Echo 9 Virus Infection and Congenital Malformations.

The properties of enteroviruses justify their consideration as possible causes of foetal damage: they are highly prevalent and cause infections which, although usually of minor severity, are often associated with viraemia. Of the enteroviruses, ECHO type 9 is of particular interest because of its periodic epidemic prevalence and the similarity to rubella of many of the infections it causes. Studies by Rantasalo, Penttinen, Saxen, and Ojala (1960) and by Kleinman, Prince, Mathey, Rosenfield, Bearman, and Syverton (1962) did not reveal unequivocal evidence of association between ECHO 9 virus infection during pregnancy and malformation of the infant born subsequently. The possibility that this infection may not cause foetal damage is also of importance to the clinician assessing the implications of a rubelliform illness during pregnancy, and to the epidemiologist evaluating the risk of congenital abnormality complicating "rubella" in studies in which an unknown proportion of maternal illnesses might have been due to ECHO 9 infection with fever, rash, and lymph-node enlargement. An epidemic of ECHO 9 infection in Glasgow in 1960 (Landsman and Bell, 1962; Combined Scottish Study, 1964) provided an opportunity to investigate the possible association of maternal infection with foetal damage.