Congenital cytomegalovirus infection and disease in Sweden and the relative importance of primary and secondary maternal infections. Preliminary findings from a prospective study

In a prospective Swedish study started in 1977 and still in progress 10 328 newborn infants in an urban district were investigated for cytomegalovirus (CMV) excretion in the urine by the virus isolation test. Congenital infection was found in 50 cases (0.5%). Of 47 infected infants with known clinical status at birth 9 (19%) had hepatomegaly, splenomegaly, jaundice and/or petechiae. The symptoms were moderate or mild. Of the infants followed up, 2 (25%) of 8 neonatally symptomatic ones and 3 (9%) of 35 asymptomatic ones developed neurologic sequelae. Altogether 5 (12%) of 43 had permanent neurologic symptoms corresponding to 0.06% in the general population. The children ranged in age from 6 months to 4 yr at the last examination. 21 mothers of the 47 infants with known status at birth had a confirmed or presumed primary infection, 15 a confirmed or presumed secondary infection and 11 an undetermined type of infection. Of the 5 infants with neurologic sequelae, 1 with a grave psychomotor retardation and deafness was born to a mother with a primary infection in the 1st trimester; 1 infant with a moderate retardation and 3 deaf infants were all exposed to confirmed or presumed secondary maternal infections. Prospective serological studies of maternal sera in early pregnancy would have suspected only the gravely retarded infant to be at risk.     

Report on a long-term study of maternal and congenital cytomegalovirus infection in Sweden. Review of prospective studies available in the literature

This report summarizes knowledge accumulated in a long-term study of congenital and maternal cytomegalovirus (CMV) infection in Sweden. Some new findings are included. We considered diagnostic methods, sources of maternal infection (including occupational risks), roles of primary and secondary maternal infections, transmission to foetuses, incidence, symptoms and prognosis of established congenital infection and relative importance of such infection in infantile sensorineural deafness, microcephaly and type 1 diabetes mellitus. Virus isolation testing was done 1977-1985 on 16,474 newborns. 76 (0.5%) congenitally infected infants were found, 22/76 (29%) with transient neonatal symptoms and 11/60 (18%) with neurological symptoms by the age of 7 y. Type of maternal CMV infection was serologically determined in 62/76 cases (30 primary, 32 secondary). CNS disturbances in the infants occurred after both primary (all trimesters) and secondary maternal infections. The negative potential of secondary maternal infections might be an obstacle to preventive vaccination.     

Infection with cytomegalovirus during pregnancy: specific IgM antibodies as a marker of recent primary infection

Specific IgM antibodies that persisted for up to four months were detected by radioimmunoassay (RIA) in the sera of 16 (55%) of 29 women with primary infections due to cytomegalovirus (CMV). The RIA for IgM detected primary infections in six (86%) of seven sera obtained within four months of seroconversion. In contrast, IgM antibodies were never detected by RIA in 104 serum samples from 18 women with recurrent infections due to CMV, irrespective of whether intrauterine transmission of virus had occurred. Specific IgM antibodies were also detected in the earliest samples during pregnancy of serum from three (14%) of 21 women whose type of infection with CMV was unknown but who had been delivered of congenitally infected infants. All of these results show that primary infection with CMV in the first trimester of pregnancy can be diagnosed by testing a single serum sample by RIA for IgM antibodies. Attempts to measure IgM antibodies by immunofluorescence gave a high frequency (19 [18%] of 104) of false-positive reactions.     

Molecular analysis of the fetal IgM response to Treponema pallidum antigens: implications for improved serodiagnosis of congenital syphilis

Western blot analysis of the fetal IgM response to Treponema pallidum antigens was examined among 39 pairs of maternal/infant sera; this included 12 mothers and infants with active syphilis (group I), 9 mothers with active syphilis and their infants with uncertain infection (group II), and 18 mothers treated for syphilis before delivery and their asymptomatic infants (group III). A fetal IgM response to T. pallidum antigens with apparent molecular masses of 72, 47, 45, 42, 37, 17, and 15 kDa was observed among sera of infants with congenital syphilis. Fractionation of sera into IgM and IgG components by high performance liquid chromatography confirmed that fetal IgM antibodies in every case were directed specifically against a 47-kDa antigen. Two asymptomatic infants from group II also showed serum IgM reactivities with the 47-kDa antigen, thereby appearing to confirm in utero infection. The combined data suggest that fetal serum IgM reactivity with the 47-kDa antigen of T. pallidum can be used as an important molecular marker for the diagnosis of congenital syphilis.     

