The Zika virus has recently become more prevalent in certain regions, particularly in Central and South America and the Caribbean. When pregnant women catch this virus, their fetus can develop microcephaly, which is an abnormally small head and brain, and is associated with significant neurologic impairment and occasionally death. The virus is transmitted by certain species of mosquitoes; thus prevention of mosquito exposure is paramount in preventing the disease. In men and non-pregnant women, a Zika infection is usually mild and self-limited. There is no vaccine and no specific treatment. We are currently recommending avoiding travel to regions where transmission has occurred.
What is the Zika virus and how is it transmitted?
The Zika virus is a mosquito-borne flavivirus transmitted primarily by the mosquito strain Aedes aegypti; Aedes albopictus mosquitoes might also transmit the virus. In order to transmit this virus, a mosquito must first bite an infected individual and subsequently bite a second susceptible individual. Zika virus cannot be spread by casual person-to-person contact.
“There is virtually no risk of acquiring Zika virus in New York State at this time as the virus cannot be spread by casual contact with an infected person, and mosquitoes are not active in cold winter months,” said NYS Department of Health Commissioner Howard Zucker. “But since this is a time of year when people travel to warmer climates and countries where Zika virus is found, we are urging residents, especially pregnant women, to check all health advisories before traveling and take preventive measures when traveling to affected countries.”
According to the CDC, local transmission of Zika virus has not been documented in the continental United States. However, Zika virus infections have been reported in travelers returning to the United States. With the recent outbreaks in the Americas, the number of Zika virus disease cases among travelers visiting or returning to the United States likely will increase. These imported cases may result in local spread of the virus in some areas of the continental United States, meaning these imported cases may result in human-to-mosquito- to-human spread of the virus.
“We believe this is a fairly serious problem,” Dr. Lyle Petersen, director of the CDC’s Division of Vector Borne Infectious Diseases, said during an evening press conference Friday. “The virus is spreading fairly rapidly throughout the Americas and a large percentage of the population may become infected,” he said.
What are the symptoms of a Zika infection?
Only one in five people infected with Zika virus will get sick, with the most common symptoms being fever, rash, joint pain, or conjunctivitis (red eyes). Symptoms typically begin 2 to 7 days after being bitten by an infected mosquito, and may last for several days to a week. The symptoms of Zika virus infection are usually very mild, and many people might not even realize they have been infected.
See your healthcare provider if you are pregnant and develop a fever, rash, joint pain, or red eyes within 2 weeks after traveling to a country where Zika virus cases have been reported. Be sure to tell your health care provider where you traveled.
Severe disease requiring hospitalization is uncommon and fatalities are rare. Guillain-Barré syndrome also has been reported in patients following suspected Zika virus infection.
No vaccine or preventive drug is available.
First and foremost, if you are pregnant or trying to become pregnant, avoid traveling to regions where transmission has been reported. There are currently 23 countries/regions involved, but this will almost certainly grow over time. Before making travel plans, consult the most current list of areas to avoid by clicking on this link to the CDC website: http://www.cdc.gov/zika/geo/index.html
These areas, as of 1/26/16, include:
¥ Dominican Republic
¥ El Salvador
¥ French Guiana
¥ Puerto Rico
¥ Saint Martin
¥ U.S. Virgin Islands
To date, two major airlines have offered refunds for passengers worried about visiting the affected areas. United Airlines said customers can get refunds or change their flight without a fee, while American Airlines is offering refunds to pregnant women.
Currently it is not clear when the travel advisory might be lifted; it will probably still be in effect when the Summer Olympics begin in Brazil in August.
Second, avoid mosquito bites. Mosquitoes are not very active in the cold, winter months, but once warmer weather arrives they will become more problematic. Since mosquitos breed in standing water and live locally, it is vital to carefully inspect your property for standing water. Search out bird baths, discarded trash or objects that can collect rain water, and remove them, drill holes to allow for drainage, or add a pump to create moving water.
It is likely that mosquito spraying will be undertaken by local authorities if transmission is documented in our region; stay alert to local news sources. The NYS Department of Health states it plans to expand mosquito surveillance in the spring, to closely monitor Aedes albopictus – one species of mosquito that can transmit Zika virus that is present in some parts of New York State. The distribution of this mosquito is currently limited to New York City and the following counties: Nassau, Putnam, Orange, Rockland, Suffolk, and Westchester.
Other mosquito bite prevention strategies include:
¥ Dress in long-sleeved shirts and long pants.
¥ Stay indoors when mosquitoes are most active.
¥ Use insect repellant products when outdoors that are registered with the US Environmental Protection Agency. Most repellents, including DEET, can be used on children older than two months. Pregnant and lactating women can use all Environmental Protection Agency (EPA)-registered insect repellents, including DEET, according to the product label. When used as directed on the product label, insect repellents containing DEET, picaridin, and IR3535 are safe for pregnant women.
