Typically, four out of five individuals infected with the Zika virus will never develop symptoms. When symptoms occur, they will be rather mild and include one or more of the following:
- Mild fever
- Joint pain (arthralgia)
- Red rash with small bumps (maculopapular rash)
- Red, irritated eyes (conjunctivitis)
- Muscle pain
- Headache
- Vomiting
With mild symptoms, Zika infection usually lasts for several days to a week. Individuals typically do not require hospitalization, and very rarely do individuals die from the infection. Because symptoms are usually mild or non-existing, many people may not realize they have been infected.
On the other hand, more severe symptoms or conditions can occur in the following situations:
- Microcephaly and other birth defects during pregnancy: More information on this condition will be presented later in this course.
- Increased incidence of Guillain-Barre syndrome (GBS): GBS is a rare but serious autoimmune disorder that affects the central nervous system.