Seroprevalence of cytomegalovirus infection in pregnant women and associated role in obstetric complications: a preliminary study

The objective of this study was to determine the seroprevalence of cytomegalovirus (CMV) infections through antenatal screening data and the association of this virus with obstetric complications. Serum samples from 125 apparently healthy pregnant women sent for antenatal screening from various hospitals in Malaysia between January 2007 and December 2008, were examined for CMV specific IgM and IgG antibodies using an enzyme-linked immunosorbent assay method. Of the 125 pregnant women tested, anti-CMV IgG antibody was found in 105 (84%) of the cases and anti-CMV IgM in 9 cases (7.2%). Both CMV IgM and IgG were also found in another 37 women whose serum samples were sent for investigation of various obstetric complications: 17 cases of spontaneous abortions, 15 cases of fetal anomalies detected during ultrasound examination, 1 case of incomplete abortion, 3 cases with premature delivery of infant with congenital anomalies and 1 case of infertility. Our preliminary data which only represented a small study group has shown the prevalence of CMV infection among the local population and the association of CMV in obstetric complications.     

Evaluation of the postnatal treatment efficacy in congenital toxoplasmosis identified by the newborn screening programme

The effectiveness of neonatal screening for anti-Toxoplasma IgM or IgA and IgM specific antibodies followed by an intensive anti-parasitic therapy for a prevention of clinical and immunological reactivations of congenital infection was studied. Thirty-five congenitally infected infants were included into clinical and serological follow-up. The children were mostly asymptomatic at birth or they expressed some non-specific reversible clinical abnormalities in neonatal period. Clinically overt toxoplasmosis occurred in 10 patients, including one infant with a severe form; 2 children had co-existing CMV infections. During the follow-up period, no clinical relapses were reported. Asymptomatic immunological rebounds of IgG or of IgG and IgA specific antibodies were observed in 16 patients. Anti-parasitic treatment initiated soon after birth seems to be promising in a prevention of early clinical sequelae of congenital T. gondii infection.     

Clinical,Virologic and Immunologic Correlates of Breast Milk Acquired Cytomegalovirus (CMV) Infections in Very Low Birth Weight (VLBW) Infants in a Newborn Intensive Care Unit (NICU) Setting

Cytomegalovirus (CMV) infections acquired by very-low-birthweight (VLBW) infants are incompletely characterized. To examine CMV transmission in VLBW infants, we evaluated maternal DNAlactia, infant DNAemia, and presence of clinical disease in a blinded study in VLBW infants in our newborn intensive care unit (NICU). To examine these issues, 200 VLBW infants were enrolled in a surveillance study, with weekly breast milk and infant whole blood samples collected, as available. Virologic (breast milk and infant whole blood real time PCR) and immunologic (IgG, IgM, and IgG avidity) correlates were evaluated. A chart review examined whether infants had symptoms compatible with CMV disease. DNAlactia was identified in 65/150 (43%) of lactating mothers. Nine CMV infections were identified in 9/75 CMV-exposed infants (12% of exposed infants). A higher median breast milk viral load (DNAlactia) correlated with an increased likelihood of DNAemia (p = 0.05). Despite potential symptoms compatible with CMV infection, clinicians had not considered the diagnosis of CMV in 6/9 cases (66%). All of these infants had chronic lung disease at discharge. There was no correlation between IgG antibody titer or IgG avidity index and the likelihood of transmission or CMV disease. In conclusion, in VLBW infants receiving milk from seropositive mothers, CMV infections are commonly acquired, and are frequently unrecognized. Future studies are needed to determine whether routine surveillance for CMV of either breast milk or infant plasma is beneficial in preventing or recognizing infection.     

