Current epidemiology of the Zika virus disease in the United States & Territories (as of June 14, 2017)



Map of counties where scientists have collected Aedes aegypti mosquitoes between 1995-2016

On June 9, 2016, the (CDC) scientists published an updated map of known regions of Aedes aegypti mosquito habitats. The map represents the best knowledge of the current distribution of the species based on collection records. Counties in yellow represent one recorded year of Aedes aegypti being present, those in orange represent two years and those in red represent three of more years.



NGA in the News: NGA CEO Write Op-Ed on Congress and Zika Funding

On September 12, 2016, NGA CEO Scott Pattison wrote an op-ed in The Hill detailing governors’ desire for Congress to fund Zika response and preparedness efforts. In response to the growing public health emergency that has now resulted in 16,700 cases across 48 states and the U.S. territories, the nation’s governors have urged Congress to fund efforts to combat the virus. Federal dollars can support state public health efforts to prevent and reduce the impact of the Zika virus, which can cause infants to be born with severe, lifelong birth defects. Governors are urging Congress to follow their model of bipartisan cooperation and reach an agreement to take action to stop the spread of the Zika virus in the United States.

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Has Congress funded Zika preparedness?

On September 28, Congress passed much needed funding to fight Zika virus. The continuing resolution, which expired on December 9 2016, included $1.1 billion in funding to fight Zika. Importantly, $44 million went to states to backfill their public health emergency preparedness funds that were shifted earlier in 2016. According to Senate Appropriations, the majority of the FY2016 Zika Response and Preparedness supplemental supports the following:  

  • Public Health & Care: $75 million to reimburse health care provided in states and U.S. territories with active Zika transmission for those without private health insurance. The Zika supplemental also provides:
    • $40 million for Community Health Centers in Puerto Rico and other U.S. territories;
    • $6 million for National Health Service Corps in Puerto Rico and other U.S. territories; and
    • $20 million for Maternal and Child Health special projects of regional and national significance (SPRANS) in Puerto Rico and other U.S. territories.
  • Mosquito Control and Surveillance: $394 million for the Centers for Disease Control and Prevention (CDC) to support vector control, technical assistance for states and international response activities. Of this amount, $44 million is to reimburse states for Public Health Emergency Preparedness funding transferred for Zika response activities.
  • Vaccine and Diagnostic Development: $397 million for the National Institutes of Health and the Biomedical Advanced Research and Development authority for research related to Zika, vaccine development and commercialization of diagnostic tests for Zika virus.
  • On October 26, 2016, the Department of Health and Human Services released the Zika Supplemental Funding Spend Plan, which provides a detailed spending plan for the funds made available by the Zika Response Preparedness Act, 2017.
  • Note that on May 9, 2016 NGA released a statement asking for swift funding for the Zika virus. And on September 12, 2016, NGA CEO Scott Pattison wrote an op-ed in The Hill detailing governors' desire for Congress to fund Zika response and preparedness efforts.
  • According to Kaiser Health News, states will likely not receive continued support as federal funds for Zika may run out after the summer of 2017. Deep funding cuts to the CDC may weaken states’ ability to respond effectively to disease outbreaks, as county level agencies have relied on federal funding for Zika testing and surveillance.

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What is Zika virus and should I be concerned?

  • Zika virus is spread to humans primarily through the bite of an infected Aedes species mosquito and has been associated with birth defects, adverse pregnancy outcomes and neurological problems. Zika virus is part of a family of viruses that cause other diseases like dengue fever, chikungunya, yellow fever, Japanese encephalitis and West Nile viruses.
  • In addition to the Aedes mosquito species, a preliminary study has found that the common Culex quinquefasciatus mosquito may also be linked with the spreading of Zika virus and the current epidemic in Brazil.
  • Pregnant women are a highly vulnerable population to Zika virus and require special protections. The virus can be spread from a pregnant woman to her fetus and has been linked to a serious birth defect of the brain called microcephaly in babies of mothers who had Zika virus while pregnant.
  • According to research from the CDC, Zika virus infections acquired during pregnancy, and especially in the first trimester, may cause birth defects including brain abnormalities and/or microcephaly, eye abnormalities, other consequences of central nervous system dysfunction, and neural tube defects and other early brain malformations.
  • Zika virus is expected to have the most significant impact on southern states and territories, given their weather patterns, proximity to Zika-affected countries and the fact they are home to the Aedes aegypti mosquitoes, which spread the virus most effectively (See map of the estimated range of mosquitoes carrying Zika within the United States and territories).

