Symptoms and Signs of Zika Virus

Medical Author:
Medically Reviewed on 3/11/2019

Doctor's Notes on Zika Virus

Zika virus (Flavivirus) is a viral pathogen that causes Zika fever; the virus is transmitted to humans by mosquito bites or human to human by sexual contact and can be a cause of severe birth defects. Signs and symptoms of Zika fever include fever and chills, joint pain, skin rash and red eyes. The signs and symptoms usually resolve on their own. However, the virus can remain viable for many months in the body. For example, Zika virus can be found in the eyes and the semen for many months even if symptoms have resolved. It can infect the fetus at almost anytime the mother becomes infected during pregnancy, with microcephaly (small head) and other birth defects such as delayed development, intellectual disability and neurological abnormalities as possible outcomes of the infection for the fetus.

The cause of zika fever is infection by the Zika virus. Zika virus is mainly transmitted by mosquito bites in endemic areas (tropical and sub-tropical) but can be transmitted person to person by any sexual activity. Because the virus remains viable in the body even months after symptoms resolve, the infected person may still transmit the Zika viruses by sexual contact to others; over time, however, the risk of infection decreases. Researchers are trying to determine how long people are infective to others.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.