Zika virus: Colorado Medical Society guidance to physician members

Tuesday, March 01, 2016 12:27 PM
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updated Feb. 29, 2016

The World Health Organization (WHO) rang a global alarm over the Zika virus at the end of January 2016. WHO indicates the disease is spreading explosively in the Americas and as many as four million people could be infected by the end of the year. The group declared the Zika virus outbreak a public health emergency on Feb. 1. Health officials at the Centers for Disease Control and Prevention (CDC) have taken a lead in the U.S. in terms of research on Zika virus, its spread, and guidelines for prevention, testing, and diagnosis.

The Colorado Medical Society will be assisting physicians with information and guidance as the Zika virus situation progresses both here in the U.S. and internationally. Currently, the CDC recommends reassuring patients that the vast majority of those who are exposed to the virus never have symptoms or very mild symptoms. The risk of a homegrown outbreak is low, largely because of more effective mosquito control and the type of mosquito that transmits the virus. The average American who is not traveling to the affected area is at very low risk. The greatest danger is risk of infection in pregnant women, especially in the first trimester. However, now that we know the infection can be transmitted sexually the issue has become more complex.

Below are specific guidelines and facts for physicians:

General information

  • Zika virus is a mosquito-borne flavivirus transmitted primarily by the Aedes aegypti mosquitoes, which are the same vectors that transmit dengue and chikungunya virus and are found throughout much of the Americas, including parts of the U.S.
  • These mosquitoes are aggressive daytime biters and feed both indoors and outdoors. They can also bite at night.
  • It is estimated that 80 percent of persons infected with Zika virus are asymptomatic. Symptomatic disease is generally mild and characterized by acute onset of fever, maculopapular rash, arthralgia and nonpurulent conjunctivitis. These symptoms last from several days to one week. Severe disease requiring hospitalization is uncommon, and fatalities are rare.
  • Once a person has been infected, he or she is likely to be protected from future infections.
  • Guillain-Barré syndrome has been reported in patients with suspected infection.
  • Affected areas currently include Cape Verde, the Caribbean, Central America, Mexico, some Pacific Islands (America Samoa, Marshall Islands, Samoa and Tonga), and South America.

General international travel guidance

  • All travelers going to affected areas should receive general information about the virus to make informed decisions.
  • This is very important when families are traveling together and at-risk members are included. This includes infants and children, at-risk fertile women, pregnant women, and those who have immunosuppressive conditions.
  • Vector control education and guidance should be included, including avoidance of outdoor activities during high-risk times, air conditioning or window and door screens when indoors, long sleeve and pant use, bed nets, permethrin-treated clothing and gear, and insect repellent (DEET and oil of lemon eucalyptus) use in affected areas.
  • Most EPA-registered insect repellents can be used to protect children aged 2 months or older against mosquito bites. Products containing oil of lemon eucalyptus should not be used on children under the age of three years. Mosquito netting can be used to cover infants in carriers, strollers or cribs to protect them against mosquito bites.

International travel guidance for pregnant women

  • Pregnant women should avoid all travel to affected areas and delay travel plans if at all possible.
  • It is reported that airlines and cruise lines are working with pregnant women to cancel, delay or reschedule travel until a later time.

Guidance for women who of reproductive age during travel

  • Women who are fertile are a very high-risk group, including adolescents and adult women who are sexually active or potentially could be during travel to affected areas.
  • Detailed reproductive histories, pregnancy tests and contraceptive guidance, including education regarding abstinence and contraceptive prescriptions, are critical prior to travel.
  • Hormonal forms of birth control (long-acting reversible contraceptives are most effective) are recommended, along with condoms. An option to consider for women who are not currently using a reliable form of contraception is a Depo Provera (progesterone) injection prior to travel, which lasts for three months. If a woman is currently using birth control pills, careful counselling is important in terms of maintaining effectiveness. The pills should be taken as directed and at the same time each day without missing a day. Emergency Contraception to be taken up to five days after unprotected sex is available as Plan B One Step progesterone pill.

Guidance for the prevention of sexual transmission of Zika virus

  • Sexual transmission of Zika virus is possible and is of particular concern during pregnancy.
  • There is new evidence the Zika virus can be sexually transmitted from men to women.
  • The duration of persistence of Zika virus in semen remains unknown and might persist in semen when it is no longer detectable in blood.
  • Men who have had Zika infection or have current symptoms should avoid sexual activity until medically evaluated and should inform all female partners of the infection potential.
  • Men who reside in or who have traveled to an area of active Zika virus transmission and have a pregnant partner should abstain from sexual activity or consistently and correctly use condoms during any type of sex.
  • Men who reside in or who have traveled to an area of active Zika virus transmission who are concerned about sexual transmission of Zika virus might consider using condoms or abstaining from sexual activity.
  • Sexual transmission of many infections, including those caused by other viruses, is reduced by consistent and correct use of condoms.