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What is the current state of Zika virus in the United States?

  • On November 28, 2016, Texas reported its first locally-transmitted case of the Zika virus located in Cameron County. Since then there have been additional cases reported for a total of six non-travel related Zika infections in Texas in 2016, according to the CDC. Texas is now the second state with mosquitos spreading the virus.
  • On Friday, August 19, 2016 a second Zika transmission site was located in Miami, Florida. CDC issued an advisory for pregnant women to avoid travel to the area.
  • On Friday, July 29, 2016, Florida Governor Rick Scott announced local transmission of Zika in south Florida. From then until the end of 2016, there were additional cases reported for a total of 218 non-travel related Zika infections in Florida in 2016, according the CDC. As of June 14, 2017, there have been no new cases of locally acquired Zika infection in 2017.
  • CDC has issued travel guidance to parts of Florida where there is active local transmission.
  • Cases in pregnant women are being tracked through two enhanced surveillance systems: the U.S. Zika Pregnancy Registry and the Puerto Rico Zika Active Pregnancy Surveillance System. These updated numbers reflect counts of pregnant women in the United States with any laboratory evidence of possible Zika virus infection, with or without symptoms.
  • As of May 23, 2017, the surveillance systems are monitoring 1,883 pregnant women in the U.S. states—including the District of Columbia (D.C.)—and 3,916 pregnant women in the U.S. territories with laboratory evidence of possible Zika virus infection.
  • As of June 14, 2017, CDC reports that 5,020 cases of travel-associated Zika infection, 224 cases of locally acquired mosquito-borne cases, 46 sexually transmitted cases, one laboratory acquired case and one case of person-to-person transmission through an unknown route have been reported across 49 states and D.C.
  • As of June 14, 2017, CDC reports that 36,447 locally acquired cases and 143 travel-acquired cases have been reported across three territories. The majority of those locally acquired cases are in Puerto Rico. In 2017, there have been 465 locally-acquired cases of Zika infection in Puerto Rico as of June 14.
  • There have been Zika-related deaths reported in Puerto Rico, Texas and Utah.
  • Texas, Florida and Hawaii are likely to have the highest incidence of local transmission of Zika virus by mosquitoes, historically based on similar virus patterns. However, additional states are assumed to be at some risk because of the presence of Aedes aegypti mosquitoes.

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How are states preparing and responding effectively to Zika virus?

