As the public health and research community mobilizes to contend with the Zika virus epidemic, the Centers for Disease Control and Prevention (CDC) has published updated biosafety guidance for transport, import, and laboratory handling of the virus and related vector and patient diagnostic specimens.
Zika virus is a member of the Flaviviridae family and the genus Flavivirus (which includes yellow fever virus, West Nile virus, Japanese encephalitis virus, and dengue virus). It is enveloped and icosahedral with a non-segmented, single-stranded, positive-sense RNA genome.
Zika virus is primarily transmitted to humans through the bite of an infected Aedes species mosquito. Evidence suggests that transmission may also occur from mother to child in utero, through sexual contact, or through blood transfusion. No vaccines or antiviral treatments are currently available for Zika virus infection.
Cultures of Zika virus and specimens collected from individuals for Zika virus studies may be transferred within the U.S. as Category B Biological substances in accordance with Department of Transportation Hazardous Materials Regulations.
Guidance for packaging samples in accordance with Category B Biological substance requirements can be found in the CDC/NIH Publication Biosafety in Microbiological and Biomedical Laboratories, 5th edition (BMBL5).
A CDC Import Permit is required to import Zika virus and specimens for Zika virus testing into the United States. A USDA Permit is required for the importation of arthropods (infected or uninfected) that could serve as vectors for Zika virus transmission, and may be required for importation and subsequent transfer of other Zika virus-containing materials.
Handling of Diagnostic Specimens
Specimens from individuals suspected of having Zika virus infection should be handled in accordance with the Healthcare Infection Control Practices Advisory Committee Standard Precautions Standard.
These include the use of gloves, a laboratory gown or coat, and eye protection when handling these specimens. In general, Biosafety Level 2 precautions, as described in the CDC/NIH Biosafety in Microbiological and Biomedical Laboratories manual, are appropriate for the handling of these specimens.
Laboratories should perform a risk assessment to determine if there are certain procedures or specimens that may require higher levels of biocontainment. For example, potential aerosol generating procedures should be performed in a biological safety cabinet. Specimens for which chikungunya virus is also a concern, since this virus is known to produce high levels of viremia, may also require higher levels of biocontainment.
Laboratory Work with Zika Virus
Zika virus preparations generally may be handled under Biosafety Level 2 precautions. A risk assessment should be performed to determine if there are certain procedures that may require higher levels of biocontainment such as those that could potentially create aerosols.
Experiments involving recombinant or synthetic Zika virus nucleic acids should be done in accordance with relevant NIH Guidelines.
In areas where the Zika virus has not been established in the mosquito population, in order to reduce the risk of environmental establishment, Arthropod Containment Level 3 (ACL-3) should be used for all work with live, infected arthropods. In areas where the Zika virus is established in the resident mosquito population, it is recommended that ACL-2 be used for all work with live, infected arthropods.
Occupational Health Issues
Until the association between Zika virus infection and congenital anomalies, including microcephaly, is better understood, pregnancy should be considered a significant factor in risk assessment for individuals working with Zika virus, and the involvement of pregnant workers in studies with Zika virus should be minimized.
Workers with partners who are pregnant or are considering pregnancy should be aware of the risk associated with sexual transmission of Zika virus.
Guillain-Barré syndrome (GBS) is an uncommon illness involving the nervous system in which a person’s own immune system damages the nerve cells, causing muscle weakness, and sometimes, paralysis. The Brazil Ministry of Health has reported an increased number of people who have been infected with Zika virus who also have GBS. CDC is working with Brazil to study the possibility of a link between Zika virus and GBS.
Updates on Zika virus transmission can be found at the CDC Zika virus website.
Source: CDC, adapted. Please visit the CDC’s Zika virus biosafety guidance page for complete information and references.