Zika virus is a disease transmitted by mosquitoes, and there is no indication that it can spread person to person through casual contact. However, the Centers for Disease Control and Prevention (CDC) has reported several cases of Zika virus infection in non-travelers in the continental United States after their sexual partners returned from an affected area and developed symptoms.
The disease has historically occurred in Africa, Southeast Asia and islands in the Pacific Ocean. In May 2015, Zika virus was found for the time in the Western Hemisphere in northeastern Brazil. The virus has since spread through much of the Caribbean, Central America and South America. The CDC maintains an updated list of affected countries and territories as well as associated travel notices.
Most people, 80 percent, infected with Zika virus do not have any symptoms. Of those who do experience symptoms, they are usually mild and include fever, rash, joint pain or conjunctivitis (red eyes). Other symptoms can include muscle pain and headache. Severe disease requiring hospitalization is uncommon. Despite these relatively mild symptoms, health officials have determined that there is an association between Zika virus infections in pregnant women and birth defects.
Travel advisory for pregnant women:
Because of the association between Zika virus infections in pregnant women and certain birth defects, CDC recommends that pregnant women consider postponing travel to any area where Zika virus transmission is ongoing. More information on Zika virus and pregnancy is available on CDC's website.
The primary mosquito that transmits Zika virus is the yellow fever mosquito, Aedes aegypti. This mosquito is found in the tropics and in the southern United States. It is not known to be established in Ohio. The Asian tiger mosquito, Aedes albopictus, is a related mosquito that is found in Ohio and may potentially transmit Zika virus, although it has not yet been implicated in the transmission of human cases in the United States. This species was introduced into the U.S. in the 1980s and has been collected in 37 counties (see current map), and it likely occurs in other counties as well. As a precaution, it is recommended that suspected cases of Zika virus infection avoid mosquito exposure the week after symptom onset when mosquitoes are active in Ohio (May to October) in order to prevent the possibility that mosquitoes might become infected by biting an infected person and then transmitting the virus to other people. Because most people who have Zika virus will have no symptoms, it is recommended that anyone returning from travel to a Zika-affected area use repellents and otherwise avoid mosquito exposure for three weeks after they return.
The best way to avoid Zika virus infection and other mosquito-borne diseases is to prevent mosquito bites:
- When outdoors, wear Environmental Protection Agency (EPA) registered insect repellents. All EPA registered insect repellents have been evaluated for effectiveness. Always follow the product label instructions.
- Unlike many mosquitoes, the Asian tiger mosquitoes are most active during the day and are most common in shade conditions. Be sure to use insect repellent and wear long sleeves and pants where these mosquitoes are active.
- Make sure you have good screens on your windows and doors to keep mosquitoes out.
- Yellow fever mosquitoes and Asian tiger mosquitoes are both container breeding mosquitoes. They do not breed in ponds, puddles or marshes. Remove their breeding sites by emptying standing water from flower pots, buckets and barrels. Change the water in pet dishes, and replace the water in bird baths weekly. Drill holes in tire swings so water drains out. Keep children's wading pools empty and on their sides when they aren't being used.
What travelers should know about Zika virus:
On July 29, 2016, CDC announced that it had been informed by the State of Florida that Zika virus infections in four people in one small area of Miami-Dade County were likely caused by bites of local Aedes aegypti mosquitoes. The cases were likely the first known occurrence of local mosquito-borne Zika virus transmission in the continental United States. The Florida Department of Health and its partners conducted aggressive mosquito control activities in the neighborhoods of the four cases to mitigate the risk of further spread of Zika virus. CDC said that it would not designate the impacted area or the entire state of Florida as areas with active Zika virus transmission because it was believed that the area no longer had active Zika virus transmission.
All people traveling to areas with Zika virus transmission should take precautions to prevent mosquito bites. These precautions include:
- Wearing long-sleeved shirts and long pants.
- Staying in places with air conditioning or that use window and door screens to keep mosquitoes outside.
- Sleeping under a mosquito bed net if outside and not able to protect against mosquito bites.
- Wearing EPA registered insect repellents. All EPA registered insect repellents have been evaluated for effectiveness.
- Always follow the product label instructions.
- Reapply repellent as instructed.
- Do not spray insect repellent underneath clothing.
- Apply sunscreen to skin first then insect repellent.
- Do not use insect repellent on babies younger than 2 months of age.
- Treating clothing and gear with permethrin or purchasing permethrin-treated items. Treated clothing remains protective after multiple washings.
- Avoiding mosquito exposure for three weeks after return from travel.
In addition, travelers to areas with active Zika virus transmission should take precautions to reduce the risk of sexually transmitting the virus to their partners:
- Men who traveled to Zika-affected areas and have pregnant sexual partners should abstain or use condoms during sex for the duration of their partner's pregnancy.
- Men diagnosed with Zika virus infection or who experienced symptoms compatible with Zika virus infection within two weeks of return from an area with active transmission should abstain or use condoms during sex for 6 months after return from their trip.
- Women diagnosed with Zika virus infection or who experienced symptoms compatible with Zika virus infection within two weeks of return from an area with active transmission should abstain or use condoms during sex for 8 weeks after return from their trip.
- Men and women who traveled to an area with active Zika virus transmission and did not develop any symptoms compatible with Zika virus infection within two weeks of their trip should wait 8 weeks after return from their trip before trying to conceive.
Animals associated with Zika virus in Ohio include:
- Mosquitoes: Mosquitoes, particularly Aedes aegypti and possibly Aedes albopictus, become infected with Zika virus through taking blood meals from infected humans.
Zika virus cases in Ohio:
Cases acquired outside Ohio during travel
Cases acquired in Ohio by mosquito
Cases acquired by sexual transmission
Ohio statistics and maps:
Information for travelers:
Mosquito-borne disease prevention literature:
Last updated: 08/29/2016
Zoonotic Disease Program