[Epidemics of conjunctivitis caused by avian influenza virus and molecular basis for its ocular tropism]

Avian influenza virus (AIV) has caused several outbreaks in humans, leading to disasters to human beings. The outbreak of H7N9 avian influenza in China in 2003 re-attracted our close attention to this disease. More and more evidences demonstrated that eye is one of invasion portals of AIV, leading to conjunctivitis. The current studies showed that only subtypes H7 and H5 could cause severe systemic infections. Abundant distribution of α-2, 3 siliac acid receptor in conjunctiva and cornea as well as specific activiation of NF-κB signal transduction pathway by subtype H7 virus may contribute to the ocular tropism of the virus. These studies suggest that avian influenza conjunctivitis should be considered as a differential diagnosis during influenza epidemic seasons, and eyes should be well protected for disease control personnel when handling avian influenza epidemics. This review focused on AIV conjunctivitis and the molecular basis of ocular tropism.