Zika Virus

Zika virus is an enveloped, single stranded RNA virus, initially isolated from a Rhesus monkey in Uganda in 1947. It is a member of the Flaviviridae family, genus Flavivirus, which also includes other major pathogens such as the Japanese encephalitis virus, West Nile virus, Murray Valley encephalitis, tick-borne encephalitis and dengue virus. Genomic comparisons have revealed two lineages of the virus, Asian and African. Phylogenetic studies indicate that the virus emerging in the Americas is closely related to the Asian lineage.

Potential Health Hazards

Most Zika infections are asymptomatic or mildly symptomatic with symptoms lasting several days to a week. Common symptoms associated with the virus include fever, rash, joint pain, or conjunctivitis. In rare cases, neurologic complications such as Guillain-Barre syndrome were reported by individuals suspected of being infected with Zika virus.

The Center for Disease Control and Prevention (CDC) recently concluded that Zika virus infection during pregnancy is a cause of microcephaly and other severe fetal brain defects.  It is strongly recommended that pregnant women not work with Zika virus and individuals considering pregnancy should be aware of the risks associated with sexual transmission of Zika virus.

Modes of Transmission

The primary mode of transmission is through blood; the virus is primarily transmitted to humans through the bite of an infected Aedes species mosquito. Other modes of transmission could include perinatal, in utero, sexual and transfusion events.

Laboratory Acquired Infections

A potential laboratory exposure was reported in 1964; the mode of transmission was unknown. Recently, a laboratory worker was reported to have contracted the virus through a needlestick injury while conducting research.

In a laboratory setting, transmission of Zika virus may occur through broken skin exposure (such as needlestick, animal bite, or scratch) or contact with mucous membranes (eyes, nose or mouth). There is also a theoretical risk of exposure by ingestion or inhalation of aerosolized droplets.

Host Range

Human and non-human primates are the primary reservoirs for Zika virus.


Zika virus is stable at temperatures up to 500C.

Dried Zika virus is infectious for up to 18 hours and may remain infectious for more than three days.

Laboratory Practices

Biosafety level 2 (BSL2) practices and facilities must be used for research activities involving the Zika virus; however, additional risk assessments should be performed for specific procedures, to determine necessary safety precautions, or if higher levels of containment are required.  SOPs for individual laboratories will outline additional containment, safety practices, and PPE, if appropriate.

  • Biohazard signs and labels must be displayed in areas and on equipment where Zika virus is used or stored.  This includes, but is not limited to, laboratory entrance doors, biological safety cabinets, incubators, refrigerators, and freezers.
  • All procedures involving the manipulation of infectious materials must be conducted within a biological safety cabinet (BSC) (a.k.a., tissue culture hood), or other physical containment devices. No work with open vessels is conducted on the bench. 
  • Use aerosol containment devices when centrifuging. These include sealed canisters that fit in the centrifuge bucket, covers for the centrifuge bucket, heat sealed tubes, or sealed centrifuge rotors.  Rotors should be removed and opened inside a BSC. Centrifuge tubes should be filled and opened in a BSC.  
  • Vacuum lines must be protected with liquid disinfectant traps and a micron filter.
  • Policies for handling and disposing of sharps (needles, pipettes, broken glassware, etc.) must be implemented.  Work practice controls and engineering devices should be implemented to reduce sharps injuries.
  • Decontaminate work surfaces after completion of work and after any spill or splash of potentially infectious material with appropriate disinfectant.
  • All cultures, stocks and other potentially infectious materials should be decontaminated prior to disposal with an effective method, such as autoclaving or treatment with a bleach solution.
  • Potentially infectious materials must be placed in a durable, leak proof container during collection, handling, processing, storage, or transport within a facility.

Clinical samples sent for testing could also be contaminated with denge virus (requires BSL2 containment) or chikungunya virus (requires BSL3 containment) and therefore a risk assessment must be performed by each laboratory for the specific procedures utilized.  All organisms should be handled in accordance with Biosafety in Microbiological and Biomedical Laboratories (BMBL) guidelines.  Refer to the CDC’s website on Zika virus as updated information becomes available.