  • On April 1, 2016, state and local senior officials attended the CDC-NGA Zika Action Plan Summit to accelerate readiness for local Zika virus transmission. Thirty-four jurisdictions were represented at the summit, with a total of 178 state, local and territory representatives, as well as three Tribal Advisory Committee representatives. In order to prepare, states are taking the following actions:
    • Appointing an empowered Zika coordinator;
    • Reviewing preparedness plans;
    • Coordinating efforts at the state and local levels; and
    • Implementing phased, jurisdictional, risk-based Zika plans that include strategies around communication, surveillance, laboratory testing, mosquito control, outreach to pregnant women and blood safety.
    • States with known Aedes aegypti mosquitoes are also focusing intensively on monitoring for Zika cases in travelers returning to the United States and preventing clusters of Zika infections, which can lead to the virus becoming widespread.
    • States with Aedes albopictus mosquitoes, which have the ability to spread the virus but not as effectively, need to assume transmission is possible and therefore be ready to prevent, detect and respond to cases and possible clusters of Zika infection.
  • State Actions:
    • California In May, 2016, the California Department of Public Health released their “California Zika Response Activities and Resources” as guidance for local public health, vector control agencies, and health care providers in the state. California has directed federal funds towards tracking birth defects related to Zika virus and towards mosquito surveillance and control where the Aedes mosquito exists.
    • Connecticut On March 10, 2017, Gov. Malloy launched a new public awareness campaign targeted at college students, many of whom may be travelling to Zika-infected areas during the spring and summer. On February 11, 2016, Gov. Dan Malloy established a cross-agency surveillance and response plan in order to ensure a coordinated and rapid response to the virus.
    • Florida As Florida approaches their 2017 rainy season, Gov. Scott urged residents to take precautions and emphasized the Florida public awareness campaign "Fight the Bite," which advertises preventative measures against Zika. In 2016, Gov. Rick Scott has directed the Florida Department of Health (DOH) to provide Zika testing to pregnant women at all county health departments at no cost. On August 15, Gov. Scott announced that the state department of health and private pest control companies will coordinate to expand mosquito control efforts in Miami-Dade County. Gov. Scott had allocated $26.2 million in state funds for Zika preparedness on June 23; on August 23, Gov. Scott directed $5 million of that for additional Zika preparedness efforts in Miami-Dade County. On September 16, Gov. Scott authorized an additional $10 million in state funding to combat the disease. On September 22, Gov. Scott announced that $25 million in state funds will be used to support research to develop a vaccine for the Zika virus.
    • Hawaii Gov. David Ige has directed the state's health department to carry out a large public awareness campaign on mosquito borne diseases.
    • Maryland The Maryland Department of Agriculture’s Mosquito Control program resumed surveillance and control measures to reduce mosquito numbers across the state for the summer of 2017. Gov. Larry Hogan declared “Zika Virus Awareness Week” in Maryland on April 24-30 to urge residents to reduce their chances of contracting the virus. The state has also allocated funding to prepare Zika prevention kits across the states.
    • Missouri Gov. Jay Nixon announced that the Missouri Department of Health and Senior Services has developed a statewide plan to address Zika. The plan includes procedures to monitor cases, control exposure, research mosquitoes, and educate citizens.
    • Mississippi started a statewide study of the Aedes aegypti population to accurately predict risk and preparedness response.
    • New York Gov. Andrew Cuomo is implementing a six-step plan to combat Zika, which focuses on reducing and monitoring the mosquito population, providing pregnant women with free prevention kits, deploying rapid response teams for confirmed cases, requiring local health departments to submit control plans and launching a public awareness campaign. Gov. Cuomo has also announced a coordinated effort by the state DOH and Metropolitan Transportation Authority (MTA) to prevent the spread of Zika within the public transportation system in the New York City metropolitan area. The DOH and MTA will work with other state and local agencies to prevent the breeding of mosquitos within the subway system.
    • Pennsylvania Gov. Tom Wolf announced plans to bolster his state's surveillance, mitigation and response plans for Zika virus. The plans include enhancing surveillance for Zika cases and mosquitoes, improving virus testing capabilities and ensuring collaboration between state agencies and partners.
    • Puerto Rico On June 5, 2017 the Puerto Rican government released a statement announcing that the Zika virus epidemic has ended in the territory. The CDC maintains travel warnings for the region. Former Gov. Alejandro Garcia Padilla established the National Alliance to Combat Zika, which is a multi-disciplinary group composed of state, federal and community officials responsible for developing strategies to prevent, protect and treat Zika. The territory has instituted free Zika testing, increased surveillance efforts, opened up access/enrollment to WIC services, and is conducting a national educational campaign on the dangers of Zika to reduce transmission and risks on the island.
    • Tennessee, under the direction of Gov. Haslam, set up a Zika response center as well as provided training to local health departments to deal with an outbreak should it arise in their jurisdiction.
    • Texas Gov. Greg Abbott directed the state's infectious disease task force to prepare for the virus as well as launching a large statewide health campaign. The state has also worked with the CDC to review their Zika response plan to ensure local, state, and federal cooperation. On November 28, 2016, Texas reported its first locally-transmitted case of the Zika virus located in Cameron County. As a result, Texas reinstated the Medicaid benefit for mosquito repellent. Texas is now the second state with mosquitos spreading the virus.
