Hematospermia, the presence of blood in semen, is most often a benign symptom. Among men age 40 or older, hematospermia is a slight predictor of cancer, typically prostate cancer. No specific cause is found in up to 70% of cases.

Symptoms of orchitis are similar to those of testicular torsion. These can include:

- hematospermia (blood in the semen)

- hematuria (blood in the urine)

- severe pain

- visible swelling of a testicle or testicles and often the inguinal lymph nodes on the affected side.

Orchitis can be related to epididymitis infection that has spread to the testicles (then called "epididymo-orchitis"), sometimes caused by the sexually transmitted diseases chlamydia and gonorrhea. It has also been reported in cases of males infected with brucellosis. Orchitis can also be seen during active mumps, particularly in adolescent boys.

Ischemic orchitis may result from damage to the blood vessels of the spermatic cord during inguinal herniorrhaphy, and may in the worst event lead to testicular atrophy.

Most people who are infected have no or few symptoms. Otherwise the most common signs and symptoms of Zika fever are fever, rash, conjunctivitis (red eyes), muscle and joint pain, and headache, which are similar to signs and symptoms of dengue and chikungunya fever. The time from a mosquito bite to developing symptoms is not yet known, but is probably a few days to a week. The disease lasts for several days to a week and is usually mild enough that people do not have to go to a hospital.

Due to being in the same family as dengue, there has been concern that it could cause similar bleeding disorders. However that has only been documented in one case, with blood seen in semen, also known as hematospermia.

Zika virus infections have been strongly associated with Guillain–Barré syndrome (GBS), which is a rapid onset of muscle weakness caused by the immune system damaging the peripheral nervous system, and which can progress to paralysis. While both GBS and Zika infection can simultaneously occur in the same individual, it is difficult to definitively identify Zika virus as the cause of GBS. Several countries affected by Zika outbreaks have reported increases in the rate of new cases of GBS. During the 2013–2014 outbreak in French Polynesia there were 42 reported cases of GBS over a 3-month period, compared to between 3 and 10 annually prior to the outbreak.