Four new enteroviruses have been described that include enteroviruses 68, 69, 70, and 71. Of these, enterovirus 69 does not cause any human diseases, but rest of the three enterovi-ruses cause diseases in humans. Type 68 causes pneumonia and bronchitis, type 70 causes acute hemorrhagic conjunctivitis (AHC), and type 71 causes meningoencephalitis and paralysis.
Enterovirus 70 is the causative agent of acute hemorrhagic con-junctivitis (AHC). The condition was first recognized in 1969 in Ghana and Indonesia. Subsequently, the condition spread widely, involving several parts of Japan, England, Europe, Africa, Middle East, and Southeast Asia including India. Coxsackievirus A 24 has also been known to cause the similar disease.
AHC is a highly contagious ocular infection, which can cause large-scale epidemics. Transmission is facilitated by over-crowding and nonsanitary conditions. The infection is trans-mitted directly from finger or fomite to eye. The condition is most prevalent in adults between 20 and 50 years.
The incubation period is about 24 hours, and the onset is abrupt. The most common symptoms include pain in the eyes, burning sensation, swelling of the eyelids, and foreign body sensation in the eye. Photophobia and watery discharge may also be found in some cases. The other eye becomes infected a few hours after infection of the first eye. Fever, mal-aise, and headache are the nonspecific symptoms. AHC is a self-limiting condition. The symptoms typically improve by second or third day of infection, and the recovery is complete within 7–10 days.
Isolation of the virus is made by culturing in human diploid embryonic kidney and HeLa cell lines.