    • The U.S. Virgin Islands created an internal infrastructure to respond to Zika outbreaks. This includes distributing free Zika prevention kits to pregnant women and providing them with free inspections and mosquito treatments at their homes. Additionally, pregnant women can receive free Zika testing at 12 sites throughout the territory.
    • Virginia Gov. Terry McAuliffe pushed citizens to prevent the spread of the Zika virus. The state's department of health has created a statewide Zika response plan as well as a Zika website to keep citizens up to date on relevant information and tips to prevent contracting or spreading the virus. The state also will distribute Zika prevention pregnancy kits, as the virus is linked to birth defects.
    • Wisconsin Gov. Scott Walker approved a plan to add additional positions at the department of health services to assist with to assist in the response and investigation of the Elizabethkingia anophelis outbreak, Zika Virus and an increase in Tuberculosis cases.
  • Federal Action: On May 5, 2017, with the approaching mosquito season, the CDC released an interim response plan for the continental United States and Hawaii. The Plan replaces previous versions with revisions based on lessons learned in 2016 and feedback from state and local health partners.
  • Federal Action: On April 4, 2017, the CDC posted a Morbidity and Mortality Weekly Report (MMWR) which includes an analysis of completed pregnancies with laboratory evidence of possible recent Zika virus infection reported to the U.S. Zika Pregnancy Registry (USZPR) from January 15 to December 27, 2016. According to the report, potential birth defects associated with Zika virus infection during pregnancy include brain abnormalities and/or microcephaly, eye abnormalities, other consequences of central nervous system dysfunction, and neural tube defects and other early brain malformations.
  • Federal Action: On December 22, 2016, CDC announced $184 million in funding to states, territories, local jurisdictions and universities to support efforts to protect Americans from the Zika virus and related health implications as part of the funding provided to the CDC under the Zika Response and Preparedness Appropriations Act of 2016.
  • Federal Action: On October 26, 2016, the Department of Health and Human Services has released the Zika Supplemental Funding Spend Plan, which provides a detailed spending plan for the funds made available by the Zika Response Preparedness Act, 2017.
  • Federal Action: On September 28, Congress passed much needed funding to fight Zika. The continuing resolution, which will last for 10 weeks and expire on December 9, 2016, includes $1.1 billion in funding to fight Zika virus. Importantly, $44 million will go to states to backfill their public health emergency preparedness funds that were shifted earlier this year.
  • Federal Action: On August 30, 2016, CDC announced that it had disbursed $194 million of the $222 million allocated to the agency to combat the Zika virus. The CDC Director advised that CDC’s capacity to respond to potential additional local transmission sites in the future could be limited due to funding constraints if no new money were appropriated.
  • Federal Action: On August 26, 2016 the U.S. Food and Drug Administration (FDA) advised that all blood and blood product donations be tested for Zika virus.
  • Federal Action: On August 12, 2016, HHS declared a public health emergency in Puerto Rico to respond to the spread of Zika in the territory. The public health emergency declaration will allow the governor to use federal resources to hire and train unemployed individuals to work in vector control and public health education and outreach and to request that federally-funded public health staff be reassigned to respond to the Zika outbreak.
  • Federal Action: On August 11, 2016 HHS announced it will transfer $34 million within NIH and $47 million to Biomedical Advanced Research and Development Authority (BARDA) "in order to ensure that neither is forced to delay their Zika vaccine work as the fiscal year closes.”
  • Federal Action: On August 2, 2016 CDC announced awards for more than $16 million to 40 states and territories to “establish, enhance, and maintain information-gathering systems to rapidly detect microcephaly–a serious birth defect of the brain–and other adverse outcomes caused by Zika virus infection.”
  • Federal Action: On July 1, 2016 the CDC awarded $25 million for Zika preparation to states. Florida was awarded $1.38 million, Texas was awarded $1.52 million and Puerto Rico was awarded $5 million in the latest round of funds to help prepare for Zika virus
  • Federal Action: HHS has been working to assist local health officials in Puerto Rico and the U.S. Virgin Islands with their Zika response including but not limited to deploying emergency public health staff to the islands, expanding diagnostic testing capacity, keeping the blood supply Zika virus free, directly reducing mosquito populations, distributing prevention kits, and increasing funding for local health clinics.
  • Federal Action: On June 14, 2016 CDC released a draft interim response plan for the first cases of locally acquired cases of Zika infection in the continental U.S. and Hawaii. The plan outlines federal assistance including the use of federal rapid response teams to bolster local and state efforts as well as preparedness and prevention best practices.
  • Federal Action: CDC has developed and is distributing Zika testing kits to states. Additionally, on March 17, 2016, the CDC received an emergency use authorization from the Food and Drug Administration to develop a test that can detect Zika, dengue fever, and the chikungunya virus.
  • Federal Action: On Feb. 8, 2016, the White House requested approximately $1.9 billion in emergency funding from Congress to combat Zika virus; however, Congress has not yet approved the request. As a result, on April 6, 2016, the White House announced it would reprogram $589 million of existing Ebola funds for Zika response. That shift will also reduce the amount of funds states receive through the public health emergency preparedness grant program.

