Neonatal cytomegalovirus infections due to blood

Overview of congenitally and perinatally acquired cytomegalovirus infections: recent advances in antiviral therapy

Congenital and perinatal infection with human cytomegalovirus (CMV) are commonly encountered in newborns. In recent years there has been increased awareness of the disabilities that result from congenital CMV infection, which in turn has prompted interest in examining the potential efficacy of antiviral agents to prevent or ameliorate neurodevelopmental injury. Currently, there are three licensed systemic antivirals for the treatment of CMV: ganciclovir (Cytovene, Roche] and its prodrug valganciclovir [Valcyte, Roche); foscarnet (Foscavir, AstraZeneca); and cidofovir (Vistide, Pharmacia). A CMV-specific immunoglobulin is also available. Experience with these agents in the setting of congenital and perinatal CMV infection is very limited, but there are encouraging data from a controlled clinical trial indicating that ganciclovir therapy may be of value in limiting one form of neurodevelopmental injury caused by congenital infection, that of sensorineural hearing loss. Licensed antivirals for the treatment of CMV all share the common mechanism of targeting the viral DNA polymerase, but novel therapies that employ alternative modes of action are in development. Ultimately, the problem of perinatal CMV infection may be best controlled by the development of CMV vaccines, which could be administered to young women of childbearing age to help control this important public health problem.

Breast milk as a source for acquisition of cytomegalovirus (HCMV) in a premature infant with sepsis syndrome: Detection by real-time PCR

Symptomatic disease due to human cytomegalovirus (HCMV) has been increasingly recognized in low birth weight (LBW) premature infants. Breast milk has been identified as a potential source for these infections. At approximately 60 days of life a LBW, premature infant was diagnosed with HCMV sepsis syndrome, prompting further investigation of the source for HCMV acquisition. The infant had received a combination of both fresh and frozen breast milk from his mother throughout his first 2 months of life. We utilized a real-time PCR assay for HCMV DNA to retrospectively examine viral genome copy number in serial samples of stored, frozen breast milk. This analysis indicated an increase in breast milk viral load over the first 45 days of life, heralding the HCMV sepsis syndrome that was observed clinically. Real-time PCR may be a useful tool in the evaluation of HCMV viral load in breast milk.

Antiviral therapy of congenital cytomegalovirus infection

Congenital infection caused by human cytomegalovirus (CMV) is a common occurrence, but its significance is underappreciated. In the developed world, congenital CMV infection confers a tremendous medical and economic burden on society. In recent years, appreciation of the scope of disability produced by such infections in newborns, which includes neurodevelopmental sequelae and sensorineural hearing loss (SNHL), has increased. Although much of the injury produced by infection in utero likely is irreversible, antiviral therapy of newborns with CMV infection is an option available to clinicians. Currently three antivirals are licensed for treatment of CMV: ganciclovir (and its prodrug, valganciclovir), foscarnet, and cidofovir. Novel antiviral therapies, which employ mechanisms of action that differ from these agents, also are in development. Experience with these agents in the setting of congenital and perinatal CMV infection is limited, but encouraging data come from a controlled clinical trial indicating that ganciclovir therapy may be of value in limiting the neurodevelopmental injury, particularly SNHL, caused by congenital infection. Newborn screening programs for CMV infection need to be developed and implemented. Infants with congenital CMV infection, once identified, could then be considered as candidates for antiviral therapy, and careful neurodevelopmental and hearing screening follow-up care plans could be established. CMV vaccines, once available, may ultimately be the best control strategy for this important public health problem.

Cytomegalovirus infection of extremely low-birth weight infants via breast milk

In addition to seroprevalence and transmission rate, the clinical symptoms of postnatal cytomegalovirus (CMV) infection in infants with a very low birth weight (VLBW; <1500 g; <32 weeks gestational age at birth) were assessed in a 3-year prospective study. CMV monitoring included serologic testing (of the mother and child) and virus culture and PCR (of samples of both breast milk and the infant's urine). Within 3 weeks of the initial virus detection in the infant, clinical and laboratory parameters were evaluated. Of 170 infants, no CMV transmission was found in the 80 infants of seronegative mothers and in the 3 infants of seropositive mothers who did not shed CMV DNA into breast milk. Transmission occurred in 33 of the 87 CMV-exposed infants, 16 of whom presented with such symptoms as hepatopathy, neutropenia, thrombocytopenia, and sepsis-like deterioration. Low birth weight and early postnatal virus transmission were risk factors for symptomatic infection. VLBW infants of CMV-seropositive mothers are at high risk of acquiring a symptomatic CMV infection postnatally via breast milk.

Epidemiology of transmission of cytomegalovirus from mother to preterm infant by breastfeeding

BACKGROUND

Breastfeeding practices strongly influence the epidemiology of human cytomegalovirus infection. By contrast with term neonates, few data are available on transmission of infection from mothers to preterm infants during breastfeeding.

METHODS

151 mothers and their 176 preterm infants (gestational age at birth <32 weeks or birthweight <1500 g) were prospectively screened for cytomegalovirus infection by serology, virus culture, and PCR. The roles of cell-free and cell-associated cytomegalovirus excretion during lactation were analysed longitudinally in relation to transmission, by maximum-likelihood estimates.

FINDINGS

Of the 69 seronegative breastfeeding control mothers, none had detectable cytomegalovirus DNA in breastmilk and none of their 80 infants shed the virus in urine. The proportion of cytomegalovirus reactivation in seropositive breastfeeding mothers was 96% (73 of 76). The early appearance of viral DNA in milk whey (median 3.5 days post partum in transmitters; 8 days in non-transmitters; p=0.025) and infectious virus in milk whey (10 days and 16 days, respectively; p=0.005) were risk factors for transmission. The cumulative rate of transmission was 37% (27 of 73 mothers; 33 infants). The infection of the neonates had a mean incubation time of 42 days (95% CI 28-69). About 50% of the infected infants had no symptoms, but four had sepsis-like symptoms.

