Coxsackievirus

Coxsackieviruses are non-enveloped, positive-sense single-stranded RNA viruses from the genus enterovirus, a genus which itself is part of the larger picornavirus family. The Enterovirus genus also includes echovirus, poliovirus and rhinovirus. Enteroviruses are among the most common and important human pathogens, and ordinarily these viruses are transmitted by the oral-oral or fecal-oral route.

Coxsackieviruses are divided into the Coxsackie A group and the Coxsackie B group. Coxsackie B viruses can sometimes cause persistent non-cytolytic infections, and have been associated with numerous cases of epidemic and sporadic  myalgic encephalomyelitis.

Immune response
In a mouse model of myocarditis, coxsackievirus infection was found to upregulate Toll-like receptor 4 on mast cells and macrophages immediately following infection. It also increased numbers of mast cells.