Biological characterisation of avian enteroviruses and enterovirus-like viruses

The antigenic relationships and in vitro growth properties of 10 avian enteroviruses and enterovirus-like viruses were investigated. By cross-indirect immunofluorescence tests, six serogroups were identified. The lack of an antigenic relationship between viruses selected from three of these serogroups was confirmed by cross-neutralisation tests. Most of the viruses grew poorly or not at all in a range of primary avian cell cultures, but the majority grew following inoculation of chick embryos via the yolk sac. The ability of these viruses to produce growth retardation in commercial broiler chickens was variable. Following oral inoculation of 1-day-old chicks, most had little or no effect. The most severe growth retardation was observed with avian encephalomyelitis virus and an enterovirus-like virus isolated from broilers in Northern Ireland which subsequently developed the runting-stunting syndrome. The latter produced 28 to 37% growth retardation in a 14-day period.