Diagnostic testing
       
Who can be tested for Zika virus?
Patients (men and women) who have had two or more symptoms (acute onset of mild fever, maculopapular rash, arthralgia, headache, malaise and/or conjunctivitis) during or within two weeks of travel to an area with local Zika virus transmission can be tested. Patients should have specimens collected within seven days (sooner is better) of symptom onset. The appropriate test for individuals who have been ill for fewer than seven days is RT-PCR (reverse transcription polymerase chain reaction). If the individual became ill more than four days before sample collection, IgM (immunoglobulin) testing is also appropriate. Asymptomatic pregnant women with a history of travel to an area with local Zika virus transmission may also be tested. Specimens should be collected between two to 12 weeks after returning from travel. The appropriate test for asymptomatic pregnant women is IgM. At this time, asymptomatic people who are not pregnant are not being tested.

Where can patients go to get tested?
Patients should request testing from their health care provider. The Colorado Department of Public Health and Environment (CDPHE) is unable to collect specimens directly from patients. Health care providers should submit patients’ specimens for testing to the CDPHE laboratory. Providers must indicate clearly the testing type they are requesting on the form (IgM and/or RT-PCR for Zika virus).

What specimens can be tested for Zika virus?
Serum is the only acceptable sample for RT-PCR testing. Serum, CSF and amniotic fluid can be used for IgM and plaque-reduction neutralization tests (PRNT- if IgM serology results are positive).

How should samples be collected?
Serum samples can be collected using red top, tiger top or serum separator tubes.

How much serum, CSF or amniotic fluid needs to be collected for testing?
One red top, tiger top or serum separator tube is recommended for serum. CDC requires a minimum of 0.25 mL of serum or CSF for testing, and CDPHE requires 0.25 mL for RT-PCR testing. If you are requesting both RT-PCR and IgM testing, please send at least 0.5 mL of serum. For amniotic fluid, 1 mL is preferred, but 0.5 mL is acceptable for testing.

Where do I send specimens for testing?
All specimens need to be sent directly to CDPHE’s lab (address below). CDPHE will conduct RT-PCR testing for symptomatic patients with samples collected within seven days of symptom onset. For asymptomatic pregnant women or symptomatic patients with samples collected after seven days of symptom onset, CDPHE’s lab will send the samples to CDC for IgM serology and PRNT testing, as applicable.

How do I get the specimen from my clinic to the CDPHE lab?
Specimens can be dropped off for CDPHE routine courier pick up at your hospital laboratory, local public health department or be sent to the CDPHE Laboratory Services Division by the courier of your choice or via FedEx. The specimens should be sent to:

CDPHE Laboratory Services Division
8100 Lowry Blvd
Denver, CO 80230

For a current list of pickup times and locations for the CDPHE lab routine courier, please go to www.colorado.gov/pacific/sites/default/files/Kangaroo%20Update.7.29.14-SK.pdf for more information.

Besides the specimen, what else needs to be submitted to the CDPHE lab for testing?

  • All submitters MUST submit the CDPHE Request for Analytical Services form.
  • If IgM testing is being requested, submitters should complete both the CDPHE request form and the CDC Specimen Submission form.
  • The CDPHE form, #270/271, can be requested by calling the CDPHE Serology Laboratory at 303-692-3485 or CDPHE at 303-692-2700.
    • The CDC 50-34 form can be found online (www.cdc.gov/laboratory/specimen-submission/pdf/form-50-34.pdf), on the CDC website through the Zika virus page, or CDPHE can fax or email the form to you. In order to get the 50-34 form from CDPHE, call 303-692-2700. The CDC 50-34 form must be filled out in its entirety (including any symptoms, date of onset, travel & vaccination history, and pregnancy status) or the specimen will not be tested, or testing will be delayed.
  • On the top left corner on side one of the form, the submitter can simply put “Zika.” Since IgM serology for Zika virus can cross react with immune responses of other flaviviruses, it is imperative to note if the patient has had a Yellow Fever vaccine.

How do I know which test (RT-PCR vs. IgM) to order?

  • RT-PCR testing can be performed only for symptomatic patients with samples collected within seven days of symptom onset. If your patient meets these criteria, order the RT-PCR test on the CDPHE 270/271 requisition form.
  • For asymptomatic pregnant women or symptomatic patients with samples collected after seven days of symptom onset, RT-PCR testing cannot be performed, and the submitter will need to order IgM testing to be conducted by CDC.
  • If providers would like IgM serology when RT-PCR testing is negative, they will need to indicate both RT-PCR and IgM testing on the test requisition form (CDPHE #270/271 form) and fill out the CDC 50-34 form to include with the sample. The CDPHE lab will not automatically send samples for additional CDC testing unless this is indicated on the form. The lab will also not make the determination for which test to perform.

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