No single diagnostic test for cytomegalovirus (CMV) infection is currently available for pregnant women at all stages of gestation. Improved accuracy in estimating the timing of primary infections can be used to identify women at higher risk of giving birth to congenitally infected infants. A diagnostic algorithm utilizing immunoglobulin G (IgG), IgM, and IgG avidity was used to prospectively screen serum from 600 pregnant women enrolled from two groups: <20 weeks gestation (n ‫؍‬ 396) or >20 weeks gestation (n ‫؍‬ 204). PCR testing of urine and/or blood was performed on all seropositive women (n ‫؍‬ 341). The majority (56.8%) of women were CMV IgG seropositive, with 5.5% being also CMV IgM positive. In the IgM-positive women, 1.2% had a low-avidity IgG, indicating a primary CMV infection and a high risk of intrauterine transmission. Two infants with asymptomatic CMV infection were born of mothers who had seroconverted in the second trimester of pregnancy. Baseline, age-stratified CMV serostatus was established from 1,018 blood donors. Baseline seropositivity from a blood donor population increased with age from 34.9% seroprevalence at less than 20 years of age to 72% seroprevalence at 50 years of age. Women at high risk of intrauterine transmission of CMV were identified at all stages of gestation. Women infected with CMV during late gestation may be more likely to transmit the virus, so failure to detect seroconversions in late gestation may result in failure to detect infected neonates.Human cytomegalovirus (CMV) is the most common cause of congenital malformation resulting from viral intrauterine infection in developed countries (12,21,48). Primary CMV infection occurs in 0.15 to 2.0% of all pregnancies and may be transmitted to the fetus in up to 40% of cases (48). Up to 15% of intrauterine CMV infections result in symptomatic congenital disease at birth, and 10 to 15% of those born with asymptomatic congenital CMV will develop significant clinical sequelae in infancy (7,10,18). In utero transmission of CMV can occur during primary maternal infection, reactivation, or reinfection of seropositive mothers. Most concern centers on primary maternal infection, due to the potential for significant fetal damage when the infection is acquired and transmitted during the first trimester (30, 48). Perinatal infections can result through virus transmission from many parts of the birth canal (39); however, the majority of these infections are asymptomatic (43).The usefulness of prenatal testing for CMV has been questioned due to the absence of clearly effective intervention (1, 27) and to evidence for severe congenital malformation resulting from viral reactivation (6,8,20). Continuing advancements in technology, however, mean reliable and inexpensive serologic tests are available, prenatal diagnostic procedures with acceptable negative predictive values (NPV) can be performed, and trials of neonatal antiviral treatments are ongoing (25,34,37,50,52). Proposed diagnostic algorithms have focused on first-trimester screeni...

Potential causes of congenital infection include Toxoplasma gondii and viruses such as cytomegalovirus (CMV), enterovirus, hepatitis C virus, herpes simplex virus types 1 and 2 (HSV-1 and -2), human herpesvirus types 6, 7, and 8, lymphocytic choriomeningitis virus, parvovirus, rubella virus, and varicella-zoster virus. Testing for each of these agents using nucleic acid tests is time consuming and the availability of clinical samples such as amniotic fluid or neonatal blood is often limited. The aim of this study was to develop multiplex PCRs (mPCRs) for detection of DNA and RNA agents in the investigation of congenital infection and an mPCR for the viruses most commonly requested in a diagnostic virology laboratory (CMV, Epstein-Barr virus, enterovirus, HSV-1, HSV-2, and varicella-zoster virus). The assays were assessed using known pathogenpositive tissues (cultures, placentae, plasma, and amniotic fluid) and limits of detection were determined for all the agents studied using serial dilutions of plasmid targets. Nested PCR was performed as the most sensitive assay currently available, and detection of the amplicons using hybridization to labeled probes and enzyme-linked immunosorbent assay detection was incorporated into three of the four assays. This allowed detection of 10 to 10 2 copies of each agent in the samples processed. In several patients, an unexpected infection was diagnosed, including a case of encephalitis where HSV was the initial clinical suspicion but CMV was detected. In the majority of these cases the alternative agent could be confirmed using reference culture, serology, or fluorescence methods and was of relevance to clinical care of the patient. The methods described here provide useful techniques for diagnosing congenital infections and a paradigm for assessment of new multiplex PCRs for use in the diagnostic laboratory.Nucleic acid testing has allowed more sensitive and specific detection of infectious agents and is being increasingly adopted by diagnostic laboratories. The technology is particularly useful in virology as it can replace conventional culture methods that are often expensive and labor intensive, detect fastidious organisms such as hepatitis C virus (HCV), detect low-copynumber agents such as herpes simplex virus (HSV) in cerebrospinal fluid, and improve turn-around times for detection of treatable agents such as herpesviruses (30,42,48,50). In the clinical and diagnostic setting, accurate and rapid diagnosis of the causative agent of disease is paramount. Testing for various agents using multiple primer sets in multiplex PCR (mPCR) reactions is an innovation that offers significant benefits in costs, time and accurate diagnosis (20,35). Furthermore, for any given clinical syndrome there a number of candidate agents that may be implicated, particularly with regard to congenital infection.In the diagnostic setting, standardization of assays, use of quality controlled (usually commercially available) reagents, extensive validation of the assays used, and sensitive detection ...

This study documents symptomatic congenital CMV cases in Australia.

Transplacental transmission of human cytomegalovirus (CMV) can result in congenital malformations, although details on the mechanisms of transmission and the location of CMV in infected placentae need to be described.METHODS. Placental tissue from term (third trimester) deliveries was screened for CMV infection by polymerase chain reaction (PCR), in situ PCR (IS-PCR), and IS reverse-transcriptase PCR (IS RT-PCR).RESULTS. CMV DNA was detected in tissue samples from 11 placentae that had been determined to be negative for CMV during routine pathological examination. IS-PCR demonstrated the presence of CMV DNA in all cell types within placental villi, and IS RT-PCR further defined this result by identifying viral transcripts from all stages of replication. CMV DNA and RNA were shown to be highly concentrated in placental trophoblast cells. The infecting viruses were detected with primers specific for the major immediate early section of the genome (UL122/123), the UL21.5 virion gene, and the glycoprotein B (gB) gene and were determined to be predominantly genotype gB2. Therefore, maternal and fetal host factors, as well as viral load and possibly viral genotype, may all affect the outcome of placental CMV infection.CONCLUSION. Placental villi are involved in the transfer of blood from maternal to fetal circulation. Infection and replication of CMV within placental trophoblasts suggests that these structures may be involved in the transmission of CMV.