consequence of a maternal primary infection at the fetus

The attacks characteristic of MVC on the level of the fetus are:

  • a neurological attack more or less severe, backwardness, a cerebral calcification with echography.

  • an attack of the sensory nerves: deafness , chorioretinitis.
  • a hepatic attack (hemorrhagic ictère, disorders)
  • a digestive attack with a hyperechogenicity of the intestinal handles.
  • a thrombopénie.
  • an intra-uterine delay of growth .

The diagnosis is generally evoked with echography. The forecast is function of the neurological attack.

Echographic signs

  1. Microcéphalie
  2. Dilatation of the side ventricles of the Cerveau
  3. Retard of growth will intra uterine
  4. Hyperéchogénicité of the internal

With the birth

Weights and size of the child are in lower part of the normal. Sometimes a feverish state is found.

Consequence of a maternal réinfection at the fetus

Diagnosis

Indirect method

  • is based on the presence of antibody in the blood of the mother
This method has in practice only little interest for the positive diagnosis of an infection with cytomegalovirus.
  1. the commercial tests have sometimes a low sensitivity
  2. the traditional distinction between IgG (Immunoglobuline of the type G) and IgM (Immunoglobulin of the type M) does not resist the practice: many women keep years IgM; impossibility of diagnosing the réinfestations. And 70% of the primary infections do not have IgM
  3. the search for greed of the Immunoglobuline S makes it possible to distinguish the infections from the réinfestations
  • Its only interest is to eliminate an infection with cytomegalovirus when the séro-diagnosis is negative.

Direct method

This method requires to collect Amniotic liquid during a Amniocentèse

  • Highlighted by culture of the Technical virus

of reference but the brittleness of the virus makes sometimes difficult its realization
  • specific Demande from one to three weeks
  • Très (100%) but by average sensitivity (50%)
  • the technique known as of fast culture increases the sensitivity
    • Mise in obviousness of the viral antigens: pp65

    • Highlighted by genic amplification or PCR of the virus

    Method of reference for the diagnosis of the fetal attack by the virus

    Treatment

    There does not exist any treatment available to decrease the risk of fetal attack. When the diagnosis of fetal infections with MVC is posed on echographic criteria and search for cytomegalovirus by PCR, it is possible to practice a medical Interruption of pregnancy. One lays out of 2 antiviral drugs the DHPG (Ganciclovir) and the acid phosphonoformic (Foscarnet). A third drug, the HPMPC (Cidofovir) is reserved in the event of resistance to the two precedents. There is no vaccine currently at the point against MVC. The gammaglobulines with high ac title anti MVC have, in repeated injections, a preventive activity (Clerc's Offices).

    Prevention

    • No vaccine is available.
    • the prevention is not possible that in the séro-negative expectant mothers. The constraining precautions following make it possible to reduce the risk:
    professional ousting of the séro-negative women if they deal with infants;
  • frequent washings of the hands;
  • wearing of latex gloves to avoid the contact with body liquids or objects soiled by these liquids;
  • not to give a kiss on the mouth (even with his/her own children);
  • washing with large water of the pot of the child, the every day either with gloves, or by another person with ebullient water or one disinfecting.
  • during its meal, use the covers separated for you and your child. Never taste its meals with its spoon. Never taste its feeding-bottle.
  • do not take a bath with your child
  • in the event of transfusion of an expectant mother, to make a transfusion with déleucocyté blood or negative MVC;
  • sexual relations with condoms, even at a stable couple.

    Tracking of the infection with MVC in the expectant mother

    The National College of the Gynecologists and French Obstétriciens considers that in the actual position of knowledge, a systematic policy of tracking of MVC during the pregnancy is not justified by shown benefit and that it would undoubtedly have fatal consequences. No country in the world practices the systematic tracking of the infection with MVC in the expectant mother because
    • 80% of the fetuses of the infected women will have any after-effect
    • serology is of even impossible delicate interpretation in the event of reinfestation
    • No treatment is not available

    Cellular tropism

    • Cellules cibles:
      • Monocyte and Macrophage
      • muscular Cellule endothéliale
      • Cellule smoothes
      • glandular Cellule
    • Sites of latences:
      • Monocytes of circulating blood
      • Progéniteurs of the osseous Marrow of the type CD34+

    Private clinic

    • asymptomatic Form ( 90% of the cases )
    • benign Form ( that the patient takes for simple tiredness )
    • traditional Forme:
      • AEG
      • mononucleosic Fever
      • Arthralgie
      • Syndrome
    • complicated Form
    • severe Form

    Cytomegalovirus and AIDS

    Introduction

    Cytomegalovirus and People under immunodépresseurs

    References

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