Coxsackievirus

Coxsackievirus is a virus that belongs to a family of non enveloped linear positive-sense ssRNA viruses, Picornaviridae and the genus Enterovirus, which also includes poliovirus and echovirus. Enteroviruses are among the most common and important human pathogens and ordinarily its members are transmitted by the fecal-oral route. Coxsackieviruses share many characteristics with poliovirus. With control of poliovirus infections in much of the world, more attention has been focused on understanding the nonpolio enteroviruses such as coxsackievirus.

Coxsackieviruses are among the leading causes of aseptic meningitis, the other usual suspects are echovirus and mumps virus.

Groups
Coxsackieviruses are divided into group A and group B viruses based on early observations of their pathogenicity in mice. Group A coxsackieviruses were noted to cause a flaccid paralysis, which was caused by generalized myositis, while group B coxsackieviruses were noted to cause a spastic paralysis due to focal muscle injury and degeneration of neuronal tissue. At least 23 serotypes (1-22, 24) of group A and 6 serotypes (1-6) of group B are recognized.

Group A
In general, group A coxsackieviruses tend to infect the skin and mucous membranes, causing herpangina, acute hemorrhagic conjunctivitis (AHC), and hand, foot and mouth (HFM) disease. Both group A and group B coxsackieviruses can cause nonspecific febrile illnesses, rashes, upper respiratory tract disease, and aseptic meningitis.

Group B
Group B coxsackieviruses tend to infect the heart, pleura, pancreas, and liver, causing pleurodynia, myocarditis, pericarditis, and hepatitis (inflammation of the liver not related to the hepatotropic viruses). Coxsackie B infection of the heart can lead to pericardial effusion. Muffled heart sounds and pulsus paradoxus are signs of this.

The development of insulin-dependent diabetes (IDDM) has recently been associated with recent enteroviral infection, particularly coxsackievirus B pancreatitis. This relationship is currently being studied further.

Sjogren's Syndrome is also being studied in connection with coxsackievirus, as of January 2010.

History
The coxsackieviruses were discovered in 1948-49 by Gilbert Dalldorf, a scientist working at the New York State Department of Health in Albany, New York.

Dr. Dalldorf, in collaboration with Grace Sickles, had been searching for a cure for the dreaded disease polio. Earlier work Dalldorf had done in monkeys suggested that fluid collected from a non-polio virus preparation could protect against the crippling effects of polio. Using newborn mice as a vehicle, Dalldorf attempted to isolate such protective viruses from the feces of polio patients. In carrying out these experiments, he discovered viruses that often mimicked mild or nonparalytic polio. The virus family he discovered was eventually given the name Coxsackie, for the town of Coxsackie, New York, a small town on the Hudson River where Dalldorf had obtained the first fecal specimens.

Dalldorf also collaborated with Gifford on many early papers.

The Coxsackie viruses subsequently were found to cause a variety of infections, including epidemic pleurodynia (Bornholm disease), and were subdivided into groups A and B based on their pathology in newborn mice. (Coxsackie A virus causes paralysis and death of the mice, with extensive skeletal muscle necrosis; Coxsackie B causes less severe infection in the mice, but with damage to more organ systems, such as heart, brain, liver, pancreas, and skeletal muscles.)

The use of suckling mice was not Dalldorf's idea, but was brought to his attention in a paper written by Danish scientists Orskov and Andersen in 1947, who were using such mice to study a mouse virus. The discovery of the Coxsackie viruses stimulated many virologists to use this system and ultimately resulted in the isolation of a large number of so-called enteric viruses from the gastrointestinal tract that were unrelated to poliovirus, and some of which were oncogenic (cancer-causing).

The discovery of the Coxsackie viruses yielded further evidence that viruses can sometimes interfere with each other's growth and replication within a host animal. Other researchers found that this interference can be mediated by a substance produced by the host animal, a protein now known as interferon. Interferon has since become prominent in the treatment of a variety of cancers and infectious diseases.

In 2007, an outbreak of Coxsackie virus occurred in Eastern China. It has been reported that 22 children died. More than 800 people were affected, with 200 children hospitalized.