Intellectual ability of children after perinatal cytomegalovirus infection

Differences in cognitive functions between cytomegalovirus-infected and cytomegalovirus-free university students: a case control study

Cytomegalovirus (CMV) is the herpetic virus, which infects 45–100% people worldwide. Many reports suggest that CMV could impair cognitive functions of infected subjects. Here we searched for indices of effects of CMV on infected subjects’ intelligence and knowledge. The Intelligence Structure Test I-S-T 2000 R was used to compare IQ of 148 CMV-infected and 135 CMV-free university students. Infected students expressed higher intelligence. Paradoxically, their IQ decreased with decreasing concentration of anti-CMV antibodies, which can be used, statistically, as a proxy of the time passed from the moment of infection in young subjects when the age of subjects is statistically controlled. The paradox of seemingly higher intelligence of CMV infected subjects could be explained by the presence of the subpopulation of about 5–10% CMV-positive individuals in the population of “CMV-negative students”. These false negative subjects had probably not only the oldest infections and therefore the lowest concentration of anamnestic antibodies, but also the lowest intelligence among the infected students. Prevalence of CMV infection in all countries is very high, approaching sometimes 90%. Therefore, the total impact of CMV on human intelligence may be large.

Effects of maternal worm infections and anthelminthic treatment during pregnancy on infant motor and neurocognitive functioning

We tested the hypothesis that maternal worm infections in pregnancy affect infant motor and neurocognitive development, and that anthelminthic treatment during pregnancy can reverse these effects. We used measures which examine infant motor, cognitive and executive function, including inhibition. We assessed 983 Ugandan infants aged 15 months, using locally appropriate measures within the Entebbe Mother and Baby Study, a trial of anthelminthic treatment during pregnancy. Key exposures were maternal worm infections and anthelminthic treatment during pregnancy. Effects of other health and social factors were controlled for statistically. Of the five major worm species found in the pregnant women, two had influences on the developmental measures: Maternal Mansonella perstans and Strongyloides stercoralis infections showed negative associations with the A-not B-task, and Language, respectively. Performance on other psychomotor and cognitive measures was associated with illnesses during infancy and infants' behavior during assessment, but not with maternal worm infections. There were no positive effects of maternal anthelminthic treatment on infant abilities. Mansonella perstans and Strongyloides stercoralis infection during pregnancy seem associated with impaired early executive function and language, respectively, but single-dose anthelminthic treatment during pregnancy was not beneficial. The biological mechanisms that could underlie these neurocognitive effects are discussed.

Long-term outcome in preterm children with human cytomegalovirus infection transmitted via breast milk

AIM

To investigate neurodevelopmental outcome and hearing in preterm children with breast milk transmitted human cytomegalovirus (HCMV) infection.

METHODS

Forty-one preterm children (born before 32 weeks of gestation or birth weight <1500 g; 20 HCMV positive, 21 HCMV negative) from an original cohort of 44 children were examined at school age. Assessments included neurological examination, assessment of motor [Movement Assessment Battery for Children (M-ABC)] and cognitive function [Kaufman Assessment Battery for Children (K-ABC)], audiological tests and anthropometric measures.

RESULTS

In both groups, irrespective of the presence or absence of a history of HCMV infection, performance in assessments of cognitive and motor function was within the normal range. However, significant differences between the HCMV-positive and the HCMV-negative group were found in both motor and cognitive function, with poorer performance in the HCMV-positive group. There were no significant differences in anthropometric parameters, and all 20 HCMV-positive children had normal hearing function.

CONCLUSIONS

In this study, cognitive and motor function in preterm children with early postnatally acquired HCMV infection transmitted via breast milk was within the normal range. However, the findings suggest that their outcome is poorer than outcome in preterm children without HCMV infection. These findings need to be replicated in larger scale studies.

[Review and guidelines on the prevention, diagnosis and treatment of post-natal cytomegalovirus infection]

Postnatal cytomegalovirus (CMV) infection in the newborn can occur from exposure to maternal cervical secretions during birth, ingestion of breast milk, transfusion of blood products or transmission by body fluids of infected people. Breast milk is the main source of infection, given the high rate of CMV-positive mothers excreting CMV in milk. Freezing reduces the risk of CMV transmission by breastfeeding, although it does not eliminate it completely. Pasteurisation prevents such transmission, but it can alter the immunological properties of breast milk. Postnatal CMV infection is usually asymptomatic, as it normally results from viral reactivation in the mother, and the neonate is born with protective antibodies. However, in the very low birth weight premature infant the amount of transferred antibodies is smaller and a symptomatic infection can occur. Symptomatic post-natal CMV infection in the newborn typically causes hepatitis, neutropenia, thrombocytopenia or sepsis-like syndrome. Pneumonitis and enteritis are less common, but very characteristic. Diagnosis is based on urine virus detection at the time of onset of symptoms. Postnatal CMV infection in the newborn generally resolves spontaneously without antiviral treatment. Ganciclovir should be reserved for severe cases. Unlike congenital CMV disease, post-natal CMV infection in the preterm infant does not seem to be associated with hearing loss or abnormal neuro-development in long term follow-up.

Ophthalmologic findings in children with congenital cytomegalovirus infection

BACKGROUND

Cytomegalovirus (CMV) infection is the most common congenital viral infection in the United States, affecting 0.5% to 2% of live births. Approximately 90% of infected infants are asymptomatic at birth. We undertook this study to determine the incidence and etiology of visual impairment and other ophthalmologic abnormalities in children with congenital CMV infection.

METHODS

We prospectively evaluated 42 symptomatic and 83 asymptomatic children with congenital CMV infection, along with 21 control patients. One or more comprehensive ophthalmologic examinations were performed on each patient. The frequency and etiology of visual impairment and other ophthalmologic problems were tabulated for each patient.

RESULTS

Nine of 42 (22%) patients in the symptomatic group had moderate to severe visual impairment in 16 eyes. Visual impairment was primarily due to optic atrophy in 6 of 16 (37%) eyes, macular scars in 2 of 16 (13%) eyes, and cortical visual impairment in 8 of 16 (50%) eyes. In comparison, none of 83 asymptomatic patients had severe visual impairment (P <.001). One asymptomatic patient had mild unilateral visual impairment caused by a macular scar. Strabismus developed in 12 of 42 (29%) symptomatic patients compared with 1 of 83 (1.2%) asymptomatic patients (P <.001).

CONCLUSIONS

Visual impairment and strabismus are common in patients with symptomatic congenital CMV infection and rare in patients with asymptomatic congenital CMV infection. Visual impairment may be caused by cortical, optic nerve, and/or retinal abnormalities. Infants with symptomatic congenital CMV infection should undergo careful ophthalmologic screening and follow-up examinations.