CDC Makes Zika Recommendations

On May 13, 2016, the Centers for Disease Control and Prevention (CDC) issued interim guidance ( that recommends Zika virus rRT-PCR testing of urine collected less than 14 days after symptom onset, along with testing of patient-matched serum samples, for the diagnosis of suspected Zika virus infection (1). The purpose of this Health Alert Network (HAN) health update is to further disseminate information about the interim guidance to clinical and public health professionals.

Zika virus is a mosquito-borne flavivirus. Zika virus infection during pregnancy can cause microcephaly and other severe fetal brain defects. Zika virus infection is also associated with Guillain-Barré syndrome. Transmission of Zika can occur through mosquito bite, from a pregnant woman to her fetus, through sexual contact with an infected male, and possibly through blood transfusion. The most common symptoms of Zika virus disease are fever, rash, joint pain, or conjunctivitis. Other common symptoms include muscle pain and headache. Evidence from case reports and experience from related flavivirus infections indicate that the incubation period for Zika is likely a few to 14 days.

Diagnostic testing for Zika virus infection can be accomplished using molecular and serologic methods. The U.S. Food and Drug Administration (FDA) has issued Emergency Use Authorizations (EUA) (…/Safe…/EmergencySituations/ucm161496.htm) for several diagnostic assays to detect Zika virus infection (2). The EUAs authorize real-time reverse transcription-polymerase chain reaction (rRT-PCR) assays to detect Zika virus RNA in specified clinical sample types, and an immunoglobulin M (IgM) antibody capture enzyme-linked immunosorbent assay (ELISA) to detect anti-Zika virus IgM antibodies in serum and cerebrospinal fluid. The CDC Trioplex rRT-PCR assay is authorized by FDA for Zika virus testing of urine and serum. Anti-Zika IgM antibodies develop during the first week of illness and persist for approximately 12 weeks following infection. However, extensive cross-reactivity can occur in flavivirus serological assays, and therefore additional tests, such as the plaque reduction neutralization test (PRNT), are necessary to distinguish Zika virus infection from other flavivirus infections.

Although Zika virus RNA is unlikely to be detected in serum after the first week of illness, recent data suggest that Zika virus RNA can persist in urine for at least two weeks post symptom onset (3). Given this information, on May 13, 2016, CDC issued interim guidance on rRT-PCR testing for Zika virus RNA in urine (1). CDC now recommends that, for persons with suspected Zika virus disease, Zika virus rRT-PCR should be performed on both urine and serum specimens collected within 7 days after onset of symptoms. Zika virus rRT-PCR also should be performed on urine specimens collected within 14 days after onset of symptoms. A positive rRT-PCR result in either specimen confirms Zika virus infection. However, a negative rRT-PCR in a serum or urine sample collected at any time point after illness onset does not exclude Zika virus infection, and in these cases IgM antibody testing should be performed on serum.

CDC recommendations for Zika virus testing of serum and other clinical specimens remain unchanged at this time. Please contact your state or local health department to facilitate testing.

Recommendations for Health Care Providers and Public Health Practitioners
Collect urine samples within 14 days post symptom onset along with patient-matched serum samples for those who match CDC Zika virus clinical and/or epidemiological testing criteria for Zika virus infection.
Perform Zika virus rRT-PCR testing on urine, in conjunction with testing of serum using the appropriate molecular or serologic assay, based on days post symptom onset.
Additional Considerations
Further investigation is needed to determine the sensitivity and utility of Zika virus rRT-PCR on urine specimens collected >= 14 days after onset of symptoms: limited data in pregnant women suggest that viremia in serum might be prolonged in pregnancy (4, 5).


Every major American medical organization with expertise in breast cancer care, including the American Congress of Obstetricians and Gynecologists, American Cancer Society, American College of Radiology, National Accreditation Program for Breast Centers and Society of Breast Imaging recommend that women start getting annual mammograms at age 40.

Mammography Lifesaving Benefit

According to National Cancer Institute data, since mammography screening became widespread in the early 1990s, the US breast cancer death rate, unchanged for the previous 50 years, has dropped well over 30 percent. By not getting a yearly mammogram after age 40, women increase their odds of dying from breast cancer and that treatment for any advanced cancers ultimately found will be more extensive and more expensive.

    The largest (Hellquist et al) and longest running (Tabar et al) breast cancer screening studies in history, re-confirmed that regular mammography screening cut breast cancer deaths by roughly a third in all women ages 40 and over (including women ages 40-49).

    A recent study (Otto et al) published in Cancer Epidemiology, Biomarkers & Prevention shows mammography screening cuts the risk of dying from breast cancer nearly in half.

    A recent study published in Cancer showed that more than 70 percent of the women who died from breast cancer in their 40s at major Harvard teaching hospitals were among the 20 percent of women who were not being screened. The most rigorous scientific studies have shown that the most lives are saved by screening beginning at age 40.

    Recent case control studies have shown that the death rate from breast cancer was lower among women screened compared to those not screened. Women who were diagnosed with breast cancer were treated in the same way, whether screened or not screened. Therefore, the lower death rate among screened women is due to screening, and cannot be attributed to treatment differences. 

    While screening can find cancers that might never go on to become clinically evident or have the potential to be lethal (over diagnosis), best estimates show this modest and probably less than 10 percent. 

    The goal of screening is to detect breast cancer early enough so that women’s life is saved- a priceless benefit. Nevertheless, mammography has also been shown to be cost-effective compared to the other screening studies used in medicine. 

    Mammography can detect cancer early when it’s most treatable and can be treated less invasively - which not only save lives, but helps preserve quality of life. For more information regarding the proven effectiveness of regular mammography screening at reducing breast cancer deaths, please visit