Secondary haemophagocytic lymphohistiocytosis triggered by postnatally acquired cytomegalovirus infection in a late preterm infant

Haemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory condition with impairment of cytotoxic T-cells and natural killer cells. Causes in infants are mostly hereditary immune defects as well as various infectious triggering factors, amongst these cytomegalovirus (CMV). Vertical CMV transmission may occur in utero, during birth, and by breast feeding. Usually, a CMV infection transmitted via breast milk is symptomatic only in very immature preterm infants. We report on a late preterm infant born after 35 + 5 weeks of gestation with a birth weight of 1840 g, being admitted to our intensive care unit at the age of 9 weeks with acute enteritis and severe dehydration. After a prolonged recovery, the infant developed a sepsis-like condition with hyperpyrexia, hepatosplenomegaly, and pancytopenia. Combination with high ferritin levels (2809 μg/l), hypertriglyceridaemia (481 mg/dl), elevated soluble IL-2 receptor (sCD25, 9120 U/ml), and reduced perforin expression allowed diagnosis of HLH, caused by an acute CMV infection. Since connatal CMV infection had been ruled out earlier, we report the rare case of secondary HLH triggered by a postnatally acquired symptomatic CMV infection in an immunocompetent infant, most likely transmitted via breast milk. The infant was successfully treated with ganciclovir without need for immunosuppressive therapy.     

Incidence of toxoplasmosis in pregnant women in the city of Malm?, Sweden

The incidences of latent and primary Toxoplasma gondii infections in pregnant women were studied using stored sera from 4,351 women delivered in the city of Malm?, Sweden in 1982 and 1983. Infants born to mothers with signs of primary infection (seroconversion or specific IgM in sera collected during pregnancy) were studied with regard to serological evidence of congenital infection (specific IgM in cord serum). Sera were tested for specific IgG antibodies by direct agglutination test and enzyme-linked immunosorbent assay, and for specific IgM by immunosorbent assay. 40% of the women were seropositive at delivery. Seroconversion (change from negative to positive serological status) was demonstrated in 12 pregnant women and specific IgM in the first postconceptional serum sample (indicating infection in the first trimester or in the last year(s) before conception) in another 17. The incidence of primary maternal infection was calculated to 4-6:1,000 deliveries. Among the 29 infants born to mothers with seroconversion or, alternatively, IgM in the first postconceptional sample, 6 had laboratory signs of congenital infection. One of the 6 had a positive toxoplasma isolation test in autopsy material and 5 had a clearly positive IgM value in cord serum. The real incidence of congenital infection in this material is unknown since IgM might be absent or sparse in cord serum in spite of congenital infection. The noticeable prevalence of maternal toxoplasmosis in Malm? calls for further incidence studies in Sweden.     

Group B beta-hemolytic streptococci as an important cause of perinatal mortality.

Bacteriological and pathological examinations of all 73 stillborn infants and 96 infants dying soon after delivery in V?ster?s, Sweden during the period 1971-1974 are reported. 35 infants had a severe infection. Beta-hemolytic streptococci group B were isolated in 7 cases from different organs. Intrauterine death occurred in 2 cases; 4 liveborn infants showed early signs of respiratory distress, apneic episodes and cyanosis; 1 infant showed signs of intrauterine asphyxia and was severely asphyctic at birth. Thus, infection with group B streptococci occurred in 20% of the infants who succumbed to infections during this period.     

Perinatal transmission of HIV-1: lack of impact of maternal HIV infection on characteristics of livebirths and on neonatal mortality in Kigali, Rwanda

We present the baseline results of a prospective cohort study on the perinatal transmission of HIV-1 in Kigali, Rwanda. HIV-1-antibody testing was offered to all women of urban origin delivering a live newborn at the maternity ward of the Centre Hospitalier de Kigali from November 1988 to June 1989; 218 newborns of 215 HIV-positive mothers were matched to 218 newborns of 216 HIV-negative mothers. The matching criteria were maternal age and parity. No differences in socioeconomic characteristics were observed between HIV-positive and HIV-negative women. HIV-positive mothers more frequently reported a history of at least one death of a previously born child (P less than 0.01) and a history of abortion (P less than 0.001). Most of the HIV-positive women were asymptomatic, but 72.4% of them had a CD4; CD8 ratio less than 1 versus 10.1% in the HIV-negative group (P less than 0.001). The frequency of signs and symptoms was not statistically different in the two groups, except for a history of herpes zoster or chronic cough, which was more frequent among HIV-positive women. The rates of prematurity, low birth weight, congenital malformations and neonatal mortality were comparable in the two groups. However, infants of HIV-positive mothers had a mean birth weight 130 g lower than the infants of HIV-negative mothers (P less than 0.01). The impact of maternal HIV-1 infection on the infant seems limited during the neonatal period.     

