Update on Ophthalmic Implications of Highly Pathogenic Avian Influenza A (H5N1) Virus.

Abstract

Introduction: Highly Pathogenic Avian Influenza (HPAI) A(H5N1) represents a growing public health challenge, given broadening zoonotic vectors, with a previously reported human mortality rate of roughly 50%. Late March 2024 marked the start of a new outbreak of HPAI A(H5N1) in the United States. While offering unique public health challenges, this outbreak also provides insight into clinical presentation and ocular involvement implications, transmission vectors, and the implementation of successful surveillance strategies.

Objectives: This review seeks to highlight current and historical outbreak trends, transmission and ocular tropism significance, and strategies to mitigate viral spread.

Methods: A comprehensive narrative literature review was completed using PubMed database as well as local, federal, and international public health press releases.

Discussion: The 2024 US outbreak of H5N1 demonstrates the unique adaptability of the virus. Traditionally transmitted to humans via infected poultry, this outbreak marks the first confirmed case of dairy cow-transmitted human infection. Unlike many past H5N1outbreaks, the majority of patients in the current US outbreak have presented with conjunctivitis either alone or alongside systemic symptoms. This ocular-specific disease manifestation offers new clinical and screening implications. Awareness of ophthalmic involvement among physicians and public health organizations can help guide screening candidates and identify potential infections.