Thursday, June 23, 2011

Cytomegalovirus infection in children - Epidemiology

CMV infection can occur at any stage of life and is considered as "almost inevitable event."As a result of its spread, and the many health problems they raise (miscarriages, premature births, congenital infections, persistent infection with the possibility of reactivation in immunosuppressed states, participation in pathology after organ transplantation and transfusion), infection CMV has a wealth of epidemiological and clinical aspects.WHO estimates that CMV infection would be 1, 5% of neonatal infections.
Source of pathogens in human infection with CMV is exclusive: patients with typical or atypical forms of disease, chronic asymptomatic children with congenital unapparent infection.
The mode of transmission of infection is varied. Cytomegalovirus can be removed by various biological products contaminated from the patient or carrier of the virus: oral fluid, urine, vaginal secretions, semen, faeces, blood, tissues.
Prenatal, transplacental infection with CMV is the most common cause of prenatal viral infection that can cause congenital disease.The passage is effected by marrow occurs during a maternal viral load, often present during primo-infection in the first 6 months of pregnancy. Also, maternal infections can be endogenous, because of possible reactivation. Primary infection is responsible for the risk of prenatal infection in 30-60% of cases and 10-15% of neonatal clinical abnormalities.Primo-infection time is directly related sequelae, namely: 34-40% for the quarter, 8-25 in the second quarter and 0, 7% in the third quarter.The children infected in utero can produce specific IgM synthesis and circulating immune complexes in large quantity, but CMV-specific cellular immune response and nonspecific low.
Contamination by contact perinatal cervico-vaginal secretions of children with the mother during labor is produced in 10% of cases.Reactivity of neonatal infection is unlikely because children may be partially protected by maternal IgG Ac.
Contamination postnatal child contact is achieved by maternal products (milk, oral fluid, urine). It has been shown that 10-20% of nursing mothers may eliminate the virus in the milk. Child this way contamination chances are 50% and consecutive events are mostly subclinical infection.Regarding the elimination of CMV in the milk has been shown that this begins after the first month after birth so that colostrum is rarely involved in the transmission mechanism.
A lot of people who receive transfusions, with a significant volume of blood can acquire CMV infection in various stages of manifestation.The risk depends on two parameters citomegaliei transfusion: the amount of blood transfused, so after one transfusion risk is 5% and increases 4-5 times for several tranfuzii and immunological status (in people with immune deficiencies this risk reaches 50%, and cytomegalovirus disease that develops is a serious evolution with multiple determinations lung, liver).Risk of getting a transfusion cytomegalovirus infection exceeds 4-5 times the risk of hepatitis B transfusion. Proved that CMV is present in 36-50% of blood donors, which increases the risk of citomegaliei posttransfuzio-tional.
In the postnatal period and childhood can discuss the role of oral fluid can directly contaminate baby (kiss, originally chewed food for her mother and then administrated child) or indirectly by objects used in common (toys, instruments), contaminated hands.This mode of transmission is common for premature neonatal wards or children in the first year of life and institutionalized in medical and social service.It has been shown that 20-25% of children in nurseries excrete virus. Thus it plays the source of the pathogen to uninfected left utero or at birth. Back in the family, viral load, children can transmit the virus from mother to urge pregnancy infection and childbearing.
Infection often occurs when an organ transplant (kidney, heart, liver, bone marrow).
Responsiveness is general. Pregnant women show a high receptivity to infection with CMV (6 times higher than the rest of the adult population, 10-60% of pregnant women of childbearing age are still susceptible to infection with CMV).

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