Hand, foot, and mouth disease (HFMD) is a reemerging illness caused by a variety of enteroviruses. The main causative agents are enterovirus 71 (EV71), coxsackievirus A16 (CVA16), and, most recently, coxsackievirus A6 (CVA6). Enterovirus infections can vary from asymptomatic infections to those with a mild fever and blisters on infected individuals’ hands, feet, and throats to infections with severe neurological complications. Viral persistence for weeks postinfection (wpi) has also been documented by the demonstration of virus in children’s stools. However, little is known about disease progression, viral spread, and tissue tropism of these viruses. These types of studies are limited because many recently developed mouse models mimic the severe neurological complications that occur in a small percentage of enterovirus infections. In the present study, we documented real-time EV71 infection in two different mouse strains by the use of in vivo imaging. Infection of BALB/c mice with a bioluminescent mouse-adapted EV71 construct (mEV71-NLuc) resulted in a lack of clinical signs of disease but in relatively high viral replication, as visualized by luminescence, for 2 wpi. In contrast, mEV71-NLuc infection of AG129 mice (alpha/beta and gamma interferon receptor deficient) showed rapid spread and long-term persistence of the virus in the brain. Interestingly, AG129 mice that survived infection maintained luminescence in the brain for up to 8 wpi. The results we present here will allow future studies on EV71 antiviral drug susceptibility, vaccine efficacy, transmissibility, and pathogenesis.
Read more here.
Article Source: Journal of Virology