Cytomegalovirus infection in the neonate and its prevention

Progressive hearing loss in children with congenital cytomegalovirus

Case studies of five children with congenital cytomegalovirus (CMV) who were referred for audiological evaluation are presented. Significant deterioration of hearing was noted in all cases within the first 4 years of life. It is essential that neonates with congenital CMV be referred for hearing assessment and that the child's hearing be monitored on a long-term basis. Early intervention is vital for the speech and language development of the hearing-impaired child.

Congenital cytomegalovirus infection: a cause of sensorineural hearing loss

Prospective studies have suggested that about 108 children with congenital cytomegalovirus (CMV) infection and bilateral sensorineural hearing loss are born each year in England and Wales; this represents about 12% of all children with congenital sensorineural hearing loss. Over a nine year period 1644 children aged between 6 months and 4 years who were attending the Nuffield Hearing and Speech Centre were screened for CMV infection. The prevalence of CMV in the urine of children with sensorineural hearing loss but no immediate family history of deafness was nearly twice that (13%) found in other children with impaired hearing and those with normal hearing (7%). These findings indicate the importance of CMV as a cause of hearing loss.

Cytomegalovirus infection in pregnancy

Cytomegalovirus (CMV) is the most common agent of prenatal (peri- and early postnatal) infection of the newborn with an incidence of 0.2-2.0% (5-10%) depending on the socio-economic status. Only one out of 20 congenitally CMV-infected newborns shows serious symptoms. Another two may reveal mental retardation and other significant handicaps in later age. Perinatal CMV infection occasionally causes atypical pneumonia, mostly combined with Pneumocystis carinii infections similar to reports of AIDS cases. The risk of vertical infection has been quantified. About 2-4% of pregnant seronegative women (40-60% of all) pass a primary, 10-20% of seropositives a recurrent CMV infection. Every third primary infection may result in vertical CMV transmission with poor prognosis in about 25% (40%) of the offspring infected (in the first half of pregnancy). Sources of vertical infection are semen, maternal cell-associated viraemia, ascending genital virus (prenatally), cervical secretion (perinatally), breast milk and saliva (early postnatally). Laboratory diagnosis of CMV infection is performed by many virological and immunological techniques for detecting viral infectivity, structural components, humoral and cellular immunoresponses. Routine diagnostic service is mainly established by virus cultivation in human fibroblasts and by ELISAs on antibodies and antigens.

An early marker of fetal infection after primary cytomegalovirus infection in pregnancy

Fourteen patients with primary cytomegalovirus infection diagnosed by serological screening at antenatal attendances were examined for their responses in the lymphocyte transformation test against cytomegalovirus. Tests were done during pregnancy, shortly after the diagnosis of primary infection. Eight women showed positive lymphocyte transformation responses and gave birth to uninfected babies. Six showed negative responses and four of the babies were born congenitally infected. Cellular immunity therefore plays a part in preventing intrauterine transmission of cytomegalovirus, and its depression after primary infection in the mother during pregnancy may be used as an early marker of fetal infection.

Congenital cytomegalovirus infection

Clinical details of 50 infants with congenital cytomegalovirus infection identified in a prospective study are reported. The mean birthweight, gestational age, and head circumference of children with congenital cytomegalovirus infection were not significantly different from those of controls. Three (6%) had symptoms at birth--two neurological and one pneumonitis. In the first four months of life transient hepatosplenomegaly occurred in two infected children and six suffered interstitial pneumonitis. Three congenitally infected children have major neurological handicaps including spastic quadriplegia, microcephaly, and psychomotor delay, and five (10%), including the one with quadriplegia, have sensorineural deafness which is bilateral in three (6%). Estimates based on these findings suggest that the impact of congenital cytomegalovirus infection is comparable to that of congenital rubella in the era before vaccination. Of the 42 children where the nature of maternal infection was classifiable, congenital infection followed primary maternal infection in 32 (76%) and recurrent infection in 10 (24%). Neurological defects followed exposure to primary maternal infection in all three trimesters of pregnancy and also recurrent maternal infection.