INTERPRETATION

The proportion of cytomegalovirus reactivation during lactation almost equals maternal seroprevalence. Breastfeeding as a source of postnatal cytomegalovirus infection in preterm infants has been underestimated and may be associated with a symptomatic infection.

Transfusion-transmitted cytomegalovirus: the part-time pathogen

Viral infection is a well-known risk of blood product transfusion and much work has been devoted to the detection of such well-known pathogens as human immunodeficiency virus and hepatitis viruses in blood donors. Cytomegalovirus (CMV) is found in a much larger percentage of donor units than these other viruses but will cause disease in only a minority of recipients. Many pediatric patients (especially premature infants) are at risk for transfusion-transmitted CMV. This review describes work delineating the populations of patients most at risk for transfusion-transmitted CMV, describes methods for detecting CMV in blood donors, evaluates current methods for leuko-depletion of blood products, and provides recommendations for patients most likely to benefit from blood products with low risk of CMV transmission.

Systemic viral infections and their retinal and choroidal manifestations

Viruses are one of the most common causes of infections involving the posterior segment of the eye. Such infections can occur either on a congenital or an acquired basis, and may affect primarily the retina or the choroid. Congenital cytomegalovirus (CMV) and rubella infections may result in retinitis. CMV retinitis is also the most common cause of acquired viral retinitis, primarily because of the acquired immunodeficiency syndrome (AIDS). Other types of viral retinitis, such as those caused by herpes simplex or herpes zoster, can occur in immunocompromised or immunocompetent individuals. Retinitis or choroiditis caused by viruses such as measles, influenza, Epstein-Barr virus, and Rift Valley fever virus, typically occurs subsequent to an acute viral systemic illness. The systemic and ocular manifestations, as well as the histopathology, laboratory tests, differential diagnoses, and treatment regimens for each of the individual viruses are discussed in detail.

Decreasing blood donor exposure in neonates on extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) has been successful treatment (80% survival) in over 2,000 neonates with severe respiratory failure (80% predicted mortality without ECMO). Neonates on ECMO require frequent blood product replacement, which increases donor exposure (DE) and the risk of transfusion related complications. Successful, widespread usage of ECMO in neonatal respiratory failure is placing increased numbers of surviving infants at risk for acute and long-term transfusion related problems. We assessed DE rates in 21 consecutive neonatal ECMO survivors. In the first 12 patients packed red blood cell (PRBC) transfusions were administered as 10 mL/kg body weight for hematocrit less than 45%. PRBC exchange transfusions were used in patients with hematocrit less than 45% and hypervolemia. Fresh frozen plasma (FFP) and cryoprecipitate (CRYO) infusions were used empirically for evidence of hemorrhage. DE rates (donors per ECMO day, mean +/- SD) were: PRBC (2.8 +/- 0.6), FFP/CRYO (0.5 +/- 0.7), and platelet (2.0 +/- 1.0), with a total donor exposure rate of 5.3 +/- 2.0 donors per ECMO day. Mean duration of ECMO was 4.6 +/- 2.0 days and total DE per infant was 22.8 +/- 9.5 donors per ECMO run. In a protocol (n = 9) to minimize DE risks, exchange transfusions were eliminated and PRBC transfusion volumes were increased to 15 mL/kg. Empiric use of FFP and CRYO was discontinued. The blood bank divided standard units of PRBCs into four aliquots and dispensed each aliquot sequentially before dispensing blood from another unit.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevention of transfusion-acquired cytomegalovirus infection in infants by blood filtration to remove leucocytes. Neonatal Cytomegalovirus Infection Study Group

A multicentre, controlled trial was carried out to determine whether removal of leucocytes from blood by means of 'Imugard IG500' (Terumo) filters would prevent transfusion-acquired cytomegalovirus (CMV) infection in newborn infants. 72 infants whose mothers were seronegative and who received some seropositive blood were followed for 6 months for evidence of CMV infection. There were no significant differences between the groups who received filtered and unfiltered blood in median gestation, birthweight, or amount of seropositive blood received (median volume 32.5 ml and 34.5 ml, respectively). 9 (21%) of the 42 infants who received unfiltered blood and none of the 30 who received filtered blood were infected with CMV. All infected infants weighed less than 1500 g at birth; they represented 31% of very low birthweight (VLBW) infants at risk of CMV infection. None of 24 VLBW infants who received filtered seropositive blood was infected. 1 infected infant died and 5 had clinical features consistent with CMV infection. The results show that transfusion-acquired CMV infection is preventable by filtration of blood through a leucocyte filter. This method has advantages over other methods of removing leucocytes or the use of only seronegative blood for newborn infants.

Transfusion-associated viral infections

Viral infections are a frequent occurrence following transfusion of blood products. While generally benign, these infections are capable of causing significant morbidity and mortality. Therefore, it is prudent to follow several general approaches diligently to reduce the risks of these infections in patients undergoing transfusions of blood products. These suggested measures include the following: 1. Prescribe and administer blood and blood products only when absolutely needed. 2. Use volunteer blood donors only. 3. Avoid use of pooled blood products when possible. 4. Use only blood and blood products that have been appropriately tested for HBsAg and HIV. 5. Use ALT determinations to screen blood products and eliminate those with high level. 6. Avoid the use of clotting-factor concentrates but, if necessary, use only those which have been heat-treated. 7. Limit use of leukocyte transfusion. 8. Use only CMV seronegative blood and blood products or frozen deglycerolized red cells in patients at high risk for posttransfusion CMV infection.