Name a behavioral symptom of Zika virus infection.

Conjunctivitis, often referred to as red eyes, is indeed a recognized symptom associated with Zika virus infection. This occurs when the virus causes inflammation of the conjunctiva, the membrane that covers the front of the eye and lines the inside of the eyelids, leading to redness, discomfort, and sometimes discharge. While Zika can cause a variety of symptoms, including fever, rash, and muscle pain, conjunctivitis is a notable behavioral symptom due to its visibility and impact on a person's daily life.

In contrast, extreme fatigue, abdominal pain, and severe headaches are more general symptoms that could be associated with various illnesses. They do not specifically point to Zika as clearly as conjunctivitis does. The presence of red eyes is often documented in cases of those infected with Zika, making it more uniquely identifiable in the context of this viral infection.