Correct Answer: A. Entervirus 70
Acute hemorrhagic conjunctivitis (AHC) is a highly contagious viral infection characterized by sudden onset of subconjunctival hemorrhages, chemosis, and follicular reaction. Enterovirus 70 (EV-70) is the primary causative agent of AHC worldwide, including in India. EV-70 was first identified during a pandemic in Ghana in 1969 and has since caused multiple outbreaks globally. The virus spreads through direct contact with infected ocular secretions and has an incubation period of 12–48 hours. Clinically, patients present with acute pain, photophobia, foreign body sensation, and characteristic subconjunctival hemorrhages that may be petechial or confluent. The condition is self-limiting, resolving within 5–7 days without scarring. EV-70 is the only enterovirus consistently associated with epidemic AHC; other enteroviruses (particularly Coxsackievirus A24) can also cause AHC but with lower frequency. In India, EV-70-related AHC outbreaks have been documented, particularly in densely populated urban areas. The diagnosis is clinical, though viral culture and PCR can confirm the etiology. Management is supportive with topical antibiotics to prevent secondary bacterial infection and analgesics for pain relief.
Why the other options are wrong
B. Enterovirus 71 — Enterovirus 71 (EV-71) is primarily associated with hand-foot-and-mouth disease (HFMD) and can cause severe neurological complications including brainstem encephalitis and poliomyelitis-like paralysis, particularly in children. While EV-71 can occasionally cause conjunctivitis, it is NOT the characteristic cause of acute hemorrhagic conjunctivitis. This is an NBE trap pairing a different enterovirus with a different ocular manifestation. C. Enterovirus 68 — Enterovirus 68 (EV-68) is associated with respiratory infections and acute flaccid paralysis outbreaks, particularly in children. It does not cause acute hemorrhagic conjunctivitis. EV-68 gained attention in India and globally during paralysis outbreaks but has no established link to AHC, making this a distractor for students confusing enterovirus serotypes with their clinical presentations. D. Enterovirus 69 — Enterovirus 69 (EV-69) is not a recognized cause of acute hemorrhagic conjunctivitis and is rarely encountered in clinical practice. This option serves as a pure distractor with no clinical relevance to AHC. Students may select this by process of elimination if unfamiliar with the specific EV-70–AHC association, representing a knowledge-based trap.
High-Yield Facts
- Enterovirus 70 is the primary cause of epidemic acute hemorrhagic conjunctivitis (AHC) with 12–48 hour incubation and 5–7 day self-limited course.
- Coxsackievirus A24 is the second most common enteroviral cause of AHC, though EV-70 remains the classic pandemic agent.
- AHC presents with subconjunctival hemorrhages, chemosis, and follicular reaction without corneal involvement or vision loss in uncomplicated cases.
- EV-70 spreads via direct contact with ocular secretions; high transmissibility in crowded settings makes it an outbreak pathogen in Indian urban centers.
- Management of AHC is supportive only (topical antibiotics, analgesics, cool compresses); no antiviral therapy is effective, and steroids are contraindicated.
Mnemonics
AHC Enterovirus Rule EV-70 = AHC (Acute Hemorrhagic Conjunctivitis). Remember: 70 is the 'classic' number for epidemic hemorrhagic eye disease. EV-71 → HFMD/paralysis; EV-68 → respiratory/paralysis; EV-69 → not clinically relevant. Enterovirus Clinical Associations EV-70: Eyes (AHC) | EV-71: Extremities (HFMD) + Encephalitis | EV-68: Respiratory + Paralysis. Use this to quickly differentiate which enterovirus causes which syndrome.
NBE Trap
NBE pairs multiple enterovirus serotypes (EV-71, EV-68, EV-69) with ocular disease to trap students who know 'an enterovirus causes AHC' but cannot recall the specific serotype. The trap exploits confusion between EV-70 (AHC), EV-71 (HFMD/paralysis), and EV-68 (respiratory/paralysis).</trap> <parameter name="textbookRef">Jawetz, Melnick & Adelberg's Medical Microbiology (Enterovirus section); Robbins & Cotran Pathologic Basis of Disease (Viral Infections of the Eye)
Clinical Pearl
In Indian outpatient settings, AHC typically presents as a self-limiting epidemic in schools and crowded urban areas during monsoon/post-monsoon months. Recognition of the characteristic subconjunctival hemorrhages without corneal involvement helps distinguish AHC from bacterial conjunctivitis and prevents unnecessary antibiotic overuse—a critical point in resource-limited Indian primary care settings.