Intra-uterine transmission of cytomegalovirus in women known to be immune before conception

A prospective study identified 785 pregnant women who had been shown to possess complement fixing antibodies against cytomegalovirus (CMV) during a previous pregnancy. As these women were thus known to have been immune prior to their subsequent conception, their neonates were examined for evidence of congenital CMV infection. Specimens were obtained from 725 (92%) of the neonates and congenital infection was found in only one (0.14%). The elder sister of the infected child was also shown, by retrospective testing of her stored cord serum for specific IgM antibodies, to have been infected in utero. Thus, one woman was identified who had delivered consecutive siblings congenitally infected with CMV. We conclude that some women have a propensity for intra-uterine transmission of CMV, despite being immune prior to conception, and speculate that such women may have acquired their infections perinatally.

Cytomegalovirus infection in pregnancy: preliminary findings from a prospective study

8278 (56%) of 14 789 pregnant women who were screened for cytomegalovirus (CMV) antibodies at their first antenatal visit were seropositive. 42 (3 per 1000) infants screened were congenitally infected. 3 (7%) have serious handicaps, 14 (33%) have minor or transient problems, and 25 (60%) have so far had no problems. In 26 of the 42 mothers with infected infants CMV antibodies were present in the first antenatal blood sample. 28 (67%) of the infected infants were born to mothers who had experienced a primary infection in pregnancy and 7 (17%) to mothers who had experienced recurrent infection. In the remaining 7 (17%) it was not possible to determine the type of maternal infection. One handicapped infant was born after a probable recurrent CMV infection during pregnancy. These preliminary findings suggest that routine screening of pregnant women to detect evidence of primary CMV infection is not helpful.

Comparison of enzyme-linked immunosorbent assay, radioimmunoassay, complement fixation, anticomplement immunofluorescence and passive haemagglutination techniques for detecting cytomegalovirus IgG antibody

The radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques were found to be comparable in sensitivity and specificity for detecting cytomegalovirus IgG antibody, and 10 to 100 times more sensitive than complement-fixation (CF), anticomplement immunofluorescence (ACIF) and passive haemagglutination (PHA). In screening tests for antibody, the frequency of false-positive and -negative results was 0.6% for RIA and ELISA, 1.5% for CF, 1.6% for ACIF and 3.6% for PHA. PHA was the least satisfactory test, largely because of technical problems. Cytomegalovirus (CMV) infection is an important cause of congenital brain damage and is also a major complication of both prolonged immunosuppressive therapy, especially in patients with organ transplants, and multi-donor blood transfusions. For serological diagnosis of infection, as well as for screening for antibody in patients and in blood donors, the solid-phase indirect radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques offer distinct improvements in sensitivity over previous methods. Although the principle of both tests, based on the detection of antigen-antibody reactions by means of a labelled anti-antibody, is the same, each possesses its own particular technical advantages and disadvantages, and both require their own expensive equipment for the reading of the results. There is still a lack of data on how they compare in sensitivity and specificity. The present study was undertaken to compare the two methods for the detection of CMV IgG and to evaluate them against the older techniques of complement-fixation (CF), passive haemagglutination (PHA) and anticomplement immunofluorescence (ACIF).

Comparison of the pharmacological actions of desmethylclomipramine and clomipramine

This research compares the effects, in mice and rats, of desmethylclomipramine (DCLOM) and clomipramine (CLOM). DCLOM antagonized the hypothermia induced in mice by reserpine or apomorphine to a much greater extent than CLOM. Reserpine ptosis in mice was depressed by DCLOM only. Similarly, only DCLOM was effective in the behavioral despair test in rats. DCLOM increased the 5-hydroxytryptamine (5-HT) pressor effect in pithed rats, but to a lesser extent than CLOM by several factors. Only DCLOM increased the noradrenaline (NA) pressor effect. The depletion of NA induced by 6-hydroxydopamine was depressed by DCLOM only. The 5-HT depletion induced by p-chloromethamphetamine was antagonized only by CLOM. The results obtained show that the noradrenergic mechanism is of prime importance in the action of DCLOM and of much more importance than in the action of CLOM.

Viral vaccines under development: a third generation

In summary then, my purpose has been two-fold: on the one hand, I have tried to highlight the kinds of basic science advances in both cellular and virologic research that can (and should) be focussed both on vaccines under development and, retrospectively, on those whose origins were strictly empiric. On the other hand, I have attempted a partial survey of some of the prominent members of a potential new generation of vaccines to point out areas where these advances can and should contribute either to progress or to a sense of caution about the further reliance on pure empiricism. It is clear that we are not finished with new viral vaccines. It is equally clear that narrowing the persistent gap between basic science and its application to public health needs will require much energy and attention as vaccine development progresses.