We report a previously well 10-month-old Somalian girl who acquired asymmetric lower limb weakness in July 2013 in Mogadishu, Banadir, before arriving in Malaysia at 12 months of age. In May 2013, there was a wild poliomyelitis outbreak in that area, as reported by the World Health Organization. Laboratory investigation, including cerebrospinal fluid, was unremarkable, and electrophysiological studies showed active axonal denervation in the left lower limb. The whole spine T2-weighted MRI revealed non-enhancing hyperintensities of the bilateral anterior horn cells, predominantly on the left side at T11-12. The viral isolations from two stool specimens at her presentation to our centre, 2 months after the onset of illness and 2 weeks apart, were negative. Despite lacking the acute virological evidence of poliomyelitis, in view of the girl's clinical, electrophysiological and classical spinal neuroradiological features, together with her temporal relationship with a World Health Organization reported wild poliomyelitis outbreak, we believe these findings are consistent with a diagnosis of imported poliomyelitis. A review at 30 months of age showed persistent left lower limb monoplegia with little recovery. Our patient reiterates the importance of maintaining awareness of wild polio importation, and keeping abreast of the latest news of global poliomyelitis outbreaks when treating patients with flaccid paralysis, even if they arrive from non-endemic poliomyelitis areas.
Enterovirus A71 (EV-A71) belongs to the species group A in the Enterovirus genus within the Picornaviridae family. EV-A71 usually causes self-limiting hand, foot and mouth disease or herpangina but rarely causes severe neurological complications such as acute flaccid paralysis and encephalomyelitis. The pathology and neuropathogenesis of these neurological syndromes is beginning to be understood. EV-A71 neurotropism for motor neurons in the spinal cord and brainstem, and other neurons, is mainly responsible for central nervous system damage. This review on the general aspects, recent developments and advances of EV-A71 infection will focus on neuropathogenesis and its implications on other neurotropic enteroviruses, such as poliovirus and the newly emergent Enterovirus D68. With the imminent eradication of poliovirus, EV-A71 is likely to replace it as an important neurotropic enterovirus of worldwide importance.