Human cytomegalovirus
| Human cytomegalovirus | ||||||||||||||||||||
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Cytomegalovirus infection of the lungs. |
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| Human beta herpesvirus 5 | ||||||||||||||||||||
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| CMV, HHV-5 | ||||||||||||||||||||
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The human cytomegalovirus ( HCMV ) (also human betaherpesvirus 5 ( HHV-5 ), cytomegalovirus ( ZMV ), cytomegalovirus ( CMV )) is an enveloped , double-stranded DNA virus (dsDNA), belongs to the family of herpesviridae , genus cytomegalovirus and is worldwide spread. It is transmitted via saliva , urine, sperm secretions and during blood transfusion .
features
The virus has a total diameter of around 200 nanometers and its genome consists of linear, double-stranded DNA of around 230,000 base pairs that encode 151 different genes . Its icosahedral capsid , made up of various capsomeres , is surrounded by a lipid membrane . This virus envelope contains six glycoproteins against which the host organism can form antibodies . The membrane envelope is also the reason that the virus can only survive outside the organism for a short time and dries out easily. The virus is also very sensitive to ethanol , solvents , detergents and acids . HCMV binds to integrin β-3 .
Characteristic for this virus - as for all other species of the subfamily Betaherpesvirinae - is a narrow host range and a noticeably slow reproduction cycle. The infected cells are usually greatly enlarged ( cytomegaly - in the sense of giant cell formation), which is why the virus was named that way.
distribution
The human cytomegalovirus is widespread ( ubiquitously ) worldwide, the infection rate is 30 to 90% depending on the standard of living.
Consequences of infection
The virus causes cytomegaly in humans . The initial infection with the human cytomegalovirus occurs in healthy immunocompetent people in 75-99% of the cases with no or only minor symptoms. The main symptom is a high fever, sometimes for weeks, with typically elevated liver values. Life-threatening complications such as myocarditis , thrombocytopenia or pneumonia are rare in immunocompetent persons, so that no antiviral therapy has to be started.
However, in immunocompromised patients or premature infants, a new HCMV infection or HCMV reactivation can lead to serious problems. HCMV-associated colitis with diarrhea can occur; in kidney transplant people, manifest HCMV reactivation can lead to a deterioration in the function of the transplant and possibly even to the loss of the transplant. In 30% of AIDS patients who do not receive highly active antiretroviral therapy , the virus attacks the retina and leads to blindness.
Children who were infected with HCMV as a fetus during pregnancy through an initial infection of the mother, can develop growth retardation, microcephaly , intellectual disability and especially hearing damage. Long-term neurological effects are also observed. The risk of transmission to the fetus when pregnant women are first infected in the first trimester is around 20%, with over 50% of these children suffering severe, permanent damage. In the third trimester, the probability of transmission is significantly higher at approx. 80%, although damage to the fetus has not yet been reliably observed at this point in time. The rate of new infections during pregnancy is around 0.5% in Germany and France.
In the case of an initial infection, the incubation time is approx. 4 to 6 weeks.
prevention
As of 2015, there was no vaccination against the human cytomegalovirus approved for humans. A phase 2 study of a CMV vaccine published in 2009 showed only limited effectiveness of 50%. A number of the test persons developed a CMV infection despite being vaccinated.
Diagnosis
Serology for status determination: IgG , IgM , complement fixation (KBR) - mainly here for the detection of IgG antibodies , Virämienachweis pp65 ( phosphoprotein 65 of the HCMV) HCMV IEA (triggered by the HCMV Erythrozytenabnormalität , inherited erythrocyte abnormality ), quantified nPCR (nested polymerase Chain reaction). Normal PCR is basically worthless with over 25% false positive results.
The Society for Pediatric Infectious Diseases (DGPI) recommends determining the HCMV antibody status before starting a pregnancy. Since this is not provided for in the general maternity guidelines (as of June 2015), this examination is only carried out as an individual health service (IGeL).
therapy
For the treatment of a symptomatic initial infection, reactivation or complications in immunocompromised patients, the intravenously administered antiviral ganciclovir can be used, or alternatively foscarnet . In addition, the preparation valganciclovir with improved bioavailability is available for oral use . For the treatment of CMV retinitis is also cidofovir suitable.
literature
- Birgit Schrage: Development of a DNA vaccine against the human cytomegalovirus. Dissertation, University of Stuttgart, 2002, (1.40 MB; PDF).
- Heike Jennert: Polymerase Chain Reaction (PCR) for the detection of the human cytomegalovirus. Dissertation, Justus Liebig University Gießen, 2003, (1.35 MB; PDF).
Web links
- University of Veterinary Medicine Vienna, systematics and characteristics of the Herpesviridae ( Memento from July 7, 2007 in the web archive archive.today )
- Initiative for the prevention of congenital cytomegaly infections
- detailed information on CMV retinitis in HIV / AIDS patients
- Disruption of cell communication: HCM virus is only apparently harmless.
- Robert Koch Institute - Advice for doctors, cytomegalovirus infection: Merkblaetter / Ratgeber Zytomegalievirus
- Annika Röcker: Cytomegalovirus: How a virus goes to sleep . On: Spektrum.de from July 8, 2020.
Individual evidence
- ↑ a b c d e ICTV: ICTV Taxonomy history: Human alphaherpesvirus 1 , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
- ↑ genome database of the NCBI
- ↑ Heike Jennert: Polymerase Chain Reaction (PCR) for the detection of the human cytomegalovirus (PDF; 1.4 MB), pp. 7–8.
- ↑ Klaus Miksits, Helmut Hahn: Basic knowledge of medical microbiology and infectious diseases. 3. Edition. Springer, Berlin 2007, ISBN 3-540-01525-6 .
- ↑ a b c Robert Koch Institute: Cytomegalovirus infection. In: RKI advice for doctors. January 20, 2014, accessed July 3, 2015 .
- ↑ RF Pass, C. Zhang, A. Evans et al .: Vaccine prevention of maternal cytomegalovirus infection . In: New England Journal of Medicine (N. Engl. J. Med.) . Volume 360, No. 12, March 2009, pp. 1191-1199. doi : 10.1056 / NEJMoa0804749 . PMID 19297572 . PMC 2753425 (free full text).
- ^ Marianne Abele-Horn: Antimicrobial Therapy. Decision support for the treatment and prophylaxis of infectious diseases. With the collaboration of Werner Heinz, Hartwig Klinker, Johann Schurz and August Stich, 2nd, revised and expanded edition. Peter Wiehl, Marburg 2009, ISBN 978-3-927219-14-4 , p. 307.