Pathogenicity of a poliomyelitis-like disease in monkeys infected orally with enterovirus 71: a model for human infection.

Ten cynomolgus monkeys were given enterovirus 71 (E71) by mouth. Clinically, only one monkey showed weakness of the lower extremities. Histopathologically, vascular lesions of variable intensity, perivascular cuffing, degeneration and necrosis of the neurons and neuronophagia were observed in the CNS of 7 monkeys. E71 was recovered from the CNS and specific immunofluorescence was detected in the neurons and in associated macrophages in the CNS. Serum neutralizing antibody titres rose from 14 to 21 days. These monkeys are as susceptible to E71 infection by the oral route as by the subcutaneous route as previously shown, and its neuronal virulence was confirmed by its producing CNS lesions after oral infection. The orally infected monkey with E71 appears to provide an excellent model for infection by this agent in man.