Which Haemophilus species is commonly associated with conjunctivitis in children?

Haemophilus influenzae is the species commonly associated with conjunctivitis, particularly in children. This bacterium can cause various infections, including respiratory tract infections and, notably, conjunctivitis (inflammation of the eye's conjunctiva). The age group of children makes them more susceptible to this infection due to factors such as close contact in schools and daycare environments, where the bacteria can easily spread.

Haemophilus influenzae is a member of the normal flora in the respiratory tract but can act as a pathogen under certain conditions, leading to ocular infections. In particular, since this bacterium can be transmitted through respiratory droplets, it poses a higher risk for conjunctivitis outbreaks among children.

The other Haemophilus species listed do not have the same strong association with conjunctivitis. Haemophilus parahaemolyticus mainly causes gastrointestinal infections, Haemophilus haemolyticus has been less studied and is not primarily linked to conjunctivitis, and Haemophilus aphrophilus is generally considered non-pathogenic and is more often associated with endocarditis rather than conjunctivitis. Thus, Haemophilus influenzae stands out as the primary species related to this eye condition in children.