Infective causes of human malformations

Seasonal distribution of idiopathic congenital talipes equinovarus in Scotland

Idiopathic congenital talipes equinovarus has a reported prevalence of between 0.64 and 2.5 per thousand live births in the Scottish population. A retrospective study of neonates (n=162), who presented with idiopathic congenital talipes equinovarus in Scotland over a 3 year period (1994-1996) revealed a seasonal increased incidence of the condition in neonates born in March and April. The probable aetiological factors for congenital talipes equinovarus are discussed.

Connective tissue naevi in a child with intra-uterine varicella infection

A child with connective tissue naevi is described. She was exposed in utero to maternal varicella and has evidence of congenital varicella infection. It is proposed that her cutaneous lesions are also a manifestation of this infection.

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.

Congenital infections with nonarbo togaviruses

The present review deals with the similarities and differences of selected aspects of prenatal pestivirus infections of domestic animals and congenital rubella of man. Hog cholera virus, bovine virus diarrhoea virus and border disease virus are antigenically closely related, but unrelated to rubella virus. The nonarbo togaviruses are capable of producing congenital infections resulting in a wide spectrum of abnormalities. The infected foetus can die in utero, in the neonatal period, or it may be born with teratogenic defects. In addition, apparently healthy progeny can be delivered that develop a late onset disease, months, or years after birth, or remain clinically normal for life. The ultimate outcome of a congenital infection is mainly determined by the stage of foetal development, at which infection occurs. Foetuses exposed to rubella virus raise an antibody response to the virus, whereas domestic animals frequently fail to respond immunologically to a congenital pestivirus infection. In congenital rubella the virus usually disappears from the host's body 1-2 years after birth. However, congenital pestivirus infections may be characterized by a lifelong and widespread persistence of virus in clinically healthy animals. Such animals are of significance in the epizootiology of bovine virus diarrhoea, border disease or hog cholera.

Fatal congenital varicella syndrome

A baby with clinical and serological evidence of congenital varicella syndrome died 36 hours after birth. Her mother had developed clinical varicella at 12 weeks gestation. Ultrasound at 37 weeks gestation had shown poor foetal growth and a lacuna within the foetal skull. Varicella-zoster-specific IgM was demonstrated in the baby's serum.

Congenital malformations in a post-mortem series

Of 8,390 children necropsies, 1,249 showed congenital malformations. Thirteen different malformations were recorded relatively often and are here designated as common. Of the necropsied children 914 had only one of these common malformations, and 140 more than one. A variety of less common anomalies was found in the remaining 195 necropsies. The 13 selected common malformations were analyzed statistically to establish whether there was significant clustering of them. Only five of the common malformations proved to be significantly associated. Both frequency and variability of complication differed considerably between groups of common malformations. There was an overall preponderance of males with the common anomalies but the different anomalies differed in respect to sex ratio.

Teratoepidemiology

A review of the field of human teratoepidemiology—the epidemiology of congenital malformations—is presented here along with a discussion of the importance of international collaboration in monitoring congenital malformations. Studies implicating various environmental teratogens such as drugs, industrial and agricultural chemicals, intrauterine infections, radiation and nutritional factors are discussed at some length as well as problems encountered in detecting human teratogenic agents.