Cytolytic IgM antibody to cytomegalovirus in primary cytomegalovirus infection in humans

Suspensions of cytomegalovirus (CMV)-infected human foreskin fibroblasts were used to measure cytolytic antibody (CyA) to CMV in serum by a 51Cr release assay. CyA was associated with IgM but not with IgG antibody to CMV, required rabbit or human complement, and was directed at a surface antigen. CyA was detectable for one to three months in the sera of 16 patients with community-acquired CMV infection and in the sera of 20 of 22 renal transplant recipients with primary CMV infection. CyA was found less frequently in the sera of renal transplant recipients with reactivated CMV infection and occurred almost exclusively when the donor was seropositive for CMV. One individual, unlike many patients with CyA, was free of symptoms. Sera from patients with either rheumatoid factor-positive arthritis or heterophil-positive infectious mononucleosis and from 70 of 71 control patients with other types of antibody to CMV yielded no 51Cr release.     

A prospective study on congenital and acquired cytomegalovirus infections in infants.

A preliminary report is presented on a current prospective virological and clinical study of congenital and acquired infant cytomegalovirus (CMV) infections. During a 1-year period, 7/2200 newborn Swedish infants investigated (0.3%) had a congenital CMV infection as shown by positive virus isolation. Two of them had typical symptoms, hepatosplenomegaly and petechiae in one case and splenomegaly in the other one. All of them had a normal birth weight and normal head circumference. No sequelae have been observed during an observation period of up to 9 months. Five out of 10 control infants followed-up acquired a CMV infection within a few months. 5/7 mothers of the congenitally infected infants and 3/14 mothers of the control infants were primiparas.     

Clinicopathological study of liver involvement in cytomegalovirus infection in infant autopsy cases

To clarify the pathogenesis of hepatic cytomegalovirus (CMV) infection, we clinicopathologically investigated 18 infants and 10 adults with cytomegalic inclusion bodies (CIB) in the liver among a total of 75 autopsy cases with CIB in any organ of the body. CMV infection was confirmed by immunohistochemistry and in situ hybridization. When CIB were present in the liver, CMV infection also tended to be systemic. All the adults were immunocompromised patients, but diseases inducing immunodeficiency were present in only two of the infants. The severe and systemic CMV infections we found in infants might have been associated with congenital CMV infection. Histotogically, hepatocyte necrosis, cholestasis, extramedullary hematopoiesis and fatty degeneration were more frequent and prominent in infants than in adults. However, inflammatory cell infiltration was only slight. In addition, the frequent association with premature birth and hypoplasia of the thymus suggested that insufficient development of immunity may result in hepatic CMV involvement in infants. CIB were most frequently observed in hepatocytes in both infants and adults, but in infants they were also frequently seen in the bile duct epithelium. These histopathological findings and the high incidence of jaundice in infant patients suggest that the bile duct is also an important site of CMV proliferation in infants, and that CMV infection may be one cause of infantile jaundice.     

Low Maternal Immunoglobulin G Avidity and Single Parity as Adverse Implications of Human Cytomegalovirus Vertical Transmission in Pregnant Women with Immunoglobulin M Positivity

Human cytomegalovirus (CMV) is the leading cause of neurological sequelae in infants. Understanding the risk factors of primary CMV infection is crucial in establishing preventive strategies. Thus, we conducted a retrospective cohort study to identify risk factors of vertical transmission among pregnant women with immunoglobulin (Ig) M positivity. The study included 456 pregnant women with IgM positivity. Information on age, parity, occupation, clinical signs, IgM levels, and IgG avidity index (AI) was collected. The women were divided into infected and non-infected groups. The two groups showed significant differences in IgM level, IgG AI, number of women with low IgG AI, clinical signs, and number of pregnant women with single parity. In the multiple logistic regression analysis, pregnant women with single parity and low IgG AI were independent predictors. Among 40 women who tested negative for IgG antibody in their previous pregnancy, 20 showed low IgG AI in their current pregnancy. Among the 20 women, 4 had vertical transmission. These results provide better understanding of the risk factors of vertical transmission in pregnant women with IgM positivity.     

