Zika Health Alert - 08/24/17

HEALTH ALERT

Enhanced Zika Disease Surveillance and Modified Testing Guidelines
August 24, 2017

Summary

The Texas Department of State Health Services (DSHS) has long considered the southernmost areas of the state to be at greater risk of supporting local mosquito transmission of Zika virus. This is based upon historical experience with local transmission of dengue virus, which is related to the Zika virus and transmitted by the same type of mosquitoes. Local transmission of dengue is most commonly reported in Texas from August through December. Additionally, Mexico continues to report local transmission of Zika in some of its border states.

Since we are now in peak mosquito season, the likelihood of local Zika transmission is increased. As such, DSHS has added Kinney, Maverick, and Val Verde counties to the list of high risk areas under expanded testing criteria. DSHS has also adjusted its statewide testing guidance based on local and national trends and increasing scientific knowledge of the disease. These changes are explained below.

Enhanced Zika Surveillance in High-Risk Areas

  • New: Test symptomatic pregnant women in Kinney, Maverick, and Val Verde counties regardless of travel or sexual exposure history
    • This recommendation is also still in effect for symptomatic pregnant women in Cameron, Hidalgo, Starr, Webb, Willacy, and Zapata counties.
  • New: Test asymptomatic pregnant women in Cameron, Hidalgo, Kinney, Maverick, Starr, Val Verde, Webb, Willacy, and Zapata counties three times during pregnancy using both PCR and IgM concurrently*
    • Previously, the recommendation was to test pregnant women in Cameron, Hidalgo, Starr, Webb, Willacy, and Zapata counties during the first and second trimester.
  • New: Test other non-pregnant Kinney, Maverick, and Val Verde County residents who exhibit a rash and at least one other common Zika symptom [either fever, joint pain, or conjunctivitis (eye redness)]
    • This recommendation is also still in effect for symptomatic individuals in Cameron, Hidalgo, Starr, Webb, Willacy, and Zapata counties.

Revised Statewide Testing Guidelines:

  • New: For all symptomatic individuals who meet testing criteria: test as soon as possible up to 12 weeks after onset using both PCR and IgM concurrently*
    • Previous guidance differentiated the types of tests used between <2 weeks of symptom onset and 2-12 weeks after onset
  • New: For all asymptomatic pregnant women who meet testing criteria: test as soon as possible up to 12 weeks after exposure using both PCR and IgM concurrently*
    • Previous guidance differentiated the type of tests used between <2 weeks of exposure and 2-12 weeks after exposure

DSHS continues to recommend that healthcare providers consult with their local health department or DSHS Regional Office to facilitate appropriate test selection and submission of specimens. Preconception counseling should be provided to patients contemplating having a baby. The current comprehensive guidance on Zika testing can be found at http://texaszika.org/healthcareprof.htm.

*IgM tests are used as a Zika screening tool, and without confirmation by plaque reduction neutralization testing (PRNT) by the CDC, a positive IgM test result does not by itself confirm Zika infection. Clinical prognosis and decision-making should not be based solely on positive results of an IgM screening test. If an individual tests positive on IgM, PRNT testing MUST be conducted to confirm results.

For More Information

Texas-specific information and links to CDC resources: TexasZika.org.

Last updated August 24, 2017