The Delaware Division of Public Health (DPH) is issuing this health alert to provide updated information to health care providers regarding the ongoing Zika virus epidemic
The Zika virus outbreak in the Americas that started in early 2015 continues to evolve. More information about the virus, the nature of the infection, and the distribution of the disease is emerging on a continual basis. As more is learned, the Centers for Disease Control and Prevention (CDC), state and local health departments will continue to release updated guidance to educate the public and health care providers on measures to take to prevent Zika virus transmission, as well as updated information about the health effects that result from infection with the virus.
Zika virus is an arbovirus (virus spread by arthropods) that is a member of the flavivirus family along with other viruses including yellow fever, West Nile, dengue and Saint Louis encephalitis viruses. First isolated in 1947, it did not appear in the Americas until early 2014 when it was identified on Easter Island (Chile). By early 2015, an outbreak of the virus began in Brazil. As of March, 31, 2016, locally acquired cases of Zika virus have been reported from 33 countries and territories in the Americas. Previously thought to be a generally mild illness, the ongoing epidemic has highlighted serious complications, from the infection that were previously unidentified or unreported (particularly in infants whose mothers were infected with the virus while pregnant).
As of March 30, the U.S. has 312 reported travel-associated cases of Zika from 34 states, including three confirmed cases in Delaware. None of the three Delaware cases were pregnant and all acquired the disease due to a mosquito bite while traveling abroad.
Sexual transmission of Zika has been documented in six U.S. states so far. No sexual transmission has been reported in Delaware. Apart from Puerto Rico, American Samoa, and the U.S. Virgin Islands where there is ongoing transmission, there have (as of March 31) been no cases of mosquito-borne Zika virus infection in the U.S.
Transmission of Zika virus is primarily through the bites of infected Aedes mosquitos with the primary vector being Aedes aegypti (also known as the yellow fever mosquito). Aedes aegypti is also an important vector for dengue virus and chikungunya virus. Isolation of the virus in, or transmission by other Aedes species in natural or laboratory settings has been reported. Of particular interest is Aedes albopictus (Asian Tiger Mosquito) given its relative abundance in the continental U.S., including Delaware.
The sexual route of transmission for the Zika virus has been recently described (2008) with several Zika virus infections in the current epidemic also being linked to sexual transmission. As of March 31, all cases of sexual transmission of Zika were from an infected male to a female. It is yet to be determined if Zika can be transmitted from a female to her sexual partners. It has also not been established which forms of sex (vaginal, anal or oral) pose the highest risk for sexual transmission of Zika virus. The CDC is currently conducting studies to determine how long Zika persists in the semen of infected men.
Mother to child transmission of Zika virus during pregnancy and/or child birth is a third mode of transmission. Zika infection during pregnancy has been shown to result in poor pregnancy outcomes including miscarriage, stillbirths, and fetal growth retardation. Particularly concerning are the severe neurologic consequences including microcephaly that are associated with Zika infection in pregnancy. It remains unclear during which trimester of pregnancy the risk of transmission is highest. Studies are also ongoing to determine the impact of infection at different stages of pregnancy and how frequently an infected mother will transmit the virus to her unborn child.
Transmission of Zika virus through the inadvertent transfusion of infected blood is yet another means by which the virus can spread. New guidance from the federal government on blood transfusions is expected soon.
Most Zika virus infections are asymptomatic. About one in five people infected with the virus develop the disease and symptoms are generally mild comprising any combination of fever, rash, joint pain, or conjunctivitis. Symptoms typically begin after an incubation period of a few days to a week. In most cases, symptoms resolve within a few days to a week.
Differential diagnoses for the characteristic symptoms of Zika are myriad and (given the relevant travel or exposure history) might include Leptospirosis, malaria, Rickettsia, group A Streptococcus, rubella, measles, parvovirus, enterovirus, adenovirus, dengue fever, and chikungunya (or other alpha viruses).
The current Zika epidemic has brought to light serious consequences of what was previously thought to be a benign disease. Poor pregnancy outcomes (stillbirth, miscarriages) and microcephaly have been linked to Zika virus infection. There is also accumulating evidence that implicates the virus in a spectrum of neurologic syndromes in adult/adolescents including Guillaine-Barre syndrome and acute myelitis amongst others. Long term consequences of Zika virus infection are yet to be determined.