Principal Investigators are responsible for communicating all relevant information regarding handling procedures and risks associated with research involving Zika virus to their staff.  Due to the association of Zika virus infection and congenital microcephaly, pregnancy should be considered a significant factor in the risk assessment for individuals working with the virus.

Personal Protective Equipment

Personal protective equipment (PPE) includes, but is not limited to:

  • Disposable gloves (nitrile, latex, etc.).
  • Lab coat when working in the laboratory.  Remove before leaving the area.
    • Protective laboratory clothing must be laundered by the University and not taken home for cleaning.
  • Face and eye protection when splash/spray is possible.

Precautions When Using Animals 

Animal use requests are made to the Institutional Animal Care and Use Committee (IACUC) by submitting an Animal Protocol (AP) found at http://animal.research.uiowa.edu/animal-protocol.

When animals are infected with Zika virus, the Animal Biosafety Level (ABSL) of the project will be generally assigned to ABSL2a.  A risk assessment will be performed to determine if any procedures require higher levels of containment.  The Animal Biosafety Level protocol is available through EHS’s website: http://ehs.research.uiowa.edu/animal-biosafety-level-2a. Animal cages must be labeled with a biohazard sign.

Recombinant Zika virus Research

Protocols involving recombinant Zika virus must be approved by the Institutional Biosafety Committee (IBC); complete an online “rDNA Registration Document” available through eIBC: https://eibc.research.uiowa.edu/rdna/

Employee Exposure

Mucous membrane exposure – Flush eyes, mouth or nose at an eyewash for at least 15 minutes.

Skin exposure - Rinse skin with soap and water.

Accidental Needlestick Injury - Scrub contaminated skin with soap and water for at least 15 minutes.

Remove any potentially contaminated garments and place them in a biohazard bag.

Report Incidents and Seek Treatment - Report actual or suspected exposure incidents to your supervisor immediately. Seek medical attention as soon as possible.

If the incident occurs after 4:30 pm, during the weekend, or on holidays, proceed to UIHC’s Emergency Treatment Center (ETC).  The phone number is 356-2233.

University of Iowa Employees: Seek treatment at University Employee Health Center.  It is located in the General Hospital, first floor Boyd Tower near Elevator A. Phone: 356-3631. Office hours: Mon-Fri 7.00 AM – 5.00 PM. 

Students Not Paid by UIOWA: Seek treatment at the Student Health Services, located at 4189 Westlawn South, 200 Newton Road. Their phone number is 335-8394 or 335-8370.

After seeking treatment, the individual and/or supervisor should fill out the following forms:

  1. First report of Injury form: The employee is required to electronically file a First Report of Injury at the HR Self-Service Site within 24 hours of the incident.
  2. Incident Investigation Report: The supervisor of the employee is required to complete an Incident Investigation Report within 24 hours of the event. 
  • Immunizations and Prophylaxis - None available. Treatment is symptomatic.
  • Incubation Period – unknown.

Spill and Disposal Procedures

For spills outside a biological safety cabinet, notify others working in the lab, and leave the area while holding your breath.  Once outside the area, wash hands and face with soap and water.  Do not allow anyone inside the area or room where the spill occurred.  Allow 30 minutes for the aerosols to settle.  Enter the room wearing required protective clothing, gently cover the spill with paper towels, and apply disinfectant starting at the perimeter and working towards the center.  Allow the disinfectant to remain on the spill for at least 30 minutes before initiating spill clean-up. After initial clean up, disinfect the area a second time.

For spills inside a biological safety cabinet, cover the spill with paper towels or wipes.  Gently pour disinfectant over the spill area.  Let the disinfectant soak for 30 minutes before cleaning up the spill. After initial clean up, disinfect area a second time.

