ENTEROVIRUSES

Properties:

@ Family: Picornaviruses

@ Small, spherical, non-enveloped.

@ Icosahedral, Single stranded RNA

Classification of Enteroviruses:@ Poliovirus: types 1,2,3

@ Coxsackie virus : divided into: * Group A: types 1-24 * Group B: types 1-6

@ ECHO virus: types 1-34

@ Enterovirus 70: causes conjunctivitis

@ Enterovirus 71: causes meningitis, encephalitis, and paralysis.

@ Enterovirus 72: is hepatitis A virus

Poliovirus

@ Poliovirus causes poliomyelitis.

@ It is transmitted by the fecal-oral route.

@ It replicates in the oropharynx and the intestinal tract.

@ Humans are the only natural hosts.

@ Poliomyelitis is common in areas where hygiene and sanitation are poor

@ No carrier state

Poliovirus

Symptoms of Poliomyelitis:

@ Sometimes no symptoms

@ Fever, headache, sore throat, vomiting

@ Symptoms of meningitis

@ Muscle spasms and paralysis

Muscle spasms and paralysis

Lab. Diagnosis of Poliomyelitis:

@ Specimens: faeces, throat swabs

@ Inoculate: monkey kidney, or human embryo lung cell cultures. Look for CPE.

@ Type by neutralization tests

@ Serology by ELISA

Vaccination against Poliomyelitis:

@ Two vaccines are available:

1. Sabin live attenuated vaccine: * Contains the three polioviruses , and prepared in monkey kidney tissue culture. * Administered in three oral doses at 2,3, 4 months of age, and booster on school entry * Good protection, good safety, * Vaccinated children are infectious @ Albert Sabin (inventor of the vaccine) is giving the oral dose

2. Salk inactivated vaccine:

@ Contains the three polioviruses

@ Given in three injections.

@ Good protection against paralysis, and has high potency.

@ Jonas Salk (inventor of the vaccine) is injecting a child

Coxsackieviruses

@ Named for the town of Coxsackie, USA

@ Transmitted by the fecal-oral route, and by respiratory aerosols

@ Coxsackieviruses replicate in the oropharynx and the intestinal tract.

@ Humans are the only natural hosts.

Coxsackievirus

Diseases of Coxsackieviruses:

@ Upper respiratory tract infection

@ Fever, skin rash, meningitis.

@ Transient paralysis.

@ Associated with hand-foot-mouth disease

Lab. Diagnosis of Coxsackieviruses

@ Specimens: faeces, throat swabs,

@ Inoculate suckling mice and observe for signs of paralysis in the mice.

@ ELISA to detect IgM antibodies

No vaccination for Coxsackie infection

Echoviruses@ ECHO is an abbreviation of Enteric Cytopathic Human Orphan.

@ It causes: * Meningitis, URT infection, * Fever, skin rash, diarrhea, * Conjunctivitis.

@ Echoviruses has over 30 serotypes

@ Transmitted by the fecal-oral route

Lab. Diagnosis of ECHO viruses:

@ Specimens: faeces, throat swabs, CSF

@ Isolation in human embryo lung cell cultures. Look for CPE using a light microscope.

@ Serology not done because of the large number of serotypes.

No vaccine available.