The Coxsackie B viruses are members of the enterovirus (link) genus and are the most common agent for myocarditis and dilated cardiomyopathy constituting 50% of infections. Myocarditis is an uncommon disease that occurs in only 1% of the American population. Myocarditis predominantly affects middle-aged men with the average age of disease onset occurring around 42 years of age. The incubation period for most coxsackie virus infections is about two to ten days and onset of cardiac symptoms typically occurs two weeks after viral infection. The coxsackie B viruses, like most enteroviruses are transmitted fecal-orally and through direct contact with mucosal secretions.
Symptomology and Outcome:
Coxsackie B infection is characterized by fever, fatigue, malaise and chest pains. Infection of the heart by a coxsackie B virus can lead to viral myocarditis. Viral myocarditis is a inflammatory disease of the heart which can result in heart failure. Although the disease does not usually cause death, there is a 20% incidence of reoccurrence and permanent heart damage typically results.
Pathogenesis:
The coxsackie B virus initially replicates in the gut and spleen and eventually spreads to its target organ, the heart. Once in the heart, replication of the virus causes damage to the heart cells and induces migration of white blood cells into the heart tissue. The white blood cells subsequently activate an autoimmune process in which the white blood cells kill the virus infected heart cells and normal heart cells which are not infected. This autoimmune process persists long after viral particles are no longer detected. The destruction and damage to the heart cells results in myocarditis and heart failure.
Prevention and Management:
While coxsackie virus infection cannot be prevented it can be controlled through sanitary measures. As a fecal-orally transmitted virus, spread of the virus can be limited by improving sanitation and thoroughly washing hands.
Myocarditis can be managed by reducing inflammation with analgesics and thus limiting the amount of heart damage that occurs. Because myocarditis impairs the functioning of the heart activity should be limited and excessive dietary intake of salt should be avoided. Oxygen can also be given to reduce the workload on the heart and in cases of heart failure, heart transplants can be performed.