Zika virus infection is a reportable disease in Delaware. It is important to identify and report cases or suspected cases of Zika virus infection both for the benefit of the individual patient and for the public’s health. It is also important to report pregnant women who have had potential exposures to Zika virus. Exposure of a pregnant woman would include travel to areas with ongoing Zika virus infection at any time during her pregnancy or eight weeks prior to conception (See http://www.cdc.gov/zika/geo/ for an updated listing of affected areas). Unprotected sex, during her pregnancy with a man known to have Zika virus infection would also constitute exposure for a pregnant woman. Such individuals should be referred for laboratory testing (See DPH contact information below).
Although most non-pregnant people do not have serious consequences from Zika virus infection, it is also important to refer individuals with relevant travel and exposure AND consistent symptoms for testing. This referral will allow the Division of Public Health and the Department of Natural Resources and Environmental Control (DNREC) to apply measures to help protect the public’s health. Report these cases by using the phone numbers and email addresses listed under “Contacting the Division of Public Health.”
The Delaware Division of Public Health Laboratory (DPHL) is able to perform testing for Zika virus infection. The specific type of testing depends on presence or absence of symptoms and how long after symptom onset the test is being performed.
Testing is done by Polymerase Chain Reaction (PCR) and/or IgM ELISA (Serology) performed on serum and urine specimens. As of March 31, DPHL is doing PCR testing in-house and sending specimens to the CDC for IgM ELISA. It is expected that DPHL will be able to add on Zika IgM ELISA in the next few weeks.
Priority for testing is given to pregnant women. Thus, testing of non-pregnant individuals will be limited to only those who have symptoms consistent with Zika virus infection PLUS a history of travel to areas with ongoing transmission of Zika virus.
Testing will be performed on pregnant women who have concerning exposures (consistent travel history or unprotected sex with a male Zika case) regardless of whether or not the pregnant woman has symptoms. This includes women who traveled to affected areas within eight weeks prior to becoming pregnant (or six weeks before last menstrual period).
It is important that such pregnant women be referred to DPH for testing as soon as possible after their exposure/travel as testing can only be offered during the two to 12 weeks after they return from travel for asymptomatic patients. Those presenting with symptomatic disease should be tested as soon as possible (preferably within the first week of illness).
Contact the Delaware Division of Public Health to arrange for testing of patients (See contact listed under “Contacting DPH”). When specimens are submitted to the DPHL, specimens will also be tested for dengue and chikungunya viruses.
There is currently no vaccine to prevent, or antiviral to treat Zika virus. Patients should be managed symptomatically. Given the significant overlap in geography and symptomatology with dengue virus infection, aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) should be avoided until dengue is ruled out in order to avoid potential hemorrhagic complications that might ensue if the patient has dengue.
The primary means of preventing Zika virus infection is by mosquito avoidance including personal protective measures and reduction of mosquito breeding habitats.
Although as of April 5, there have been no locally transmitted cases of Zika virus infection in DE, as the weather warms up, both approaches will become important for the prevention of not only Zika virus but also other mosquito-borne illnesses including dengue, chikungunya, West Nile virus and Saint Louis encephalitis.
It is also important to counsel pregnant women to avoid travel to areas with ongoing transmission if at all possible and to avoid unprotected sex with men who have traveled to such areas (See “Patient Counseling” above).
To understand more about Zika virus infection, CDC established the U.S. Zika Pregnancy Registry and is collaborating with state, tribal, local, and territorial health departments (including Delaware DPH) to collect information about Zika virus infection during pregnancy and about congenital Zika virus infection. The data collected through this registry will be used to update recommendations for clinical care, to plan for services for pregnant women and families affected by Zika virus, and to improve prevention of Zika virus infection during pregnancy.
Contact the Division of Public Health to enroll patients in the Zika pregnancy registry (see DPH contact details below)
Contact DPH Office of Infectious Disease Epidemiology at 888-295-5156 or 302-744-4990 for guidance with regard to specimen collection, coordination of testing, and further information and to report suspected cases of Zika virus infection or exposure of pregnant women.
You are receiving this email because you are a registered member of the Delaware Health Alert Network. If you are not a member and would like to subscribe, please register at https://healthalertde.org
Please note: Some of the files available on this page are in Adobe PDF format which requires Adobe Acrobat Reader. A free copy of Adobe Acrobat Reader can be downloaded directly from Adobe . If you are using an assistive technology unable to read Adobe PDF, please either view the corresponding text only version (if available) or visit Adobe's Accessibility Tools page.