Transmission of Zika Virus Cassandra Salgado, MD, MS, FIDSA, FSHEA Professor of Medicine and Public Health Division Director, Infectious Diseases Medical University of South Carolina

Active Zika Virus Transmission June 2016

Spread of the Zika Virus By Khamar - Own work, CC BY-SA 4.0,

How Zika Spreads

Transmission: Mosquito Bites Zika virus is transmitted to people primarily through the bite of an infected Aedes species mosquito (A. aegypti and A. albopictus) These are the same mosquitoes that spread dengue and chikungunya viruses

Transmission: Mosquito Bites These mosquitoes typically lay eggs in and near standing water They prefer to bite people, and live indoors and outdoors They are aggressive daytime biters, but they can also bite at night Mosquitoes become infected when they feed on an infected person and then spread the virus to other people through bites

Transmission: Mosquito Bites

Zika Virus in the United States US Territories Commonwealth of Puerto Rico, the US Virgin Islands, and American Samoa Jan 01, 2015 to June 01, 2016 CDC Arboviral Disease Branch US States Travel-associated cases: 618 Local vector-borne cases: 0 Total: 618 Sexually transmitted: 11 Guillain-Barré syndrome: 1 US Territories Travel-associated cases: 4 Locally acquired cases: 1,110 Total: 1,114 Guillain-Barré syndrome: 8

Aedes Aegypti Potential abundance

Daily Global Airline Travel

How Zika Spreads

Transmission: Mother to Child A pregnant woman infected with Zika can pass the virus to her fetus during pregnancy Zika is a cause of microcephaly and other severe birth defects To date, there are no reports of infants getting Zika virus through breastfeeding

How Zika Spreads

Transmission: Sexual Contact Zika virus can be spread by a man to his sex partners Unknown how long the virus can stay in the semen of men who have had Zika, and how long the virus can be spread through sex The virus is present in semen longer than in blood At least two weeks to 62 days In known cases of sexual transmission, the men developed Zika virus symptoms The virus may be spread before symptoms start and after symptoms resolve

Transmission: Sexual Contact

How Zika Spreads

Transmission: Blood Transfusion There is a strong possibility that Zika virus can be spread through blood transfusions Most people infected with the Zika virus don’t have symptoms, blood donors may not know they have been infected There have not been any confirmed blood transfusion transmission cases in the United States Multiple reports of blood transfusion transmission cases in Brazil During the French Polynesian outbreak, 2.8% of blood donors tested positive for Zika and in previous outbreaks, the virus has been found in blood donors

Transmission: Prevention Travel restrictions Take measures to protect against mosquito bites Take measures to protect against sexual transmission Blood donation restrictions or testing

Travel Restrictions Women who are pregnant or wish to become pregnant should not travel to areas of the world where Zika transmission is ongoing

Travel Restrictions

Protect Against Mosquito Bites

Protect Against Mosquito Bites After Travel If you have Zika, protect others from getting sick During the first week of infection, Zika virus can be found in the blood and passed from an infected person to another mosquito through mosquito bites An infected mosquito can then spread the virus to other people To help prevent others from getting sick, strictly follow steps to prevent mosquito bites during the first week of illness If you do not feel sick Take steps to prevent mosquito bites for 3 weeks as to not spread Zika to mosquitoes that could spread the virus to other people

Protect Against Sexual Transmission If you are a man who lives in or has traveled to an area with Zika If your partner is pregnant, either use condoms from start to finish, every time you have sex, or do not have sex during the pregnancy If your partner is not pregnant, to reduce transmission use condoms from start to finish, every time you have sex Duration of condom use or abstinence depends on man’s illness Confirmed illness or clinical symptoms after travel to area with Zika- consider precautions for 6 months No symptoms after travel to area with Zika- consider precautions for 8 weeks If man resides in area with Zika- consider precautions for entire duration of known Zika transmission

Blood Donation Guidance In areas of active transmission, FDA recommends blood be screened by laboratory testing, subjected to pathogen reduction technology, or outsourced from other areas Blood donor screening on the basis of a questionnaire, without a laboratory test, is insufficient for identifying Zika-infected donors in areas with active mosquito-borne transmission of Zika virus due to the high rate of asymptomatic infection

Additional Resources UPDATE: Interim Guidance for Prevention of Sexual Transmission of Zika Virus – United States, 2016 (March 25, 2016)Interim Guidance for Prevention of Sexual Transmission of Zika Virus – United States, 2016 MMWR: Transmission of Zika Virus Through Sexual Contact with Travelers to Areas of Ongoing Transmission — Continental United States, 2016 MMWR: Transmission of Zika Virus Through Sexual Contact with Travelers to Areas of Ongoing Transmission — Continental United States, 2016 Interim Guidelines for Prevention of Sexual Transmission of Zika Virus – United States, 2016 Zika and Sexual Transmission( (Feb. 12, 2016) Zika and Sexual Transmission( Questions and Answers on Zika and Sexual Transmission( sexual-transmission.html) Questions and Answers on Zika and Sexual Transmission( sexual-transmission.html) Mosquito Life-Cycle Mosquitoes’ Main Aquatic Habitats Help Control Mosquitoes that Spread Dengue, Chikungunya, and Zika Viruses[PDF - 2 pages] (English) Help Control Mosquitoes that Spread Dengue, Chikungunya, and Zika Viruses[PDF - 2 pages] Help Control Mosquitoes that Spread Dengue, Chikungunya, and Zika Viruses[PDF - 2 pages] (Spanish) Help Control Mosquitoes that Spread Dengue, Chikungunya, and Zika Viruses[PDF - 2 pages] Prevent Mosquito Production in your Septic Tank[PDF - 1 page]

Additional Resources Morbidity and Mortality Weekly Report (MMWR) Zika Reports Emerging Infectious Diseases (EID) Zika Spotlight The conclusions, findings, and opinions expressed by authors contributing to EID do not necessarily reflect the official position of the U.S. Department of Health and Human Services (HHS), the Public Health Service (PHS), the Centers for Disease Control and Prevention (CDC), or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by PHS or by HHS. Emerging Infectious Diseases (EID) Zika Spotlight New England Journal of Medicine, Zika Virus Collection BMJ, Zika Virus Elsevier Zika Virus Resource Center Lancet Zika Virus Resource Centre Oxford University Press (including Journal of Infectious Diseases, Clinical Infectious Diseases, and American Journal of Tropical Medicine and Hygiene), Special Collection on Aedes aegypti and Zika Virus Research Oxford University Press (including Journal of Infectious Diseases, Clinical Infectious Diseases, and American Journal of Tropical Medicine and Hygiene), Special Collection on Aedes aegypti and Zika Virus Research PLOS Collections, Zika