Perinatal cytomegalovirus infection: influence of placentally transferred maternal antibody.

The kinetics of the response to passively transferred maternal neutralizing antibody were studied for determination of whether this antibody offered protection against primary cytomegalovirus (CMV) infection in the offspring. Antibody response was determined in 17 infants infected in the immediate perinatal period and in 18 appropriate control subjects. Levels of neutralizing antibody in serum obtained at birth and at one month of age were similar in infected and in exposed, uninfected neonates. In addition, the quantity of neutralizing antibody did not influence the time of onset of viruria. Clearly, passive humoral immunity failed to prevent naturally acquired primary CMV infection in a significant number of young infants exposed to virus during and shortly after delivery.     

Outcome of Preterm Infants With Postnatal Cytomegalovirus Infection via Breast Milk: A Two-Year Prospective Follow-Up Study

Approximately 15% of preterm infants may develop postnatal cytomegalovirus (CMV) infection from seropositive mothers via breast milk and are at risk for neurological sequelae in childhood. The aims of this study were to assess the effects and outcomes on growth, neurodevelopmental status, and hearing in very low birth weight (VLBW) premature infants with postnatal CMV infection via breast milk at the corrected age of 12 and 24 months.The prospective follow-up study population comprised all living preterm children (n = 55) with a birth weight ≤1500 g and gestational age of ≤35 weeks, who had been participated in our “postnatal CMV infection via breast milk” studies in 2000 and 2009, respectively. The cohort of children was assessed at 12 and 24 months. Clinical outcomes were documented during hospitalization and after discharge. Long-term outcomes included anthropometry, audiologic tests, gross motor quotient, Infant International Battery, and neurodevelopmental outcomes; all were assessed at postcorrected age in 12 and 24 months during follow-up visits.Of the 55 infants enrolled in the study (4 noninfected infants were excluded because their parents did not join this follow-up program later), 14 infants postnatally acquired CMV infection through breast-feeding (infected group) and were compared with 41 infants without CMV infection (control group). No significant differences were observed between the groups with regard to baseline characteristics, clinical outcomes, anthropometry, or psychomotor and mental development on the Bayley scale of infant development. None of the infants had CMV-related death or permanent sensorineural hearing loss.Transmission of CMV from seropositive mother via breast milk to preterm infants does not appear at this time to have major adverse effects on clinical outcomes, growth, neurodevelopmental status, and hearing function at 12 and 24 months corrected age.     

Disseminated Adenoverus Infection in Two Premature Infants

Summary We present two premature infants with disseminated neonatal adenovirus infection, whose epidemiology, clinical course and outcome differ to a great extent. The first infant, born vaginally at 35 weeks gestational age after premature rupture of membranes and maternal illness, developed pneumonia, hepatitis and coagulopathy and died of circulatory failure at the age of 17 days. The other infant, delivered by cesarian section at 36 weeks gestational age, did – in contrast to all documented cases in the literature – not show any signs of pneumonia and survived meningitis without sequelae. The mode of transmission of the viral infection may have been via the maternal birth canal in the first infant and transplacental in the second one. Diagnosis was obtained by direct immunofluorescent test and serology in the first patient and by maternal serology and the detection of viral antigen in tracheal aspirates (ELISA) in the second patient. Disseminated neonatal adenovirus infection has a high mortality and should be considered in the differential diagnosis of neonatal sepsis, especially when pneumonia, hepatitis and neurologic symptoms develop together with thrombocytopenia or disseminated intravascular coagulopathy. Received: March 2, 1999 · Revision accepted: January 31, 2000