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How can states protect pregnant women and others?

  • As part of the CDC’s comprehensive phased plan for Zika virus preparedness and response for states, it outlined specific strategies to prepare for mosquito season and protect pregnant women. Drawing from those, states should:
    • Plan enhanced surveillance for suspected Zika virus infections, including for pregnant women through OB/GYN clinics, etc.;
    • Reach out to clinicians and provide guidance for management and testing of possible cases;
    • Identify intervention resources, including Zika prevention kits and communications campaigns; and  
    • Prepare a Zika registry to collect information on cases during pregnancy that could be used for future monitoring and following up on birth outcomes. That information should be reported to the National Zika Birth Registry.
    • Appoint a senior representative to coordinate Zika response efforts and incident management.
    • Prepare a communication campaign for pregnant women, travelers and health care providers to raise awareness and increase preparedness for possible Zika infections; and
    • Implement vector control to limit breeding ground and habitat for mosquitos.

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What are additional key concerns related to Zika virus?

  • Currently, there is no vaccine to protect against the Zika virus, but on August 3, 2016 the National Institutes of Health announced the start of clinical trials in humans and plans to launch a Phase 2 trial in spring 2017. Various other vaccine trials are being conducted by other institutions. Furthermore, scientists at Indiana University have mapped a key protein that causes the Zika virus to replicate, which may speed along the search for a cure to the virus.
  • The virus remains in an individual’s blood stream from 10 days to two weeks. Once individuals are infected, it is believed they are immune to future infections.
  • Aside from being bitten by mosquitoes, individuals can be infected through sexual transmission from male and female partners.
  • Diagnosis is difficult because 80 percent of people infected with the Zika virus are asymptomatic. That is particularly concerning for pregnant women, who may experience complications regardless of whether they show symptoms.
  • People who do show symptoms may experience fever, rash, joint pain and red eyes, which can last anywhere from a few days to one week.
  • Current CDC research suggests a strong link between Guillain-Barré syndrome (GBS) and the Zika virus. GBS is a disorder that can cause muscle weakness and sometimes paralysis. It is likely to be triggered by Zika in a small proportion of infections, similar to other infections.
  • Infants with congenital Zika virus who show no signs of microcephaly at birth may develop microcephaly months later.

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Additional resources and up-to-date information on Zika virus

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Key Contacts

Centers for Disease Control and Prevention (available 24 hours a day)

National Governors Association

  • Kelly Murphy, program director, Health Division, National Governors Association Center for Best Practices, 202-624-5399
  • Jeffrey McLeod, director, Homeland Security and Public Safety Division, National Governors Association Center for Best Practices
  • Peter Eckrich, legislative director, Health and Human Services Committee, National Governors Association Office of Federal Relations

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Zika Infection Curve

One of the most critical issues in preventing public health outbreaks of infectious diseases is preventing infection levels from reaching a critical “tipping point”, after which there is a rapid increase in infections and, in the most severe instances, an epidemic (see current Zika infection curve below).

Thus, a central strategy in preventing widespread Zika virus outbreaks is to ensure that states and the federal government have taken the steps necessary to prevent local-transmission of infections from escalating to this “tipping point,” which underscores the urgency of preparing for and preventing Zika now.

Zika Virus Infection Curve and associated Neurological Syndrome Cases,  Columbia1


1 “Zika Epidemiological Update – 30 June 2016.” Pan American Health Organization. Available at: (accessed July 7, 2016).

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