Contaminated materials must be disposed of as biohazardous waste.

Decontaminate adjacent surfaces with disinfectant due to the potential for splashing of spilled material.


Disinfectants should be allowed a minimum of 20-30 minutes contact time.  The susceptibility of Zika virus to disinfectants was recently published; the following methods were determined to be effective:

  • Sodium hypochlorite (use 1-10% dilution of fresh bleach)
  • 70% Ethanol
  • 2% paraformaldehyde
  • 2% glutaraldehyde


Autoclave cultures for 30 minutes at 121°C or 250°F (15 lbs per square inch of steam pressure).

Disinfect work surfaces using an effective germicide (see above).  This may be followed by an alcohol wipe to lessen the corrosive nature of the germicide.

Transport Requirements

Both CDC and USDA permits may be required for importation of Zika virus samples (eg. specimens for testing, Zika virus cultures exposed to animal products, live or killed mosquito vectors etc.). The CDC and USDA import permit regulations may be accessed at http://www.cdc.gov/od/eaipp, and http://www.aphis.usda.gov/animal-health/organisms-vectors, respectively.

Materials must be appropriately contained and labeled for transport within the University.  Shipping infectious substances, diagnostic specimens, and/or shipping with dry ice off-campus require training and certification.  See EHS’s fact sheet “Transporting and Shipping Infectious Substances” found at http://ehs.research.uiowa.edu/transporting-and-shipping-infectious-substances for additional information.

If You Have Questions

Contact EHS’s Biological Safety Section at 335-9553.

References and Resources

CDC, Zika virus web site: http://www.cdc.gov/zika/hc-providers/. Accessed 4/18/2016.

CDC, Biosafety Guidance for Transportation of Specimens and for Work with Zika Virus in the Laboratory: http://www.cdc.gov/zika/state-labs/biosafety-guidance.html. Accessed 4/18/2016.

CDC, Zika Virus- What Clinicians Need to Know, Clinician outreach and Communication Activity: http://emergency.cdc.gov/coca/ppt/2016/01_26_16_zika.pdf. Accessed 4/18/2016.

CDC, National Institute for Occupational Safety and Health (NIOSH), Zika Virus: http://www.cdc.gov/niosh/topics/outdoor/mosquito-borne/zika.html. Accessed 4/26/16.

CDC, OSHA, NIOSH FactSheet, Interim Guidance for Protecting Workers from Occupational Exposure to Zika Virus: http://www.cdc.gov/niosh/topics/outdoor/mosquito-borne/pdfs/osha-niosh_fs-3855_zika_virus_04-2016.pdf. Accessed 4/26/16.

CDC, CDC Concludes Zika Causes Microcephaly and Other Birth Defects: http://www.cdc.gov/media/releases/2016/s0413-zika-microcephaly.html. Accessed 4/18/2016.

Dick, G.W., Kitchen, S.F., Haddow, A.J. 1952. Zika Virus. 1. Isolations and Serological Specificity. Trans R Soc Trop Med Hyg (46). 509-520.

European CDC, http://ecdc.europa.eu/en/healthtopics/zika_virus_infection/factsheet-health-professionals/Pages/factsheet_health_professionals.aspx. Accessed 4/18/2016.

Müller, J.A, et. al., 2016.  Inactivation and Environmental Stability of Zika Virus.  Emerging Infectious Diseases (22). 1685-1687.

Simpson, D.I.H. 1964. Zika Virus Infection in Man. Trans R Soc Trop Med Hyg (58). 335-337.  http://trstmh.oxfordjournals.org/content/58/4/335.full.pdf+html.  Accessed 4/18/2016.

The New York Times. 2016. Lab Worker in Pittsburgh is Accidentally Infected with Zika Virus. http://www.nytimes.com/2016/06/11/science/lab-worker-in-pittsburgh-is-accidentally-infected-with-zika-virus.html?_r=1. Accessed 6/24/2016.



Created April 26, 2016

Updated August 22, 2016