**Author details**

be identified in advance. *In vitro* experiments performed have shown effective inhibition of EV71 infection [113] however *in vivo* experiments utilizing murine models have yet to repli‐

There are cases where spontaneous recoveries do not occur and neurological symptoms per‐ sist. A retrospective study of 105 patients from 1966 to 1972, with documented enterovirus infection and CNS complications, revealed that half, 9 out of 18, of the children not lost to follow up still displayed signs after 1-5 years [78]. Magnetic resonance imaging of two cases with neurological sequelae demonstrated hypointense lesions on T1-weighted images and hyperintense lesions on T2-weighted images, implying tissue destruction [61]. In a more re‐ cent retrospective study of 177 cases with enterovirus isolated via throat swab or stool speci‐ men, 92 patients (52%) had nervous system involvement, out of which 13 patients (7%) had persistent neurological deficits at discharge [19]. Out of the 92 patients with neurological in‐ volvement, 67 (73%) had EV71 isolated and of the 13 patients with deficits at discharge, 11 (85%) had EV71 isolated. The persistent neurological deficits ranged from dysphagia and weakness to lack of regular, spontaneous respiration despite presence of brain function [19]. Studies have also linked EV71 CNS infections to increased symptoms of inattention, hyper‐ activity, oppositional defiance, internalizing problems, and greater likelihood of the diagno‐

Overall, mortality rates for HFMD is reported to be at 0.05% in China [19]. In the aforemen‐ tioned retrospective study of 177 cases, 5 mortalities were reported and in all these 5 cases, EV71 was isolated [19]. Of the 5 mortalities, 2 were attributed to neurogenic pulmonary ede‐ ma, 2 to shock and 1 to brain-death. Mortalities in EV71 infection is generally due to neuro‐ genic pulmonary edema secondary to medulla destruction [13, 80, 116, 117]. In Taiwan, the Department of Health has recorded a decrease of incidence in recent years, however the

The reemergence and emergence of viral infections with involvement of the neurological system is a challenge to public health officers, clinicians and researchers. Enterovirus infec‐ tion is a major concern with changing circulating genotypes in Asia. While CNS complica‐ tions of encephalitis are being increasingly reported in enterovirus infections, further research is needed to understand whether this is due to increased virulence or due to unde‐ tected immune system defects. The epidemiology continuously evolves with shifting popu‐ lation and hence, there is also a need to have better diagnostic methods and treatment

mortality rate is still high (9 deaths in 1999, 41 deaths in 2000, 58 deaths in 2001) [60].

cate similar results [114].

sis of attention deficit hyperactivity disorder [115].

**14. Prognosis**

274 Encephalitis

**15. Conclusion**

options.

Po-Ying Chia1 and Justin Jang Hann Chu2\*

\*Address all correspondence to: miccjh@nus.edu.sg; poying.chia@mohh.com.sg

1 Tan Tock Seng Hospital, Singapore

2 Laboratory of Molecular RNA Virology and Antiviral Strategies, Yong Loo Lin School of Medicine, Department of Microbiology, National University of Singapore, Singapore
