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 several Ohio 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 Miami-Dade County were caused by bites of local Aedes aegypti mosquitoes. The cases are the only known occurrences of local mosquito-borne Zika virus transmission in the continental United States. The Florida Department of Health and its partners continue to conduct aggressive mosquito control activities in the areas of concern to mitigate the risk of further spread of Zika virus. CDC has posted advice for people living or traveling to South Florida.
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:
- Pregnant couples in which one or both partners live in or traveled to an area with Zika virus transmission should:
- Use condoms from start to finish every time they have sex or not have sex during the pregnancy. This is important, even if the pregnant woman's partner does not have symptoms of Zika virus disease or feel sick.
- Not share sex toys during the pregnancy.
- People with a partner who traveled to an area with Zika virus transmission can use condoms or not have sex. The period of time for taking these precautions depends on whether the traveler is male or female:
- If the traveler is female: Use condoms or do not have sex for at least 8 weeks after her return from an area with active Zika virus transmission (if she doesn't have symptoms) or for at least 8 weeks from the start of her symptoms (or Zika virus diagnosis) if she develops Zika virus disease.
- If the traveler is male: Use condoms or do not have sex for at least 6 months after his return from an area with active Zika virus transmission (if he doesn't have symptoms) or for at least 6 months from the start of his symptoms (or Zika virus diagnosis) if he develops Zika virus disease. This extended period is because Zika virus stays in semen longer than in other body fluids.
- CDC recommends Zika virus testing for people who may have been exposed to Zika virus through sex and who have symptoms of Zika virus disease.
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: 01/10/2017
Zoonotic Disease Program