¥ Do not overuse repellant – only apply as much as you need to provide protection.
¥ Read and follow label directions before you use any kind of repellant.
¥ Use air conditioning or window and door screens when indoors.
¥ When outdoors, enclose your seating area in a screen. Here’s a link for a $21 screen that fits over your umbrella: http://www.bedbathandbeyond.com/store/product/jobar-umbrella-table-screens-in-black/125920?Keyword=umbrella+screen
¥ Mosquitoes that spread Zika virus bite both indoors and outdoors, mostly during the daytime; therefore, it is important to ensure protection from mosquitoes throughout the entire day.
¥ Further guidelines for using insect repellents are available online: http://wwwnc.cdc.gov/travel/yellowbook/2016/the-pre- travelconsultation/protection-against-mosquitoes-ticks-other-arthropods and http://wwwnc.cdc.gov/travel/page/avoid-bug-bites
What is the current scope of this problem?
In May 2015, the World Health Organization reported the first local transmission of Zika virus in the Western Hemisphere in Brazil. As of January 28, 2016, local transmission had been identified in at least 23 countries or territories in the Americas, including Puerto Rico. Further spread to other countries in the region is likely.
The Brazil Ministry of Health has reported a marked increase in the number of babies born with microcephaly. The CDC reports that at least 3,500 cases of microcephaly appeared in Brazil between October 2015 and January 2016.
However, it is not known how many of the microcephaly cases are associated with Zika virus infection and what factors increase risk to the fetus. Brazilian health officials think the greatest risk of microcephaly and malformations happens during the first trimester of pregnancy.
As of January 28, 2016, the New York State Department of Health states that seven individuals who recently traveled to areas outside of the United States where Zika virus transmission is ongoing have tested positive for the virus.
Blood testing is not available for asymptomatic non-pregnant or pregnant individuals with only a history of travel to an affected area. Blood testing is not indicated for women without a travel history to an area with Zika virus transmission. Testing of asymptomatic pregnant women is not recommended in the absence of fetal microcephaly or intracranial calcifications.
Blood testing will only be considered for patients who present with compatible illness (as described above) and a history of travel to a Zika-affected country within 2 weeks of illness onset. Testing will also be available for infants diagnosed with microcephaly whose mothers were pregnant while in an area with ongoing Zika virus transmission since the outbreak began in 2015.
Pregnant women with a history of travel to an area with Zika virus transmission and who report two or more symptoms consistent with Zika virus disease (acute onset of fever, maculopapular rash, arthralgia, or conjunctivitis) during or within 2 weeks of travel, or who have ultrasound findings of fetal microcephaly or intracranial calcifications, should be tested for Zika virus infection in consultation with their state or local health department.
In pregnant women with laboratory evidence of Zika virus infection, serial ultrasound examinations should be considered to monitor fetal growth and anatomy and referral to a maternal-fetal medicine or infectious disease specialist with expertise in pregnancy management is recommended.
Women who traveled to an area with ongoing Zika virus transmission during pregnancy should be evaluated for Zika virus infection and tested in accordance with CDC Interim Guidance. This includes serial ultrasound evaluations of the fetal brain to exclude either overt microcephaly or brain calcifications. Either of these findings should prompt blood testing and possibly an amniocentesis.
Because of the similar geographic distribution and clinical presentation of Zika, dengue, and chikungunya virus infection, patients with symptoms consistent with Zika virus disease should also be evaluated for dengue and chikungunya virus infection, in accordance with existing guidelines.
Currently, it is unknown how sensitive or specific this blood test is for congenital infection. Also, it is unknown if a positive result is predictive of a subsequent fetal abnormality, and if so, what proportion of infants born after infection will have abnormalities.
There is no commercially available test for Zika virus. Testing for Zika virus infection is performed at CDC and several state health departments.
There is currently no vaccine or prophylactic medication to prevent infection, nor is there any specific antiviral treatment for Zika virus.
Treatment is generally supportive and can include rest, fluids, and use of analgesics and antipyretics. Aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided until dengue can be ruled out to reduce the risk of hemorrhage. In particular, pregnant women who have a fever should be treated with acetaminophen. People infected with Zika, chikungunya, or dengue virus should be protected from further mosquito exposure during the first few days of illness to reduce the risk of local transmission.
For More Information
General information about Zika virus and disease: http://www.cdc.gov/zika/
Travel notices related to Zika virus: http://wwwnc.cdc.gov/travel/notices
Information about Zika virus for travelers and travel health providers: http://wwwnc.cdc.gov/travel/yellowbook/2016/infectious-diseases-related-to-travel/zika
Information on microcephaly: http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html
Approximate distribution of Aedes aegypti and Ae. albopictus mosquitoes in the United States: http://www.cdc.gov/chikungunya/resources/vector-control.html
Interim guidelines for care for pregnant women, including recommendations for screening, testing, and management of returning travelers: http://www.cdc.gov/zika/pregnancy/.