Special features of Coxsackie viruses
Coxackieviruses are similar with other enteroviruses. They are divided into two groups, A and B with multiple serotypes spread among various enteroviral species. Most of Coxackie viruses possess hemagglutinin.
Pathogenesis, clinical findings and immunity
The incubation period of coxsackieviral infection ranges from 2 to 9 days.
Coxsackieviruses produce a great variety of disorders in humans:
– herpangina or vesicular pharyngitis;
– aseptic meningitis and meningoencephalitis;
– respiratory febrile diseases;
– pleurodynia or epidemic myalgia;
– hand, foot and mouth disease or vesicular stomatitis with exanthem;
– acute hemorrhagic conjunctivitis;
– generalized disease of infants;
– various clinical forms of myocarditis and pericarditis;
– hepatitis, pancreatitis.
It is generally ascertained that group В coxsackieviruses attack presumably inner organs, whereas group A viruses affect central and peripheral nervous system and muscular system.
Various diseases can be spread among humans via fecal-oral or airborne transmission.
Virus has been recovered from the blood in the early stages of infection in humans. It is also found in the throat for a few starting days of infection and in the stools for up to 5-6 weeks.
Coxsackie herpangina is a severe febrile pharyngitis. It is caused by certain group A viruses. There is an abrupt onset of fever and sore throat with discrete vesicles on the soft palate, pharynx, tonsils, or tongue. The disorder is self-limited and most common in young children. Hand, foot and mouth disease also known as vesicular stomatitis with exanthem may affect persons of all ages but predominantly young children before 4-5 years. It is caused by group A Coxsackie viruses and by enterovirus serotype 71.
This self-limited but contagious ailment is manifested by damage of skin and mucosa with ulcerations and eruptions of small vesicles in oral cavity, upon hands and feet.
Pleurodynia, or epidemic myalgia, or Bornholm disease is provoked by group В viruses. It is followed by fever, chest and abdominal pain. The disease is also self-limited and recovery is complete; nevertheless, the relapses are common.
Coxsackie myocarditis is a serious disease with acute inflammation of myocardium and pericardium (pericarditis). It can occur in adults as well as in children. Infection can be fatal in neonates. Coxsackie В virus infections are supposed to trigger host autoimmune response that leads to cardiomyopathies.
Aseptic meningitis is similar with same disorders of picornavirus origin. Fever, malaise, headache, nausea, and abdominal pain are common clinical findings. The muscle weakness occurs, but the patients usually recover completely.
Generalized disease of infants is followed by total coxsackie viremia, affecting baby’s heart, liver, and brain. The disease is caused by group В coxsackieviruses and has a serious prognosis.
Seroepidemiological data links type 1 (insulin-dependent) diabetes mellitus with coxsackie В viruses.
Immunity in Coxsackie infections is mediated by type-specific neutralizing antibodies that appear early and persist for years. Antibodies are transferred passively from mother to fetus, protecting newborns for about 6 months.
Laboratory diagnosis of Coxsackie infections
Specimens are taken from throat washings during the first several days of infection and from feces during the first few weeks. In cases of aseptic meningitis, the viruses can be recovered from cerebrospinal fluid as well as from intestine.
Viral cultivation is performed by sample inoculation into cell cultures and by infection of suckling mice. In cell cultures a cytopathic effect evolves within 5-14 days. In suckling mice, signs of the disease appear usually within 3-8 days with group A strains and 5-14 days with group В strains. The virus is identified by neutralization reaction or by hemagglutination inhibition test.
Serological testing is performed in paired sera tests, where fourfold rise in antibody titer is observed. ELISA and hemagglutination inhibition tests are available.
Principles of prophylaxis and treatment of infections
There are no vaccines or antiviral drugs currently applied for prevention or treatment of diseases caused by coxsackieviruses.