Zika virus infection

This page is about clinical aspects of the disease.  For microbiologic aspects of the causative organism(s), see Zika virus.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nate Michalak, B.A.; Luke Rusowicz-Orazem, B.S.

Synonyms and keywords: Zika virus; ZIKV; ZIKV disease; Zika; Zika virus disease; Zika disease; Zika fever

Overview

Zika fever is an illness caused by the Zika virus, a member of the family Flaviviridae. The fever and virus are named after the Ugandan forest where the virus was first isolated. The virus is commonly found in Africa but has also been found in Malaysia and Micronesia. Symptoms are similar to dengue fever, but are milder in form and usually last four to seven days. No hemorrhagic manifestations have been documented. Common symptoms include a maculopapular skin rash that starts on the face or trunk before moving to the rest of the body, conjunctivitis, joint pain, low-grade fevers and headache.

Historical Perspective

• Zika virus was first isolated in 1947 from a rhesus monkey in the Zika Forest of Uganda. The first human isolation of the virus occurred in 1968 in Nigeria.
• Between 1951 through 1981, evidence of human infection was additionally reported in the following countries:
  • Africa: Tanzania, Egypt, Central African Republic, Sierra Leone, and Gabon
  • Asia: India, Malaysia, the Philippines, Thailand, Vietnam, and Indonesia
• The first outbreak of Zika virus outside of Africa and Asia occurred in April 2007 on the Yap Island in the Federated States of Micronesia. The disease was initially thought to be dengue, but the Chikungunya and Ross River viruses were also suspected.
• A larger outbreak of Zika virus occurred in the Brazilian district of Camaçari and neighboring Salvador City in April 2015. An unknown agent was causing flu-like symptoms, followed by rash and arthralgia, in approximately 500 individuals. RT-PCR techniques by researchers at the Federal University of Bahia confirmed the causative organism to be Zika virus.

Classification

The illness caused by Zika virus is usually mild with symptoms lasting from several days to a week. Severe cases requiring hospitalization are uncommon. A schema for classification of Zika virus infection is yet to be identified.

Risk Factors

Most Common

• Mosquito Bites in Endemic Areas (as listed below as areas of prior outbreaks).
• The most potent risk factors related to contracting Zika virus are travelling to endemic areas, such as Asia and Africa (reported prior to 2007), The Federated States of Micronesia (reported in 2007), and most recently in the South American regions of Chile (reported in 2014), Brazil and Colombia(reported in 2015), Guatemala, El Salvador, Paraguay, Suriname, Venezuela, and Mexico (all cases were reported in 2015.)

Less Common

• Blood transfusion from an asymptomatic donor in an endemic area.
• Perinatal and sexual transmission.

Symptoms

Symptoms associated with the contraction of the Zika virus typically span from several days to a week. The disease is rarely fatal and hospitalization is uncommon. The following symptoms are the associated with contracting the Zika Virus:

• Acute onset fever
• Maculopapular rash
• Arthralgia
• Conjunctivitis
• Myalgia
• Headache
• Retro-orbital pain
• Vomiting

Diagnosis

• The Zika virus is commonly misdiagnosed as many other diseases. These diseases include dengue, leptospirosis, malaria, rickettsia, group Astreptococcus, rubella, measles, parvovirus, enterovirus, adenovirus, and alphavirus infection.
• Diagnosis is initially based on patients recent history, including places traveled.
• Blood serum and plasma testing is conducted to detect viral nucleic acids or virus specific IgM. Laboratory testing is the primary source when differentiating between Zika and other commonly misdiagnosed viruses.

Medical Therapy

• There is currently no specific antiviral treatment for the Zika virus.
• Modern therapy tactics include increased rest, fluids, antipyretics (fever reducers) and analgesics (pain relievers).
• Non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided until dengue fever is no longer a potential diagnosis.

Primary Prevention

Avoid mosquito bites:

• Use insect repellent.
• Wear long sleeves and long pants.
• If outdoors or cannot protect against mosquitos entering the home, use bed nets, air conditioning, or insect screens
• Avoid standing water: gardening pots, swampy areas, etc.